PNEUMONIA

Infectious pneumonias

Bacterial pneumonia Viral pneumonia Fungal pneumonia Parasitic pneumonia Atypical pneumonia Community-acquired pneumonia Healthcare-associated pneumonia Hospital-acquired pneumonia Ventilator-associated pneumonia Severe acute respiratory syndrome

Pneumonias caused by infectious or noninfectious agents

Aspiration pneumonia Lipid pneumonia Eosinophilic pneumonia Bronchiolitis obliterans organizing pneumonia

Noninfectious pneumonia

Chemical pneumonia

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Pneumonia is an inflammatory illness of the lung. See Pneumonia for a general overview of pneumonia and its other causes Viral pneumonia is an Inflammation of the Lung caused by a Virus. Fungal pneumonia is an Infection of the Lungs by fungi. It can be caused by either endemic or opportunistic fungi or a combination Parasitic pneumonia is an infection of the lungs by Parasites It is a rare cause of Pneumonia, occurring almost exclusively in immunocompromised persons Atypical pneumonia is a term used to describe a form of Pneumonia not caused by one of the more traditional pathogens Community-acquired pneumonia ( CAP) is a Disease in which individuals who have not recently been Hospitalized develop an Infection of the In Medicine, healthcare-associated pneumonia (HCAP is a novel category of Pneumonia in patients with recent close contact with the health care system Hospital-acquired pneumonia (HAP or Nosocomial pneumonia refers to any Pneumonia contracted within 48-72 hours of being admitted in hospital Ventilator-associated pneumonia ( VAP) is a sub-type of Hospital-acquired pneumonia (HAP which occurs in people who are on Mechanical ventilation through Aspiration pneumonia is Bronchopneumonia that develops due to the entrance of foreign materials that enter the bronchial tree usually oral or gastric contents (including food Lipid pneumonia or lipoid pneumonia is a specific form of lung inflammation ( Pneumonia) that develops when Lipids enter the bronchial tree Eosinophilic pneumonia ( EP) is a Disease in which a certain type of White blood cell called an Eosinophil accumulates in the Lung. Bronchiolitis obliterans organizing pneumonia ( BOOP) is an Inflammation of the Bronchioles and surrounding tissue in the Lungs BOOP is often caused Chemical pneumonitis is inflammation of the lung caused by irritation from aspirated Vomitus or barium used in gastro-intestinal imaging ingested Gasoline or The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings J00-J99 - Diseases of the respiratory system (J00-J06 Acute upper respiratory infections ( Acute Nasopharyngitis ( Common cold) J00-J99 - Diseases of the respiratory system (J00-J06 Acute upper respiratory infections ( Acute Nasopharyngitis ( Common cold) J00-J99 - Diseases of the respiratory system (J00-J06 Acute upper respiratory infections ( Acute Nasopharyngitis ( Common cold) J00-J99 - Diseases of the respiratory system (J00-J06 Acute upper respiratory infections ( Acute Nasopharyngitis ( Common cold) J00-J99 - Diseases of the respiratory system (J00-J06 Acute upper respiratory infections ( Acute Nasopharyngitis ( Common cold) J00-J99 - Diseases of the respiratory system (J00-J06 Acute upper respiratory infections ( Acute Nasopharyngitis ( Common cold) J00-J99 - Diseases of the respiratory system (J00-J06 Acute upper respiratory infections ( Acute Nasopharyngitis ( Common cold) P00-P96 - Certain conditions originating in the Perinatal period (P00-P04 Fetus and newborn affected by maternal factors and by complications of pregnancy labour and The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. The Diseases Database is a free Website that provides information about the relationships between medical conditions Symptoms, and Medications. eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely two medical doctors Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Inflammation ( Latin, inflamatio, to set on fire is the complex biological response of vascular tissues to harmful stimuli such as Pathogens Illness (sometimes referred to as ill-health or ail) can be defined as a state of poor Health. lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive ^[1] Frequently, it is described as lung parenchyma/alveolar inflammation and abnormal alveolar filling with fluid. Parenchyma is a term used to describe a bulk of a substance It is used in different ways in Animals and in Plants. An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity (The alveoli are microscopic air-filled sacs in the lungs responsible for absorbing oxygen from the atmosphere. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five ) Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, or parasites, and chemical or physical injury to the lungs. An infection is the detrimental Colonization of a host Organism by a foreign Species. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Parasitism is a type of symbiotic relationship between Organisms of different Species. Its cause may also be officially described as idiopathic—that is, unknown—when infectious causes have been excluded. In Medicine, idiopathic interstitial pneumonia, often Abbreviated IIP, is a term used for a type of Diffuse lung disease; diffuse lung disease

Typical symptoms associated with pneumonia include cough, chest pain, fever, and difficulty in breathing. In Medicine, a cough ( Latin: tussis) is a sudden and often repetitively occurring defence Reflex which helps to clear the large breathing passages In Medicine, chest pain is a Symptom of a number of serious conditions and is generally considered a Medical emergency. Fever (also known as pyrexia, from the Greek pyretos meaning fire or a febrile response, from the Latin word Febris Dyspnea or dyspnoea (pronounced disp-nee-ah, IPA /dɪsp'niə/ from Latin dyspnoea, from Greek dyspnoia from Diagnostic tools include x-rays and examination of the sputum. Diagnosis is the identification by Process of elimination, of the nature of anything X-radiation (composed of X-rays) is a form of Electromagnetic radiation. Sputum is matter that is Expectorated from the respiratory tract such as Mucus or Phlegm, mixed with Saliva, which can then be spat Treatment depends on the cause of pneumonia; bacterial pneumonia is treated with antibiotics. In modern usage an antibiotic is a Chemotherapeutic agent with activity against Microorganisms such as Bacteria, fungi or Protozoa

Pneumonia is a common illness which occurs in all age groups, and is a leading cause of death among the elderly and people who are chronically and terminally ill. Death is the termination of the biological functions that define living Organisms It refers both to a specific Vaccines to prevent certain types of pneumonia are available. A vaccine is a biological preparation which is used to establish or improve immunity to a particular disease The prognosis depends on the type of pneumonia, the appropriate treatment, any complications, and the person's underlying health. Prognosis (older Greek πρόγνωσις modern Greek πρόγνωση - literally fore-knowing foreseeing) is a medical term denoting the Health is a state of complete physical mental and social well-being and not merely the absence of disease or infirmity

Signs and symptoms

Pneumonia fills the lung's alveoli with fluid, keeping oxygen from reaching the bloodstream. An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity The alveolus on the left is normal, while the alveolus on the right is full of fluid from pneumonia.

People with infectious pneumonia often have a cough producing greenish or yellow sputum, or phlegm and a high fever that may be accompanied by shaking chills. Sputum is matter that is Expectorated from the respiratory tract such as Mucus or Phlegm, mixed with Saliva, which can then be spat Phlegm ( is sticky Fluid secreted by the Mucous membranes of Humans and other Animals. Fever (also known as pyrexia, from the Greek pyretos meaning fire or a febrile response, from the Latin word Febris Rigor is a shaking occurring during a high Fever. It occurs because cytokines and Prostaglandins are released as part of an Immune Shortness of breath is also common, as is pleuritic chest pain, a sharp or stabbing pain, either experienced during deep breaths or coughs or worsened by it. Dyspnea or dyspnoea (pronounced disp-nee-ah, IPA /dɪsp'niə/ from Latin dyspnoea, from Greek dyspnoia from In Medicine, chest pain is a Symptom of a number of serious conditions and is generally considered a Medical emergency. People with pneumonia may cough up blood, experience headaches, or develop sweaty and clammy skin. Hemoptysis or haemoptysis (see American and British spelling differences) is the expectoration ( Coughing up of Blood or of blood-stained A headache ( cephalalgia in medical terminology is a condition of pain in the Head; sometimes Neck or upper back pain may also be interpreted Diaphoresis is excessive sweating commonly associated with shock and other Medical emergency conditions Other possible symptoms are loss of appetite, fatigue, blueness of the skin, nausea, vomiting, mood swings, and joint pains or muscle aches. Anorexia (deriving from the Greek "α(ν-" ( a(n-, a prefix that denotes absence + "όρεξη (orexe = appetite is the decreased sensation Cyanosis is a blue coloration of the Skin and mucous membranes due to the presence of deoxygenated Hemoglobin in Blood vessels near the skin surface Nausea ( Latin: Nausea, Greek:, " Sea-sickness " also called wamble) is the sensation of unease and discomfort Vomiting (also called throwing up, emesis) is the forceful expulsion of the contents of one's Stomach through the Mouth and sometimes the Arthralgia (from Greek arthro-, joint + -algos, pain literally means joint pain; it is a symptom of injury infection illnesses -- in particular Myalgia means " Muscle Pain " and is a symptom of many diseases and disorders Less common forms of pneumonia can cause other symptoms; for instance, pneumonia caused by Legionella may cause abdominal pain and diarrhea, while pneumonia caused by tuberculosis or Pneumocystis may cause only weight loss and night sweats. Legionella is a Gram negative Bacterium, including species that cause Legionellosis or Legionnaires' disease most notably L In Medicine, diarrhea, also spelled diarrhoea (see spelling differences) is frequent loose or liquid Bowel movements Acute diarrhea Tuberculosis (abbreviated as TB for tubercle bacillus or T u' b' erculosis Bacillus --> is a common Pneumocystis pneumonia ( PCP) is a form of Pneumonia caused by the yeast-like Fungus, Pneumocystis jirovecii (Jirovecii is pronounced Weight loss, in the context of Medicine or Health or Physical fitness, is a reduction of the total Body weight, due to a mean loss of fluid Sleep hyperhidrosis, more commonly known as the night sweats, is the occurrence of excessive sweating ( Hyperhidrosis) during Sleep. In elderly people manifestations of pneumonia may not be typical. They may develop a new or worsening confusion or may experience unsteadiness, leading to falls. Infants with pneumonia may have many of the symptoms above, but in many cases they are simply sleepy or have a decreased appetite. ^[2]

Symptoms of pneumonia need immediate medical evaluation. Physical examination by a health care provider may reveal fever or sometimes low body temperature, an increased respiratory rate, low blood pressure, a fast heart rate, or a low oxygen saturation, which is the amount of oxygen in the blood as indicated by either pulse oximetry or blood gas analysis. Physical examination or clinical examination is the process by which a Health care provider investigates the body of a Patient for signs Fever (also known as pyrexia, from the Greek pyretos meaning fire or a febrile response, from the Latin word Febris Hypothermia is a condition in which an organism's temperature drops below that required for normal Metabolism and bodily functions Tachypnea (or "tachypnoea" ( Greek: "rapid breathing" is characterized by rapid breathing and is not identical with Hyperventilation - tachypnea In Physiology and Medicine, hypotension refers to an abnormally low Blood pressure. Oxygen saturation is a relative measure of the amount of Oxygen that is Dissolved or carried in a given medium Pulse oximetry is a non-invasive method allowing the monitoring of the Oxygenation of a patient's Hemoglobin. An arterial blood gas ( ABG) is a Blood test that is performed specifically on Blood from an Artery. People who are struggling to breathe, who are confused, or who have cyanosis (blue-tinged skin) require immediate attention. Cyanosis is a blue coloration of the Skin and mucous membranes due to the presence of deoxygenated Hemoglobin in Blood vessels near the skin surface

Physical examination of the lungs may be normal, but often shows decreased expansion of the chest on the affected side, bronchial breathing on auscultation with a stethoscope (harsher sounds from the larger airways transmitted through the inflamed and consolidated lung), and rales heard over the affected area. Physical examination or clinical examination is the process by which a Health care provider investigates the body of a Patient for signs A bronchus (plural bronchi, adjective bronchial) is a caliber of airway in the Respiratory tract that conducts air into the Lungs No Gas The stethoscope (from Greek στηθοσκόπιο, of στήθος stéthos - chest and σκοπή skopé - examination) is an acoustic Rales, crackles or crepitations, are the clicking rattling or crackling noises heard on auscultation of (listening to the Lung with a Stethoscope Percussion may be dulled over the affected lung, but increased rather than decreased vocal resonance (which distinguishes it from a pleural effusion). Percussion is a method of tapping on a surface to determine the underlying structure and is used in Clinical examinations to assess the condition of the Thorax or Vocal resonation is the process by which the basic product of Phonation is enhanced in timbre and/or intensity by the air-filled cavities through which it passes on its way to Pleural effusion is excess fluid that accumulates in the Pleural cavity, the fluid-filled space that surrounds the Lungs Excessive amounts of such fluid can impair ^[2] While these signs are relevant, they are insufficient to diagnose or rule out a pneumonia; moreover, in studies it has been shown that two doctors can arrive at different findings on the same patient. ^{[3] [4]}

Diagnosis

If pneumonia is suspected on the basis of a patient's symptoms and findings from physical examination, further investigations are needed to confirm the diagnosis. The medical history or Anamnesis of a Patient is information gained by a Physician or other healthcare professional by asking specific questions Physical examination or clinical examination is the process by which a Health care provider investigates the body of a Patient for signs Information from a chest X-ray and blood tests are helpful, and sputum cultures in some cases. A chest X-ray, commonly abbreviated CXR, is a projection radiograph ( X-ray) taken by a Radiographer, of the Thorax which is used A blood test is a laboratory analysis performed on a Blood sample that is usually extracted from a Vein in the arm using a needle, or via A microbiological culture, AKA microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory The chest X-ray is typically used for diagnosis in hospitals and some clinics with X-ray facilities. However, in a community setting (general practice), pneumonia is usually diagnosed based on symptoms and physical examination alone. A general practitioner, or GP is a medical practitioner who provides Primary care and specializes in Family medicine. Diagnosing pneumonia can be difficult in some people, especially those who have other illnesses. Occasionally a chest CT scan or other tests may be needed to distinguish pneumonia from other illnesses. Computed tomography (CT is a Medical imaging method employing Tomography.

Investigations

Pneumonia as seen on chest x-ray. A: Normal chest x-ray. B: Abnormal chest x-ray with shadowing from pneumonia in the right lung (white area, left side of image).

An important test for pneumonia in unclear situations is a chest x-ray. X-radiation (composed of X-rays) is a form of Electromagnetic radiation. Chest x-rays can reveal areas of opacity (seen as white) which represent consolidation. Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation especially visible Light. Pneumonia is not always seen on x-rays, either because the disease is only in its initial stages, or because it involves a part of the lung not easily seen by x-ray. In some cases, chest CT (computed tomography) can reveal pneumonia that is not seen on chest x-ray. Computed tomography (CT is a Medical imaging method employing Tomography. X-rays can be misleading, because other problems, like lung scarring and congestive heart failure, can mimic pneumonia on x-ray. Heart failure is a Cardiac condition that occurs when a problem with the structure or function of the Heart impairs its ability to supply ^[5] Chest x-rays are also used to evaluate for complications of pneumonia. (See below. Pneumonia is an inflammatory illness of the Lung. Frequently it is described as lung Parenchyma / alveolar inflammation and abnormal )

If antibiotics fail to improve the patient's health, or if the health care provider has concerns about the diagnosis, a culture of the person's sputum may be requested. A microbiological culture, AKA microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory Sputum is matter that is Expectorated from the respiratory tract such as Mucus or Phlegm, mixed with Saliva, which can then be spat Sputum cultures generally take at least two to three days, so they are mainly used to confirm that the infection is sensitive to an antibiotic that has already been started. A blood sample may similarly be cultured to look for infection in the blood (blood culture). Blood culture is Microbiological culture of Blood. It is employed to detect Infections that are spreading through the bloodstream ( Bacteremia, Any bacteria identified are then tested to see which antibiotics will be most effective.

A complete blood count may show a high white blood cell count, indicating the presence of an infection or inflammation. A complete blood count ( CBC) also known as full blood count ( FBC) or full blood exam ( FBE) or blood panel, is Leukocytosis is a raised white blood cell count (the Leukocyte count above the normal range In some people with immune system problems, the white blood cell count may appear deceptively normal. In Medicine, immunodeficiency (or immune deficiency) is a state in which the Immune system 's ability to fight Infectious disease is compromised Blood tests may be used to evaluate kidney function (important when prescribing certain antibiotics) or to look for low blood sodium. The kidneys are complicated organs that have numerous biological roles Hyponatremia ( British: hyponatraemia) is an Electrolyte disturbance (disturbance of the salts in the blood in which the Sodium ( Natrium Low blood sodium in pneumonia is thought to be due to extra anti-diuretic hormone produced when the lungs are diseased (SIADH). Arginine vasopressin ( AVP) also known as vasopressin, argipressin or antidiuretic hormone ( ADH) is a Hormone found in The syndrome of inappropriate antidiuretic hormone (SIADH is a condition commonly found in the hospital population especially in patients being hospitalized for Central nervous system Specific blood serology tests for other bacteria (Mycoplasma, Legionella and Chlamydophila) and a urine test for Legionella antigen are available. Serology is the scientific study of blood serum. In practice the term usually refers to the Diagnostic identification of antibodies in the serum Urine is a liquid waste product of the body secreted by the Kidneys by a process of filtration from Blood and Excreted through the Urethra. An antigen (from antibody-generating) or immunogen is a substance that prompts the generation of Antibodies and can cause an immune response Respiratory secretions can also be tested for the presence of viruses such as influenza, respiratory syncytial virus, and adenovirus. Human respiratory syncytial virus (RSV is a negative-sense single-stranded RNA virus of the family Paramyxoviridae, which includes Adenoviruses are medium-sized (90–100 nm) Nonenveloped (naked Icosahedral viruses composed of a nucleocapsid and a double-stranded linear DNA Liver function tests should be carried out to test for damage caused by sepsis. Liver function tests (LFTs or LFs which include liver enzymes, are groups of Clinical biochemistry laboratory blood assays designed to give information about the ^[2]

Combining findings

One study created a prediction rule that found the five following signs best predicted infiltrates on the chest radiograph of 1134 patients presenting to an emergency room:^[6]

• Temperature > 100 degrees F (37. 8 degrees C)
• Pulse > 100 beats/min
• Crackles
• Decreased breath sounds
• Absence of asthma

The probability of an infiltrate in two separate validations was based on the number of findings:

• 5 findings - 84% to 91% probability
• 4 findings - 58% to 85%
• 3 findings - 35% to 51%
• 2 findings - 14% to 24%
• 1 findings - 5% to 9%
• 0 findings - 2% to 3%

A subsequent study^[7] comparing four prediction rules to physician judgment found that two rules, the one above^[6] and also^[8] were more accurate than physician judgment because of the increased specificity of the prediction rules. Rales, crackles or crepitations, are the clicking rattling or crackling noises heard on auscultation of (listening to the Lung with a Stethoscope

Differential diagnosis

Several diseases and/or conditions can present with similar clinical features to pneumonia and as such care must be taken in the proper diagnosis of the disease. Chronic obstructive pulmonary disease (COPD) or asthma can present with a polyphonic wheeze, similar to that of pneumonia. Chronic obstructive pulmonary disease ( COPD) is a Disease of the lungs in which the Airways become narrowed Asthma is a chronic Condition involving the Respiratory system in which the airways occasionally constrict become inflamed, and are In Music, polyphony is a texture consisting of two or more independent Melodic voices, as opposed to music with just one voice ( Monophony Pulmonary edema can be mistaken for pneumonia due to it's ability to show a third heart sound and present with an abnormal ECG. Pulmonary Edema (American English or oedema (British English is swelling and/or fluid accumulation in the Lungs It leads to impaired gas exchange and may cause Other diseases to be taken into consideration include bronchiectasis, lung cancer and pulmonary emboli. Bronchiectasis is a disease that causes localized irreversible dilatation of part of the Bronchial tree. Lung cancer is a Disease of uncontrolled Cell growth in tissues of the Lung. Pulmonary embolism (PE is a blockage of the Pulmonary artery or one of its branches usually occurring when a venous Thrombus (blood clot from a vein ^[2]

Pathophysiology

Upper panel shows a normal lung under a microscope. The white spaces are alveoli that contain air. An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity Lower panel shows a lung with pneumonia under a microscope. The alveoli are filled with inflammation and debris.

Pneumonia can be caused by microorganisms, irritants and unknown causes. When pneumonias are grouped this way, infectious causes are the most common type.

The symptoms of infectious pneumonia are caused by the invasion of the lungs by microorganisms and by the immune system's response to the infection. A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually An immune system is a collection of mechanisms within an Organism that protects against Disease by identifying and killing Pathogens and Tumor Although more than one hundred strains of microorganism can cause pneumonia, only a few are responsible for most cases. The most common causes of pneumonia are viruses and bacteria. A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Less common causes of infectious pneumonia are fungi and parasites. A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Parasitism is a type of symbiotic relationship between Organisms of different Species.

Viruses

Main article: Viral pneumonia

Viruses invade cells in order to reproduce. Viral pneumonia is an Inflammation of the Lung caused by a Virus. Typically, a virus reaches the lungs when airborne droplets are inhaled through the mouth and nose. The mouth, buccal cavity, or oral cavity is the first portion of the Alimentary canal that receives food and begins digestion by mechanically breaking up Anatomically a nose is a protuberance in Vertebrates that houses the Nostrils or nares which admit and expel air for respiration in conjunction with the Once in the lungs, the virus invades the cells lining the airways and alveoli. This invasion often leads to cell death, either when the virus directly kills the cells, or through a type of cell controlled self-destruction called apoptosis. When the immune system responds to the viral infection, even more lung damage occurs. White blood cells, mainly lymphocytes, activate certain chemical cytokines which allow fluid to leak into the alveoli. A lymphocyte is a type of White blood cell in the Vertebrate Immune system. Cytokines are a category of signalling Proteins and Glycoproteins that like Hormones and Neurotransmitters, are used extensively in cellular This combination of cell destruction and fluid-filled alveoli interrupts the normal transportation of oxygen into the bloodstream.

As well as damaging the lungs, many viruses affect other organs and thus disrupt many body functions. In Biology, an organ ( Latin: organum, "instrument tool" from Greek όργανον - organon "organ instrument Viruses can also make the body more susceptible to bacterial infections; for which reason bacterial pneumonia often complicates viral pneumonia.

Viral pneumonia is commonly caused by viruses such as influenza virus, respiratory syncytial virus (RSV), adenovirus, and metapneumovirus. The Orthomyxoviridae (Derivation of name orthos is Greek for straight myxa is Greek for Mucus) are a family of RNA viruses that Human respiratory syncytial virus (RSV is a negative-sense single-stranded RNA virus of the family Paramyxoviridae, which includes Adenoviruses are medium-sized (90–100 nm) Nonenveloped (naked Icosahedral viruses composed of a nucleocapsid and a double-stranded linear DNA Human metapneumovirus (hMPV was isolated for the first time in 2001 in the Netherlands by using the RAP-PCR (RNA arbitrarily primed PCR) technique for identification of Herpes simplex virus is a rare cause of pneumonia except in newborns. Herpes simplex virus 1 and 2 ( HSV-1 and HSV-2) are two species of the herpes virus family Herpesviridae, which cause infections People with immune system problems are also at risk of pneumonia caused by cytomegalovirus (CMV). Cytomegalovirus (CMV (from the Greek cyto-, "cell" and -megalo-, "large" is a viral

Bacteria

Main article: Bacterial pneumonia

Bacteria typically enter the lung when airborne droplets are inhaled, but can also reach the lung through the bloodstream when there is an infection in another part of the body. See Pneumonia for a general overview of pneumonia and its other causes Many bacteria live in parts of the upper respiratory tract, such as the nose, mouth and sinuses, and can easily be inhaled into the alveoli. The Upper respiratory tract refers to the following parts of the Respiratory system: Nose and Oral cavity Throat Once inside, bacteria may invade the spaces between cells and between alveoli through connecting pores. This invasion triggers the immune system to send neutrophils, a type of defensive white blood cell, to the lungs. An immune system is a collection of mechanisms within an Organism that protects against Disease by identifying and killing Pathogens and Tumor Neutrophil granulocytes, generally referred to as neutrophils, are the most abundant type of White blood cells in humans and form an essential part of the The neutrophils engulf and kill the offending organisms, and also release cytokines, causing a general activation of the immune system. Phagocytosis is the cellular process of engulfing solid particles by the Cell membrane to form an internal Phagosome, or "food vacuole Cytokines are a category of signalling Proteins and Glycoproteins that like Hormones and Neurotransmitters, are used extensively in cellular This leads to the fever, chills, and fatigue common in bacterial and fungal pneumonia. The neutrophils, bacteria, and fluid from surrounding blood vessels fill the alveoli and interrupt normal oxygen transportation.

The bacterium Streptococcus pneumoniae, a common cause of pneumonia, photographed through an electron microscope. Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the Genus An electron microscope is a type of Microscope that uses Electrons to illuminate a specimen and create an enlarged image

Bacteria often travel from an infected lung into the bloodstream, causing serious or even fatal illness such as septic shock, with low blood pressure and damage to multiple parts of the body including the brain, kidneys, and heart. Septic shock is a very serious medical condition caused by decreased tissue perfusion and oxygen delivery as a result of Infection and Sepsis, though the The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain The kidneys are complicated organs that have numerous biological roles The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic Bacteria can also travel to the area between the lungs and the chest wall (the pleural cavity) causing a complication called an empyema. An empyema is a collection of Pus within a naturally existing anatomical cavity

The most common causes of bacterial pneumonia are Streptococcus pneumoniae, Gram-positive bacteria and "atypical" bacteria. Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the Genus Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. The terms "Gram-positive" and "Gram-negative" refer to the bacteria's color (purple or red, respectively) when stained using a process called the Gram stain. Gram staining (or Gram's method) is an empirical method of differentiating bacterial species into two large groups ( Gram-positive and The term "atypical" is used because atypical bacteria commonly affect healthier people, cause generally less severe pneumonia, and respond to different antibiotics than other bacteria.

The types of Gram-positive bacteria that cause pneumonia can be found in the nose or mouth of many healthy people. Streptococcus pneumoniae, often called "pneumococcus", is the most common bacterial cause of pneumonia in all age groups except newborn infants. Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the Genus Another important Gram-positive cause of pneumonia is Staphylococcus aureus, with Streptococcus agalactiae being an important cause of pneumonia in newborn babies. Staphylococcus aureus (ˌstæfɨləˈkɒkəs ˈɔriəs literally "Golden Cluster Seed" and also known as golden staph) is the most common cause of Streptococcus agalactiae also known as Group B Streptococcus (GBS and more colloquially as Strep B and group B Strep is a Gram-positive Streptococcus Gram-negative bacteria cause pneumonia less frequently than gram-positive bacteria. Some of the gram-negative bacteria that cause pneumonia include Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Moraxella catarrhalis. Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile Gram-negative Coccobacillus Klebsiella pneumoniae is a Gram-negative, non- Motile, Encapsulated, Lactose fermenting, Facultative anaerobic Pseudomonas is a Genus of gamma Proteobacteria, belonging to the larger family of Pseudomonads Recently 16S rRNA sequence Moraxella catarrhalis is a Gram-negative, Aerobic, oxidase-positive Diplococcus which may both colonize and cause Respiratory These bacteria often live in the stomach or intestines and may enter the lungs if vomit is inhaled. "Atypical" bacteria which cause pneumonia include Chlamydophila pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila. Mycoplasma pneumoniae is a very small Bacterium in the class Mollicutes. Legionella pneumophila is a thin pleomorphic, Flagellated Gram-negative bacterium of the genus Legionella.

Fungi

Main article: Fungal pneumonia

Fungal pneumonia is uncommon, but it may occur in individuals with immune system problems due to AIDS, immunosuppresive drugs, or other medical problems. Fungal pneumonia is an Infection of the Lungs by fungi. It can be caused by either endemic or opportunistic fungi or a combination In Medicine, immunodeficiency (or immune deficiency) is a state in which the Immune system 's ability to fight Infectious disease is compromised For a list of immunosuppressive drugs see the Transplant rejection page. The pathophysiology of pneumonia caused by fungi is similar to that of bacterial pneumonia. Fungal pneumonia is most often caused by Histoplasma capsulatum, blastomyces, Cryptococcus neoformans, Pneumocystis jiroveci, and Coccidioides immitis. Histoplasmosis, also known as Darling's disease, is a Disease caused by the Fungus Histoplasma capsulatum which was discovered in Cryptococcus neoformans is an encapsulated yeast-like Fungus that can live in both Plants and Animals This species also known by its Pneumocystis pneumonia ( PCP) is a form of Pneumonia caused by the yeast-like Fungus, Pneumocystis jirovecii (Jirovecii is pronounced Coccidioides immitis is a Pathogenic Fungus that resides in the Soil in certain parts of the southwestern United States Histoplasmosis is most common in the Mississippi River basin, and coccidioidomycosis in the southwestern United States. Histoplasmosis, also known as Darling's disease, is a Disease caused by the Fungus Histoplasma capsulatum which was discovered in The Mississippi embayment is a physiographic feature in the south-central United States, part of the Mississippi Alluvial Plain. Coccidioidomycosis (also known as Valley fever, San Joaquin Valley Fever, California valley fever, desert fever and (incorrectly The Southwestern area of the United States could be defined as the states west of the Mississippi River, with the qualification of a certain northern limit such as the 37

Parasites

Main article: Parasitic pneumonia

A variety of parasites can affect the lungs. Parasitic pneumonia is an infection of the lungs by Parasites It is a rare cause of Pneumonia, occurring almost exclusively in immunocompromised persons These parasites typically enter the body through the skin or by being swallowed. Once inside, they travel to the lungs, usually through the blood. There, as in other cases of pneumonia, a combination of cellular destruction and immune response causes disruption of oxygen transportation. One type of white blood cell, the eosinophil, responds vigorously to parasite infection. Eosinophil granulocytes, usually called eosinophils (or less commonly acidophils) are White blood cells that are one of the Immune System components Eosinophils in the lungs can lead to eosinophilic pneumonia, thus complicating the underlying parasitic pneumonia. Eosinophilic pneumonia ( EP) is a Disease in which a certain type of White blood cell called an Eosinophil accumulates in the Lung. The most common parasites causing pneumonia are Toxoplasma gondii, Strongyloides stercoralis, and Ascariasis. Toxoplasma gondii is a species of parasitic Protozoa in the Genus Toxoplasma. Strongyloides stercoralis, also known as the threadworm is the Scientific name of a Human Parasitic Roundworm causing the disease Ascariasis is a Human Disease caused by the parasitic Roundworm Ascaris lumbricoides.

Idiopathic

Main article: Idiopathic interstitial pneumonia

Idiopathic interstitial pneumonias (IIP) are a class as diffuse lung diseases. In Medicine, idiopathic interstitial pneumonia, often Abbreviated IIP, is a term used for a type of Diffuse lung disease; diffuse lung disease Interstitial lung disease (ILD, also known as diffuse parenchymal lung disease (DPLD, refers to a group of Lung diseases affecting the Interstitium In some types of IIP, e. g. some types of usual interstitial pneumonia, the cause, indeed, is unknown or idiopathic. Usual interstitial Pneumonia, commonly abbreviated UIP, is the name of a histopathological pattern seen in Diffuse lung diseases Diffuse lung In some types of IIP the cause of the pneumonia is known, e. g. desquamative interstitial pneumonia is caused by smoking, and the name is a misnomer. Smoking is a practice where a substance most commonly Tobacco, is burned and the Smoke tasted or inhaled A misnomer is a term which suggests an interpretation that is known to be untrue

Classification

Pneumonias can be classified in several ways. Pathologists originally classified them according to the anatomic changes that were found in the lungs during autopsies. Anatomy (from the Greek anatomia, from ana separate apart from and temnein, to cut up cut open is a branch of Biology that is the consideration An autopsy, also known as a post-mortem examination, necropsy, or obduction, is a Medical procedure that consists of a thorough Examination As more became known about the microorganisms causing pneumonia, a microbiologic classification arose, and with the advent of x-rays, a radiological classification. Microbiology (from Greek grc μῑκρος mīkros, "small" grc βίος bios, " Life " and grc -λογία X-radiation (composed of X-rays) is a form of Electromagnetic radiation. Radiology is the medical specialty directing Medical imaging technologies to diagnose and treat diseases Another important system of classification is the combined clinical classification, which combines factors such as age, risk factors for certain microorganisms, the presence of underlying lung disease and underlying systemic disease, and whether the person has recently been hospitalized.

Early classification schemes

Initial descriptions of pneumonia focused on the anatomic or pathologic appearance of the lung, either by direct inspection at autopsy or by its appearance under a microscope. Anatomy (from the Greek anatomia, from ana separate apart from and temnein, to cut up cut open is a branch of Biology that is the consideration Pathology (from Greek grc πάθος pathos, "fate harm" and grc -λογία -logia) is the study and An autopsy, also known as a post-mortem examination, necropsy, or obduction, is a Medical procedure that consists of a thorough Examination A microscope ( Greek: ( micron) = small + ( skopein) = to look or see is an instrument for viewing objects that are A lobar pneumonia is an infection that only involves a single lobe, or section, of a lung. lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive Lobar pneumonia is often due to Streptococcus pneumoniae. Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the Genus Multilobar pneumonia involves more than one lobe, and it often causes a more severe illness. Interstitial pneumonia involves the areas in between the alveoli, and it may be called "interstitial pneumonitis. " It is more likely to be caused by viruses or by atypical bacteria.

The discovery of x-rays made it possible to determine the anatomic type of pneumonia without direct examination of the lungs at autopsy and led to the development of a radiological classification. Radiology is the medical specialty directing Medical imaging technologies to diagnose and treat diseases Early investigators distinguished between typical lobar pneumonia and atypical (e. g. Chlamydophila) or viral pneumonia using the location, distribution, and appearance of the opacities they saw on chest x-rays. Certain x-ray findings can be used to help predict the course of illness, although it is not possible to clearly determine the microbiologic cause of a pneumonia with x-rays alone.

With the advent of modern microbiology, classification based upon the causative microorganism became possible. Determining which microorganism is causing an individual's pneumonia is an important step in deciding treatment type and length. Sputum cultures, blood cultures, tests on respiratory secretions, and specific blood tests are used to determine the microbiologic classification. Because such laboratory testing typically takes several days, microbiologic classification is usually not possible at the time of initial diagnosis.

Combined clinical classification

Traditionally, clinicians have classified pneumonia by clinical characteristics, dividing them into "acute" (less than three weeks duration) and "chronic" pneumonias. This is useful because chronic pneumonias tend to be either non-infectious, or mycobacterial, fungal, or mixed bacterial infections caused by airway obstruction. Acute pneumonias are further divided into the classic bacterial bronchopneumonias (such as Streptococcus pneumoniae), the atypical pneumonias (such as the interstitial pneumonitis of Mycoplasma pneumoniae or Chlamydia pneumoniae), and the aspiration pneumonia syndromes. Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the Genus Mycoplasma pneumoniae is a very small Bacterium in the class Mollicutes.

The combined clinical classification, now the most commonly used classification scheme, attempts to identify a person's risk factors when he or she first comes to medical attention. The advantage of this classification scheme over previous systems is that it can help guide the selection of appropriate initial treatments even before the microbiologic cause of the pneumonia is known. There are two broad categories of pneumonia in this scheme: community-acquired pneumonia and hospital-acquired pneumonia. A recently introduced type of healthcare-associated pneumonia (in patients living outside the hospital who have recently been in close contact with the health care system) lies between these two categories. In Medicine, healthcare-associated pneumonia (HCAP is a novel category of Pneumonia in patients with recent close contact with the health care system

Community-acquired pneumonia

Main article: Community-acquired pneumonia

Community-acquired pneumonia (CAP) is infectious pneumonia in a person who has not recently been hospitalized. Community-acquired pneumonia ( CAP) is a Disease in which individuals who have not recently been Hospitalized develop an Infection of the Community-acquired pneumonia ( CAP) is a Disease in which individuals who have not recently been Hospitalized develop an Infection of the CAP is the most common type of pneumonia. The most common causes of CAP vary depending on a person's age, but they include Streptococcus pneumoniae, viruses, the atypical bacteria, and Haemophilus influenzae. Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the Genus Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile Gram-negative Coccobacillus Overall, Streptococcus pneumoniae is the most common cause of community-acquired pneumonia worldwide. Gram-negative bacteria cause CAP in certain at-risk populations. CAP is the fourth most common cause of death in the United Kingdom and the sixth in the United States. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The United States of America —commonly referred to as the An outdated term, walking pneumonia, has been used to describe a type of community-acquired pneumonia of less severity (hence the fact that the patient can continue to "walk" rather than require hospitalization). Walking pneumonia is usually caused by a virus or by atypical bacteria.

Hospital-acquired pneumonia

Main article: Hospital-acquired pneumonia

Hospital-acquired pneumonia, also called nosocomial pneumonia, is pneumonia acquired during or after hospitalization for another illness or procedure with onset at least 72 hrs after admission. Hospital-acquired pneumonia (HAP or Nosocomial pneumonia refers to any Pneumonia contracted within 48-72 hours of being admitted in hospital Nosocomial infections are Infections which are a result of treatment in a Hospital or a healthcare service unit but secondary to the patient's original condition The causes, microbiology, treatment and prognosis are different from those of community-acquired pneumonia. Up to 5% of patients admitted to a hospital for other causes subsequently develop pneumonia. Hospitalized patients may have many risk factors for pneumonia, including mechanical ventilation, prolonged malnutrition, underlying heart and lung diseases, decreased amounts of stomach acid, and immune disturbances. In Medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing when patients cannot do so on their own Malnutrition is a general term for a medical condition caused by an improper or insufficient diet. The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive Additionally, the microorganisms a person is exposed to in a hospital are often different from those at home . Hospital-acquired microorganisms may include resistant bacteria such as MRSA, Pseudomonas, Enterobacter, and Serratia. Pseudomonas is a Genus of gamma Proteobacteria, belonging to the larger family of Pseudomonads Recently 16S rRNA sequence Enterobacter is a genus of common Gram-negative, facultatively-anaerobic, rod-shaped Bacteria of the family Enterobacteriaceae Serratia is a Genus of Gram-negative, facultatively anaerobic, rod-shaped Bacteria of the Enterobacteriaceae Because individuals with hospital-acquired pneumonia usually have underlying illnesses and are exposed to more dangerous bacteria, it tends to be more deadly than community-acquired pneumonia. Ventilator-associated pneumonia (VAP) is a subset of hospital-acquired pneumonia. Ventilator-associated pneumonia ( VAP) is a sub-type of Hospital-acquired pneumonia (HAP which occurs in people who are on Mechanical ventilation through VAP is pneumonia which occurs after at least 48 hours of intubation and mechanical ventilation. In Medicine, intubation refers to the placement of a tube into an external or internal orifice of the body In Medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing when patients cannot do so on their own

Other types of pneumonia

• Severe acute respiratory syndrome (SARS)

SARS is a highly contagious and deadly type of pneumonia which first occurred in 2002 after initial outbreaks in China. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National SARS is caused by the SARS coronavirus, a previously unknown pathogen. The SARS coronavirus, sometimes shortened to SARS-CoV, is the virus that causes Severe acute respiratory syndrome (SARS A pathogen (from Greek πάθος pathos "suffering passion" and γἰγνομαι (γεν- gignomai (gen- "I give birth to" infectious

• Bronchiolitis obliterans organizing pneumonia (BOOP)

BOOP is caused by inflammation of the small airways of the lungs. Bronchiolitis obliterans organizing pneumonia ( BOOP) is an Inflammation of the Bronchioles and surrounding tissue in the Lungs BOOP is often caused It is also known as cryptogenic organizing pneumonitis (COP).

• Eosinophilic pneumonia

Eosinophilic pneumonia is invasion of the lung by eosinophils, a particular kind of white blood cell. Eosinophilic pneumonia ( EP) is a Disease in which a certain type of White blood cell called an Eosinophil accumulates in the Lung. Eosinophil granulocytes, usually called eosinophils (or less commonly acidophils) are White blood cells that are one of the Immune System components Eosinophilic pneumonia often occurs in response to infection with a parasite or after exposure to certain types of environmental factors. Parasitism is a type of symbiotic relationship between Organisms of different Species.

• Chemical pneumonia

Chemical pneumonia (usually called chemical pneumonitis) is caused by chemical toxins such as pesticides, which may enter the body by inhalation or by skin contact. Chemical pneumonitis is inflammation of the lung caused by irritation from aspirated Vomitus or barium used in gastro-intestinal imaging ingested Gasoline or Chemical pneumonitis is inflammation of the lung caused by irritation from aspirated Vomitus or barium used in gastro-intestinal imaging ingested Gasoline or A toxin ( Greek:, toxikon, lit (poison for use on arrows is a Poisonous substance produced by living cells or organisms that is active at very low A pesticide is a substance or mixture of substances used to kill a pest. Inhalation (also known as respiration) is the movement of air from the external environment through the air ways and into the Alveoli. When the toxic substance is an oil, the pneumonia may be called lipoid pneumonia.

• Aspiration pneumonia

Aspiration pneumonia (or aspiration pneumonitis) is caused by aspirating foreign objects which are usually oral or gastric contents, either while eating, or after reflux or vomiting which results in bronchopneumonia. Aspiration pneumonia is Bronchopneumonia that develops due to the entrance of foreign materials that enter the bronchial tree usually oral or gastric contents (including food In Medicine, aspiration is the entry of secretions or foreign material into the trachea and Lungs The patient may either inhale the material Bronchopneumonia (also known as lobular pneumonia) is a type of Pneumonia characterized by multiple foci of isolated acute consolidation affecting one or more The resulting lung inflammation is not an infection but can contribute to one, since the material aspirated may contain anaerobic bacteria or other unusual causes of pneumonia. An anaerobic organism is any Organism that does not require Oxygen for growth and may even die in its presence Aspiration is a leading cause of death among hospital and nursing home patients, since they often cannot adequately protect their airways and may have otherwise impaired defenses. SNF redirects here For the sports show see NBC Sunday Night Football.

• Dust pneumonia

Dust pneumonia describes disorders caused by excessive exposure to dust storms, particularly during the Dust Bowl in the United States. Dust pneumonia describes disorders caused by excessive exposure to Dust storms, particularly during the Dust Bowl in the United States The Dust Bowl, or the dirty thirties, was a period of severe Dust storms causing major ecological and agricultural damage to American and With dust pneumonia, dust settles all the way into the alveoli of the lungs, stopping the cilia from moving and preventing the lungs from ever clearing themselves.

Treatment

Most cases of pneumonia can be treated without hospitalization. Typically, oral antibiotics, rest, fluids, and home care are sufficient for complete resolution. Home care, (commonly referred to as domiciliary care) is Health care or supportive care provided in the patient's Home by Healthcare However, people with pneumonia who are having trouble breathing, people with other medical problems, and the elderly may need more advanced treatment. If the symptoms get worse, the pneumonia does not improve with home treatment, or complications occur, the person will often have to be hospitalized.

Antibiotics are used to treat bacterial pneumonia. In modern usage an antibiotic is a Chemotherapeutic agent with activity against Microorganisms such as Bacteria, fungi or Protozoa In contrast, antibiotics are not useful for viral pneumonia, although they sometimes are used to treat or prevent bacterial infections that can occur in lungs damaged by a viral pneumonia. Viral pneumonia is an Inflammation of the Lung caused by a Virus. The antibiotic choice depends on the nature of the pneumonia, the most common microorganisms causing pneumonia in the local geographic area, and the immune status and underlying health of the individual. Treatment for pneumonia should ideally be based on the causative microorganism and its known antibiotic sensitivity. Antibiotic sensitivity is a term used to describe the susceptibility of Bacteria to Antibiotics Antibiotic susceptibility testing (AST is usually carried out to determine However, a specific cause for pneumonia is identified in only 50% of people, even after extensive evaluation. Because treatment should generally not be delayed in any person with a serious pneumonia, empiric treatment is usually started well before laboratory reports are available. Empiric therapy is a medical term referring to the initiation of treatment prior to determination of a firm diagnosis In the United Kingdom, amoxicillin and clarithromycin or erythromycin are the antibiotics selected for most patients with community-acquired pneumonia; patients allergic to penicillins are given erythromycin instead of amoxicillin. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Amoxicillin ( INN) or amoxycillin ( BAN) is a moderate-spectrum bacteriolytic β-lactam antibiotic used to treat Bacterial Infections Clarithromycin is a Macrolide Antibiotic used to treat Pharyngitis, Tonsillitis, acute maxillary Sinusitis, acute bacterial exacerbation Erythromycin is a Macrolide Antibiotic that has an antimicrobial spectrum similar to or slightly wider than that of Penicillin, and is often used for people Penicillin (sometimes abbreviated PCN or pen) is a group of Beta-lactam antibiotics used in the treatment of Bacterial Infections Erythromycin is a Macrolide Antibiotic that has an antimicrobial spectrum similar to or slightly wider than that of Penicillin, and is often used for people In North America, where the "atypical" forms of community-acquired pneumonia are becoming more common, azithromycin, clarithromycin, and the fluoroquinolones have displaced amoxicillin as first-line treatment. Azithromycin is an Azalide, a subclass of Macrolide Antibiotics. Clarithromycin is a Macrolide Antibiotic used to treat Pharyngitis, Tonsillitis, acute maxillary Sinusitis, acute bacterial exacerbation The quinolones are a family of synthetic Broad-spectrum antibiotics. The duration of treatment has traditionally been seven to ten days, but there is increasing evidence that shorter courses (as short as three days) are sufficient. ^[9][10][11]

Antibiotics for hospital-acquired pneumonia include vancomycin, third- and fourth-generation cephalosporins, carbapenems, fluoroquinolones, and aminoglycosides. Vancomycin ( INN) (ˌvæŋkoʊˈmaɪsɪn is a Glycopeptide Antibiotic used in the Prophylaxis and treatment of infections caused by The cephalosporins (ˌsɛfələˈspɔrən/ /ˌkɛfə- are a class of β-lactam antibiotics. Carbapenems are a class of Beta-lactam antibiotics with a broad spectrum of antibacterial activity and have a structure which renders them highly resistant to Beta-lactamases The quinolones are a family of synthetic Broad-spectrum antibiotics. An aminoglycoside is a molecule composed of a sugar group and an Amino group These antibiotics are usually given intravenously. Intravenous therapy or IV therapy is the giving of Liquid substances directly into a Vein. Multiple antibiotics may be administered in combination in an attempt to treat all of the possible causative microorganisms. Antibiotic choices vary from hospital to hospital because of regional differences in the most likely microorganisms, and because of differences in the microorganisms' abilities to resist various antibiotic treatments.

People who have difficulty breathing due to pneumonia may require extra oxygen. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Extremely sick individuals may require intensive care treatment, often including intubation and artificial ventilation. Intensive Care Medicine or critical care medicine is a branch of medicine concerned with the provision of Life support or organ support systems in patients In Medicine, intubation refers to the placement of a tube into an external or internal orifice of the body In Medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing when patients cannot do so on their own

Viral pneumonia caused by influenza A may be treated with rimantadine or amantadine, while viral pneumonia caused by influenza A or B may be treated with oseltamivir or zanamivir. Viral pneumonia is an Inflammation of the Lung caused by a Virus. Rimantadine ( INN, sold under the trade name Flumadine) is an orally administered Antiviral drug used to treat and in rare cases prevent Influenzavirus Amantadine is the Organic compound known formally as 1-aminoadamantane Oseltamivir ( INN) (ɒsəlˈtæmɨvɪr is an Antiviral drug that is used in the treatment and Prophylaxis of both Influenzavirus A and Influenzavirus Zanamivir ( INN) (zəˈnæmɨvɪr is a Neuraminidase inhibitor used in the treatment of and Prophylaxis of both Influenzavirus A and Influenzavirus These treatments are beneficial only if they are started within 48 hours of the onset of symptoms. Many strains of H5N1 influenza A, also known as avian influenza or "bird flu," have shown resistance to rimantadine and amantadine. Influenza A virus subtype H5[[Neuraminidase N1]], also known as A(H5N1 or simply H5N1, is a subtype of the Influenza A virus which can cause For the H5N1 subtype of Avian influenza see H5N1. Avian influenza, sometimes Avian flu, and commonly Bird flu refers There are no known effective treatments for viral pneumonias caused by the SARS coronavirus, adenovirus, hantavirus, or parainfluenza virus. Adenoviruses are medium-sized (90–100 nm) Nonenveloped (naked Icosahedral viruses composed of a nucleocapsid and a double-stranded linear DNA Hantaviruses belong to the Bunyaviridae family of Viruses There Bunyaviridae family is divided into 5 genera Human parainfluenza viruses (HPIVs are a group of four distinct Serotypes of single-stranded RNA Viruses belonging to the Paramyxovirus

Complications

Sometimes pneumonia can lead to additional complications. Complication, in Medicine, is an unfavorable evolution of a Disease, a Health condition or a medical treatment Complications are more frequently associated with bacterial pneumonia than with viral pneumonia. The most important complications include:

Respiratory and circulatory failure

Because pneumonia affects the lungs, often people with pneumonia have difficulty breathing, and it may not be possible for them to breathe well enough to stay alive without support. Non-invasive breathing assistance may be helpful, such as with a bi-level positive airway pressure machine. In other cases, placement of an endotracheal tube (breathing tube) may be necessary, and a ventilator may be used to help the person breathe.

Pneumonia can also cause respiratory failure by triggering acute respiratory distress syndrome (ARDS), which results from a combination of infection and inflammatory response. The lungs quickly fill with fluid and become very stiff. This stiffness, combined with severe difficulties extracting oxygen due to the alveolar fluid, create a need for mechanical ventilation.

Pleural effusion. Chest x-ray showing a pleural effusion. The A arrow indicates "fluid layering" in the right chest. The B arrow indicates the width of the right lung. The volume of useful lung is reduced because of the collection of fluid around the lung.

Sepsis and septic shock are potential complications of pneumonia. Sepsis is a serious medical condition characterized by a whole-body inflammatory state (called a Systemic inflammatory response syndrome or SIRS caused Septic shock is a very serious medical condition caused by decreased tissue perfusion and oxygen delivery as a result of Infection and Sepsis, though the Sepsis occurs when microorganisms enter the bloodstream and the immune system responds by secreting cytokines. An immune system is a collection of mechanisms within an Organism that protects against Disease by identifying and killing Pathogens and Tumor Cytokines are a category of signalling Proteins and Glycoproteins that like Hormones and Neurotransmitters, are used extensively in cellular Sepsis most often occurs with bacterial pneumonia; Streptococcus pneumoniae is the most common cause. See Pneumonia for a general overview of pneumonia and its other causes Individuals with sepsis or septic shock need hospitalization in an intensive care unit. An intensive care unit (ICU critical care unit (CCU intensive therapy unit or intensive treatment unit (ITU is a specialized department used in They often require intravenous fluids and medications to help keep their blood pressure from dropping too low. Intravenous therapy or IV therapy is the giving of Liquid substances directly into a Vein. Sepsis can cause liver, kidney, and heart damage, among other problems, and it often causes death.

Pleural effusion, empyema, and abscess

Occasionally, microorganisms infecting the lung will cause fluid (a pleural effusion) to build up in the space that surrounds the lung (the pleural cavity). Pleural effusion is excess fluid that accumulates in the Pleural cavity, the fluid-filled space that surrounds the Lungs Excessive amounts of such fluid can impair If the microorganisms themselves are present in the pleural cavity, the fluid collection is called an empyema. An empyema is a collection of Pus within a naturally existing anatomical cavity When pleural fluid is present in a person with pneumonia, the fluid can often be collected with a needle (thoracentesis) and examined. Thoracentesis (also known as thoracocentesis or pleural tap) is an invasive procedure to remove fluid or air from the pleural space Depending on the results of this examination, complete drainage of the fluid may be necessary, often requiring a chest tube. A chest tube ( chest drain or tube thoracostomy) is a flexible plastic tube that is inserted through the side of the chest into the pleural space. In severe cases of empyema, surgery may be needed. Decortication is a medical procedure involving the surgical removal of the surface layer Membrane, or fibrous cover of an organ. If the fluid is not drained, the infection may persist, because antibiotics do not penetrate well into the pleural cavity.

Rarely, bacteria in the lung will form a pocket of infected fluid called an abscess. An abscess (abscessus is a collection of Pus (dead Neutrophils) that has accumulated in a cavity formed by the tissue on the basis of an infectious process Lung abscesses can usually be seen with a chest x-ray or chest CT scan. Abscesses typically occur in aspiration pneumonia and often contain several types of bacteria. Aspiration pneumonia is Bronchopneumonia that develops due to the entrance of foreign materials that enter the bronchial tree usually oral or gastric contents (including food Antibiotics are usually adequate to treat a lung abscess, but sometimes the abscess must be drained by a surgeon or radiologist. Surgery (from the χειρουργική cheirourgikē, via chirurgiae meaning "hand work" is a medical specialty that uses operative manual and instrumental Interventional radiology (abbreviated IR or sometimes VIR for vascular and interventional radiology) is a subspecialty of Radiology in which

Prognosis and mortality

With treatment, most types of bacterial pneumonia can be cleared within two to four weeks. ^[12] Viral pneumonia may last longer, and mycoplasmal pneumonia may take four to six weeks to resolve completely. ^[12] In cases where the pneumonia progresses to blood poisoning (bacteremia), just over 20% of sufferers will die. Bacteremia ( Bacteræmia in British English is the presence of bacteria in the Blood. ^[13]

The death rate (or mortality) also depends on the underlying cause of the pneumonia. Mortality rate is a measure of the number of Deaths (in general or due to a specific cause in some population scaled to the size of that population per unit time Pneumonia caused by Mycoplasma, for instance, is associated with little mortality. However, about half of the people who develop methicillin-resistant Staphylococcus aureus (MRSA) pneumonia while on a ventilator will die. ^[14] In regions of the world without advanced health care systems, pneumonia is even deadlier. Limited access to clinics and hospitals, limited access to x-rays, limited antibiotic choices, and inability to treat underlying conditions inevitably leads to higher rates of death from pneumonia.

Clinical prediction rules

Clinical prediction rules have been developed to more objectively prognosticate outcomes in pneumonia. These rules can be helpful in deciding whether or not to hospitalize the person.

• Pneumonia severity index (or PORT Score)^[15] - online calculator
• CURB-65 score, which takes into account the severity of symptoms, any underlying diseases, and age^[16] - online calculator

Prevention

There are several ways to prevent infectious pneumonia. The Pneumonia severity index ' or PORT Score' is a clinical prediction rule that medical practitioners can use to calculate the probability of Morbidity CURB-65 is a Clinical prediction rule that has been validated for predicting mortality in Community-acquired pneumonia and infection of any site Appropriately treating underlying illnesses (such as AIDS) can decrease a person's risk of pneumonia. Smoking cessation is important not only because it helps to limit lung damage, but also because cigarette smoke interferes with many of the body's natural defenses against pneumonia. Smoking cessation is the effort to stop smoking Tobacco products

Research shows that there are several ways to prevent pneumonia in newborn infants. Research is defined as Human activity based on Intellectual application in the investigation of Matter. Testing pregnant women for Group B Streptococcus and Chlamydia trachomatis, and then giving antibiotic treatment if needed, reduces pneumonia in infants. Infection with Group B Streptococcus (GBS also known as Streptococcus agalactiae and more colloquially as Strep B and group B Strep can cause serious Chlamydia trachomatis, an obligate intracellular human pathogen is one of three bacterial species in the genus Chlamydia, family Chlamydiaceae In modern usage an antibiotic is a Chemotherapeutic agent with activity against Microorganisms such as Bacteria, fungi or Protozoa Suctioning the mouth and throat of infants with meconium-stained amniotic fluid decreases the rate of aspiration pneumonia. Meconium is the earliest Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the Amnion of a pregnant woman Aspiration pneumonia is Bronchopneumonia that develops due to the entrance of foreign materials that enter the bronchial tree usually oral or gastric contents (including food

Vaccination is important for preventing pneumonia in both children and adults. Vaccination is the administration of Antigenic material (the Vaccine) to produce immunity to a disease Vaccinations against Haemophilus influenzae and Streptococcus pneumoniae in the first year of life have greatly reduced their role in pneumonia in children. Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile Gram-negative Coccobacillus Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the Genus Vaccinating children against Streptococcus pneumoniae has also led to a decreased incidence of these infections in adults because many adults acquire infections from children. A vaccine against Streptococcus pneumoniae is also available for adults. Pneumococcal polysaccharide vaccine (PPV also known as Pneumovax, is a Vaccine used to prevent Streptococcus pneumoniae (pneumococcus infections In the U. S. , it is currently recommended for all healthy individuals older than 65 and any adults with emphysema, congestive heart failure, diabetes mellitus, cirrhosis of the liver, alcoholism, cerebrospinal fluid leaks, or those who do not have a spleen. Emphysema is a chronic obstructive Pulmonary disease ( COPD) formerly termed a chronic obstructive Lung disease (COLD Heart failure is a Cardiac condition that occurs when a problem with the structure or function of the Heart impairs its ability to supply Diabetes mellitus (ˌdaɪəˈbiːtiːz or /ˌdaɪəˈbiːtəs/ /məˈlaɪtəs/ or /ˈmɛlətəs/ often referred to simply as diabetes ( Ancient Greek: grc Cirrhosis is a consequence of chronic Liver Disease characterized by replacement of liver tissue by fibrous Scar tissue as well as regenerative The liver is a vital organ in the human body and is present in Vertebrates and some other animals Alcoholism is a term with multiple and sometimes conflicting definitions Cerebrospinal fluid ( CSF) Liquor cerebrospinalis, is a clear Bodily fluid that occupies the Subarachnoid space and the Ventricular system This article is about the medical condition For the Moth Genus, see Armadini. A repeat vaccination may also be required after five or ten years. ^[17]

Influenza vaccines should be given yearly to the same individuals who receive vaccination against Streptococcus pneumoniae. A Vaccine is an Inoculation designed to increase immunity against a specific disease Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus aerotolerant anaerobe and a member of the Genus In addition, health care workers, nursing home residents, and pregnant women should receive the vaccine. ^[18] When an influenza outbreak is occurring, medications such as amantadine, rimantadine, zanamivir, and oseltamivir can help prevent influenza. Amantadine is the Organic compound known formally as 1-aminoadamantane Rimantadine ( INN, sold under the trade name Flumadine) is an orally administered Antiviral drug used to treat and in rare cases prevent Influenzavirus Zanamivir ( INN) (zəˈnæmɨvɪr is a Neuraminidase inhibitor used in the treatment of and Prophylaxis of both Influenzavirus A and Influenzavirus Oseltamivir ( INN) (ɒsəlˈtæmɨvɪr is an Antiviral drug that is used in the treatment and Prophylaxis of both Influenzavirus A and Influenzavirus ^[19][20]

Epidemiology

Pneumonia is a common illness in all parts of the world. It is a major cause of death among all age groups. In children, the majority of deaths occur in the newborn period, with over two million deaths a year worldwide. The World Health Organization estimates that one in three newborn infant deaths are due to pneumonia^[21] and WHO also estimates that up to 1 million of these (vaccine preventable) deaths are caused by the bacteria Streptococcus pneumoniae, and 90% of these deaths take place in developing countries. ^[22] Mortality from pneumonia generally decreases with age until late adulthood. Elderly individuals, however, are at particular risk for pneumonia and associated mortality.

In the United Kingdom, the annual incidence of pneumonia is approximately 6 cases for every 1000 people for the 18-39 age group. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located For those over 75 years of age, this rises to 75 cases for every 1000 people. Roughly 20-40% of individuals who contract pneumonia require hospital admission of which between 5-10% are admitted to a critical care unit. An intensive care unit (ICU critical care unit (CCU intensive therapy unit or intensive treatment unit (ITU is a specialized department used in Similarly, the mortality rate in the UK is around 5-10%. ^[2]

More cases of pneumonia occur during the winter months than during other times of the year. Pneumonia occurs more commonly in males than females, and more often in Blacks than Caucasians. Individuals with underlying illnesses such as Alzheimer's disease, cystic fibrosis, emphysema, tobacco smoking, alcoholism, or immune system problems are at increased risk for pneumonia. Alzheimer's disease ( AD) also called Alzheimer disease or simply Alzheimer's, is the most common form of Dementia. Cystic fibrosis (also known as CF, mucoviscoidosis, or mucoviscidosis) is a hereditary disease affecting the exocrine (mucus glands of the lungs Emphysema is a chronic obstructive Pulmonary disease ( COPD) formerly termed a chronic obstructive Lung disease (COLD Tobacco Smoking is the inhalation of smoke from burned dried or cured leaves of the Tobacco plant most often in the form of a Cigarette. Alcoholism is a term with multiple and sometimes conflicting definitions Immunosuppression involves an act that reduces the activation or Efficacy of the Immune system. ^[23] These individuals are also more likely to have repeated episodes of pneumonia. People who are hospitalized for any reason are also at high risk for pneumonia.

History

Hippocrates, the ancient Greek physician known as the "father of medicine. Hippocrates of Cos II or Hippokrates of Kos ( ca. 460 BC – ca "

The symptoms of pneumonia were described by Hippocrates (c. Hippocrates of Cos II or Hippokrates of Kos ( ca. 460 BC – ca 460 BC–370 BC):

Peripneumonia, and pleuritic affections, are to be thus observed: If the fever be acute, and if there be pains on either side, or in both, and if expiration be if cough be present, and the sputa expectorated be of a blond or livid color, or likewise thin, frothy, and florid, or having any other character different from the common. . . When pneumonia is at its height, the case is beyond remedy if he is not purged, and it is bad if he has dyspnoea, and urine that is thin and acrid, and if sweats come out about the neck and head, for such sweats are bad, as proceeding from the suffocation, rales, and the violence of the disease which is obtaining the upper hand. ^[24]

However, Hippocrates referred to pneumonia as a disease "named by the ancients. " He also reported the results of surgical drainage of empyemas. Maimonides (1138–1204 AD) observed "The basic symptoms which occur in pneumonia and which are never lacking are as follows: acute fever, sticking [pleuritic] pain in the side, short rapid breaths, serrated pulse and cough. Moses Maimonides ( March 30 1135 – December 13 1204) also known as the Rambam, was a Rabbi, Physician, and In Medicine, a person's pulse is the throbbing of their arteries. "^[25] This clinical description is quite similar to those found in modern textbooks, and it reflected the extent of medical knowledge through the Middle Ages into the 19th century.

Bacteria were first seen in the airways of individuals who died from pneumonia by Edwin Klebs in 1875. Edwin Klebs ( 6 February 1834 &ndash 23 October 1913) was a German - Swiss Pathologist. ^[26] Initial work identifying the two common bacterial causes Streptococcus pneumoniae and Klebsiella pneumoniae was performed by Carl Friedländer^[27] and Albert Fränkel^[28] in 1882 and 1884, respectively. Carl Friedländer (1847-1887 was a German Pathologist and Microbiologist who helped discover the Bacterial cause of Pneumonia in 1882 Albert Fraenkel ( March 10, 1848, Frankfurt/Oder – July 6, 1916, Berlin) was a German Physician Friedländer's initial work introduced the Gram stain, a fundamental laboratory test still used to identify and categorize bacteria. Gram staining (or Gram's method) is an empirical method of differentiating bacterial species into two large groups ( Gram-positive and Christian Gram's paper describing the procedure in 1884 helped differentiate the two different bacteria and showed that pneumonia could be caused by more than one microorganism. Hans Christian Joachim Gram ( September 13, 1853 - November 14, 1938) was a Danish Bacteriologist. ^[29]

Sir William Osler, known as "the father of modern medicine," appreciated the morbidity and mortality of pneumonia, describing it as the "captain of the men of death" in 1918. Sir William Osler 1st Baronet ( July 12, 1849 &ndash December 29, 1919 Age 70 was a Canadian Physician. However, several key developments in the 1900s improved the outcome for those with pneumonia. With the advent of penicillin and other antibiotics, modern surgical techniques, and intensive care in the twentieth century, mortality from pneumonia dropped precipitously in the developed world. Penicillin (sometimes abbreviated PCN or pen) is a group of Beta-lactam antibiotics used in the treatment of Bacterial Infections Vaccination of infants against Haemophilus influenzae type b began in 1988 and led to a dramatic decline in cases shortly thereafter. Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile Gram-negative Coccobacillus ^[30] Vaccination against Streptococcus pneumoniae in adults began in 1977 and in children began in 2000, resulting in a similar decline. ^[31]

See also

• List of pneumonia victims
• Pneumonitis
• Antibiotic

Notes

External links

• Merck Manual: Pneumonia
• Merck Manual of Geriatrics: Pneumonia in the elderly
• British Lung Foundation
• British Thoracic Society
• ICU Medicus Pneumonia Severity Score
• Pneumococcal vaccines Accelerated Development and Introduction Plan