Concussion Classification and external resources
Deceleration can exert rotational forces in the brain, especially the midbrain and diencephalon. In biological anatomy the mesencephalon (or midbrain) comprises the Tectum (or corpora quadrigemini Tegmentum, the ventricular mesocoelia (or "iter" The diencephalon (or interbrain is the region of the Brain that includes the Thalamus, Hypothalamus, Epithalamus, Prethalamus or
ICD-10	S06.0
ICD-9	850
MedlinePlus	000799
eMedicine	aaem/123  sports/27
MeSH	D001924

Concussion, from the Latin concutere ("to shake violently"),^[1] is the most common and least serious type of traumatic brain injury. 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 S00-T14 - Injury (S00-S09 Head ( Superficial Injury of head ( Superficial injury of 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. MedlinePlus, with the MedlinePlus Medical Encyclopedia, is a website network containing Health information from the world's largest medical Library 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 Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Traumatic brain injury (TBI also called intracranial injury, occurs when Physical trauma injures the Brain. The terms mild brain injury, mild traumatic brain injury (MTBI), mild head injury (MHI), and minor head trauma and concussion may be used interchangeably,^[2][3] although the latter is often treated as a narrower category. ^[4] The term 'concussion', has been used for centuries and is still commonly used in sports medicine, while 'MTBI' is a technical term used more commonly nowadays in general medical contexts. Sports medicine specializes in preventing diagnosing and treating injuries related to participating in sports and/or exercise specifically the rotation or deformation of joints or Frequently defined as a head injury with a transient loss of brain function, concussion can cause a variety of physical, cognitive, and emotional symptoms. Traumatic brain injury. THIS PAGE IS FOR INFORMATION ON HEAD INJURY (NOT SPECIFICALLY THE BRAIN--> Head injury is Wikipedia articles related to Brain Function Visual system Auditory system Olfactory system Cognition is a concept used in different ways by different disciplines but is generally accepted to mean the process of awareness or thought

Concussion can be diagnosed and assigned a level of severity based largely on symptoms. Treatment involves monitoring and rest. Symptoms usually go away entirely within three weeks, though they may persist, or complications may occur. ^[5] Repeated concussions can cause cumulative brain damage such as dementia pugilistica or severe complications such as second-impact syndrome. Brain damage, or Acquired brain injury, is the destruction or degeneration of Brain cells. Dementia pugilistica ( DP) also called chronic traumatic encephalopathy ( CTE) chronic boxer’s encephalopathy, traumatic boxer’s encephalopathy Second-impact syndrome ( SIS) is an extremely rare condition in which the brain swells rapidly and catastrophically after a person suffers a second Concussion before

Due to factors such as widely varying definitions and possible underreporting of concussion, the rate at which it occurs annually is not known; however it may be more than 6 per 1000 people. ^[6] Common causes include sports injuries, bicycle accidents, car accidents, and falls; the latter two are the most frequent causes among adults. ^[7] Concussion may be caused by a blow to the head, or by acceleration or deceleration forces without a direct impact. The forces involved disrupt cellular processes in the brain for days or weeks. The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain

It is not known whether the concussed brain is structurally damaged the way it is in other types of brain injury (albeit to a lesser extent) or whether concussion mainly entails a loss of function with physiological but not structural changes. Physiology (from Greek grc φύσις physis, "nature origin" and grc -λογία -logia) is the study of the mechanical physical ^[8] Cellular damage has reportedly been found in concussed brains, but it may have been due to artifacts from the studies. ^[9] A debate about whether structural damage exists in concussion has raged for centuries and is ongoing.

Definitions

No single definition of concussion, mild head injury,^[10] or mild traumatic brain injury is universally accepted, though a variety of definitions have been offered. ^[11] In 2001, the first International Symposium on Concussion in Sport was organized by the International Olympic Committee Medical Commission and other sports federations. ^[12] A group of experts called the Concussion in Sport Group met there and defined concussion as "a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces. "^[13] They agreed that concussion typically involves temporary impairment of neurological function which quickly resolves by itself, and that neuroimaging normally shows no gross structural changes to the brain as the result of the condition. Neuroimaging includes the use of various techniques to either directly or indirectly image the structure, function/ Pharmacology of the Brain ^[5]

According to the classic definition, no structural brain damage occurs in concussion;^[14] it is a functional state, meaning that symptoms are caused primarily by temporary biochemical changes in neurons, taking place for example at their cell membranes and synapses. Biochemistry is the study of the chemical processes in living Organisms It deals with the Structure and function of cellular components such as Neurons (ˈnjuːɹɒn also known as neurones and nerve cells) are responsive cells in the Nervous system that process and transmit information The cell membrane (also called the plasma membrane, plasmalemma, or "phospholipid bilayer" is a Selectively permeable Lipid bilayer Chemical synapses are specialized junctions through which Neurons signal to each other and to non-neuronal cells such as those in Muscles or Glands ^[5] However, in recent years researchers have included injuries in which structural damage does occur under the rubric of concussion. Injury or bodily injury is Damage or Harm caused to the Structure or function of the Body caused by an outside agent or According to the National Institute for Health and Clinical Excellence definition, concussion may involve a physiological or physical disruption in the brain's synapses. Chemical synapses are specialized junctions through which Neurons signal to each other and to non-neuronal cells such as those in Muscles or Glands ^[15]

Definitions of mild traumatic brain injury (M. T. B. I) have been inconsistent since the 1970s, but the World Health Organization's International Statistical Classification of Diseases and Related Health Problems (ICD-10) described MTBI-related conditions in 1992, providing a consistent, authoritative definition across specialties. The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings ^[3] In 1993, the American Congress of Rehabilitation Medicine defined MTBI as 30 minutes or fewer of loss of consciousness (LOC), 24 hours or fewer of post-traumatic amnesia (PTA), and a Glasgow Coma Scale (GCS) score of at least 13. See also Unconscious mind. Unconsciousness, more appropriately referred to as loss of Consciousness or lack of consciousness is Post-traumatic amnesia ( PTA) is a state of confusion that occurs immediately following a Traumatic brain injury (TBI in which the injured person is The Glasgow Coma Scale or GCS, sometimes also known as the Glasgow Coma Score is a neurological scale which aims to give a reliable objective ^[16] In 1994, the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders defined MTBI using PTA and LOC. The American Psychiatric Association (APA is the main Professional organization of Psychiatrists and trainee psychiatrists in the United States, and the The Diagnostic and Statistical Manual of Mental Disorders' ( DSM) is published by the American Psychiatric Association ^[3] Other definitions of MTBI incorporate focal neurological deficit and altered mental status, in addition to PTA and GCS. ^[11]

Concussion falls under the classification of mild TBI. ^[17] It is not clear whether concussion is implied in mild brain injury or mild head injury. ^[18] "MTBI" and "concussion" are often treated as synonyms in medical literature. ^[16] However, other injuries such as intracranial hemorrhages (e. An intracranial hemorrhage is a Hemorrhage, or bleeding within the Skull. g. intra-axial hematoma, epidural hematoma, and subdural hematoma) are not necessarily precluded in MTBI^[5] or mild head injury,^[19][20] but they are in concussion. A cerebral hemorrhage (or intracerebral hemorrhage, ICH) is a subtype of Intracranial hemorrhage that occurs within the Brain tissue itself Epidural or extradural hematoma is a type of Traumatic brain injury (TBI in which a buildup of blood occurs between the Dura mater (the tough outer A subdural Hematoma (Subdural haematoma (SDH is a form of Traumatic brain injury in which Blood gathers between the dura (the outer protective ^[21] MTBI associated with abnormal neuroimaging may be considered "complicated MTBI". ^[22] "Concussion" can be considered to imply a state in which brain function is temporarily impaired and "MTBI" to imply a pathophysiological state, but in practice few researchers and clinicians distinguish between the terms. Pathophysiology is the study of the disturbance of normal Mechanical, Physical, and Biochemical functions either caused by a Disease, or resulting ^[5] Descriptions of the condition, including the severity and the area of the brain affected, are now used more often than "concussion" in clinical neurology. ^[23]

Although the term "concussion" is still used in sports literature as interchangeable with "MHI" or "MTBI", the general clinical medical literature now uses "MTBI" instead. ^[24]

Controversy exists about whether the definition of concussion should include only those injuries in which loss of consciousness occurs. See also Unconscious mind. Unconsciousness, more appropriately referred to as loss of Consciousness or lack of consciousness is ^[1] Historically, concussion by definition involved a loss of consciousness, but the definition has changed over time to include a change in consciousness, such as amnesia. ^[25] The best-known concussion grading scales count head injuries in which loss of consciousness does not occur to be mild concussions and those in which it does to be more severe. ^[26]

Causes

The leading causes of MTBI in adults are falls and vehicle accidents, and other causes include sports injuries, assaults, industrial and work-related injuries, and injuries that occur in the home^[11] and school. Among children aged 5 to 14, sports and bicycle accidents cause the greatest number of concussions. ^[7] Soldiers are at elevated risk for concussion from causes such as bomb blasts, with as many as 15% of U. S. infantry soldiers who return from the Iraq War meeting the criteria for MTBI. The Iraq War, also known as the Second Gulf War, the Occupation of Iraq, or the War in Iraq, is an ongoing Military campaign ^[27]

The relative contribution of causes of mild head injury differs by region, gender, and age. ^[5] For example, in Scotland and Sweden, falls account for the greatest percentage of MHIs, while in the U. S. and Australia, transportation is the largest cause. ^[5]

Mechanism

Rotational force is key in concussion. Punches in boxing deliver more rotational force to the head than impacts in sports such as football, and boxing carries a higher risk of concussion than football. ^[28]

The brain is surrounded by cerebrospinal fluid, one of the functions of which is to protect it from light trauma, but more severe impacts or the forces associated with rapid acceleration and deceleration may not be absorbed by this cushion. The human brain controls the Central nervous system (CNS by way of the Cranial nerves and Spinal cord, the Peripheral nervous system (PNS Cerebrospinal fluid ( CSF) Liquor cerebrospinalis, is a clear Bodily fluid that occupies the Subarachnoid space and the Ventricular system ^[8] Concussion may be caused by impact forces, in which the head strikes or is struck by something, or impulsive forces, in which the head moves without itself being subject to blunt trauma (for example, when the chest hits something and the head snaps forward). In Physics, a force is whatever can cause an object with Mass to Accelerate. In medical terminology blunt trauma, blunt injury, non-penetrating trauma or blunt force trauma refers to a type of Physical trauma ^[4]

Forces may cause linear, rotational, or angular movement of the brain, or a combination of these types of motion. The centripetal force is the external force required to make a body follow a curved path ^[4] In rotational movement, the head turns around its center of gravity, and in angular movement it turns on an axis other than its center of gravity. ^[4] The amount of rotational force is thought to be the major type of force to cause concussion^[29] and the largest component in its severity. ^[5] Studies with athletes have shown that the amount of force and the location of the impact are not necessarily correlated to the severity of the concussion or its symptoms, and have called into question the threshold for concussion previously thought to exist at around 70-75g. g-force (also G-force, g-load) is a measurement of an object's Acceleration expressed in g s ^[30][31]

The parts of the brain most affected by rotational forces are the midbrain and diencephalon. ^[1][7] It is thought that the forces from the injury disrupt the normal cellular activities in the reticular activating system located in these areas, and that this disruption produces the loss of consciousness often seen in concussion. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called The reticular activating system (or ARAS for Ascending Reticular Activating System is the name given to the part of the Brain (the Reticular formation and its connections ^[7] Other areas of the brain that may be affected include the upper part of the brain stem, the fornix, the corpus callosum, the temporal lobe, and the frontal lobe. The brain stem (or brainstem) is the lower part of the Brain, adjoining and structurally continuous with the Spinal cord. The corpus callosum is a structure of the Mammalian Brain in the longitudinal fissure that connects the left and right Cerebral hemispheres It also facilitates The temporal lobes are parts of the cerebrum that are involved in speech, Memory, and Hearing. The frontal lobe is an area in the Brain of Mammals It is located at the front of each Cerebral hemisphere and positioned anterior to (in front of the ^[32]

Pathophysiology

In both animals and humans, MTBI can alter the brain's physiology for hours to weeks, setting into motion a variety of pathological events. Pathology (from Greek grc πάθος pathos, "fate harm" and grc -λογία -logia) is the study and ^[33] Though these events are thought to interfere with neuronal and brain function, the metabolic processes that follow concussion are reversed in a large majority of affected brain cells; however a few cells may die after the injury. Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. Brain Cell is a Mail art project begun by Ryosuke Cohen in June 1985 ^[22]

Included in the cascade of events unleashed in the brain by concussion is impaired neurotransmission, loss of regulation of ions, deregulation of energy use and cellular metabolism, and a reduction in cerebral blood flow. Neurotransmission (latin transmissio = passage crossing from transmitto = send let through also called synaptic transmission, is an electrical movement An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Cerebral blood flow, or CBF, is the blood supply to the Brain in a given time ^[22] Excitatory neurotransmitters, chemicals such as glutamate that serve to stimulate nerve cells, are released in excessive amounts as the result of the injury. See Chemical synapse for an introduction to concepts and terminology used in this article Glutamic acid (abbreviated as Glu or E) is one of the 20 Alpha Amino acids It is not among the human Essential amino acids Its ^[34] The resulting cellular excitation causes neurons to fire excessively. In Neurophysiology, the action potential is a self-regenerating Wave of Electrochemical activity that allows Nerve cells to carry a signal ^[35] This creates an imbalance of ions such as potassium and calcium across the cell membranes of neurons (a process like excitotoxicity). Potassium is the an essential mineral macronutrient and is the main Intracellular Ion for all types of cells It is important in maintaining fluid Calcium (Ca2+ plays a vital role in the Anatomy, Physiology and Biochemistry of Organisms and of the cell, particularly Excitotoxicity is the pathological process by which nerve cells are damaged and killed by glutamate and similar substances ^[22] Since the neuron firing involves a net influx of positively charged ions into the cell, the ionic imbalance causes cells to have a more positive membrane potential (i. Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. Membrane potential (or transmembrane potential) is the Voltage difference (or Electrical potential difference between the interior and exterior of a e. it leads to neuronal depolarization). In biology depolarization is a decrease in the Absolute value of a cell's Membrane potential. This depolarization in turn causes ion pumps that serve to restore resting potential within cells to work more than they normally do. "Ion pump" redirects here For pumps that reduce pressure see Ion pump (physics. The Membrane potential, or better Membrane Voltage, is the difference of Electric potentials between two Aqueous solutions separated by a ( ^[22] This increased need for energy leads cells to require greater-than-usual amounts of glucose, which is made into ATP, an important source of energy for cells. Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy ^[22] The brain may stay in this state of hypermetabolism for days or weeks. Hypermetabolism is the Physiological state of increased rate of Metabolic activity ^[36] At the same time, cerebral blood flow is relatively reduced for unknown reasons,^[37] though the reduction in blood flow is not as severe as it is in ischemia. In Medicine, ischemia ( Greek ισχαιμία, isch- is restriction hema or haema is Blood) is a restriction ^[22] Thus cells get less glucose than they normally do, which causes an "energy crisis". ^[37]

Concurrently with these processes, the activity of mitochondria may be reduced, which causes cells to rely on anaerobic metabolism to produce energy, which increases levels of the byproduct lactate. In Cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed Organelle found in most eukaryotic cells. Fermentation is the process of deriving energy from the oxidation of organic compounds such as carbohydrates using an endogenous electron acceptor which is ^[22]

For a period of minutes to days after a concussion, the brain is especially vulnerable to changes in intracranial pressure, blood flow, and anoxia. Intracranial pressure, ( ICP) is the pressure exerted by the Cranium on the Brain tissue Cerebrospinal fluid (CSF and the brain's circulating Chronic Hypoxia is a pathological condition in which the body as a whole ( generalized hypoxia) or region of the body ( tissue hypoxia) is deprived of adequate ^[37] According to studies performed on animals, large numbers of neurons can die during this period in response to slight, normally innocuous changes in blood flow. Animal testing or animal research is the use of non-human Animals in scientific experimentation. ^[37]

Concussion involves diffuse brain injury (as opposed to focal brain injury), meaning that the dysfunction occurs over a widespread area of the brain rather than in a particular spot. ^[38] Concussion is thought to be a milder type of diffuse axonal injury because axons may be injured to a minor extent due to stretching. Diffuse axonal injury (DAI is one of the most common and devastating types of Traumatic brain injury, occurring in about half of all cases of severe head trauma and An axon or nerve fiber is a long slender projectionof a nerve cell or Neuron, that conducts electrical impulses away from the neuron's Cell ^[4] Animal studies in which primates were concussed have revealed damage to brain tissues such as small petechial hemorrhages and axonal injury. Animal testing or animal research is the use of non-human Animals in scientific experimentation. A petechia (pɨˈtiːkiə plural petechiae (pɨˈtiːkɪiː is a small (1-2mm red or purple spot on the body caused by a minor Hemorrhage (broken Capillary ^[39] Axonal damage has been found in the brains of concussion sufferers who died from other causes, but inadequate blood flow to the brain due to other injuries may have contributed to the damage. ^[9]

Signs and symptoms

Common symptoms in MTBI include headache and difficulty concentrating. ^[16]

Concussion can be associated with a variety of symptoms, which typically occur rapidly after the injury. ^[12] Early symptoms usually subside within days or weeks. ^[9] The number and type of symptoms a person suffers varies widely. ^[11]

Physical

Headache is the most common MTBI symptom. A headache ( cephalalgia in medical terminology is a condition of pain in the Head; sometimes Neck or upper back pain may also be interpreted ^[16] Other symptoms include dizziness, vomiting, nausea, lack of motor coordination, difficulty balancing,^[16] or other problems with movement or sensation. Nausea ( Latin: Nausea, Greek:, " Sea-sickness " also called wamble) is the sensation of unease and discomfort Gross motor coordination addresses the Gross motor skills walking running climbing jumping crawling lifting one's head sitting up etc In Biomechanics, balance is an ability to maintain the Center of gravity of a body within the Base of support with minimal Postural sway. In Psychology, sensation is the first stage in the biochemical and neurologic events that begins with the impinging of a stimulus upon the receptor cells of a Visual symptoms include light sensitivity,^[37] seeing bright lights,^[40] blurred vision,^[9] and double vision. Photophobia is a Symptom of excessive sensitivity to Light and the aversion to Sunlight or well-lit places Blurred vision is an Ocular Symptom. Causes There are many causes of blurred vision including use of Atropine. Diplopia, commonly known as double vision, is the simultaneous Perception of two images of a single object ^[41] Tinnitus, or a ringing in the ears, is also commonly reported. Tinnitus (tɪˈnaɪtəs or /ˈtɪnɪtəs/ from the Latin word for " Ringing " is the perception of sound within the human ear in the absence of corresponding ^[9] In one in about seventy concussions, concussive convulsions occur, but these are not actual post-traumatic seizures, which are a symptom of more serious injury. An epileptic seizure is caused by excessive and/or hypersynchronous electrical Neuronal activity and is usually self-limiting Post-traumatic seizures ( PTS) are Seizures that result from Traumatic brain injury (TBI Brain damage caused by Physical trauma. ^[42] Concussive convulsions are thought to result from temporary loss of brain function rather than from structural damage and are usually associated with a good outcome. ^[43]

Cognitive and emotional

Cognitive symptoms include confusion, disorientation, and difficulty focusing attention. Orientation is a function of the Mind involving awareness of three dimensions Time, Place and Person. Attention is the Cognitive process of selectively concentrating on one aspect of the environment while ignoring other things Loss of consciousness may occur but is not necessarily correlated with the severity of the concussion if it is brief. ^[13] Post-traumatic amnesia, in which the person cannot remember events leading up to the injury or after it, or both, is a hallmark of concussion. Post-traumatic amnesia ( PTA) is a state of confusion that occurs immediately following a Traumatic brain injury (TBI in which the injured person is ^[16] Confusion, another concussion hallmark, may be present immediately or may develop over several minutes. Confusion, of a Pathological degree usually refers to loss of orientation (ability to place oneself correctly in the world by time location and personal identity and ^[16] A patient may, for example, repeatedly ask the same questions,^[44] be slow to respond to questions or directions, have a vacant stare, or have slurred^[16] or incoherent speech. ^[45] Other MTBI symptoms include changes in sleeping patterns^[9] and difficulty with reasoning,^[41] concentrating, and performing everyday activities. ^[16]

Affective results of concussion include crankiness, loss of interest in favorite activities or items,^[46] tearfulness,^[4] and displays of emotion that are inappropriate to the situation. Affect, like the adjective affective, refers to the experience of feeling or Emotion. ^[45] Common symptoms in concussed children include restlessness, lethargy, and irritability. ^[36]

Diagnosis

Diagnosis of MTBI is based on physical and neurological exams, duration of unconsciousness (usually less than 30 minutes) and post-traumatic amnesia (PTA; usually less than 24 hours), and the Glasgow Coma Scale (MTBI sufferers have scores of 13 to 15). ^[47] Neuropsychological tests exist to measure cognitive function. Neuropsychological tests are specifically designed tasks used to measure a psychological function known to be linked to a particular Brain structure or pathway ^[9] The tests may be administered hours, days, or weeks after the injury, or at different times to determine whether there is a trend in the patient's condition. ^[48] Athletes may be tested before a sports season begins to provide a baseline comparison in the event of an injury. ^[49]

Unequal pupil size is a sign of a brain injury more serious than concussion.

Health care providers examine head trauma survivors to ensure that the injury is not a more severe medical emergency such as an intracranial hemorrhage. A medical emergency is an Injury or Illness that is acute and poses an immediate risk to a person's life or long term health Indications that screening for more serious injury is needed include worsening of symptoms such as headache, persistent vomiting,^[50] increasing disorientation or a deteriorating level of consciousness,^[51] seizures, and unequal pupil size. Anisocoria is a condition characterized by an unequal size of the Pupils Causes In the absence of any deformities of the iris or eyeball proper anisocoria is ^[52] Patients with such symptoms, or who are at higher risk for a more serious brain injury, are given MRIs or CT scans to detect brain lesions and are observed by medical staff. Computed tomography (CT is a Medical imaging method employing Tomography.

Health care providers make the decision about whether to give a CT scan using the Glasgow Coma Scale. ^[7] In addition, they may be more likely to perform a CT scan on people who would be difficult to observe after discharge or those who are intoxicated, at risk for bleeding, older than 60,^[7] or younger than 16. Intoxication is the state of being affected by one or more psychoactive drugs. Most concussions cannot be detected with MRI or CT scans. ^[29] However, changes have been reported to show up on MRI and SPECT imaging in concussed people with normal CT scans, and post-concussion syndrome may be associated with abnormalities visible on SPECT and PET scans. Post-concussion syndrome, also known as postconcussive syndrome or PCS, is a set of symptoms that a person may experience for weeks months or occasionally years Single photon emission computed tomography (SPECT or less commonly SPET is a Nuclear medicine tomographic imaging technique using Gamma rays. Positron emission tomography ( PET) is a Nuclear medicine imaging technique which produces a three-dimensional image or map of functional processes in the ^[22] Mild head injury may or may not produce abnormal EEG readings. ^[53]

Concussion may be under-diagnosed. The lack of the highly noticeable signs and symptoms that are frequently present in other forms of head injury could lead clinicians to miss the injury, and athletes may cover up their injuries in order to be allowed to remain in the competition. ^[24] A retrospective survey in 2005 found that more than 88% of concussions go unrecognized. ^[54]

Diagnosis of concussion can be complicated because it shares symptoms with other conditions. For example, post-concussion symptoms such as cognitive problems may be misattributed to brain injury when they are in fact due to post-traumatic stress disorder (PTSD). Post traumatic stress disorder It is a severe and ongoing emotional reaction to ^[55]

Grading systems

Main article: Concussion grading systems

At least 41 systems exist to measure the severity, or grade, of a mild head injury,^[5] and there is little agreement among professionals about which is the best. Concussion grading systems are sets of criteria used in sports medicine to determine the severity or grade of a Concussion, the mildest form of Traumatic brain injury ^[40] Several of the systems use loss of consciousness and amnesia as the primary determinants of the severity of the concussion. ^[40]

The decision about when to allow athletes to return to contact sports is frequently based on the grade of concussion. Injured athletes are prohibited from returning to play before they are symptom-free during rest and exertion and their neuropsychological tests are normal again, in order to avoid a risk of cumulative effects.

Three grading systems are followed most widely: one was developed by Robert Cantu, one by the Colorado Medical Society, and a third by the American Academy of Neurology. The Colorado Medical Society (CMS is the largest group of organized Physicians in Colorado. The American Academy of Neurology (AAN is a professional society for neurologists and neuroscientists ^[26] Each divides concussion into three grades, as summarized in the following table:^[40]

Prevention

Further information: Association football headgear, Bicycle helmet, Football helmet, Hockey helmet, Motorcycle helmet, and Ski helmet

Prevention of MTBI involves taking general measures to prevent traumatic brain injury, such as wearing seat belts and using airbags in cars. Association football headgear is worn by Association football (soccer players to protect the head from Injury. A bicycle helmet is a Helmet intended to be worn while riding a Bicycle. A football helmet is a protective device used primarily in American football and Canadian football, the modern hard plastic version of which was created by A hockey helmet is worn by Ice hockey players and Field hockey goalkeepers to protect the head from potential Injury. A motorcycle helmet is a type of protective headgear used by Motorcycle riders The ski helmet is an optional protection measure in Skiing that is built and designed for multiple impacts A seat belt, sometimes called a safety belt, is a Safety harness designed to secure the occupant of a Vehicle against harmful movement that may result from An airbag is part of a vehicle's safety restraint system a flexible envelope designed for rapid inflation in an automobile Collision, to prevent vehicle occupants ^[16] Older people are encouraged to try to prevent falls, for example by keeping floors free of clutter and wearing thin, flat, shoes with hard soles that do not interfere with balance. ^[46]

Use of protective equipment such as headgear has been found to reduce the number of concussions in athletes. ^[28] Improvements in the design of protective athletic gear such as helmets may decrease the number and severity of such injuries. ^[56] Changes to the rules or the practices of enforcing existing rules in sports, such as those against "head-down tackling", or "spearing", which is associated with a high injury rate, may also prevent concussions. ^[28]

Treatment

Usually concussion symptoms go away without treatment,^[57] and no specific treatment exists. ^[58] About one percent of people who receive treatment for MTBI need surgery for a brain lesion. ^[47] Traditionally, concussion sufferers are prescribed rest,^[58] including plenty of sleep at night plus rest during the day. ^[52] Health care providers recommend a gradual return to normal activities at a pace that does not cause symptoms to worsen. ^[52] Education about symptoms, how to manage them, and their normal time course can lead to an improved outcome. ^[11]

Medications may be prescribed to treat symptoms such as sleep problems and depression. ^[11] Analgesics such as ibuprofen can be taken for the headaches that frequently occur after concussion. Ibuprofen ( INN) (ˌaɪbjuːˈpɹəʊfɛn (from the now outdated nomenclature i so- bu tyl- pro panoic- phen olic acid is a Non-steroidal ^[5] Concussed individuals are advised not to drink alcohol or take drugs that have not been approved by a doctor, as they could impede healing. A drug, broadly speaking is any chemical substance that when absorbed into the body ^[52]

Observation to monitor for worsening condition is an important part of treatment. ^[59] Health care providers recommend that those suffering from concussion return for further medical care and evaluation 24 to 72 hours after the concussive event if the symptoms worsen. Health care is the prevention treatment and management of illness and the preservation of mental health through the services offered by the medical, Nursing Athletes, especially intercollegiate or professional athletes, are typically followed closely by team trainers during this period. Professional sports, as opposed to amateur Sports are those in which athletes receive payment for their performance But others may not have access to this level of health care and may be sent home with no medical person monitoring them unless the situation gets worse. Patients may be released from the hospital to the care of a trusted person with orders to return if they display worsening symptoms^[7] or those which might indicate an emergent condition, like unconsciousness or altered mental status; convulsions; severe, persistent headache; extremity weakness; vomiting; or new bleeding or deafness in either or both ears. The mental status examination (or mental state examination in the UK and Australia abbreviated MSE, is an important part of the clinical assessment process ^[60] Repeated observation for the first 24 hours after concussion is recommended; however it is not known whether it is necessary to wake the patient up every few hours. ^[7]

Prognosis and lasting effects

MTBI has a mortality rate of almost zero. ^[47] The symptoms of most concussions resolve within weeks, but problems may persist. ^[5] It is not common for problems to be permanent, and outcome is usually excellent. ^[22] People over age 55 may take longer to heal from MTBI or may heal incompletely. ^[61] Similarly, factors such as a previous head injury or a coexisting medical condition have been found to predict longer-lasting post-concussion symptoms. ^[39] Other factors that may lengthen recovery time after MTBI include psychological problems such as substance abuse or clinical depression, poor health before the injury or additional injuries sustained during it, and life stress. Substance abuse is the overindulgence in and dependence of a Drug or other chemical leading to effects that are detrimental to the individual's physical and mental health Major depressive disorder, also known as major depression, unipolar depression, unipolar disorder, clinical depression, or simply depression ^[22] Longer periods of amnesia or loss of consciousness immediately after the injury may indicate longer recovery times from residual symptoms. ^[62] For unknown reasons, having had one concussion significantly increases a person's risk of having another. ^[48] The prognosis may differ between concussed adults and children. ^[48] Little research has been done on concussion in the pediatric population, but concern exists that severe concussions could interfere with brain development in children. Pediatrics (also spelled paediatrics) is the branch of Medicine that deals with the medical care of Infants Children and Adolescents The study of neural development draws on both Neuroscience and Developmental biology to describe the cellular and molecular mechanisms by which complex Nervous ^[48]

Post-concussion syndrome

Main article: Post-concussion syndrome

In post-concussion syndrome, symptoms do not resolve for weeks, months, or years after a concussion, and may occasionally be permanent. Post-concussion syndrome, also known as postconcussive syndrome or PCS, is a set of symptoms that a person may experience for weeks months or occasionally years ^[63] Symptoms may include headaches, dizziness, fatigue, anxiety, memory and attention problems, sleep problems, and irritability. Anxiety is a physiological and psychological state characterized by Cognitive, Somatic, Emotional and Behavioral components ^[64] There is no scientifically established treatment, and rest, a recommended recovery technique, has limited effectiveness. ^[58] Symptoms usually go away on their own within months. ^[21] The question of whether the syndrome is due to structural damage or other factors such as psychological ones, or a combination of these, has long been the subject of debate. ^[55]

Cumulative effects

Cumulative effects of concussions are poorly understood. The severity of concussions and their symptoms may worsen with successive injuries, even if a subsequent injury occurs months or years after an initial one. ^[65] Symptoms may be more severe and changes in neurophysiology can occur with the third and subsequent concussions. Neurophysiology (from Greek grc νεῦρον neuron, "nerve" grc φύσις physis, "nature origin" and grc -λογία ^[48] Studies have had conflicting findings on whether athletes have longer recovery times after repeat concussions and whether cumulative effects such as impairment in cognition and memory occur. ^[28]

Cumulative effects may include psychiatric disorders and loss of long-term memory. Mental disorder or mental illness is a psychological or behavioral pattern that occurs in an individual and is thought to cause distress or disability that is not expected as Long-term memory ( LTM) is Memory that can last as little as a few days or as long as decades For example, the risk of developing clinical depression has been found to be significantly greater for retired football players with a history of three or more concussions than for those with no concussion history. ^[66] Three or more concussions is also associated with a five-fold greater chance of developing Alzheimer's disease earlier and a three-fold greater chance of developing memory deficits. Alzheimer's disease ( AD) also called Alzheimer disease or simply Alzheimer's, is the most common form of Dementia. In Psychology, memory is an organism's ability to store retain and subsequently retrieve information ^[66]

Dementia pugilistica

Main article: Dementia pugilistica

Chronic encephalopathy is an example of the cumulative damage that can occur as the result of multiple concussions or less severe blows to the head. Dementia pugilistica ( DP) also called chronic traumatic encephalopathy ( CTE) chronic boxer’s encephalopathy, traumatic boxer’s encephalopathy Encephalopathy /ɛnˌsɛfəˈlɒpəθi/ literally means Disease of the Brain. The condition called dementia pugilistica, or "punch drunk" syndrome, which is associated with boxers, can result in cognitive and physical deficits such as parkinsonism, speech and memory problems, slowed mental processing, tremor, and inappropriate behavior. Parkinsonism (also known as Parkinson's syndrome, atypical Parkinson's, or secondary Parkinson's) is a neurological Syndrome characterized ^[67] It shares features with Alzheimer's disease. ^[68]

Second-impact syndrome

Main article: Second-impact syndrome

Second-impact syndrome, in which the brain swells dangerously after a minor blow, may occur in very rare cases. Second-impact syndrome ( SIS) is an extremely rare condition in which the brain swells rapidly and catastrophically after a person suffers a second Concussion before The condition may develop in people who receive a second blow days or weeks after an initial concussion, before its symptoms have gone away. ^[37] No one is certain of the cause of this often fatal complication, but it is commonly thought that the swelling occurs because the brain's arterioles lose the ability to regulate their diameter, causing a loss of control over cerebral blood flow. An arteriole is a small diameter Blood vessel that extends and branches out from an Artery and leads to capillaries. ^[48] As the brain swells, intracranial pressure rapidly rises. ^[50] The brain can herniate, and the brain stem can fail within five minutes. Herniation, a deadly side effect of very high Intracranial pressure, occurs when the Brain shifts across structures within the Skull. ^[37] Except in boxing, all cases have occurred in athletes under age 20. ^[34] Due to the very small number of documented cases, the diagnosis is controversial, and doubt exists about its validity. ^[69]

Epidemiology

Annual incidence of MTBI by age group in Canada^[70]

Most cases of traumatic brain injury are concussions. A World Health Organization (WHO) study estimated that between 70 and 90% of head injuries that receive treatment are mild. ^[6] However, due to underreporting and to the widely varying definitions of concussion and MTBI, it is difficult to estimate how common the condition is. ^[3] Estimates of the incidence of concussion may be artificially low, for example due to underreporting. At least 25% of MTBI sufferers fail to get assessed by a medical professional. ^[22] The WHO group reviewed studies on the epidemiology of MTBI and found a hospital treatment rate of 1–3 per 1000 people, but since not all concussions are treated in hospitals, they estimated that the rate per year in the general population is over 6 per 1000 people. ^[6]

Young children have the highest concussion rate among all age groups. ^[7] However, most people who suffer concussion are young adults. ^[63] A Canadian study found that the yearly incidence of MTBI is lower in older age groups (graph at right). Incidence is a measure of the risk of developing some new condition within a specified period of time ^[70] Studies suggest males suffer MTBI at about twice the rate of their female counterparts. ^[6] However, female athletes may be at a higher risk for suffering concussion than their male counterparts. ^[71]

Up to five percent of sports injuries are concussions. Sports injuries are injuries that are caused by participation in a sporting event. ^[34] The U. S. Centers for Disease Control and Prevention estimates that 300,000 sports-related concussions occur yearly in the U. The Centers for Disease Control and Prevention (or CDC) is an agency of the United States Department of Health and Human Services based in unincorporated S. , but that number includes only athletes who lost consciousness. ^[72] Since loss of consciousness is thought to occur in less than 10% of concussions,^[73] the CDC estimate is likely lower than the real number. ^[72] Sports in which concussion is particularly common include football and boxing (a boxer aims to "knock out", i. e. give a mild traumatic brain injury to, the opponent). The injury is so common in the latter that several medical groups have called for a ban on the sport, including the American Academy of Neurology, the World Medical Association, and the medical associations of the UK, the U. The World Medical Association (WMA an international organization of Physicians was formally established on September 17, 1947, pursuant to the resolutions S. , Australia, and Canada. ^[74]

Due to the lack of a consistent definition, the economic costs of MTBI are not known, but they are estimated to be very high. ^[75] These high costs are due in part to the large percentage of hospital admissions for head injury that are due to mild head trauma,^[18] but indirect costs such as lost work time and early retirement account for the bulk of the costs. ^[75] These direct and indirect costs cause the expense of mild brain trauma to rival that of moderate and severe head injuries. ^[76]

History and controversy

The Hippocratic Corpus mentioned concussion. The Hippocratic Corpus (Latin Corpus Hippocraticum) Hippocratic Collection, or Hippocratic Canon, is a collection of around seventy early medical works ^[62]

The Hippocratic Corpus, collection of medical works from ancient Greece, mentions concussion, later translated to commotio cerebri, and discusses loss of speech, hearing and sight that can result from "commotion of the brain". ^[62] This idea of disruption of mental function by 'shaking of the brain' remained the widely accepted understanding of concussion until the 19th century. ^[62] The Persian physician Muhammad ibn Zakarīya Rāzi was the first to write about concussion as distinct from other types of head injury in the 10th century AD. ^[77] He may have been the first to use the term "cerebral concussion", and his definition of the condition, a transient loss of function with no physical damage, set the stage for the medical understanding of the condition for centuries. ^[4] In the 13th century, the physician Lanfranc of Milan's Chiurgia Magna described concussion as brain "commotion", also recognizing a difference between concussion and other types of traumatic brain injury (though many of his contemporaries did not), and discussing the transience of post-concussion symptoms as a result of temporary loss of function from the injury. The surgeon Lanfranc of Milan (c1250-1306 variously called Guido Lanfranchi, Lanfranco, or Alanfrancus was ^[77] In the 14th century, the surgeon Guy de Chauliac pointed out the relatively good prognosis of concussion as compared to more severe types of head trauma such as skull fractures and penetrating head trauma. Guy de Chauliac ( c.1300 &ndash 1368 born in Chaulhac, Lozère, France, was the most eminent of Surgeons during the European A skull fracture is a break in one or more of the bones in the Skull caused by a Head injury. A penetrating head injury, or open head injury, is a Head injury in which the Dura mater, the outer layer of the Meninges, is breached ^[77] In the 16th century, the term "concussion" came into use, and symptoms such as confusion, lethargy, and memory problems were described. ^[77] The 16th century physician Ambroise Paré used the term commotio cerebri,^[4] as well as "shaking of the brain", "commotion", and "concussion". Ambroise Paré (born in Bourg-Hersent near Laval, France, c 1510 &ndash Paris, December 20, 1590) was a French surgeon ^[62]

Guillaume Dupuytren distinguished between concussion and unconsciousness associated with brain contusion. Guillaume Dupuytren, Baron ( October 5, 1778 - February 8, 1835) was a French Anatomist and military surgeon. Cerebral contusion, Latin contusio cerebri, a form of traumatic Brain injury, is a Bruise of the Brain tissue ^[62]

Until the 17th century, concussion was usually described by its clinical features, but after the invention of the microscope, more physicians began exploring underlying physical and structural mechanisms. ^[77] However, the prevailing view in the 17th century was that the injury did not result from physical damage, and this view continued to be widely held throughout the 18th century. ^[77] The word "concussion" was used at the time to describe the state of unconsciousness and other functional problems that resulted from the impact, rather than a physiological condition. ^[77]

In 1839, Guillaume Dupuytren described brain contusions, which involve many small hemorrhages, as contusio cerebri and showed the difference between unconsciousness associated with damage to the brain parenchyma and that due to concussion, without such injury. Parenchyma is a term used to describe a bulk of a substance It is used in different ways in Animals and in Plants. ^[62] In 1941, animal experiments showed that no macroscopic damage occurs in concussion. Macroscopic is commonly used to describe physical objects that are measurable and observable by the Naked eye. ^[62][78]

The debate over whether concussion is a functional or structural phenomenon is ongoing. ^[77] Structural damage has been found in the mildly traumatically injured brains of animals, but it is not clear whether these changes would be applicable to humans. ^[1] Such changes in brain structure could be responsible for certain symptoms such as visual disturbances, but other sets of symptoms, especially those of a psychological nature, are more likely to be caused by reversible pathophysiological changes in cellular function that occur after concussion, such as alterations in neurons' biochemistry. ^[5] These reversible changes could also explain why dysfunction is frequently temporary. ^[77] A task force of head injury experts called the Concussion In Sport Group met in 2001 and decided that "concussion may result in neuropathological changes but the acute clinical symptoms largely reflect a functional disturbance rather than structural injury. "^[12]

References