In medicine, a coma (from the Greek κῶμα koma, meaning deep sleep) is a profound state of unconsciousness. A symptom' (from Greek σύμπτωμα, "accident misfortune that which befalls" from συμπίπτω, "I befall" from A Sign is an indication of some fact or quality and a medical sign is an objective indication of some medical fact or quality that is detected by a Physician 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 R00-R69 - Symptoms and Signs (R00-R09 Circulatory and Respiratory systems ( Abnormalities of Heart beat 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. Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly See also Unconscious mind. Unconsciousness, more appropriately referred to as loss of Consciousness or lack of consciousness is A comatose patient cannot be awakened, fails to respond normally to pain or light, does not have sleep-wake cycles, and does not take voluntary actions. Coma may result from a variety of conditions, including intoxication, metabolic abnormalities, central nervous system diseases, acute neurologic injuries such as stroke, and hypoxia. Intoxication is the state of being affected by one or more psychoactive drugs. Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. A stroke is the rapidly developing loss of brain functions due to a disturbance in the blood vessels supplying blood to the brain 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 It may also be deliberately induced by pharmaceutical agents in order to preserve higher brain function following another form of brain trauma, or to save the patient from extreme pain during healing of injuries or diseases. A barbiturate-induced coma, or barb coma, is a temporary Coma (a deep state of Unconsciousness) brought on by a controlled dose of a Barbiturate A coma may also result from immense head trauma caused by something like a car accident or a series of very severe concussions. Traumatic brain injury. THIS PAGE IS FOR INFORMATION ON HEAD INJURY (NOT SPECIFICALLY THE BRAIN--> Head injury is The underlying cause of the coma is bilateral damage to the Reticular formation of the midbrain, which is important in regulating sleep. The reticular formation is a part of the Brain that is involved in actions such as awaking/ sleeping cycle, and lying down In biological anatomy the mesencephalon (or midbrain) comprises the Tectum (or corpora quadrigemini Tegmentum, the ventricular mesocoelia (or "iter" 
The severity of coma impairment is categorized into several levels. Patients may or may not progress through these levels. In the first level, the brain responsiveness lessens, normal reflexes are lost, the patient no longer responds to pain and cannot hear.
Contrary to popular belief, a patient in a coma does not always lie still and quiet. They may move, talk, and perform other functions that may sometimes appear to be conscious acts but are not. 
Two scales of measurement often used in TBI diagnosis to determine the level of coma are the Glasgow Coma Scale (GCS) and the Ranchos Los Amigos Scale (RLAS). Traumatic brain injury (TBI also called intracranial injury, occurs when Physical trauma injures the Brain. 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 The Rancho Los Amigos Scale (aka the Rancho Los Amigos Cognitive Scale and the Rancho Scale) is a medical scale intended to assess the level of recovery of brain The GCS is a simple 3 to 15-point scale (3 being the worst and 15 being that of a normal person) used by medical professionals to assess severity of neurologic trauma, and establish a prognosis. The RLAS is a more complex scale that has eight separate levels, and is often used in the first few weeks or months of coma while the patient is under closer observation, and when shifts between levels are more frequent.
Outcomes range from recovery to death. Death is the termination of the biological functions that define living Organisms It refers both to a specific Comas generally last a few days to a few weeks. They rarely last more than 2 to 5 weeks but some have lasted as long as several years. After this time, some patients gradually come out of the coma, some progress to a vegetative state, and others do not make it. A persistent vegetative state (PVS is a condition of patients with severe Brain damage in whom Coma has progressed to a state of wakefulness without detectable Some patients who have entered a vegetative state go on to regain a degree of awareness. Others remain in a vegetative state for years or even decades (the longest recorded period being 37 years). 
The outcome for coma and vegetative state depends on the cause, location, severity and extent of neurological damage. A deeper coma alone does not necessarily mean a slimmer chance of recovery, because some people in deep coma recover well while others in a so-called milder coma sometimes fail to improve.
People may emerge from a coma with a combination of physical, intellectual and psychological difficulties that need special attention. Recovery usually occurs gradually — patients acquire more and more ability to respond. Some patients never progress beyond very basic responses, but many recover full awareness. Regaining consciousness is not instant: in the first days, patients are only awake for a few minutes, and duration of time awake gradually increases.
Predicted chances of recovery are variable owing to different techniques used to measure the extent of neurological damage. All the predictions are based on statistical rates with some level of chance for recovery present: a person with a low chance of recovery may still awaken. Statistics is a mathematical science pertaining to the collection analysis interpretation or explanation and presentation of Data. Time is the best general predictor of a chance of recovery: after 4 months of coma caused by brain damage, the chance of partial recovery is less than 15%, and the chance of full recovery is very low. Brain damage, or Acquired brain injury, is the destruction or degeneration of Brain cells. 
The most common cause of death for a person in a vegetative state is secondary infection such as pneumonia which can occur in patients who lie still for extended periods. An infection is the detrimental Colonization of a host Organism by a foreign Species. Pneumonia is an inflammatory illness of the Lung. Frequently it is described as lung Parenchyma / alveolar inflammation and abnormal
Occasionally people come out of coma after long periods of time. After 19 years in a minimally conscious state, Terry Wallis spontaneously began speaking and regained awareness of his surroundings. A minimally conscious state (MCS is a condition distinct from Coma or the vegetative state, in which a patient exhibits deliberate, or cognitively Terry Wallis (born 7 April, 1964) is an American man living in the Ozark mountains of Arkansas who on June 11, 2003 regained 
A brain-damaged man, trapped in a coma-like state for six years, was brought back to consciousness in 2003 by doctors who planted electrodes deep inside his brain. Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar. The method, called deep-brain electrical stimulation (DBS) successfully roused communication, complex movement and eating ability in the 38-year-old American man who suffered a traumatic brain injury. His injuries left him in a minimally conscious state (MCS), a condition akin to a coma but characterized by occasional, but brief, evidence of environmental and self-awareness that coma patients lack. A minimally conscious state (MCS is a condition distinct from Coma or the vegetative state, in which a patient exhibits deliberate, or cognitively