A coma can be difficult to understand, especially because people sometimes jokingly use the words coma and comatose (say: ko-muh-tohss), which means in a coma or coma-like state) to describe people who aren't paying attention or who are drowsy or sleeping. But a coma is a serious condition that has nothing to do with sleep.

Coma is a state of unconsciousness whereby a patient cannot react with the surrounding environment. The patient cannot be wakened with outside physical or auditory stimulation. The inability to waken differentiates coma from sleep. Patients can have different levels of unconsciousness and unresponsiveness depending upon how much or how little of the brain is functioning.

Coma is a simplistic term for an altered state of consciousness in which a victim is unresponsive to verbal or physical attempts to wake him or her. Any sudden state of coma is a medical emergency and rescuers should call 911 immediately.

Signs and Symptoms of Coma

The main symptom of a coma is the inability to be aroused to consciousness. Other symptoms are: Lack of self-awareness, Lack of a sleep-wake cycle, Lack of purposeful movements, Lack of suffering and Impaired breathing.

Stupor: Someone in a stupor is unresponsive but can be aroused briefly — for example, by sharp pain.

Locked-in syndrome: People in this condition are aware and awake, but can't move or speak because of complete paralysis to their bodies.

People who have myxedema coma are in or near a coma and not able to function normally. They require emergency care.

Various types of bumps, ulcers, or, rarely, flat areas of discolored skin, that appear mostly near your nose, eyes, back, arms, legs, and scalp. They usually itch but aren't painful. They usually last a long time.

A person may also lose gag reflex, fail to respond to noxious stimuli (foul odors), and fail to respond to pain.

Causes of Coma

A coma caused through diabetes is relatively rare provided the proper care and monitoring of the the condition is followed. This said, it is important to understand how a diabetic coma can occur, what symptoms to look out for and general guidelines to ensure that it does not happen.

The presence of certain substances that disrupt the functioning of neurons. Drugs or alcohol in toxic quantities can result in neuronal dysfunction, as can substances normally found in the body, but that, due to some diseased state, accumulate at toxic levels. Accumulated substances that might cause coma include ammonia due to liver disease, ketones due to uncontrolled diabetes, or carbon dioxide due to a severe asthma attack.

Coma can be caused by a variety of things. The most often cause of coma is severe head injury. Other causes are: consumption of a very large amount of alcohol (toxic or metabolic coma), diabetes, morphine, shock or hemorrage.

Coma is caused by a number of physiological disturbances that disrupt normal brain function. A common cause of coma is traumatic brain injury. Brain injury can damage parts of the brain that control consciousness. Two ways in which brain injury can result in coma are focal and diffuse axonal injury.

Head injury or certain serious illnesses or their complications may cause a coma. The most common causes of coma include: Severe head injury Seizures Metabolic disturbances, such as low or high blood sugar Tumors or other structural lesions leading to high pressure within the skull Bleeding in the brain Alcohol or drug intoxication.

Other causes of stupor or coma include the sudden stopping of the heart's pumping (cardiac arrest), aneurysms, severe lung disorders, inhalation of carbon monoxide, stroke, seizures, an underactive thyroid gland (hypothyroidism), liver or kidney failure, and low or high body temperature (hypothermia or hyperthermia).