A coma is a state of prolonged unconsciousness that can be caused by a wide variety of problems ? traumatic head injury, stroke, brain tumor, or even an underlying illness, such as diabetes or an infection. A coma is a medical emergency. Swift action is needed to preserve life and brain function. Comas seldom last longer than a few weeks. People who are unconscious for longer than that are usually reclassified as being in a persistent vegetative state. People who are in a persistent vegetative state for more than a year are extremely unlikely to awaken.

Symptoms

Before coma sets in there may be some warning signals. These include:

• Weakness

•  Lack of energy

•  Restlessness

•  Decline in the ability to think and reason

•  Seizures.

The signs and symptoms of a coma commonly include:

• Closed eyes
• No responses of limbs except for reflex movements
• No response to painful stimuli, except for reflex movements

Causes

Many types of problems can cause a coma.

• Traumatic brain injuries. Brain injuries that result from traffic collisions or acts of violence
• Stroke. Acute loss of blood flow to the brain followed by swelling or no blood flow to a major part of the brainstem can result in a coma.
• Diabetes. Blood sugar levels that get too high (hyperglycemia) and stay too high or get too low (hypoglycemia) and stay too low can cause coma.
• Lack of oxygen. People who have escaped drowning or been resuscitated after a heart attack may not awaken due to lack of blood flow and oxygen to the brain.
• Infections. Encephalitis and meningitis are infections that cause inflammation of the brain, spinal cord or the tissues that surround the brain. Severe cases of either encephalitis or meningitis can result in a coma.
• Toxins. Exposure to toxins, such as carbon monoxide or drug overdoses, can cause brain damage and coma.
• Seizures
• Tumours
• Drug or alcohol overdose

Tests and diagnosis

Because people in a coma cannot express themselves, doctors must rely on physical clues and information provided by families and friends.

 

Physical exam

Checking your reflexes, response to painful stimuli and pupil size. Squirting ice cold or warm water into the ear canals also can be informative. In unconscious people, these tests will cause reflexive eye movements of different types, depending on the cause of unconsciousness.

Laboratory tests

Blood samples will be taken to check for:

•    Complete blood count

•     Electrolytes, glucose and liver function

•     Carbon monoxide poisoning

•     Drug overdose

A spinal tap (lumbar puncture) can check for signs of infections. During a lumbar puncture procedure, a doctor inserts a needle into your spinal canal, measures the pressure and collects fluid for analysis. The entire procedure usually takes about 10 minutes.

Brain scans

Imaging tests help doctors pinpoint areas of brain injury. Tests may include:

• CT. This is the best imaging test for assessing brain injuries because it can show a hemorrhage or brain tissue swelling. The scan takes only a few minutes.
• MRI. MRI scans are particularly useful for examining the brainstem and deep brain structures.

• Electroencephalography (EEG)

Glasgow coma scale:

It provides a standardized method of assessing a comatose patient and eliminates the use of ambiguous and easily misinterpreted terms such as unconscious and semicomatose. Additional assessment data should include evaluation of the gag and corneal reflexes. In the absence of gag reflex, regurgitation and aspiration are potential problems.

Treatments and drugs

• A coma is a medical emergency, and attention first is given to maintaining respiration and circulation. Assistance with breathing, administration of fluids and blood, and other supportive care may be necessary.

• Emergency personnel may administer glucose or antibiotics intravenously, even before blood test results return, on the chance that the person is in diabetic shock or has an infection affecting the brain.

• Treatment varies, depending on what's causing the coma. Sometimes surgery is needed to relieve the pressure due to brain swelling. Other treatments may focus on addressing an underlying disease, such as diabetes, kidney failure or liver disease.

• Sometimes the cause of a coma can be completely reversed, and the person will regain normal function. But if the brain damage is severe, the person may sustain permanent disabilities or may never regain consciousness.