1 What is Coma?

A coma is a state of prolonged unconsciousness and unresponsiveness from where a person cannot be woken up.

Various factors like traumatic head injury, stroke, brain tumor, drug or alcohol intoxication, or underlying illness, such as diabetes or an infection (encephalitis) can cause coma.

A coma is a medical emergency that requires immediate medical care to preserve brain function.

A coma rarely lasts for longer than four weeks, if it does, the person enters into persistent vegetative state.

Generally, people in persistent vegetative stage for more than a year are unlikely to wake up.

2 Symptoms

Some common signs and symptoms of a coma are:

  • Closed eyes
  • Unresponsive to external stimuli such as pain, light
  • Irregular breathing

A person in coma appears to be in a state of deep sleep.

When to see a doctor

A coma is a medical emergency. Consult your doctor if you suspect anyone near is in coma.

3 Causes

The various causes of coma are:

  • Traumatic brain injuries: Brain injuries sustained from road traffic accidents or acts of violence, are common causes of comas.
  • Stroke: Ischemic stroke (reduced or interrupted blood supply to the brain) and hemorrhagic stroke (hemorrhage due to rupture of a blood vessel in the brain) can result in a coma.
  • Tumors: Tumors in the brain or brainstem can cause a coma.
  • Diabetes: In diabetics, too high (hyperglycemia) or too low (hypoglycemia) blood sugar can cause a coma.
  • Lack of oxygen: Cerebral hypoxia due to drowning or a heart attack can cause coma.
  • Infections: When the infections that involve brain and meninges, namely encephalitis and meningitis become severe, they can result in brain damage or a coma.
  • Seizures: Continuous and repeated seizures may lead to a coma.
  • Toxins: Carbon monoxide and lead poisoning have been shown to cause brain damage and a coma.
  • Drugs and alcohol: Overdosing on drugs or alcohol can result in a coma.

4 Making a Diagnosis

Only an experienced medical professional can make a diagnosis of a coma. You must rush to the hospital immediately.

A coma is a medical emergency. If you observe signs and symptoms of coma in a person you are with, call 911 or your local emergency number immediately. Upon your arrival at the hospital, you should be ready to answer a few essential questions asked by the emergency staff.

While on the way to hospital, you have to be prepared to answer the following questions:

  • Did the coma start abruptly or gradually?
  • Did the person vomit? If so, how many episodes?
  • Did you observe any problems with vision, dizziness or numbness beforehand?
  • Do you have any idea if the affected person has a history of diabetes, seizures or strokes?
  • Did you notice any cognitive or coordination problems in the affected person frequent falls, confusion or disorientation?
  • Was the affected person under the influence of drug or alcohol when coma symptoms began?

Doctor can make further investigations only based on the information provided by you and the family members as the patient cannot be the source of information.

Better prepare to provide precise and correct information about the affected person, including:

  • Events such as vomiting or headaches
  • Details on how the affected person lost consciousness, make sure if it occurred suddenly or over time
  • The affected person's medical history, mention patient’s history of conditions, if any, such as a stroke or transient ischemic attacks

Your doctor may conduct following tests on the affected person:

  • Physical exam: Doctor will assess the reflexes, responses to painful stimuli to determine if the person responds to external stimuli. Pupil size assessment is s key to diagnose coma as unequal pupil size could indicate some serious brain conditions. Also, the doctor can look for any bruises due to trauma. Observation of breathing pattern is correlated with level of consciousness. Doctors may put ice-cold or warm water into the affected person's ear canals and observe eye reactions to determine the brain damage.
  • Laboratory tests: Blood samples are checked for complete blood count, electrolytes, glucose, thyroid, kidney and liver function, carbon monoxide poisoning, drug or alcohol overdose.
  • Spinal tap: Also called lumbar puncture, it involves drawing spinal fluid from the spinal canal and analyzing it to determine infections in the nervous system.

Brain Scans

Imaging tests provide detailed images of the affected brain. These tests help to localize and quantify brain injury.

Tests may include:

  • Computerized tomography (CT) scan: CT scan is used for diagnosis of coma and for determining the possible causes of coma such as hemorrhage. It uses several X-ray images to produce a cross sectional image of the brain and the skull. A CT scan can show a brain hemorrhage, clots, tumors, swelling and compressions in the brain.
  • Magnetic resonance imaging (MRI): MRI uses powerful radio waves and magnets to produce detailed images of the deep brain and brainstem. An MRI can detect if the brain tissue has been damaged by an ischemic stroke, brain hemorrhages and other conditions.
  • Electroencephalography (EEG): An EEG is an electrophysical monitoring method that detects abnormalities in the electrical activity inside the brain. Abnormal electrical activity in the brain as in epilepsy can be determined by EEG.

5 Treatment

Coma treatment is generally supportive and depends upon the cause of coma. In general, maintaining respiration and circulation, and preventing further complications is the prime focus of coma treatment.

The doctor provides all supportive care like breathing assistance, blood transfusions and others immediately. Glucose may be administered for maintaining blood sugar level or to reverse hypoglycemia (diabetic shock) while antibiotic administration is mainly targeted at treating infection affecting the brain.

In brain swelling is present, your doctor might prescribe some medications or surgery to remove excess water from the body to relieve pressure on the brain. Your doctor will give medications for drug overdose if coma is result of a drug overdose, if the coma is due to seizures, doctors will administer anti-seizure agents.

Once the patient is stable and improving, treatments may be redirected at treating the underlying disease, such as diabetes or liver disease.

Sometime, coma may be fully reversed if treatment begins early. However, if the brain injury is severe, it can result into permanent disabilities or progression into vegetative state, and death.

6 Risks and Complications

Prolonged inactivity during coma can cause complications like pressure sores, bladder infections, blood clots in the legs and other problems.

The recovery from coma mainly depends upon the extent, type and location of brain damage.

It is said that every brain is unique and so is recovery.

Many people wake up from coma and lead a normal life while some may never wake up and move into vegetative state.

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