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Everything About Coma: Symptoms, Causes, Diagnosis And Treatment

By Vikas Chandra Das
17 November 2022, 1:12 PM

Coma is a deep state of unconsciousness that can have many  causes. Doctors may need to place people in a coma to protect them from serious complications and pain. This may be necessary when a person has a serious medical condition, infection, or may have undergone a traumatic accident such as a blow to the head. 

As in sleep, a comatose person cannot react normally to his/her surroundings. However, unlike sleep, coma cannot be awakened. The level of awareness and reaction depends on how well your brain is functioning. A person in a coma may last for days or weeks.

When a person falls into a coma, it's usually a medical emergency. Doctors may need to act quickly to save the patient's life and brain function


Following are the common signs and symptoms when an individual is coma induced:

  • Closed eyes/pupils not responding to light
  • Unresponsiveness
  • Irregular breathing
  • No limb response other than reflexes
  • No response to pain other than reflexes

People in a coma may be able to breathe without assistance, but they may also need a machine such as a ventilator.

There are also different states of coma.

Vegetative State: The human body can perform physical movements such as growling. These movements are purely involuntary and can give false hope of recovery.  

Catatonia State: No movement or reaction at all. Patients who are strained require mechanical breathing assistance. The  brain is dead because the higher brain functions are destroyed and the brain only performs automatic functions.

Stupor: Stupor is not technically a coma, but it is sometimes called a coma. This is the case when a person can wake up, but with considerable effort. People are mostly unresponsive and respond only to strong stimuli, such as pain. 


Coma is caused by brain damage, especially when there is bilateral cortical damage (ie, bilateral damage) or damage to the reticular activation system. The reticular activation system controls arousal and cognition in the cerebral cortex. Damage here can result from many factors, including:

  • Traumatic Brain Injury: These are often caused by traffic accidents or violent acts.
  • Stroke. Reduced or interrupted blood supply to the brain (stroke) can be caused by blocked arteries or ruptured blood vessels.
  • Tumour: A tumour in the brain or brain stem can cause  coma. 
  • Blood sugar levels that are too high (hyperglycemia) or too low (hypoglycemia) can cause  coma.  
  • Lack of Oxygen: People who are rescued from drowning or who are resuscitated after a heart attack may not wake up due to lack of oxygen in the brain.
  • Infection: Infections such as encephalitis and meningitis cause swelling of the brain, spinal cord, or tissue around the brain. Severe cases of these infections can lead to brain damage or  coma. Seizure. Persistent seizures can lead to  coma.
  • Toxin: Exposure to toxins such as carbon monoxide and lead can cause brain damage and  coma.
  • Drugs and Alcohol: An overdose of drugs or alcohol can lead to coma. 


Because people in a coma cannot express themselves, doctors must rely on physical cues and information from family and friends.

  • Whether the coma or previous symptoms started slowly or suddenly, or the events that led to the coma, such as vomiting or headache.
  • Details of how the affected person lost consciousness (including whether it happened suddenly or over time).
  • Medical history of the person whether the person has diabetes, stroke, stroke, or  other illness.
  • If the affected individual had consumed alcohol or drugs, including prescription, over-the-counter, unauthorised, and illegal substances. 

In addition, doctors can conduct physical tests that would involve 

  • Checking patient's movement and reflexes, response to painful stimuli, pupil size
  • Observation of breathing patterns to diagnose cause of  coma
  • Check the skin for signs of bruising from trauma
  • Talk loudly or press the corners of your jaw or nail beds while listening for signs of arousal such as vocalisation, eye opening or mMovement
  • Examination of reflex eye movements to  determine  cause of  coma and  location of brain damage
  • Inject something cold or warm into the affected person's ear canal and observe the reaction of the eye 

Further, laboratory tests can also be conducted where the blood samples will be taken to check for

complete blood count, electrolytes, glucose, thyroid, kidney and liver function, carbon monoxide poisoning, drug or alcohol overdose

Additionally, Brain scans Imaging tests help doctors pinpoint areas of brain injury and these tests might include:

CT Scan, MRI, Electroencephalography (EEG)


A coma is a medical emergency. Doctors first check the person's airway to help maintain breathing and circulation. They can give respiratory support, intravenous fluids, and other supportive care.

Treatment depends on the cause of the coma. Treatment or medication may be needed to relieve the pressure on the brain caused by swelling of the brain. For diabetic shock or an infection that affects the brain, paramedics can administer glucose or antibiotics intravenously even before blood test results are available.

If the coma is the result of a drug overdose, the doctor will give drugs to treat the condition. If the coma is caused by a seizure, doctors use drugs to control the same. Other treatments may focus on medications or treatments to treat underlying conditions such as diabetes or liver disease.

Sometimes the cause of the coma is completely reversed, and the  person regains normal function. Recovery is usually slow. People with severe brain damage may have permanent aftereffects or never regain consciousness.


Ultimately, if doctors can successfully treat the cause of the coma, the patient can wake up without permanent damage. It can be confusing at first, but usually they would remember what happened before they fell into a coma and move on with their life. Some rehabilitation or physical therapy would be required.

Damage to the brain can result in long-term disability. When they wake up, they may have to relearn basic skills as they may not remember what happened. However, many people can improve their quality of life with help such as physical and occupational therapy.

Also, treatment of coma cannot be restricted due to the enormous costs involved. However, it is recommended to purchase critical health insurance to deal with financial disasters arising from health problems. It may not eradicate the issues, but it offers a wide range of benefits that will definitely help.


1. What is the most common cause of coma?

More than 50% of comas are related to head trauma or cerebral circulatory disturbances. Problems that can lead to coma include: Anaerobic brain injury. This is a brain disease caused by a complete lack of oxygen in the brain. 

2. What are the 6 types of comas?

They are typically categorised in six ways:

Toxic-metabolic encephalopathy, cerebral hypoxia, persistent vegetative state (PVS), locked-In syndrome, brain death, medically Induced Coma.

3. What part of the brain is damaged in a coma?

Coma is caused by dysfunction of the reticular activating system (RAS) in the brain stem or both cerebral hemispheres.

4. How long can a coma last?

A coma rarely lasts more than 2 to 4 weeks. Some patients may regain a degree of awareness after a persistent vegetative state. Others may remain in that state for years or even decades. 

5. Does health insurance cover coma?

Yes, it does! But a regular health insurance plan may not cover the same, unless you add a critical add-on to it for an additional premium. One more option - buy a dedicated critical illness policy - that comes with extensive coverage for critical illnesses including coma.

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