Coma

A coma is a state of deep unconsciousness in which a person appears to be sleeping but cannot be woken up and is unable to normally respond to stimuli. The person is very much alive but unaware of their environment and cannot move of their own will. During a coma, the patient may require breathing and cardiovascular support.

On rare occasions, as part of the treatment protocol, doctors also need to induce a temporary coma for sedating the brain (called a medically-induced coma) to protect the patient from severe pain or complications.

Coma presents itself in the form of impaired consciousness. Some of the symptoms are:

• The person looks to be in a state of sleep
• No amount of sensory stimulation can wake the person, except for eliciting certain reflexes
• Unusual breathing
• Holding the body in an irregular posture
• Pupils are affected

There are several causes of a coma including medical reasons and those that might transpire due to accidents, resulting in damage to the brain or the central nervous system. These include:

• Poorly controlled diabetes resulting in hypoglycaemia (low blood sugar) or hyperglycaemia (high blood sugar)
• Infections, such as encephalitis (brain infection) or meningitis (infection of the covering of the brain)
• Tumours in the brain or brainstem
• Swelling of the brain (cerebral oedema)
• Haemorrhage (bleeding) due to severe head injury
• After-effects of epileptic seizure
• Stroke
• Brain abscess (pus-filled swelling in the brain, due to bacteria/fungi in the brain tissue)
• Reduced oxygen or blood flow to the brain (cerebral hypoxia)
• A heart attack resulting in embolus to the brain
• Alcohol or drug overdose
• Multiorgan failure
• Hypothermia (drop in body temperature)
• Carbon monoxide poisoning
• High-grade fever
• Electrolyte imbalance

The possible complications of a coma are related to the following:

• Immobility: could result in pressure sores (bedsores)
• Unable to respond to body stimuli: resulting in loss of control over bladder and bowel movements (urinary incontinence and faecal incontinence respectively)
• Contracture (muscles shorten due to atrophy and contort the body)
• Inability to handle respiratory secretions (mucous): aspiration pneumonia is a dangerous outcome

The patient’s condition is closely monitored for avoiding any secondary brain injury. Accordingly, to prevent the above complications, the patient may require bladder care and advanced respiratory and cardiovascular support.

A coma is a medical emergency and a quick diagnosis can be life-saving.

The doctors carry out the following diagnostic procedures once threats to the life of the patient have been addressed:

• Airway, breathing pattern, pulse and blood pressure are checked
• Temperature is taken. High temperature indicates fever and infection while low temperature indicates hypothermia
• Physical examination of the body is undertaken to check for response to painful stimuli and reflexes (such as blinking, coughing, gag reflex), signs of injuries/trauma to the head and muscle tone
• Signs of brain damage such as unusual breathing patterns or complete limpness are noted
• Pupils of the eyes are observed: unequal pupils in both eyes indicate abnormal pressure in the brain, dilated or constricted pupils may indicate drug toxicity or poisoning
• Blood tests are carried out: CBC, electrolytes test, alcohol blood test, oxygen and carbon monoxide poisoning
• Urinalysis (urine tests) to check the presence of toxins and sugars
• Thyroid function test
• Liver function test
• Kidney function test
• For checking infections of the nervous system, a lumbar puncture is made to draw cerebrospinal fluid from the spine for testing in the lab (CSF test)

The doctor also asks friends and family about events or symptoms leading up to the coma, such as headaches or vomiting. A detailed medical history, recent changes in the person’s life & behaviour and history of drug usage (prescription drugs as well as recreational drugs) is taken.

While carrying out the physical examination, the doctor might use a scale such as the Glasgow Coma Scale (GCS) to assess the level of consciousness.

Brain scans are also carried out, which might include:

• CT Scan: It can show tumours, brain haemorrhage, strokes and other conditions.
• MRI Scan: It can detect brain tissue damage, tumours and brain haemorrhages and for examining brain stem and deep brain structures.
• Electroencephalography (EEG): It measures the electrical activity of the brain and can help determine any focus of abnormal activity.

A coma is a serious medical emergency. A complete diagnosis of coma can take hours, sometimes even days. Meanwhile, the doctors focus on ensuring the immediate survival of the patient.  Accordingly, the patient is to be taken to the intensive care unit (ICU) to secure breathing and circulation and to treat potentially reversible conditions.

Treatment depends on the cause and involves the use of the following:

• Monitoring vitals such as pulse, breathing and blood pressure
• Administering fluids, vitamin B1 and drugs for severe intoxication, as applicable, via IV
• Supplying oxygen after intubation via a ventilator
• Urinary bladder catheterisation
• Pumping of the stomach (also known as gastric lavage) if it is suspected that the patient ingested something poisonous. A tube is inserted (Ryles tube) to prevent aspiration of the stomach contents into the lungs of the patient
• Administering narcotic antidote in case drug overdose is suspected
• Medications to stop seizures, if necessary, may also be given
• In case of infection, antibiotics are used
• Glucose is administered in case of hypoglycaemia
• Surgery may be necessary in the case of haemorrhage to remove blood clots or to remove tumours

In general, treatment for a coma involves treating the conditions that lead to the coma. Patients often require full life support until the situation improves. For patients in a persistent vegetative state, the focus is on preventing complications from nutritional deficiencies and physical immobility.

While injuries to the brain or central nervous system can happen to anyone, a person can take the following preventive measures to reduce their chances of going into a comatose state:

• Managing diabetes: monitoring blood sugar daily, sticking to a healthy diet, regular exercise, staying hydrated, etc.
• Avoid using illicit drugs or substances and overdosing on alcohol
• Early diagnosis and treatment of brain diseases
• Maintaining oxygen saturation levels
• One of the leading causes of coma is traffic accidents. A person should follow safety regulations.

The patient’s recovery from a coma depends on early diagnosis and treatment of the coma as well its cause and severity. For example, comas that result from head injuries have a higher rate of recovery than those caused by oxygen deprivation. In case of comas due to drug poisonings, if immediate medical attention is received, it results in a higher chance of recovery.

It can be very difficult to predict recovery and the longer the person stays in a coma, the worse the prognosis. In general, a coma rarely lasts more than two to four weeks.

After emerging from it, many people are able to make full recovery, though it may take months or years. Patients may emerge from a coma with a combination of physical, psychological and intellectual problems that would need special attention. Recovery usually occurs slowly with responsiveness increasing over time.

During the recovery period, close medical supervision is needed. Some may require lifelong occupational and physical therapy, while others may only recover with basic functions. However, a persistent vegetative state for years or decades or even death cannot be ruled out as a dreaded eventuality. Death usually occurs due to infection, like pneumonia.

A coma is a medical emergency. Accordingly, it is very important for a person to receive immediate medical attention for saving the person’s life and ensure minimal brain damage.

Coma is most often caused by injury to the brain, a lack of a healthy lifestyle, delayed / no treatment of brain diseases or mismanagement of pre-existing illnesses. Hence, taking care of these conditions significantly reduces a person’s chances of developing a coma.

The prognosis depends on the cause, site of neurological damage, duration and depth of the coma. While most patients emerge from a coma within a few weeks, the outlook is unpredictable in terms of survival as well as the quality of life of the patient.