Coma is a state of prolonged and complete loss of consciousness. Comatose patients are unable to respond to stimuli and therefore cannot be awakened. They have no sleep-wake cycles, unlike patients in persistent vegetative state.

Coma may be caused by several events. The most common cause is traumatic brain injury (injury causing damage to the brain) which accounts for more than 50% of coma. Head injuries result to swelling, making the brain to push down on the brain stem. This damages the reticular activating system or RAS, the part of the brain which controls arousal and consciousness.

Another cause of coma is stroke, a medical emergency due to clogging (embolism) or bursting of blood vessels (hemorrhage). This lethally disrupts blood supply to the brain, affecting areas of the brain that control sensory perception, speech and movement. Another cause of coma is cardiac arrest wherein the heart fails to contract or pump, causing sudden interruption of blood circulation. This also disrupts supply of oxygen to the brain, resulting to loss of consciousness. After CPR or cardiopulmonary resuscitation, survivors often go into coma.

Blood sugar levels, whether high or low, could also lead to coma. Our loved ones who are diabetic have high risk of coma due to high levels of sugar in the blood which leads to diabetic ketoacidosis. It is a condition wherein there is an accumulation of keto acids, causing the pH level of the blood to dangerously fall, leading to coma. Likewise, if the level of sugar in the blood is too low, our body is devoid of sugar which is our body's energy source. If prolonged, this causes brain damage, coma and even death.

Other causes include infections of the nervous system (e.g. meningitis) and accumulation of toxins (e.g. ammonia) and other substances (e.g. drugs or alcohol). These events may disrupt normal function of the brain, leading to coma.

Prognosis

Prognosis depends on the cause, severity and site of damage to the brain. If the cause is identified and corrected, a patient may regain consciousness and fully recover. However, there are some patients who emerge from coma but become incapacitated physically, mentally and psychologically. A coma may last 2-4 weeks and if coma continues, the patient may enter into a permanent vegetative state. If the condition lasts for one year, there is a slim chance of awakening.

Treatment and Care Plan

Treatment depends on the cause. If the cause is head injury, surgery may be recommended to stop swelling or to remove hematoma, a mass of blood as a result of ruptured blood vessel. In diabetic coma, glucose may be required. For coma due to infections, antibiotics may be given.

Generally, patients in coma require life support and are taken care of in an ICU or intensive care unit. They may not able to breathe on their own and may therefore need a respirator. Some patients may also need cardiovascular support.

Members of caregiving families on the other hand, need emotional support as well. Waiting for a comatose loved one to awaken is painful and devastating. Support groups or organizations provide encouragement and advices on how to cope with the stress, pain and anxiety during this difficult time. Support groups are sometimes attended by healthcare providers such as nurses and doctors and may provide valuable discussions to keep caregiving families well-informed and on top of the situation, however challenging it may be.