 What is a coma?A Coma is an extended period of unconsciousness from which a person cannot be aroused even with the most painful stimuli. With coma, the person is alive and looks like he or she is sleeping. However, unlike in a deep sleep, the person cannot be awakened by any stimulation, including pain. Coma is not a disease. It is a symptom of a disease or a response to an event, such as a severe head injury, seizure or metabolic problem Some people in a coma shift to a persistent vegetative state, in which breathing, maintaining normal blood pressure, digesting and eliminating foods continues without the patient's awareness. This vegetative state can last for years or decades. The outcome of a coma ranges from full recovery to death. Whether a person recovers, and to what extent, depends upon the cause of the coma and the type and extent of the brain damage.
What causes a coma?Comas are caused by injury to the brain. Brain injury can be due to increased pressure, bleeding, loss of oxygen or buildup of toxins. The injury can be temporary and reversible, but it also can be permanent.More than 50% of comas are related to head trauma or disturbances in the brain's circulatory system as in : · Head injuries that can cause the brain to swell and/or bleed. When the brain swells as a result of trauma, the fluid pushes up against the skull. The swelling may eventually cause the brain to push down on the brain stem, which can damage the RAS -- a part of the brain that's responsible for arousal and awareness. · Bleeding in the layers of the brain that may cause coma due to the compression on the injured side of the brain. This compression causes the blood to shift to the unaffected side of the brain, thereby causing both cerebral hemispheres to be affected. High blood pressure, cerebral aneurysms and tumors are non-traumatic causes of bleeding in the brain. A stroke can also cause a coma. When there is no blood flow to a major part of the brain stem or loss of blood accompanied with swelling, coma can occur.But other problems that can lead to coma as well: These include:· Swelling: Swelling of brain tissue can occur even without distress. Sometimes a lack of oxygen, electrolyte imbalance, or hormones can cause swelling. · Blood sugar: In people with diabetes, coma can occur when blood sugar levels stay very high ( (hyperglycemia) or when blood sugar gets too low (Hypoglycemia).These can also lead to a coma. · Oxygen deprivation: Oxygen is essential for brain function. Cardiac arrest causes a sudden cutoff of blood flow and oxygen to the brain. After cardiopulmonary resuscitation (CPR), survivors of cardiac arrest are often in comas. Oxygen deprivation can also occur with drowning or choking. · Infection: Infections of the central nervous system, such as meningitis or encephalitis, can also cause coma. · Toxins: Substances that are normally found in the body can accumulate to toxic levels if the body fails to dispose of them correctly. As an example, ammonia due to liver disease, carbon dioxide from a severe asthma attack, or urea from kidney failure can accumulate to toxic levels in the body. Drugs and alcohol in large quantities can also disrupt neuron functioning in the brain. · Seizures: A single seizure rarely produces coma, but continuous seizures -- called status epilepticus -- can. Repeated seizures can prevent the brain from recovering in between seizures. This will cause prolonged unconsciousness and coma. What happens during a coma? There are different stages of a coma. Most people believe that a person in a coma is in a deep sleep but this is not entirely true. Some stages of coma resemble a deep sleep but not all. The progress of coma is measured by the patient's increasing awareness of external stimuli. There are many levels of coma which the patient will pass through as functionality increases. Depending on the stage, a person in a coma may make movements, sounds and experience agitation. Coma patients may also have reflex activities that mimic conscious activities. Sometimes, coma patients must be restrained to prohibit them from removing tubes and IVs. How do doctors treat a coma? Treatment for a coma depends on the cause. Persons close to the comatose patient should give doctors as much information as possible to help them determine the cause of coma. Prompt medical attention is vital to treat potentially reversible conditions. For example, if there is an infection that's affecting the brain, antibiotics may be needed. Glucose may be required in the event of a diabetic shock. Surgery may also be necessary to relieve the pressure on the brain due to swelling or to remove a tumor.Certain medications may also help relieve the swelling. Medication may also be given to stop seizures if necessary.In general, treatment for a coma is supportive. Persons in comas are looked after in an intensive care unit and may often require full life support until their situation improves.What's the prognosis for a coma?The prognosis for a coma varies with each situation. The chances of a person's recovery depend on the cause of the coma, whether the problem can be corrected and the duration of the coma. If the problem can be resolved, the person can often return to his or her original level of functioning. Sometimes, though, if the brain damage is severe, a person may be permanently disabled or never regain consciousness.Comas that result from drug poisonings have the greatest rate of recovery if prompt medical attention is received. Comas that result from head injuries tend to have a higher rate of recovery than comas related to illness. |
