A coma is a prolonged state of unconsciousness in which patients cannot react or respond to their environment, but are still alive. A coma is a medical emergency and requires prompt diagnostic testing to determine what is causing the unconscious state. Most comas do not last more than a few weeks and depending on the cause of coma, some patients may recover their normal functions again. Others may develop mental or physical disabilities as a result of a coma. People who remain in a coma for over one year are unlikely to awaken and may remain in a vegetative state for the rest of their life.
Causes of Coma
A coma may be caused by many different factors, including a traumatic head injury. Other conditions that may result in a coma may include:
- Brain tumors
- Lack of oxygen
- Overdose of drugs or alcohol
- Carbon monoxide or lead poisoning
Comas can begin suddenly after a traumatic injury or may develop gradually as patients slowly become confused, dizzy and drowsy.
Symptoms of Coma
Patients in a coma may react differently to external stimuli, may make abnormal body movements or may lie still and not respond to anything, depending on how deep the coma is. Most coma patients appear as if they are sleeping. Symptoms of a coma may include:
- Closed eyes
- Irregular breathing
- No response to pain
- Unresponsive limbs
- Pupils do not respond to light
Some patients may enter into a vegetative state in which they are still breathing and may even make spontaneous movements, but have lost all cognitive function. This type of coma may last for several years. Complications that may develop when a person is in a coma may include bladder infections, bed sores and pneumonia.
Diagnosis and Treatment of Coma
A physical examination that includes checking pupils, movement and reflexes, is performed on a patient that is comatose. Doctors may interview family members to ask about events or symptoms that lead up to the coma. Additional tests may be performed to determine the cause of the coma and may include:
- Blood tests
- CT scan
- MRI scan
- Electroencephalography or EEG
After testing, the doctor will ensure that respiratory and circulation functions are maintained, and may administer glucose or antibiotics in case of diabetic shock or an infection. In some cases, a ventilator may be used to assist with breathing. Other treatments vary depending on the cause of the coma and may include medication for seizures or other underlying problems such as diabetes or liver disease. Under certain circumstances, surgery may be needed to relieve pressure on the brain.
After awakening from a coma, some people regain all normal functions. If brain damage has occurred, the patient may suffer from a disability or may require therapy to relearn functioning skills. Some patients may remain in a coma for years or even decades and may eventually die from an infection such as pneumonia.
- National Institutes of Health
- Centers for Disease Control and Prevention
- Eunice Kennedy Shriver National Institute of Child Health and Human Development
- U.S. Department of Health & Human Services
- U.S. National Library of Medicine
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