A coma is a prolonged state of unconsciousness. A coma occurs when a part of
the brain is damaged, either temporarily or permanently. This damage results in
unconsciousness, an inability to awake, and unresponsiveness to stimuli such as
pain, sound, and light. The word “coma” is derived
from the Greek word “koma,” which means “deep sleep.”
Comas have a number of potential causes. These range from injury or illness
to stroke, to tumors, to alcohol and drug abuse.
A person who is in a coma is alive but is unable to move at will. They can’t
think, speak, or respond to their environment. Important functions, such as
breathing and blood circulation, remain intact.
A coma is a medical emergency. Healthcare providers need to work quickly to
preserve brain life and function. They also need to keep the patient healthy
during the course of his or her coma.
A coma may be challenging to diagnose and treat. It usually doesn’t last for
more than four weeks, and recovery occurs gradually. Some patients, however,
have remained in comas for years or even decades.
causes a coma?
Comas are caused by damage to the brain, specifically the diffused
bilateral cerebral hemisphere cortex or the reticular activating system. This area of
the brain controls arousal and awareness. Damage here can result from many
potential factors. This includes head injuries, loss of oxygen, bleeding or
pressure in the brain, infections, metabolic problems, and toxic factors. Some
specific examples include:
- traumatic brain injuries, such as those caused by
traffic accidents or violent fights
- stroke (reduced blood supply to the brain)
- tumors in the brain or brainstem
- lack of oxygen to the brain after being rescued from
drowning or from a heart attack
- diabetes, which causes blood sugar levels to become too
high (hyperglycemia) or too low (hypoglycemia) and can lead to swelling in
- overdosing on drugs or alcohol
- carbon monoxide poisoning
- buildup of toxins in the body, such as ammonia, urea,
or carbon dioxide
- heavy metal poisoning like lead
- infections such as meningitis or encephalitis
- repeated seizures
- electrolyte imbalance
are the symptoms of a coma?
A coma is a medical emergency and requires immediate medical attention.
Signs of a coma can include:
- closed eyes
- irregular breathing
- no response of limbs, except for reflexes
- no response to pain, except for reflexes
- pupils not responding to light
is a coma diagnosed?
People in a coma can’t speak or express themselves in other ways. Healthcare
providers must rely on information from loved ones or witnesses. They also look
for any physical signs that may give information about what caused the coma.
The healthcare provider will ask friends and family about any events or
symptoms that led up to the coma. They’ll also ask details about recent changes
in the patient’s life, medical history, and drug use. Drugs of concern include prescription
drugs and over-the-counter drugs, as well as recreational drugs.
A physical exam will be conducted. This might include:
- checking reflexes
- observing breathing patterns
- checking for signs of bruises on the skin
that may have been caused by trauma
- determining the patient’s response to
- observing pupil size
Blood tests and other laboratory tests will be used to test for the
- blood count
- thyroid and liver function
- electrolyte levels
- carbon monoxide poisoning
- drug overdose
- alcohol overdose
- infections of the nervous system
Tests may be used in order to create images of the brain (brain scans), to
locate areas of brain injury, and to look for signs of brain hemorrhage, tumors,
stroke or seizure activity. These tests include:
- computerized tomography (CT)
which use X-rays to create a detailed image of the brain
- magnetic resonance
imaging (MRI), which uses radio waves
and magnets to view the brain; and
(EEG), which measures
electrical activity inside the brain
is a coma treated?
The first priority of treatment is to preserve brain life and function.
Antibiotics may be given right away, in case there is an infection in the
brain. Medications for treating the underlying condition will be administered
if the cause of the coma is known, as in the case of a drug overdose. Surgery
may be required to reduce swelling in the brain.
A team of medical professionals will work with the comatose patient once
they are stabilized. They’ll work to prevent infections, bedsores, and
contractures of the muscles. The team will also make sure to provide the
patient with balanced nutrition during their coma.
What can be expected in the long term?
A coma usually does not last for more than four weeks. Some people may
remain in a coma for much longer, however. Long-term outcomes depend on what
caused the coma and the site and extent of damage to the brain. The prognosis
may be good for people whose comas are caused by a drug overdose. The severity
of the brain damage dictates the long-term outcome.
Some people emerge from a coma with physical, intellectual, or psychological
problems. Patients who remain in a coma for more than a year are unlikely
to come out of that state. Potential complications during a coma include
infections, blood clots, and pressure sores.