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Coma

The Basics

Written by the doctors and editors at UpToDate пїЅ пїЅ

What is a coma? " пїЅ A coma is a deep state of unconsciousness. A person in a coma: пїЅ пїЅ

  • Looks like he or she is asleep
  • Cannot be woken up
  • Cannot move at will
  • Does not respond to pain or react when spoken to, touched, or shaken

People in a coma sometimes twitch, move a hand or finger, or make faces or sounds, but that does not mean they are aware, awake, or in control. пїЅ пїЅ

What causes a coma? " пїЅ A coma can be caused by anything that disrupts normal brain function. Some of the most common causes include: пїЅ пїЅ

  • Head injury
  • Stroke or bleeding in the brain
  • Brain tumors
  • Very low blood sugar or other chemical imbalances in the body
  • Poisoning, or drug or alcohol overdose
  • Lack of oxygen or blood to brain, which could happen if a persons heart stopped or the person almost drowned
  • Infections such as meningitis or encephalitis
  • Seizures

How do doctors find the cause of a coma? " пїЅ If a person is unconscious, his or her doctors and nurses will do an exam to see how the person responds to touch and pain, and to see how the person's eyes respond to light. Then, they will order tests, such as: пїЅ пїЅ

  • Blood tests
  • Imaging tests of the brain " пїЅ These tests create pictures of the brain and can show if any parts of the brain are damaged. Examples of these tests include CT scans and MRIs.
  • EEG (which stands for electroencephalogram) " пїЅ An EEG measures the electrical activity in the brain. It can measure brain waves and shows whether a person is asleep or unconscious and whether they are having seizures.
  • Lumbar puncture (also called a "spinal tap " пїЅ) " пїЅ For this test, a doctor puts a thin needle into the person's lower back and removes a small amount of spinal fluid. Spinal fluid is the fluid that surrounds the brain and spinal cord. The spinal fluid goes to the lab for tests.

How is a coma treated? " пїЅ The only way to get a person out of a coma is to reverse the condition that caused it. That is not always possible. If it is possible, it needs to be done right away to prevent death and permanent brain damage. пїЅ пїЅ

When it is not possible to get someone out of a coma, doctors try to at least make sure the person keeps breathing and still has a heartbeat. To do that, they hook the person up to machines that monitor heart rate and breathing. That way, the medical team can respond right away if anything goes wrong. Some people who are in a coma need to be put on a machine that breathes for them. пїЅ пїЅ

People in a coma also: пїЅ пїЅ

  • Get medicines to help control basic body functions, such as blood pressure, heart rate, and body temperature
  • Get fed through an IV (a tube that goes into a vein) or a stomach tube
  • Get moved every so often so that they do not develop sores on their body
  • Have routine blood tests done often, so the doctors and nurses can look for signs of infection or other problems
  • Have their reflexes and responses to pain checked every so often
  • Have their temperature checked

How long can a coma last? " пїЅ Most people who are in a coma come out of it in 2 to 4 weeks. Comas are not permanent and do not usually last more than several weeks. Patients either recover completely or partially, or die. пїЅ пїЅ

Some people with severe brain injury transition from a coma to something called a "persistent vegetative state. " пїЅ People in a persistent vegetative state have brain activity that suggests they go to sleep and wake up but otherwise seem like they are in a coma. пїЅ пїЅ

All topics are updated as new evidence becomes available and our peer review process is complete. пїЅ пїЅ

This topic retrieved from UpToDate on: Nov 04, 2014. пїЅ пїЅ

Topic 83678 Version 2.0 пїЅ пїЅ

Release: 22.8 - C22.208 пїЅ пїЅ

пїЅ пїЅ 2014 UpToDate, Inc. All rights reserved. пїЅ пїЅ

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пїЅ пїЅ 2014 UpToDate, Inc. All rights reserved. пїЅ пїЅ