Coma

A coma is an involuntary state of prolonged unconsciousness due to a disruption in your brain activity. It requires immediate treatment to avoid dangerous complications.

This loss of consciousness can happen for many reasons. Traumatic brain injury, infection, diabetes complications or the loss of oxygen are common causes of a coma.

While in a coma, you’re unaware of the world around you. You can be comatose for a few hours, days or even longer. Symptoms, outcomes and treatment depend on the severity and cause of the coma.

A coma is a medical emergency. If someone is unconscious and unresponsive, call 911 immediately.

What is a coma?

A coma is a period of unconsciousness due to an illness or injury to your brain, surrounding tissue or spinal cord. You’ll appear to be in a deep sleep, but you won’t respond to any touch, sound or pain. You may make involuntary motor responses (generalized responses) or display spontaneous breathing.

A coma requires around-the-clock medical care since you are unable to respond to your body’s needs. Sometimes important body functions such as breathing and blood circulation are impacted during a coma. Medication and medical interventions, like a ventilator, offer support when this happens.

The Glasgow Coma Scale (GCS) is used to assess the severity of a coma. GCS is a 15-point screening that evaluates your eye, verbal and motor responses. The lower the score, the deeper the coma.

A person’s level of consciousness and the severity of brain injury is assessed by using the Glasgow Coma Scale.

Comas caused by a severe state of brain dysfunction may last longer. This is called a persistent vegetative state.

Persistent vegetative state

A chronic state of unconsciousness can be permanent. While in a persistent vegetative state, breathing, nutrition and heart function assistance will be needed. Those that do wake may not fully recover brain function.

Medically induced coma

In rare situations, your doctor may place you in a medically induced coma to prevent further brain damage. A controlled dose of anesthesia is used to temporarily induce a coma that is carefully monitored over a short period of time.

Symptoms of a coma

The main symptoms of a coma include:

• Lack of eye response (eyes closed with no response to light or movement)
• Unconsciousness (a deep sleep with no response to stimuli)
• Lack of motor response (limbs don’t respond or voluntarily move)

Stages of a coma

Comas follow a general pattern. This helps your care team track your progress.

• Vegetative state: The active coma stage when you’re unresponsive to stimuli with closed eyes.
• Minimally conscious state: You’ll have slow or inconsistent responses to sound, touch or sight, including opening your eyes. This stage is one of the early signs of coming out of a coma.
• Confusional state: You’re responding more consistently but may be confused, agitated and have memory problems.
• Full consciousness: You can complete most routine tasks but need assistance. There may be personality changes that impact your judgement and decisions. During this stage, your doctor can assess any long-term complications of the coma and underlying cause.

Coma causes

There are many health conditions or acute events that can lead to a coma.

Common causes of a coma include:

• Brain hemorrhage, such as an intraventricular hemorrhage (IVH)
• Lack of oxygen to the brain (anoxic brain injury)
• Stroke
• Seizures
• Diabetes and blood sugar level extremes (diabetic coma)
• Brain tumors
• Extreme underactive thyroid (myxedema coma)
• Kidney failure
• Traumatic brain injuries (TBI), including concussions
• Toxins and poisons, such as carbon monoxide poisoning
• Metabolic imbalances (toxic-metabolic encephalopathy)
• Inflammation of the liver due to non-viral hepatitis
• Infections, such as encephalitis, sepsis, and meningitis
• Intracranial hypertension from conditions like hydrocephalus

Coma complications

Several complications may develop during a coma. These include:

• Blood clots in the legs
• Pneumonia
• Urinary tract infections (UTIs)
• Bedsores

Another serious complication called brain death could result from the coma. Brain death is the loss of all brain function after being in a comatose state. When this happens, there’s no chance of regaining consciousness. Brain death is usually the result of a severe and catastrophic brain injury.

Diagnosing a coma

Comas can be hard to diagnose since there are so many factors involved. Your neurocritical care specialists will use the Glasgow Coma Scale to assess the severity of your coma. They’ll also focus on finding the underlying cause of your coma.

A neurological examination and a series of tests may be ordered to help diagnose your condition and rule out other possible complications.

Common diagnostic tests include:

• MRI: This imaging test combines a powerful magnetic field, radio waves and a computer to create highly detailed images of the brain and other organs or body structures and their functions.
• CT scan:This is a noninvasive test that uses special X-ray equipment that captures many cross-sectional views of an organ or area being examined.
• Electroencephalogram (EEG): This test monitors brain wave activity.
• Lumbar puncture: Also known as a spinal tap, a lumbar puncture can diagnose diseases of the central nervous system, including the brain.
• Blood tests: A blood test measures abnormal levels that may indicate the source of the brain damage.

Coma treatment

Your care team’s priority is to minimize brain damage. Once you're stable, a personalized treatment plan will be created that focuses on treating the underlying condition of the coma.

Treatment options may include:

• Surgery
• Medications
• Occupational therapy
• Physical therapy
• Speech therapy

Recovering from a coma

Coma recovery differs for everyone. Your age, type of brain damage and the severity of your coma all factor into how well you’ll recover. Some people are generally unaffected by the coma, while others have lifelong disabilities.