Stupor and Coma

Stupor and coma describe two different altered states of consciousness. Coma is the deeper of the two.

What Are Stupor and Coma?


Consciousness has two components: awareness and arousal. Awareness is the ability to receive and process all the information communicated by the five senses. People who have intact awareness are able to relate to themselves and to the outside world. Awareness itself has two components: psychological and physiological. The psychological component involves the individual's mind and mental processes, whereas the physiological component refers to the chemical and physical functioning of the individual's brain and nervous system. The cortical areas of the cerebral hemispheres govern awareness. Awareness suggests a higher level of intellectual functioning.

Arousal, however, is a more basic, physiological level of primitive functioning. Arousal is governed by the functioning of the reticular activating system, which is a network of structures (the brain stem, medulla, thalamus, and a variety of nerve pathways) that function together to produce and maintain arousal. Arousal is exemplified by the involuntary but predictable reflexes that are an individual's automatic response to specific stimuli.

The continuum of consciousness, then, ranges from full intellectual engagement at the highest end of functioning to complete brain death at the lowest end. States between these two extremes include lethargy, obtundation (reduced level of consciousness), and stupor. When in any of these states, an individual will respond to stimuli in some capacity, even though the stimulus may need to be sufficiently intense to elicit even a minimal response (as may occur with stupor). In the case of coma, however, even an intense stimulus will fail to provoke a response.

What Causes Stupor and Coma?

Stupor and coma may stem from the same kinds of disorders. In each case, the disorders affect the functioning of the brain's nerve cells, causing them to respond very slowly or to cease responding. Common causes include liver * disease, kidney failure, thyroid * disorders, hypothermia (dangerously low body temperature), hyperthermia (dangerously high body temperature), toxic exposures/poisonings, excess alcohol, drugs such as sedatives * or opioids, severe dehydration * , drug reactions, infection (particularly in the elderly), direct trauma (injury) to the brain, strokes, tumors * , aneurysms * , seizures * , brain abscesses * , heart attacks, metabolic problems (high blood glucose, low blood glucose, excess or deficient blood sodium), and oxygen deprivation (asphyxiation).

Who Is Likely to Go into a Stupor or Coma?

Given the right circumstances, anybody can suffer from stupor or coma, although the elderly are particularly vulnerable. The same level of illness, trauma, or toxic exposure that a younger person might be able to withstand successfully may well produce stupor or coma in an older individual.

What Are the Symptoms of Stupor and Coma?

The most notable symptom of stupor is the individual's inability to respond to normal stimuli. Instead, shouting, shaking, or painful stimuli are necessary to provoke a response. The individual's eyes may be open, but they are clearly not focusing. In coma, intense stimuli do not provoke a response, and the eyes are closed.

Other features of stupor and coma that may be present include abnormal breathing patterns; unusual contraction or flaccidity of muscles, resulting in odd positioning of limbs and/or head; abnormal dilation or contraction of the pupils of the eyes; and abnormal eye movements.

How Do Doctors Diagnose Stupor and Coma?

Impaired consciousness is quite evident upon initial observation, although determining the level and the cause of impairment requires further investigation. Differentiating between stupor and coma requires simple maneuvers to see whether the individual will be aroused by intense stimuli (as in stupor) or whether no arousal is possible (as in coma). Physical examinations will also be performed to look for other clues that may point to the reason for the impaired consciousness.

If coma is diagnosed, a rating system called the Glasgow Coma Scale (GCS) may be used to assess the depth of the coma, monitor the individual's progress over time, and roughly ascertain the individual's overall prognosis. The Glasgow Coma Scale uses a point system to evaluate three categories of functioning: opening of the eyes, using words or voice to respond, and motor response (moving a part of the body to respond). The highest level of functioning is assigned to individuals who spontaneously open their eyes, can give appropriate verbal responses to questions, and can carry out a simple command to move a part of their body. A GCS score of 3 to 5 may suggest fatal brain damage; a GCS score of 8 or more suggests that the chance of recovery is good.

Evaluation of the pupils of the eyes and breathing pattern are also important. Blood and urine tests will probably be performed in order to quickly diagnose the presence of toxins * (such as high levels of alcohol, drugs, carbon dioxide, or poisons), abnormalities of blood chemistry (such as sodium, potassium, and glucose), liver or kidney failure, low blood oxygen, or infection. CT scans * or MRI *

How Do Doctors Treat Stupor and Coma?

Impairment of consciousness is considered a medical emergency. Evaluation and treatment of any abnormalities in respiration or circulation should be attended to immediately. Oxygen is often given, and an intravenous (in the vein) line is placed in case fluids or medications need to be given quickly. The ultimate treatment will depend on the underlying cause of the coma, although basic measures may include elevation of the head of the bed, use of diuretics * or steroid drugs to decrease swelling in the brain, and/or administration of sedative drugs to decrease muscle contractions. Infections may require antimicrobial drugs; chemical abnormalities may respond to the administration of sodium or glucose; dehydration may improve with fluids; narcotic overdose may be treated with Narcan; and antiepileptics may stop seizures. In severe situations, surgery may be necessary to relieve excess pressure on the brain or to remove or repair abnormalities (such as a tumor or bleeding aneurysm).

If the coma persists, it may become necessary to place a tube for feeding, either through the nose or through an incision in the abdomen into the stomach. Physical therapy may be used to move the individual through passive range-of-motion exercises in order to keep joints and muscles as healthy as possible.

What Is the Prognosis of Stupor and Coma?

Prognosis (the prediction of future healing) depends on the underlying condition responsible for the impaired level of consciousness, the patient's original medical condition, the duration of the stupor or coma, how quickly the individual begins to make a recovery, and the degree of structural damage that the brain has suffered. When the impairment is due to sedative overdose, complete recovery is likely unless oxygen deprivation has caused brain damage. Prognosis for recovery after impairment due to low blood sugar is very good if the low blood sugar has been corrected in less than an hour. Head injury may have a good prognosis, although a coma lasting more than three months reverses this prognosis. A stroke that prompts a coma lasting less than six hours may have a reasonably good prognosis, although a coma lasting more than six hours has a poor prognosis. Heart attack or oxygen deprivation has a poor prognosis.

Can Stupor and Coma be Prevented?

Although there is no way to prevent stupor and coma, certain basic measures can decrease the risk, including wearing seat belts and using appropriate protective headgear (helmets while bike riding); avoiding illicit drugs and excess alcohol; using prescription medications exactly as prescribed; and following standard recommendations for avoiding or treating high blood pressure, diabetes, obesity * , high cholesterol, and other medical conditions.

See also Abscesses • Aneurysm • Brain Injuries • Cold-Related Injuries • Concussion • Consciousness • Diabetes • Drowning • Heart Attack (Myocardial Infarction) • Heat-Related Injuries • Infection • Kidney Disease • Obesity • Poisoning • Seizures • Stroke • Substance Abuse • Thyroid Disease • Trauma


Books and Articles

Arciniegas, David B., et al. Management of Adults with Traumatic Brain Injury. Arlington, VA: American Psychiatric Association Publishing, 2013.

Hall, Stephen S. “How One Brain Came Back from Unconsciousness.” New York Magazine, June 10, 2015. Available at: (accessed July 13, 2016).

Websites (accessed July 13, 2016).


American Academy of Neurology. 201 Chicago Ave., Minneapolis, MN 55415. Toll-free: 800-879-1960. Website: (accessed July 13, 2016).

Brain Injury Association of America. 1608 Spring Hill Rd., Suite 110, Vienna, VA 20036. Toll-free: 800-444-6443. Websites: (accessed July 13, 2016).

* liver is a large organ located beneath the ribs on the right side of the body. The liver performs numerous digestive and chemical functions essential for health.

* thyroid (THY-roid) is a gland located in the lower part of the front of the neck. The thyroid produces hormones that regulate the body's metabolism (me-TABo-LIZ-um), the processes the body uses to produce energy, to grow, and to maintain body tissues.

* sedatives (SAID-uh-tivs) drugs that produce a calming effect or sleepiness.

* dehydration (dee-hi-DRAY-shun) is a condition in which the body is depleted of water, usually caused by excessive and unreplaced loss of body fluids through sweating, vomiting, or diarrhea.

* tumors (TOO-morz) are abnormal growths of body tissue that have no known cause or physiologic purpose. Tumors may or may not be cancerous.

* aneurysm (AN-yoo-rizm) is a weak spot in the wall of an artery (arteries carry blood from the heart to other parts of the body). The weak spot can rupture or break, causing massive internal bleeding.

* seizures (SEE-zhurs) are sudden bursts of disorganized electrical activity that interrupt the normal functioning of the brain, often leading to uncontrolled movements in the body and sometimes a temporary change in consciousness.

* abscesses (AB-seh-sez) are localized or walled-off accumulations of pus caused by infection that can occur anywhere within the body.

* toxins are substances that cause harm to the body.

* CT scans is the shortened name for computed tomography (to-MOG-ra-fee), which uses computers to view structures inside the body. Formerly called computerized axial tomography (CAT).

* MRI, which is short for magnetic resonance imaging, produces computerized images of internal body tissues based on the magnetic properties of atoms within the body.

* diuretics (dye-yoor-EH-tiks) are medications that increase the body's output of urine.

* obesity (o-BEE-si-tee) is an excess of body fat. People are considered obese if they weigh more than 30 percent above what is healthy for their height.

  This information is not a tool for self-diagnosis or a substitute for professional care.