What are disorders of consciousness?

Disorders of consciousness (KON-shus-nes) are conditions where the state of awareness or wakefulness is disturbed. This may range from mild confusion (cannot think clearly) to being totally unconscious (passed out). Consciousness is normally controlled by different parts of the brain. These systems keep a person alert and aware of himself and his environment.

What are the different disorders of consciousness?

The following are the different disorders of consciousness, which may also be called states of consciousness:

• Coma: This is a sleep-like state of unconsciousness. The patient does not respond or cannot be awakened by any stimuli, such as voice, light touch, or pain.
  
  
• Vegetative state: This is a state where the patient is awake (eyes open) but not aware of himself or his surroundings. The patient moves by reflex (automatic reaction) only and not on his own.
  
  
• Minimally conscious state: The patient is able to do small movements, such as eye movements, on his own. He may be able to follow simple commands, answer yes or no, or talk a little.
  
  
• Akinetic mutism: This is a state where the patient is awake with limited awareness. The patient may be able to follow with eye movements but does not speak or move on his own.
  
  
• Delirium: This is a sudden state of confusion, disorientation, disordered thinking and memory, and change in the level of consciousness.

What causes disorders of consciousness?

Disorders of consciousness may be caused by any of the following:

• Head trauma: Trauma to the head may cause injury to the parts of the brain that maintain consciousness.
  
  
• Decreased oxygen supply in the brain: Oxygen supply to the brain is very important. Lack of oxygen may damage or kill the brain cells. Consciousness may be affected when blood flow to the brain, or part of the brain, is stopped. This may happen during a stroke, or when there is severe bleeding or swelling in the brain. A brain tumor may push some parts of the brain and affect its blood vessels. Seizures, heart attack, or lung problems may also decrease oxygen supply to the brain.
  
  
• Medicines, drugs, or alcohol: Certain medicines, especially anesthesia, act on the brain to keep a patient completely asleep or pain-free. Some street drugs also have effects on the brain which affect one's consciousness. Too much alcohol in the body may also affect the brain's normal activity.
  
  
• Other conditions or diseases: These may include an infection in the brain, spine, their membrane covering, or a widespread infection in the body. Certain conditions may result to formation of substances or chemicals that may be toxic to the brain. These may include electrolyte (body salts) imbalance, diabetes, kidney disease, or liver disease. Degenerative diseases affecting the brain itself, such as Alzheimer's or Parkinson's disease, may also cause disorders of consciousness.

What are the signs and symptoms of disorders of consciousness?

Signs and symptoms will depend on how bad the patient's consciousness is affected. As time passes, the patient may shift from one state of consciousness to another. Other signs and symptoms may also be present pointing to the problem causing the disorder in the patient's consciousness. Signs for the different states of consciousness are the following:

• Coma:
  
  
  • Does not speak or move on his own.
    
    
  • Does not follow commands.
    
    
  • Limited or no voice sounds can be appreciated.
    
    
  • Movement is mainly a result of reflex.
    
    
  • No sleep-wake cycle, and does not open his eyes even with painful stimulus.
  
  
• Vegetative state:
  
  
  • Breathes on his own.
    
    
  • Does not follow commands.
    
    
  • Does not move on his own with purpose. Reflex movements may be all that can be seen. These include being startled by a sudden loud sound, or moving away from a painful stimulus.
    
    
  • Has sleep-wake cycles, seen with the eyes being closed or open. Eyes may be seen blinking or moving.
    
    
  • May utter sounds but cannot speak.
  
  
• Minimally conscious state:
  
  
  • Follows simple commands.
    
    
  • May be able to answer to yes or no questions through words or movement signals.
    
    
  • Moves with purpose on his own.
  
  
• Akinetic mutism:
  
  
  • Cannot speak or move.
    
    
  • Eyes may move to follow objects.
    
    
  • Has cyclic periods of increased arousal as indicated by eye opening.
    
    
  • No movement reaction to sound, light touch, or painful stimuli.
  
  
• Delirium:
  
  
  • Disturbed sleep-wake cycle.
    
    
  • Disoriented (cannot distinguish person, place, or time).
    
    
  • Has hallucinations (sees, hears, or feels something that is not really there).
    
    
  • Restless or hyperactive. Decreased activity may also be seen.
    
    
  • Unable to think, remember, or speak clearly.

How are disorders of consciousness diagnosed?

Caregivers will need a detailed health history of the patient. This includes information on when his symptoms or other problems began, and how long he has had it. Caregivers may ask for information about other diseases, medicines, or activities of the patient.

• Physical examination: Caregivers will first check the patient's airway, breathing, and heart beat. Level of consciousness is checked by looking for voluntary movements.
  
  
  • Eyes: Eye movement, gaze, and pupil (black dot in the middle of the eye) size and reaction to light are checked. If the patient is unconscious and no eye movement is seen, caregivers may do certain tests. These may include turning the patient's head from side to side or putting cold water in the ear. A special instrument may be used to look for swelling or bleeding inside the eye.
    
    
  • Body movement: If no movement is seen, the patient may be checked using sound, touch, or pain as stimuli. Pain may be applied by putting pressure above the eye socket, or by pressing the nailbed or breast bone. Different body reflexes may also be checked.
  
  
• Blood and urine tests: Different tests, such as sugar check, electrolytes, blood counts, and blood gases may be done. Blood tests to check for the function of different organs, such as the liver and kidneys, may also be done. A sample of the patient's urine may also be sent to the lab for tests. Blood and urine may both be used to look for signs of infection.
  
  
• Imaging tests: Certain tests use a special dye to help the brain and other structures show up better. Tell caregivers if the patient is allergic to iodine or shellfish (lobster, crab, or shrimp) as he may also be allergic to this dye.
  
  
  • Chest x-ray: This is a picture of the lungs and heart. Caregivers use it to see how the lungs and heart are doing. Caregivers may use the x-ray to look for signs of infection or collapsed lungs. Chest x-rays may show tumors, broken ribs, or fluid around the heart and lungs.
    
    
  • Computed tomography scan: This is also called a CT scan. A special x-ray machine uses a computer to take pictures of the brain. It may be used to look at bones, brain tissue, and blood vessels. Before taking the pictures, a dye may be given through an IV.
    
    
  • Magnetic resonance imaging: This test is called MRI. During the MRI, pictures are taken of the patient's head. An MRI may be used to look at the brain, bones, or blood vessels. Never enter the MRI room with an oxygen tank, watch, or any other metal objects. This can cause serious injury.
    
    
  • Positron emission test: This is also called a PET scan. The test looks at different parts of the body to see how they are working. It can also find tumors.
  
  
• Electrocardiogram: This test, also called 12-lead ECG, helps caregivers look for damage or problems in different areas of the heart. Sticky pads connected to a wire that is hooked to a machine or TV-type screen are placed on the patient's chest. A short period of electrical activity in the heart muscle is recorded. Caregivers will look closely for certain problems or changes in how the heart is working.
  
  
• Electroencephalogram: This test is also called an EEG. Many small pads or metal discs are put on the patient's head. Each has a wire that is hooked to a machine. This machine prints a paper tracing of brain wave activity from different parts of the brain. Caregivers look at the tracing to see how the brain is working.
  
  
• Evoked potential test: These are also called evoked-response test or event-related potential studies. A special machine is used to measure how the nerves and brain react to sound or touch.
  
  
• Lumbar puncture: This procedure may also be called a spinal tap. During a lumbar puncture, fluid will be removed from around the spinal cord using a thin needle. The fluid will be sent to a lab for tests. The tests check for infection, bleeding around the brain and spinal cord, or other problems.

How are disorders of consciousness treated?

Treatment will depend on the cause of the disorder of consciousness. Medicines may be given to correct an electrolyte imbalance, control high blood pressure, or stop seizures. Caregivers may give antibiotics to treat a bacterial infection. If the patient is using medicines or treatments that have been found to be causing the condition, they may need to be stopped. Supportive treatment may be given as needed. This includes breathing and nutritional support.