The major characteristics of consciousness are alertness and being oriented to place and time. Alertness means that you’re able to respond appropriately to the people and things around you. Being oriented to place and time means that you know who you are, where you are, where you live, and what time it is.
When consciousness is decreased, your ability to remain awake, aware, and oriented is impaired. Impaired consciousness can be a medical emergency.
The brain is ultimately responsible for maintaining consciousness. Your brain requires certain amounts of oxygen and glucose in order to function properly.
Many substances you consume can affect your brain chemistry. These substances can help to maintain or decrease consciousness. For example, caffeine is a stimulant, which means that it raises your levels of brain activity. Caffeine can be found in many foods and beverages you consume every day, such as coffee, soda, and chocolate. On the other hand, painkillers and tranquilizers make you drowsy. This side effect is a form of impaired consciousness.
Diseases that damage your brain cells can also cause impaired consciousness. A coma is the most severe level of consciousness impairment.
Symptoms that may be associated with decreased consciousness include:
Levels of impaired consciousness include:
Confusion is marked by the absence of clear thinking and may result in poor decision-making.
Disorientation is the inability to understand how you relate to people, places, objects, and time. The first stage of disorientation is usually around awareness of your current surroundings
(e.g., why you’re in the hospital). The next stage is being disoriented with respect to time (years, months, days). This is followed by disorientation with respect to place, which means you may not know where you are.
Loss of short-term memory follows disorientation with respect to place. The most extreme form of disorientation is when you lose the memory of who you are.
If you’re delirious, your thoughts are confused and illogical. People who are delirious are often disoriented. Their emotional responses range from fear to anger. People who are delirious are often highly agitated as well.
Lethargy is a state of decreased consciousness that resembles drowsiness. If you’re lethargic, you may not respond to stimulants such as the sound of an alarm clock or the presence of fire.
Stupor is a deeper level of impaired consciousness in which it’s very difficult for you to respond to any stimuli, except for pain.
Coma is the deepest level of impaired consciousness. If you’re in a coma, you can’t respond to any stimulus, not even pain.
Common causes of decreased consciousness include:
- substance abuse
- certain medications
- low blood sugar
- lack of oxygen to the brain
Other underlying causes of decreased consciousness include:
- cerebral hemorrhage
- dementia, such as Alzheimer’s disease
- head trauma
- brain tumor
- heart disease
- heat stroke
- liver disease
- uremia, or end-stage kidney failure
Diagnosis and treatment of decreased consciousness begins with a complete medical history and physical examination, which includes a detailed neurological evaluation. Your doctor will want to know about any medical problems you have, such as diabetes, epilepsy, or depression. They’ll ask about any medications you’re taking, such as insulin or anticonvulsants. They’ll also ask if you have a history of abusing illegal drugs, prescription drugs, or alcohol.
In addition to your complete history and physical, the doctor may order the following tests:
- Complete blood count (CBC). This blood test reveals whether you have a low hemoglobin level, which indicates anemia. An elevated white blood cell (WBC) count indicates infections, such as meningitis or pneumonia.
- Toxicology screen. This test uses a blood or urine sample to detect the presence and levels of medications, illegal drugs, and poisons in your system.
- Electrolyte panel. These blood tests measures levels of sodium, potassium, chloride, and bicarbonate.
- Liver function tests. These tests determine the health of your liver by measuring levels of proteins, liver enzymes, or bilirubin in your blood.
- Electroencephalogram (EEG). This exam uses scalp electrodes to evaluate brain activity.
- Electrocardiogram (EKG). This exam measures your heart’s electrical activity (such as heart rate and rhythm).
- Chest X-ray. Doctors use this imaging test to evaluate the heart and lungs.
- CT scan of the head. A CT scan uses computers and rotating X-rays to make high-resolution images of the brain. Doctors use these images to find abnormalities.
- MRI of the head. An MRI uses nuclear magnetic resonance imaging to make high-resolution images of the brain.
Treatment for decreased consciousness depends on what’s causing it. You may need to change medications, begin new treatment, or simply treat the symptoms to address the underlying cause. For example, you need emergency medical treatment and possibly surgery to treat a cerebral hemorrhage. On the other hand, there’s no cure for Alzheimer’s. In this case, your healthcare team will work with you to come up with strategies to treat symptoms and maintain the quality of your life for as long as possible.
Talk to your doctor as soon as you think you may be experiencing decreased consciousness. They can start your treatment as soon as possible.
Decreased consciousness can be a sign of a serious condition. Getting prompt medical attention is important for your long-term outlook. Your outlook can become worse the longer you spend in less than full consciousness.