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Lethargy is a symptom that causes you to feel sleepy or fatigued and sluggish. This sluggishness may be in terms of movements or in thinking. You’re described as lethargic if you have these symptoms.
Lethargy can be related to an underlying physical or mental condition.
Lethargy can cause some or all of the following symptoms:
People with lethargy may act as if they are in a daze. They may move more slowly than they usually do.
Many kinds of acute illnesses can make you feel lethargic. This includes the flu or a stomach virus. Other physical medical conditions can also cause lethargy. These include:
Lethargy can be the result of mental health-related medical conditions. These include:
Lethargy can also be a side effect of taking certain medications. Taking narcotic medications can cause lethargy. You shouldn’t exceed your recommended dosage for this reason.
Lethargy can be a symptom that requires emergency medical attention. This is especially true if lethargy symptoms come on suddenly. Additional symptoms that may require emergency medical attention:
Any noticeable, marked changes in behavior accompanied by lethargy are often cause for concern. Seek immediate medical attention if you experience thoughts of harming yourself as well as lethargy.
Babies or young children can also experience lethargy. Symptoms in babies that may need immediate medical attention include:
You may also want to make an appointment at your doctor’s office if you have any of these symptoms as well as lethargy:
Your doctor will often take a full medical history and then do a physical exam to figure out why you are experiencing lethargy. Obtaining a medical history includes discussing any medical conditions you may have previously experienced. The medical examination may include listening to your heart and lungs, testing for bowel sounds, and evaluating your mental awareness.
Diagnostic testing typically depends on what the doctor suspects may be an underlying cause. For example, if a thyroid disorder is suspected, your doctor may order blood tests to determine if your thyroid hormones are high or low.
Your doctor may order imaging studies if they suspect a head injury, stroke, meningitis, or other brain-related disorder is the cause. The imaging studies could include a computed tomography (CT) or magnetic resonance imaging (MRI) scan to determine if there are any abnormalities in the brain.
Treatment for lethargy depends upon its underlying cause. Your doctor may prescribe medications to resolve an infection or to increase thyroid hormones. They may prescribe antidepressants if depression or another mental health-related disorder is the cause.
Remember that you can practice healthy habits at home to reduce fatigue-related symptoms if you experience lethargy. Examples include:
See a doctor if these healthy habits don’t help your symptoms go away.
Written by: Rachel Nall, RN, BSN
Medically reviewed on: Mar 04, 2015: George Krucik, MD, MBA
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