Some Common Causes and Features of Prolonged or Chronic Fatigue
Cause | Common Features* | Diagnostic Approach |
|---|---|---|
Blood disorders or cancers | ||
Decreased exercise tolerance with shortness of breath during activity greater than expected for the activity Sometimes paleness | CBC | |
Cancers (such as digestive tract cancer, lung cancer, leukemia, lymphoma, multiple myeloma) | Widespread lymph node swelling, weight loss, and/or night sweats With multiple myeloma, low back or other bone pain, often severe at night | CBC Sometimes other tests, such as endoscopy or imaging tests |
Infections | ||
Sometimes jaundice, loss of appetite, and fluid in the abdomen | Blood tests to determine how well the liver is functioning and to identify the hepatitis virus Sometimes liver biopsy | |
Fever Sometimes cough and respiratory symptoms Sometimes loss of taste and smell | Test for SARS-CoV-2 | |
Enlarged spleen and lymph nodes, fever, and night sweats | Sometimes blood tests for antibodies to cytomegalovirus | |
Heart valve infection (endocarditis) | Fever and night sweats Sometimes joint pains Usually in people who have heart murmurs or inject drugs intravenously | Cultures of blood samples and echocardiography |
Fever, night sweats, and frequent infections Sometimes difficulty breathing, cough, diarrhea, and/or rash | HIV blood test | |
Recent sore throat and lymph node swelling | Mononucleosis blood test | |
Other infections (for example, fungal pneumonias such as histoplasmosis, parasitic infections, or tuberculosis) | Fever, night sweats, and weight loss Sometimes cough, difficulty breathing, and coughing up blood | Tests based on which type of infection seems likely |
Other disorders and causes | ||
Shortness of breath, difficulty breathing when lying down that is relieved when upright (orthopnea), and/or swelling | Blood tests of kidney function | |
Connective tissue disorder (for example, rheumatoid arthritis or systemic lupus erythematosus [lupus]) | Fever, night sweats, weight loss, joint pain, rash, and/or other organ involvement (for example, effects on the heart or lungs) | Blood tests for abnormal antibodies |
Deconditioning | A history of lack of exercise or being bedbound or hospitalized | Only a doctor's examination |
Diabetes (sometimes, other symptoms often more prominent) | Excessive thirst, excessive urination, increased appetite, and unexplained weight gain or loss | Measurement of sugar (glucose) level in the blood after the person fasts overnight and sometimes glucose tolerance testing |
Drugs: Antidepressants, older antihistamines, antihypertensives, diuretics that cause low potassium levels in the blood, muscle relaxants, recreational drugs, and sedatives | History of taking a drug known to cause fatigue | Only a doctor's examination |
Headache, pain in the jaw when chewing, pain when combing hair, loss of vision, and/or muscle pains in a person over 50 | ESR and temporal artery biopsy | |
Mental health disorders: Anxiety, depression, drug addiction, panic disorder, or somatization disorder (physical symptoms caused mainly by anxiety) | Anxiety, sadness, loss of appetite, and unexplained sleep disturbance With somatization disorder, an excessive preoccupation with physical symptoms | Only a doctor's examination |
Fatigue worse with exposure to heat Past symptoms of nervous system malfunction (such as numbness, loss of coordination, and weakness), particularly if people had more than one episode of symptoms | Brain and/or spinal cord MRI | |
Pregnancy | Cessation of menstrual periods, breast tenderness, morning sickness, and abdominal swelling | Pregnancy test |
Excessive daytime sleepiness, frequent awakenings, breathing interruptions during sleep, difficulty falling asleep, unrefreshing sleep | Sleep testing (polysomnography or home testing) | |
Underactive thyroid gland (hypothyroidism) | Inability to tolerate cold, weight gain, constipation, and coarse skin | Blood tests of thyroid function |
Weight loss Sometimes loss of appetite, foul-smelling stool, abdominal pain, or a combination | A doctor's examination Sometimes other tests | |
Disorders of unknown cause | ||
Chronic fatigue syndrome (now sometimes called myalgic encephalomyelitis or systemic exertion intolerance) | Sore throat, sleep that is not refreshing, difficulty with concentration or short-term memory, muscle aches, joint pain, headaches, and/or tender lymph nodes in the neck or under the arms | Only a doctor's examination |
Long-standing and widespread muscle and bone pain in areas outside the joints, trigger points, lower abdominal pain, gas, bloating, constipation or diarrhea, migraines, and anxiety | Only a doctor's examination | |
* Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present. | ||
CBC = complete blood count; ESR = erythrocyte sedimentation rate; HIV = human immunodeficiency virus; MRI = magnetic resonance imaging. | ||