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Thomas Horton


  • 21-33% of primary care patients describe fatigue as an important problem (even if not CC)
  • Obtain a thorough history and validate the patient's concerns
  • Assess impact on daily life and accommodations the patient has made to cope
  • Description of fatigue: mental vs. physical; sleepiness/tiredness vs. "low energy"
  • Assess Chronicity: Acute <1 month; subacute 1-6 months; Chronic >6 months
  • Review medication list, age -elated cancer screening, prior lab values, imaging findings if applicable
  • Brief Fatigue Inventory or Fatigue Assessment Scale can be used for quantification

Common Etiologies

System Differential
Cardiopulmonary CHF, CAD/Angina, PVD, Obstructive lung disease, OSA, other sleep-related disorders
Endocrine Diabetes, hypothyroidism, adrenal insufficiency, electrolyte abnormalities
Hematologic/Neoplastic Anemia, occult malignancy
Infectious Disease HIV, Mononucleosis, Hepatitis, other viral, TB, fungal, parasitic
Medication Use Opioids, benzodiazepines, antihistamines, muscle relaxants, anti-depressants, beta-blockers, GABA analogues, substance use (ETOH, THC, Cocaine)
Psychological Depression, anxiety, somatization disorder, dysthymia
Rheumatologic Fibromyalgia, PMR, SLE, RA, Sjögren's


  • Complete physical exam
  • Lab tests to order if >1 month duration: CMP, CBC w/ diff, HIV, Hepatitis B/C, TSH
  • Autoimmune, inflammatory, pregnancy, CK, PPD tests based on clinical context
  • Assess for mood disorder (PHQ-9; GAD7)
  • Assess for sleep disturbance (STOP-BANG, Epworth Sleepiness Scale)
  • Age appropriate cancer screening if applicable
  • Diagnostic imaging studies based on history and physical exam findings
  • Screen for domestic violence, housing insecurity, substance use


  • Treatment is largely specific to underlying etiology of fatigue (if found)
  • Etiology may never be identified
  • Consider diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) if other causes have been ruled out
  • Continue a supportive relationship with patient
  • Consider empiric trial of antidepressant therapy in those with residual/idiopathic fatigue with depressed mood even if patient does not meet MDD criteria

Last update: 2022-07-05 15:04:16