Fatigue

Basics

Description

  • A subjective state of overwhelming, sustained exhaustion, and decreased capacity for physical and mental work that is not relieved by rest
  • Little knowledge of the physiologic and biochemical causes of fatigue
  • Occurs with or without objective findings on physical exam
  • A common complaint in many common illnesses and in people without systemic disease
  • Fatigue affects 6.0–7.5% of adults in the US
  • Reported more commonly in women
  • Fatigue affected 85% of patients with Long COVID
  • High levels of fatigue are associated with excess mortality in the general population
  • Acute fatigue: Lasts ≤1 mo, often from infections, stress, or acute illness
  • Subacute fatigue: Persists 1–6 mo, suggests chronic disease or psychological factors
  • Chronic fatigue: Lasts >6 mo, often linked to systemic or neurologic disease
    • 59% will seek care at some point
    • Orthostatic intolerance is a frequent cause for ED visits
  • Overwork, poor sleep, and stress can mimic medical fatigue causes

Etiology

  • Hematologic:
    • Anemia
    • Leukemia
  • Endocrine:
    • Thyroid disorders
    • Adrenal insufficiency
    • Diabetes
    • Pregnancy
  • Malignancy:
    • Paraneoplastic syndromes
  • Psychiatric:
    • Chronic pain
    • Emotional distress
    • Depression
    • Eating disorders
    • Chemical dependency
    • Withdrawal syndromes
  • Sleep disorders:
    • Insomnia
    • Sleep apnea
  • Cardiac and pulmonary disorders
  • Infections acute, chronic, and postinfectious
  • Rheumatic and autoimmune disorders
  • Nutritional deficiencies including electrolyte abnormalities
  • Physical inactivity and deconditioning
  • Medications
  • Chronic fatigue syndrome:
    • Symptom complex defined by the CDC
    • Severe chronic fatigue lasting >6 mo
    • Not explained by any medical or psychiatric diagnosis
    • Presence of 4 or more of the following 8 symptoms:
      • Headache
      • Arthralgias
      • Sleep disturbances
      • Lymphadenopathy
      • Exercise intolerance
      • Myalgias
      • Impaired memory/concentration
      • Sore throat

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