Fatigue / “Weakness”

Distinguish Fatigue from:

  • Dyspnea
  • True Motor Weakness
  • Somnolence
  • Generalized Pain Syndromes

DIFFERENTIAL DIAGNOSIS OF “FATIGUE”

Infections

  • Endocarditis
  • Occult Bacteria
  • Mononucleosis
  • HIV
  • Hepatitis
  • TB

Idiopathic

  • Chronic Fatigue Syndrome (CFS case-definition or not)

Metabolic

  • Hypo- / Hyper- Na+, K+, Ca++
  • Renal Failure
  • Hepatic Failure

Endocrine

  • Diabetes
  • Hypothyroidism
  • Hyperthyroidism
  • Adrenal Insufficiency
  • Pituitary Insufficiency

Other

  • Malignancy
  • Depression
  • Anxiety
  • Drugs / EtOH / Meds
  • Drug Withdrawal
  • Anemia (severe!)
  • Malnutrition
  • Rheumatologic disorders
  • Chronic GERD or Allergic Rhinitis

Red Flags suggesting serious etiology:

  • Fevers
  • Night Sweats (drenching)
  • Weight Lost

Basic Laboratory Tests (in addition to a good H&P):

  • CBC
  • Chemistry Panel
  • TSH
  • Urinalysis
  • Sedimentation Rate
  • HIV Antibody
  • ? Monospot (only for younger patient with <1 month of symptoms)
  • If muscle aches are a component of symptoms, add a CPK