Table III.

Differential diagnoses of causes of subacute and chronic fatigue

	Conditions
Cardiopulmonary	Congestive heart failure Chronic obstructive pulmonary disease Sleep apnoea
Endocrinologic/metabolic	Hypothyroidism Hyperthyroidism Chronic renal disease Adrenal insufficiency Electrolyte abnormalities: Hyponatraemia Hypercalcaemia
Haematologic/neoplastic	Anaemia Occult malignancy
Infectious diseases	Mononucleosis syndrome Viral hepatitis HIV infection Subacute bacterial endocarditis Tuberculosis
Rheumatologic	Fibromyalgia Polymyalgia rheumatica Rheumatoid arthritis
Neurological	Multiple sclerosis Parkinson’s disease
Psychological	Depression Anxiety disorder Somatisation disorder
Medication toxicity	Benzodiazepines, antidepressants, muscle relaxants, first-generation antihistamines, β-blockers, opioids
Substance use	Alcohol, marijuana, opioids, cocaine/other stimulants