Review of systems should seek symptoms suggesting possible causes, including the following: Daily fatigue and weakness that increases with heat and humidity: Multiple sclerosis Rash: Dermatomyositis, Lyme disease, or syphilis Fevers: Chronic infection Muscle pain: Myositis Neck pain: Cervical myelopathy Vomiting or diarrhea: Botulism Shortness of breath: Heart failure, a pulmonary disorder, or anemia Anorexia and weight loss: Cancer or other chronic illness Change in color of urine: Porphyria or a liver or kidney disorder Heat or cold intolerance: Thyroid dysfunction Depressed mood, poor concentration, anxiety, and loss of interest in usual activities: Mood disorder Past medical history should identify known disorders that can cause weakness or fatigue, including Thyroid, liver, kidney, or adrenal disorders Cancer or risk factors for cancer (paraneoplastic syndromes —eg, Eaton-Lambert syndrome) such as heavy smoking Osteoarthritis (cervical myelopathy) Infections Clinicians should assess risk factors for possible causes, including those for infection (eg, unprotected sexual intercourse, blood transfusions, exposure to tuberculosis) and stroke (eg, hypertension, atrial fibrillation, atherosclerosis).