A 29-year-old woman presents for second opinion evaluation of chronic fatigue syndrome. She was well until 2 years ago when she developed insidious and recalcitrant weariness. She sleeps 10 hours a night but awakes feeling unrefreshed. She is unable to tolerate exercise, which only worsens her malaise, and she is no longer able to work. She has no significant past medical or psychiatric history. In addition to a detailed history and physical, which of the following is recommended as a reasonable approach to screening patients who complain of chronic fatigue?
A. Antinuclear antibody testing
B. Electromyography with nerve conduction studies
C. Epstein-Barr virus testing
D. Lyme serologies
E. Thyroid function testing
The answer is E. (Chap. 20) Fatigue describes the near universal human experience of weariness or exhaustion. Fatigue may be a nonspecific manifestation of psychiatric disease, neurologic disease, sleep disorders, endocrine disorders, kidney or liver disease, rheumatologic disorders, infection, malignancy, anemia, obesity, malnutrition, pregnancy, or diseases of unclear cause. A suggested approach to screening includes a complete blood count with differential, electrolytes, glucose, renal function, liver function, and thyroid function tests. Testing for HIV and adrenal function can also be considered. However, extensive laboratory testing infrequently identifies the cause of chronic fatigue and may more often lead to false-positive findings and prolonged workups. Because low-titer positive antinuclear antibodies (ANAs) are not uncommon in otherwise healthy adults, ANA testing is unlikely to be helpful in isolation. Electromyography with nerve conduction studies may have a role if the presence of muscle weakness cannot be determined by physical examination. Testing for viral or bacterial infections is often unhelpful. Although complete resolution of fatigue is uncommon, longitudinal and multidisciplinary follow-up sometimes identifies a previously undiagnosed serious cause of chronic fatigue.