Fatigue is a common nonspecific symptom with a wide range of causes that are most often work and life stresses, but which may be underlying serious disorders. Assessing patients with fatigue should therefore feature careful evaluation of the costs and benefits of possible investigations.
Generalised lethargy or fatigue is a common presenting symptom in general practice, reported in 1 to 7% of general practice encounters. It can pose diagnostic challenges.1,2 Lethargy may be defined as extreme fatigue or drowsiness in the absence of increased physical activity, unrelieved by rest. Although the most common causes tend to be psychosocial or lifestyle related, serious abnormalities may underpin its presentation. The prevalence of underlying pathology ranges from less than 10% up to 50% of patients presenting with lethargy.2 This wide range may reflect a wide variation in study methods.2