Undifferentiated Presentations — Fatigue

A 38-year-old woman presents to her family physician with 4 months of persistent fatigue that has interfered with her work as a teacher. She has no fever, night sweats, weight loss, rash, joint pain or oral ulcers. Her only medications are a combined oral contraceptive and occasional cetirizine; she has 1 to 2 alcoholic drinks per week and has not started any new medications or supplements. Physical examination is normal, including no lymphadenopathy, goitre or joint swelling.