On physical examination, temperature is 38.2 °C (100.8 °F). The left ankle is slightly swollen. On musculoskeletal examination, passive motion of the left ankle elicits pain. Her skin lesions are shown and are tender to palpation.
On laboratory studies, complete blood count, serum chemistry studies, and urinalysis are normal. Arthrocentesis of the left ankle yields 1.5 mL of fluid (leukocyte count, 4,000/µL [4 × 109/L]; 45% neutrophils). Polarized light microscopy shows no crystals. Culture results are pending.
A. Left ankle radiography
B. Chest radiography
C. Initiate therapy for disseminated gonorrhea
D. Initiate therapy for Lyme disease