A 2½-year-old white boy was seen by his pediatrician because of increasing irritability and unsteady gait. Three months prior to admission the youngster had fallen down a flight of stairs without apparent injury. Several days prior to admission, the child experienced progressive low back pain and stiffness.
The boy's medical history was remarkable for multiple episodes of otitis media and upper respiratory tract infections requiring medical therapy. The patient completed a 10-day course of antibiotic therapy as recently as 1 month prior to injury.
On admission, the patient was afebrile and the results of the physical examination were normal except for a wide-base gait and pronounced lumbar lordosis. Admission laboratory values were as follows: white blood cell count, 13×109/L, with 0.70 polymorphonuclear leukocytes; hemoglobin level, 116 g/L; hematocrit value, 0.33; platelet count, 504 × 109/L; erythrocyte sedimentation rate (Westergren), 13