Index of Suspicion

Abstract

A previously healthy 23-month-old girl presents with fever and a limp. She has had fever every other day for the past 2 months. Over the past 2 weeks, she has been favoring her right leg and occasionally complains of leg pain with ambulation. Today’s clinic visit was prompted by an abrupt refusal to bear weight on the left leg. Review of systems is notable for subjective weight loss, chills, and night sweats during the past month. Her immunizations are up to date, and she has no recent travel or exposure history. She takes no medications. On physical examination, the girl is alert but fussy and has growth parameters within normal limits. She is afebrile; her heart rate is 164 beats per minute, respiratory rate is 28 breaths per minute, and blood pressure while crying is 158/91 mm Hg. Her left lower extremity is held in extension and external rotation; she will not allow abduction of her hip. There is no rash, swelling, or warmth over the hip or knee joints bilaterally. She will not bear any weight on the left leg, but she moves the right leg spontaneously. She has normal results on neurovascular examination. A few scattered ecchymoses are noted on both legs. The results of the remainder of the physical examination are normal. Laboratory studies reveal a white blood cell count of 5.9 × 103/μL, without any immature cells, hemoglobin level of 8 g/dL, and platelets of 60 × 103/μL. Her C-reactive protein level is 5.7 mg/dL, and erythrocyte sedimentation rate is 90 mm/h. Radiographs of the lower extremities show demineralization and mottling at the left femoral metaphysis. Additional laboratory and imaging studies reveal the diagnosis. A 17-year-old boy with congenital heart disease (CHD) presents with a fever and fatigue. His past medical history …