Visual Diagnosis: 15-Year-Old Girl With Fever, Extremity Pain, and Unusual Rash

Presentation

A 15-year-old girl presents to the clinic with fever, rash, and extremity pain associated with difficulty walking. The patient had been in her usual state of health until 6 days before admission, when she developed diffuse abdominal pain, nonbilious and nonbloody emesis, and subjective fever. The patient initially had been seen in the emergency department (ED) 2 days before presentation and underwent abdominal computed tomography (CT), blood work, and urine studies. The abdominal CT revealed a normal-appearing appendix and no evidence of gastrointestinal obstruction. The blood work was notable for the following: white blood cell (WBC) count, 18,700/μL (18.7 × 10⁹/L) with 39% band cells; hemoglobin, 15 g/dL (150 g/L); hematocrit, 43.1; platelet count, 94.0 × 10³/μL (94.0 × 10⁹/L); erythrocyte sedimentation rate, 30 mm/h; and C-reactive protein, 111 mg/L (1057 nmol/L). The urinalysis revealed 0 to 5 WBCs, 2 to 5 red blood cells, a protein level of greater than 300 mg/dL (3.0 g/L), and moderate bacteria (10-30 casts) but normal pH and negative leukocyte esterase and nitrite test results. A rapid streptococcal test result was negative. The patient was given a single dose of ceftriaxone and sent home with a prescription for a 10-day course of cephalexin for presumed urinary tract infection.

The next day she followed up with her pediatrician and by that time had developed chills, extremity pain that began in her lower extremities with progression to her upper extremities, and a new rash on her palms and soles. She had not filled the cephalexin prescription and was given a new prescription for amoxicillin by her pediatrician. Later, a …