A previously healthy 9-year-old girl developed a sudden onset of fever to 40°C associated with emesis and loose stools. She concurrently developed a pruritic maculopapular rash on her thighs which spread to the rest of her body. Alarmed, her parents brought her to our emergency department. On examination, she had a temperature of 39.8°C, pulse of 137 beats/min, respiratory rate of 24 breaths/min and oxygen saturation of 99% in ambient air. The patient was normotensive with systolic blood pressure of 105 mm Hg (diastolic pressure was not recorded). She appeared pale but alert. Her pharynx was red and inflamed. Auscultation of her chest was clear, and she had a normal cardiovascular examination. Her abdomen was soft and nontender with no masses. A generalized, blanching, pruritic rash was noted. The family had not travelled overseas recently, and she denied contact with farm animals or sick people. She had not experienced any recent trauma. Her immunizations were up to date. She had no known allergies.
Laboratory studies revealed a white blood cell count of 13.1 × 109/L (normal) with 45% neutrophils, 47% band forms, 6% lymphocytes and 2% eosinophils and basophils; hemoglobin of 134 g/L (normal); C-reactive protein of 203 mg/L (elevated) and erythrocyte sedimentation rate of 53 mm/h (elevated). Electrolytes, blood urea nitrogen and creatinine were normal. Total bilirubin was mildly elevated to 21 μmol/L (reference < 18), and alanine aminotransferase was 102 U/L (reference < 34). A blood culture was obtained. She was admitted to the pediatric ward for further investigation of the fever of unknown origin and was treated empirically with ceftriaxone.
After admission, further investigations were performed, including a chest radiograph (normal); urine microscopy and culture (no growth); Epstein-Barr virus immunoglobulin G and immunoglobulin M (negative) and enterovirus polymerase chain reaction (negative). Antistreptolysin O titer was 737 U/mL, and anti-DNase B titer was 885 U/mL, suggestive of a recent group A streptococcal infection. Based on this, her antibiotic regimen was changed to benzyl penicillin on day 2 of admission. She had persistent fevers between 38.5°C and 39.5°C during the first 48 hours of admission. By day 3 of hospitalization, despite ongoing fevers, the rash had resolved and she remained clinically stable with no other symptoms.
The blood culture result in combination with a new physical examination finding on day 3 of hospitalization led to the diagnosis.
For Denouement see P. 89.