A 15-year-old African American girl presented to a local hospital emergency department (ED) complaining of fever, vomiting, headache, back pain, and chills for 2 days. Physical examination was unremarkable. Laboratory testing revealed a normal complete metabolic panel; complete blood count (CBC) revealed a white blood cell (WBC) count of 5.9 x 109/L with a "left shift," hemoglobin 11.5 g/dL, and platelets 164 x 109/L. Urinalysis showed 2+ protein, positive ketones, negative nitrites, and leukocyte esterase. She was given intravenous fluids and discharged with a diagnosis of presumed viral syndrome.
Over the next 2 days she had continued fever to 40°C, worsening back and abdominal pain, vomiting, and headache, with some cough and congestion. She returned to the same ED for evaluation. She denied hematuria, dysuria, rash, neck pain, or joint complaints. ECG revealed tachycardia (110 to 120 bpm) and blood pressure values averaged 90/60 mm Hg. She was thought to be well perfused and to have normal mentation. Laboratory assessment revealed a WBC count of 4.9 x109/L (15% segmented neutrophils, 48% bands), hemoglobin 11.0 g/dL, and platelets 73 x 109/L. Urinalysis revealed 2+ protein, specific gravity 1.027, 1+ nitrites, 3 to 6 WBC/hpf, 0 to 2 red blood cells (RBC)/hpf, with marked bacteria seen. Aspartate aminotransferase (AST) was 157 U/L, alanine aminotransaminase (ALT) was 122 U/L, and total bilirubin was 3.0 mg/dL (direct bilirubin was 1.9 mg/dL), CHEM-7 was normal, INR 1.1, and partial thromboplastin time (PTT) 43.6 s. As she was thought to be in impending shock, 2 L of normal saline was administered, as well as one dose each of ceftriaxone and gentamicin. The patient was then transferred to the pediatric intensive care unit (PICU).
On arrival in the ICU, she was described as tired but cooperative and in no acute distress. Vital signs included temperature of 39.1°C, pulse 99 bpm, respiratory rate 27, blood pressure 89/36 mm Hg, and O2 saturation 96%. Over the next 12 hours her heart rate was found to be 120 to 124 bpm and blood pressure measurements were 86 to 101/41 to 61 mm Hg; dopamine was administered. Examination revealed no icterus or meningismus. She had right upper quadrant tenderness with the liver palpable 2 cm below the right costal margin, without palpable splenomegaly. No abdominal guarding or tenderness was appreciated, but there was possible right costovertebral angle tenderness. Neurologic examination was normal. Laboratory results over the next 12 hours included CBC with WBC 4.15 x109/L (62% segmented neutrophils), hemoglobin 9.1 g/dL, platelets 59 x109/L, normal prothrombin time (PT) and PTT with elevated D-dimer (>22 µg/mL), AST 96 U/L, ALT 86 U/L, albumin 2.7 g/dL, total bilirubin 1.9/1.1 mg/dL, sodium 131 mEq/L, potassium 3.5 mEq/L, chloride 94 mEq/L, PCO2 18 mm Hg, blood urea nitrogen (BUN) 9 mg/dL, and creatine 0.56 mg/dL. A respiratory viral panel was negative. Radiographs of the chest revealed prominent hilar markings, possibly representing early pulmonary edema. Results of blood and urine cultures and additional blood studies were pending.
Additional history was obtained. This child was born in Chicago, where she lived until she was 14, when she, her sister, and her mother moved to Lagos, Nigeria. No prophylactic medications were given prior to travel to Nigeria. They returned to Chicago 10 days before the onset of the patient's current symptoms. Two older brothers live with their father in Chicago. The patient has had no prior hospitalizations or surgery, nor is there history of urinary tract infection. She has wheezed on several occasions early in childhood. In Chicago she had fed cows at the local zoo 5 days before fever onset. No family members have been ill recently.
Which of the following is the most likely diagnosis?