LAUSR

An 18-month-old female with no past medical history presented to the emergency department with fevers, fatigue, and emesis for 1 day. The patient had several episodes of non-bloody, non-bilious emesis that began 1 day prior to presentation. She had subjective fevers that seemed to defervesce with Tylenol. Mom reported that the patient had only 2 wet diapers over the preceding 24 hours and appeared sleepier than usual. Vital signs on presentation to the emergency department were as follows: temperature 103.1°F, heart rate 190 beats per minute, respiratory rate of 44 breaths per minute, blood pressure of 96/74 mm Hg, and SpO2 80% in room air. On physical exam, patient was crying, appeared pale, and had diffuse jaundice. On cardiac examination, she had normal S1 and S2, no murmurs were appreciated, capillary refill was less than 2 seconds, and pulses were 2+ bilaterally in her upper and lower extremities. Her lungs were clear to auscultation bilaterally without increased work of breathing. Her abdomen was soft, non-tender and non-distended with normal bowel sounds and no organomegaly. Neurological exam was normal without focal deficits. No rashes or petechiae were noted on exam. Initial lab work showed white blood cells (WBC) of 25 x 109/l with neutrophil count of 61.7%, hemoglobin (Hb) of 5.9 g/dL, mean corpuscular volume (MCV) of 83 fL, and platelets of 405 x 109/l. Reticulocyte count was elevated at 4.2%. Peripheral blood smear was notable for spherocytes and blister cells. Venous blood gas (VBG) was obtained and showed a normal pH of 7.39, pCO2 of 32, pO2 of 40, base excess of -5.2, and bicarbonate of 19.4. The VBG also showed Hb of 5.4 g/dL, methemoglobin (MetHb) of 12.1%, and carboxyhemoglobin of 4.4% indicating methemoglobinemia. Lactate dehydrogenase (LDH) of 1405 U/l and haptoglobin of < 30 mg/ dL were consistent with a hemolytic process. The direct antiglobulin test (DAT) was negative and G6PD level was normal. Urinalysis (UA) was also performed and showed “large” 3+ blood, 2+ bacteria, 4+ granular casts, and 4+ amorphous crystals. Urine myoglobin was negative and creatinine kinase was 188 U/l. Renal function panel was within normal limits. Hepatic function panel was remarkable only for an indirect hyperbilirubinemia 2.7 mg/dL.