08/02/2026
A 5-year-old girl is seen in the emergency department for bilateral leg pain, red urine, fever, chills, and lower
abdominal pain.
She has no notable medical history, but her parents report that a few days ago, she fell and
hit her abdomen on her bicycle handlebar.
Two weeks ago, she had an upper respiratory infection that has
since resolved.
On physical examination, she has a temperature of 37.2 °C, a heart rate of 100 beats/min, a
respiratory rate of 25 breaths/min, a blood pressure of 105/55 mm Hg, and an oxygen saturation of 100
percent in room air.
She is awake, alert, and in no apparent distress.
Her mucous membranes are moist, and her oropharynx is clear.
There is mild conjunctival pallor and no scleral icterus.
Her cardiovascular
examination reveals a normal S1 and S2 at a regular rate and rhythm, a 2/3 systolic ejection murmur, 2+ peripheral pulses, and brisk capillary refill.
Her lungs are clear to auscultation bilaterally.
Her abdomen is soft, not distended, and nontender, with no palpable organomegaly or masses.
She has a full range of
motion in all extremities.
She has no focal neurologic deficits.
Results of laboratory tests obtained in the emergency department are as follows:
White blood cell count 9,500/µL (9.5 × 10 /L)
Neutrophils 72%
Lymphocytes 17%
Monocytes 8%
Eosinophils 2%
Basophils 1%
Platelet count 200 × 10³ /µL
Hemoglobin 8.5 g/dL (85 g/L)
Mean corpuscular volume 77 fL
Reticulocytes, percentage 4
Reticulocytes, absolute count 110 × 10³ /µL
Hemoglobin A 97%
Hemoglobin A 3%
Sodium 136 mEq/L (136 mmol/L)
Potassium 4.2 mEq/L (4.2 mmol/L)
Chloride 98 mEq/L (98 mmol/L)
Carbon dioxide 18 mEq/L (18 mmol/L)
Urea nitrogen 15 mg/dL (5.35 mmol/L)
Creatinine, serum 0.42 mg/dL (37.13 µmol/L)
Bilirubin, total 3 mg/dL (51.31 µmol/L)
Bilirubin, direct 0.4 mg/dL (6.85 µmol/L)
Lactate dehydrogenase 1,200 U/L (reference range: 135-225 U/L)
Haptoglobin
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