Nephrolithiasis in a child with acute pyelonephritis: Question

Excerpt

A 6-year-old boy was admitted to the hospital with presumptive diagnosis of acute pyelonephritis. He had a 2-day history of fever and vomiting. On admission he had high fever (39.7^°C) and diffuse abdominal tenderness. Renal percussion was negative. Laboratory investigations revealed high erythrocyte sedimentation rate (60 mm/h), C-reactive protein 136 mg/l and leukocytosis of 21.3×10⁹/l. His urine was cloudy; nitrite and esterase tests were positive and microscopic examination of the sediment revealed many white blood cells. Ultrasound examination of his kidneys, liver, gallbladder, spleen and urinary bladder did not show any abnormal changes. The boy was administered intravenous fluids and ceftriaxone 1.0 g/day (50 mg/kg/day). Within 48 h he became afebrile and his urine cleared. The bacteriology report showed that his pyelonephritis was due to Escherichia coli (10⁶/CFU), which was sensitive to ceftriaxone. The parenteral treatment with ceftriaxone continued at the same dose on outpatient basis. On the fifth post-admission day, the boy’s parents reported that he complained of right lumbar pains and macroscopic hematuria. Ultrasound examination was performed the same day and demonstrated a small non-obstructive calculus (5 mm) in the right kidney (Fig. 1). Also, echogenic material with acoustic shadowing was seen in the gallbladder (Fig.2). Additional laboratory investigations were performed afterwards and revealed normal complete blood counts; urinalysis was positive for blood 3+; nitrite and esterase tests were negative and pH was 5. Serum biochemistry showed normal values for calcium (2.33 mmol/l), phosphate (1.55 mmol/l), magnesium (1.0 mmol/l), uric acid (236 μmol/l), bicarbonate (23 mmol/l), alkaline phosphatase (133 U/l), and PTH (22 pg/ml). Examination of the solute/creatinine ratios (mmol/mmol) in the random urine sample were as follows: calcium/creatinine (0.22, normal <70), uric acid/creatinine (0.33, normal <1.0), oxalate/creatinine (0.03, normal<0.12) and citrate/creatinine (0.34, normal>0.15). Nitroprusside test for cystinuria was negative. There was no hyperaminoaciduria. Oral intake of fluids was encouraged and the boy was switched to oral therapy with cefixime. Ten days later, there was spontaneous painful passage of a small calculus. A follow-up ultrasound scan did not demonstrate any calculi within the urinary tract. No echogenic material was seen in the gallbladder.

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