From Hydronephrosis to Pyonephrosis: A Rare Pediatric Case of Urolithiasis

Abstract

Urolithiasis in children is uncommon and can present atypically, often leading to delayed diagnosis. We report a case of a 10-year-old boy with nephrolithiasis complicated by pyonephrosis due to extended-spectrum beta-lactamase (ESBL) Pseudomonas aeruginosa. Early recognition and prompt intervention were crucial for clinical recovery.

Introduction

Urolithiasis is a relatively rare condition in the pediatric population compared with adults, but when complicated by infection, it may result in significant morbidity. Pyonephrosis, defined as infected hydronephrosis with pus in the collecting system, is a urological emergency requiring urgent diagnosis and treatment. Here, we describe an atypical presentation of pediatric urolithiasis complicated by pyonephrosis.

Case Presentation

A 10-year-old boy presented to the emergency department with right-sided abdominal pain of two days’ duration, throbbing in nature, associated with nausea, vomiting, and loose stools. On examination, a palpable mass was noted over the right hypochondrium. He was initially managed conservatively for suspected acute appendicitis.

However, abdominal ultrasonography revealed gross hydronephrosis secondary to pelvi-ureteric junction obstruction. A subsequent CT scan showed right nephrolithiasis with vesicoureteric calculus, right hydroureter, and gross hydronephrosis, suggesting obstruction at either the vesicoureteric junction or pelvi-ureteric junction. The patient underwent urgent surgical intervention with retrograde pyelography and ureteroscopy, followed by insertion of a ureteric stent under general anesthesia. He was discharged home after the procedure.

Three days post-discharge, the patient was readmitted with fever, hematuria, and dysuria. He was treated for right pyelonephritis; however, his condition did not improve despite five days of broad-spectrum intravenous antibiotics. On re-evaluation, he was febrile (39.9°C) with tachycardia (pulse 134/min), normotensive (BP 110/70 mmHg), and reported flank pain (score 4/10). Abdominal examination revealed a ballotable right kidney and positive renal punch tenderness.

Laboratory investigations showed leukocytosis and markedly elevated C-reactive protein. Urine analysis demonstrated nitrates, leukocyturia, hematuria, and proteinuria. Urine culture grew ESBL-producing Pseudomonas aeruginosa. Abdominal X-ray showed the ureteric stent in situ with clusters of small radiopaque calculi in the right kidney. Ultrasonography revealed persistent right hydronephrosis, slightly reduced compared with the previous study, with internal echoes suggestive of pyonephrosis.

Based on the culture results, intravenous meropenem (20 mg/kg) was initiated, leading to clinical improvement and normalization of inflammatory markers within 48 hours. After seven days of meropenem, he was discharged on oral ciprofloxacin (250 mg twice daily for three weeks) for extended coverage against ESBL organisms.

Final Diagnosis: Right pyonephrosis with ESBL-producing Pseudomonas aeruginosa infection, in association with right nephrolithiasis and vesicoureteric calculus.

Discussion

This case highlights an atypical presentation of pediatric urolithiasis, initially mimicking acute appendicitis. Hydronephrosis with concurrent urolithiasis predisposed the patient to infection, progressing to pyonephrosis. Management required both surgical and antimicrobial intervention. The identification of ESBL-producing Pseudomonas emphasized the importance of tailored antibiotic therapy guided by culture and sensitivity. Early diagnosis and prompt treatment are essential to prevent renal function loss and systemic complications.

Conclusion

Urolithiasis with pyonephrosis in children is rare but potentially life-threatening. Clinicians should consider urinary tract obstruction in children presenting with atypical abdominal symptoms. A multidisciplinary approach, including timely surgical decompression and culture-directed antibiotics, is vital for optimal outcomes.

Reference

Md Sabudin SN, Yaacob LH, Draman N. An atypical presentation of urolithiasis with pyonephrosis in a child: A case report. Electron J Gen Med. 2023;20(2):em457. https://doi.org/10.29333/ejgm/12852