Introduction and importance: Pyonephrosis is a urological emergency characterized by the presence of purulent material within an obstructed renal collecting system, often leading to rapid parenchymal destruction and systemic sepsis. While it is well documented in adults and older children, its occurrence in neonates is exceedingly rare. Early diagnosis and timely drainage are essential to prevent long-term renal impairment or mortality, particularly in low-resource settings where access to advanced imaging and pediatric urology is limited. Case presentation: We report the case of a 48-day-old male infant who presented to the pediatric emergency department with a 5-day history of undocumented fever, persistent vomiting, shrill crying, and progressive abdominal distension. Physical examination revealed pallor and mild abdominal distension. Laboratory tests showed leukocytosis with neutropenia and pyuria. Ultrasonography revealed significant left-sided hydronephrosis with echogenic debris in the pelvicalyceal system, suggestive of pyonephrosis. An emergency ultrasound-guided percutaneous nephrostomy was performed, which drained approximately 15 mL of thick purulent fluid. Culture of the nephrostomy aspirate revealed the Acinetobacter baumannii complex, resistant to piperacillin and sensitive to cefotaxime and amikacin. Clinical discussion: The infant was initiated on empirical antibiotics, which were later tailored to intravenous ampicillin and amikacin based on sensitivity results. Within 2 days, the patient showed marked clinical improvement, with normalization of vital signs, improved oral intake, and resolution of fever. Repeat urine cultures were sterile, and the nephrostomy tube was removed after imaging confirmed resolution. The infant was discharged in stable condition with preserved renal function. Conclusion: This case underscores the importance of maintaining a high index of suspicion for pyonephrosis in neonates presenting with non-specific symptoms such as fever and irritability. In the absence of advanced imaging, bedside ultrasonography proved invaluable for timely diagnosis. Despite the presence of a multidrug-resistant organism, targeted antibiotic therapy and prompt percutaneous drainage led to full recovery. This report highlights that, even in resource-limited settings, favorable outcomes can be achieved through early recognition, essential diagnostics, and minimally invasive interventions.
Adhikari et al. (2026) studied this question.