Hydronephrosis and its causes identified on correlative fluoroscopy in a paediatric population at a resource-constrained tertiary hospital in Southern Africa.

BACKGROUND

Paediatric hydronephrosis has a high global prevalence. Identifying aetiologies is critical for planning investigations, management and preventing chronic renal impairment. This study reviewed the underlying causes of unilateral and bilateral hydronephrosis, specifically on voiding cystourethrogram (VCUG) examinations.

METHODS

A retrospective descriptive study (Jan 2021-June 2024) included children < 13 years who underwent VCUG following a sonographic diagnosis of hydronephrosis. Ultrasound and VCUG studies were retrieved from the institutional Radiology Information System. Data collected included demographics, hydronephrosis laterality and severity, VCUG and mercaptoacetyltriglycine-3 (MAG-3) results. Hydronephrosis was graded according to a dual grading system combining Radiology grading system and Onen's criteria. Statistical significance was set at p < 0.05.

RESULTS

Of sixty-five patients included, 67.7% were male. Bilateral hydronephrosis occurred more frequently in males, while unilateral disease was more common in females. Grade III hydronephrosis was most prevalent. A cause was identified in 85.7% of bilateral vs. 43.2% of unilateral cases (p < 0.001). Posterior urethral valves (PUV) were the leading aetiology (36% bilateral; 14% unilateral; p = 0.035) followed by vesicoureteric reflux and bladder diverticula. Of 22 MAG-3 studies, 59% showed delayed excretion or reduced cortical function consistent with obstructive VCUG findings.

CONCLUSION

Bilateral hydronephrosis correlated with higher severity grades, mostly due to posterior urethral valves. Severity grading highlights the importance of early detection and intervention to prevent renal failure. Resource constraints challenge SASPI treatment algorithm implementation, necessitating institution-specific imaging pathways.

CONTRIBUTION: This study highlights PUV as the primary aetiology of severe bilateral hydronephrosis and advocates for institution-specific, multidisciplinary imaging pathways.