Differential Diagnosis for a 9-Month-Old Girl with Unilateral Hydronephrosis and Retrograde Urine Flow
- Single Most Likely Diagnosis
- Vesicoureteral Reflux (VUR): This condition is characterized by the abnormal flow of urine from the bladder back into the ureters, which can lead to hydronephrosis and increase the risk of urinary tract infections (UTIs). The presence of unilateral hydronephrosis and retrograde urine flow into the ureter and collecting system on voiding cystourethrography (VCUG) strongly supports this diagnosis.
- Other Likely Diagnoses
- Ureteropelvic Junction Obstruction (UPJO): This condition involves a blockage of the ureter at the junction where it meets the renal pelvis, leading to hydronephrosis. While UPJO could explain the hydronephrosis, the presence of retrograde urine flow on VCUG makes VUR more likely.
- Ureterovesical Junction Obstruction (UVJO): This is a less common condition where there's an obstruction at the junction of the ureter and the bladder, which could also lead to hydronephrosis. However, the specific finding of retrograde urine flow is more indicative of VUR.
- Do Not Miss Diagnoses
- Posterior Urethral Valves (PUV): Although more common in males, PUV can occur in females and cause obstructive uropathy, leading to hydronephrosis and UTIs. It's crucial to consider this diagnosis due to its potential for severe renal damage if left untreated.
- Prune Belly Syndrome: This rare condition involves the absence or severe weakness of the abdominal muscles, undescended testes in males, and urinary tract anomalies, including obstructive uropathy. While rare, it's a critical diagnosis not to miss due to its significant implications for renal and overall health.
- Rare Diagnoses
- Congenital Megacalycosis: A rare condition characterized by the dilation of the renal calyces without obstruction, which could potentially explain some of the imaging findings but is less likely given the clinical context.
- Primary Megaureter: A condition where the ureter is dilated due to a non-obstructive, non-refluxing megaureter. It's a rare cause of hydronephrosis and would not typically present with retrograde urine flow on VCUG.