Differential Diagnosis for Bilateral Renal Pelvis Fullness on NCCT

Single Most Likely Diagnosis

• Hydronephrosis: This condition, characterized by the dilation of the renal pelvis and calyces, is often due to obstruction of the urinary tract, which can be caused by various factors such as kidney stones, tumors, or congenital abnormalities. Bilateral involvement suggests a more systemic or obstructive issue lower in the urinary tract, such as at the bladder or urethra.

Other Likely Diagnoses

• Urinary Tract Infection (UTI) or Pyelonephritis: Infections can cause inflammation and subsequent fullness or dilation of the renal pelvis. While typically unilateral, severe or systemic infections can affect both kidneys.
• Congenital Anomalies: Conditions like ureteropelvic junction obstruction (UPJO) can cause renal pelvis dilation. Though often diagnosed in childhood, some cases may not become symptomatic until adulthood.
• Nephrocalcinosis: This condition involves the deposition of calcium salts within the renal tissue, which can lead to renal pelvis fullness due to chronic inflammation and scarring.

Do Not Miss Diagnoses

• Ureteral Obstruction due to Tumors: Tumors, either primary in the ureters or metastatic, can cause obstructive uropathy leading to bilateral renal pelvis fullness. Early detection is crucial for treatment and prognosis.
• Retroperitoneal Fibrosis: A rare condition characterized by the proliferation of fibrous tissue in the retroperitoneum, which can encase and obstruct the ureters, leading to hydronephrosis.
• Trauma: Significant abdominal trauma can cause injury to the ureters or renal pelvis, leading to obstruction and subsequent fullness.

Rare Diagnoses

• Lymphoma: Though rare, lymphoma can infiltrate the retroperitoneum and cause ureteral obstruction.
• Tuberculosis: Genitourinary tuberculosis can cause strictures and obstruction in the urinary tract, leading to renal pelvis fullness.
• Sarcoidosis: This systemic granulomatous disease can rarely affect the kidneys and urinary tract, causing obstructive symptoms.

Each of these diagnoses has a different set of implications for patient management and outcome, highlighting the importance of a thorough diagnostic workup in cases of bilateral renal pelvis fullness.