Differential Diagnosis for Obstructing Ureteral Calculus
- Single most likely diagnosis
- Ureteral obstruction due to a calculus (kidney stone): This is the most direct diagnosis based on the information provided, as it explicitly mentions an "obstructing 4 mm calculus in the proximal left ureter." The presence of mild left hydronephrosis and delayed renal enhancement supports this diagnosis, as these are common consequences of ureteral obstruction.
- Other Likely diagnoses
- Pyelonephritis: The mild left perinephric stranding could be indicative of an infectious process such as pyelonephritis, especially if the obstruction leads to urinary stasis and infection.
- Ureteral stricture or other obstructive processes: Although less likely given the explicit mention of a calculus, other causes of ureteral obstruction (like strictures) could present similarly and should be considered, especially if the calculus is successfully treated but symptoms persist.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Sepsis: If the obstruction leads to infection (pyonephrosis), it could potentially progress to sepsis, a life-threatening condition that requires immediate intervention.
- Emphysematous pyelonephritis: A rare but serious infection of the kidney that can occur in the setting of urinary obstruction and diabetes, characterized by gas formation in the kidney.
- Xanthogranulomatous pyelonephritis: A rare form of chronic pyelonephritis that can occur in the setting of long-standing urinary obstruction, characterized by destruction of the renal parenchyma and the presence of granulomatous tissue.
- Rare diagnoses
- Ureteral tumor: Although rare, a tumor in the ureter could cause obstruction similar to a calculus.
- Retroperitoneal fibrosis: A rare condition characterized by the proliferation of fibrous tissue in the retroperitoneum that can encase and obstruct the ureters.
- Extraluminal causes of ureteral obstruction (e.g., endometriosis, lymphoma): These are less common causes of ureteral obstruction that could present with similar imaging findings.