Hydronephrosis and Hydroureter Caused by Obstruction by a Renal Calculus - Erler Zimmer
Clinical History
A 72-year-old female presented with colicky flank pain and increasing malaise. Intermittent hematuria was noted. Biochemical tests revealed significantly impaired renal function. A CT scan of the abdomen showed congenital renal agenesis of the left kidney and right-sided hydronephrosis and hydroureter, caused by obstruction from a smaller calculus. Attempted percutaneous lithotomy to relieve the obstruction resulted in the patient's death due to a cardiac event during the procedure.
Pathology
The specimen is the patient's right kidney, partially bisected, demonstrating marked dilatation of the pelvi-calyceal system and significant cortical atrophy. A large brown calculus is visible in the renal pelvis at the ureteropelvic junction.
Further Information
Urolithiasis (renal calculi) is a prevalent condition affecting up to 1 in 10 individuals during their lifetime, with stones primarily forming in the kidneys. Risk factors for stone formation include male gender; conditions affecting urine composition, such as hypercalciuria or high urine oxalate; systemic metabolic disorders like cystinuria and gout; dietary factors such as high oxalate and animal protein intake, low fluid intake; and environmental factors like high temperatures. 80% of renal calculi are unilateral.
Symptoms of urolithiasis include severe pain, hematuria, nausea, vomiting, fainting, dysuria, and urgency. Symptoms vary based on the size and location of the calculus. Urolithiasis can be asymptomatic, especially if stones remain within the renal pelvis or bladder. Symptoms emerge when stones move into the ureter. Calculi pain is usually colicky and severe, occurring in paroxysms. While flank pain is common, it can occur anywhere along the urinary tract and into the genitals. Pain subsides upon stone passage. Hematuria can be gross or microscopic.
Diagnosis relies on medical history and examination. Radiological tools commonly used for diagnosis include non-contrast CT or kidney and bladder ultrasound. Less common imaging methods include abdominal X-ray, intravenous pyelogram, and magnetic resonance imaging.
Untreated urolithiasis leads to renal damage and ultimately renal failure due to progressive obstruction and hydronephrosis. If the obstructing calculus is not relieved, it causes pressure to build up proximal to the obstruction. This pressure is transmitted back through the collecting ducts to the cortex, causing progressive renal parenchyma atrophy with dilatation of the renal calyces and pelvis. The pressure also compresses vasculature in the medulla, leading to ischemic medullary damage. Glomerular filtration persists until late in the disease process, gradually diminishing. Obstruction triggers an interstitial inflammatory process resulting in fibrosis. Renal calculi also predispose patients to infection secondary to obstruction and urothelium trauma.
Treatment in acute patients includes supportive measures to facilitate stone passage. Medical treatment involves analgesia, commonly NSAIDs and opiates, and agents to aid stone passage, such as alpha blockers, calcium channel blockers, and antispasmodics. Surgical intervention may be necessary for severe complications or if the stone is large and unresponsive to conservative treatment. Surgical interventions encompass lithotripsy (using lasers or electricity), laparoscopic stone removal, or percutaneous stone removal. Open surgery is rarely necessary.
