Hydronephrosis: Causes, Symptoms, Diagnosis, and Treatment

Hydronephrosis is dilation of the renal pelvis and calyces due to urine outflow obstruction. It is a sign, not a disease itself.

Common Causes

• Urolithiasis: Kidney/ureteral stones (most common).
• Benign Prostatic Hyperplasia (BPH): In older men.
• Strictures: Ureteral (congenital, post-inflammatory, iatrogenic).
• Malignancy: Bladder, cervical, prostate, retroperitoneal fibrosis.
• Pregnancy: Uterine compression (physiological, usually right-sided).
• Vesicoureteral Reflux (VUR): In children.

Symptoms

• Flank/loin pain (colicky if stone)
• Nausea/vomiting
• UTI symptoms (fever, dysuria, frequency)
• Palpable mass (severe)
• Often asymptomatic (incidental finding)

Diagnosis

• Ultrasound (first-line, no radiation)
• CT Urogram (gold standard for stones, anatomy)
• MR Urography (pregnancy, contrast allergy)
• Renal scan (MAG3) – assesses function & drainage

Treatment

• Relieve obstruction: Stent, nephrostomy tube, stone removal (ureteroscopy, lithotripsy).
• Treat underlying cause (BPH meds/surgery, tumor resection).
• Antibiotics for infection.

Early decompression preserves renal function. Chronic obstruction → irreversible atrophy.