**Hydronephrosis** **Pathogenesis:** * Obstruction of urine flow from kidneys to bladder * Causes: * Ureteropelvic junction obstruction (UPJ obstruction) * Ureteral stricture * Neurogenic bladder * Bladder outlet obstruction (BPH, prostate cancer) * Urethral stricture * Stones * Retroperitoneal fibrosis * Pregnancy * Neurogenic bladder **Clinical Manifestations:** * **Early:** * Asymptomatic * **Moderate:** * Dull, aching flank pain * Nocturia * Frequency * Urgency * Dysuria * **Severe:** * Severe flank pain * Nausea and vomiting * Gross hematuria **Diagnosis:** * **Imaging:** * Ultrasound: initial imaging study * CT scan: more sensitive for detecting stones and other abnormalities * IVP: less common now * MRI: can be used to assess renal function and detect complications **Staging:** * **Grade 0:** No dilation * **Grade 1:** Mild dilation of renal pelvis and calyces, renal parenchyma maintained * **Grade 2:** Moderate dilation of renal pelvis and calyces, mild thinning of renal parenchyma * **Grade 3:** Marked dilation of renal pelvis and calyces, moderate thinning of renal parenchyma * **Grade 4:** Severe dilation, thinning of renal parenchyma **Treatment and Management:** * **Focuses on relieving obstruction:** * **Percutaneous nephrostomy:** Tube placed through the skin into the renal pelvis to drain urine * **Ureteral stent:** Stent placed in the ureter to relieve obstruction * **Pyeloplasty:** Surgical repair of the renal pelvis * **Endoscopic procedures:** To remove stones or treat strictures * **Open surgery:** For complex cases * **Lower urinary tract obstructions:** * Medications * Minimally invasive procedures (e.g., ureteroscopy, laser lithotripsy) * Surgery (e.g., transurethral resection of the prostate)