Bilateral Ureteric Obstruction

Bilateral ureteric obstruction is simultaneous obstruction of both ureters, or obstruction of the ureter draining a solitary functioning kidney, and is a cause of obstructive uropathy that produces anuric or oliguric kidney failure unless relieved. Unlike lower tract obstruction, it is often insidious and may present with renal failure alone, so the diagnosis is made on imaging.

The commonest causes differ with age and sex:

• Malignancy (most common in adults): locally advanced cervical cancer (bilateral ureteric involvement in over 20% of presentations at diagnosis, higher at relapse), prostate and bladder cancer with trigonal infiltration, ovarian, endometrial, rectal and colon cancer, lymphoma and metastatic lymphadenopathy, retroperitoneal sarcoma
• Retroperitoneal fibrosis: idiopathic, IgG4-related, drug induced (methysergide, ergot alkaloids, some beta blockers), post-radiation, malignant mimics
• Bilateral calculi, or a stone in a solitary kidney
• Iatrogenic: ligation or injury during hysterectomy, colorectal and vascular surgery; bilateral strictures after pelvic radiotherapy
• Infection: schistosomiasis (distal ureteric strictures in endemic regions), tuberculosis
• Pregnancy related or gynaecological: gravid uterus compression, fibroids, endometriosis, pelvic organ prolapse (grade 3 to 4)
• Aortic aneurysm with inflammatory perianeurysmal fibrosis
• Bilateral ureterocele and congenital pelvic ureteric junction obstruction

Renal function declines when both kidneys are affected or the single functioning kidney is blocked. Complete bilateral obstruction produces anuria; high grade partial obstruction produces polyuria from tubular concentrating defects with a variable output.

• Anuria or abrupt oliguria, alternating anuria and polyuria (partial or intermittent block)
• Flank pain in acute obstruction; painless in slow malignant or fibrotic obstruction
• Uraemic symptoms: anorexia, nausea, vomiting, fatigue, confusion
• Cancer features: pelvic mass, vaginal bleeding or discharge, weight loss, bowel changes, ascites, lymphadenopathy, bone pain
• Retroperitoneal fibrosis: dull back pain, lower limb oedema, hypertension, weight loss, fever, raised inflammatory markers; medial deviation of the ureters
• Hyperkalaemia, metabolic acidosis, hyponatraemia; hypertension from volume expansion

Red flags: anuria, potassium above 6.0 mmol/L, pH below 7.2, fever with obstruction (pyonephrosis), pulmonary oedema, uraemic pericarditis or encephalopathy, new anuria in a patient with known pelvic malignancy, creatinine above 500 micromol/L.

• Creatinine, urea, electrolytes, bicarbonate, calcium, phosphate, full blood count, inflammatory markers, immunoglobulin G subclass 4, antinuclear antibody, tumour markers where relevant, coagulation screen before drainage.
• Urinalysis and culture; urine cytology and cystoscopy for bladder tumours.
• Ultrasound: bilateral hydronephrosis with a distended or empty bladder; cortical thinning (below 7 mm) suggests chronicity.
• Non-contrast CT to find stones and the level; contrast CT or magnetic resonance imaging for the cause (cervical mass, nodes, periaortic soft tissue mantle in retroperitoneal fibrosis, peritoneal disease).
• Fluorodeoxyglucose positron emission tomography to distinguish malignant from benign retroperitoneal disease and to direct biopsy.
• Biopsy of retroperitoneal tissue before steroid treatment when malignancy cannot be excluded.
• Renography with mercaptoacetyltriglycine or technetium labelled DTPA after drainage to quantify salvageable function.
• Cystoscopy and retrograde pyelography at the time of attempted stenting.

Differentials: acute tubular injury with mild hydronephrosis, nephrogenic hydronephrosis without obstruction, bilateral vesicoureteric reflux, pregnancy, renal vein thrombosis, glomerulonephritis.

Emergency decompression

• Relieve obstruction urgently (within 24 hours; within hours if infected, hyperkalaemic or uraemic with complications).
• Retrograde ureteric stent (double-J, 6 Fr in adults) at cystoscopy is first line when the orifices can be catheterised; percutaneous nephrostomy under ultrasound and fluoroscopy is used when stenting fails (distorted trigone, extrinsic compression) or when sepsis requires immediate drainage.
• In bilateral obstruction, decompress the better kidney first when time and risk are limited, based on cortical thickness and function; decompress the second side if function does not recover within 24 to 48 hours.
• Antibiotics for infected obstruction: piperacillin-tazobactam 4.5 g intravenously every 6 to 8 hours or ceftriaxone 2 g daily; meropenem 1 g every 8 hours for resistant organisms.

Peri-procedural care

• Correct hyperkalaemia (calcium gluconate 10% 10 mL intravenously, insulin 10 units with glucose 25 g, salbutamol 10 to 20 mg nebulised) and acidosis; correct coagulopathy (INR below 1.5, platelets above 50 x 10^9/L).
• Hold anticoagulants as procedure risk requires; low-molecular-weight heparin can be restarted 24 hours after nephrostomy.
• Monitor for post-obstructive diuresis: hourly urine output; replace 50% to 75% of the previous hour's output with 0.45% saline when output is above 200 mL/h for 2 consecutive hours and the patient is not overloaded.

Cause directed treatment

• Retroperitoneal fibrosis: after drainage and tissue exclusion of malignancy, prednisolone 0.5 to 0.75 mg/kg daily (maximum 60 mg) for 4 to 6 weeks, taper to 5 to 10 mg over 6 months and continue for 12 to 24 months; add azathioprine 2 mg/kg daily, mycophenolate mofetil 1 g twice daily or methotrexate 15 to 25 mg weekly to spare steroid; rituximab 1 g on days 1 and 15 for IgG4-related disease. Ureterolysis (laparoscopic) for refractory cases.
• Malignant obstruction: treat the primary tumour (chemotherapy, radiotherapy, surgery, hormonal therapy for prostate cancer: androgen deprivation with leuprorelin 22.5 mg every 3 months and a short course of bicalutamide 50 mg daily). Cisplatin requires an eGFR above 60 mL/min/1.73 m2 and is contraindicated in most obstructive failure, so alternatives (carboplatin dosed by eGFR) are used.
• Stones: ureteroscopy with laser fragmentation and stent; alkalinisation for uric acid stones (potassium citrate 10 mmol three times daily to urine pH 6.5 to 7.0).
• Schistosomiasis: praziquantel 40 mg/kg orally as a single dose; ureteric strictures may require reimplantation.
• Iatrogenic injury recognised early: stent or nephrostomy plus reconstruction (ureteroneocystostomy) within days or after 6 to 12 weeks if late.

Palliative decisions

• Median survival after decompression for malignant ureteric obstruction is 3 to 7 months in most solid tumours (longer in cervical cancer treated with curative or palliative therapy; shortest in pancreatic and gastric disease). Decompression is appropriate when the patient has potential for further oncological therapy or when the expected quality of life justifies it; discuss with the patient and family and involve palliative care early.
• Metal ureteric stents last up to 12 months; polymer stents are exchanged every 3 to 6 months; nephrostomy tubes every 6 to 12 weeks.

Dialysis. Required for refractory hyperkalaemia, acidosis (pH below 7.15), uraemic complications or overload until drainage takes effect; most patients recover enough function to avoid permanent dialysis if decompressed within weeks.

Follow up. Creatinine at 1 and 4 weeks, renography at 6 to 8 weeks, imaging to confirm stent patency every 3 to 6 months.