Urinary tract obstruction

• Common – consider in any patient with impaired renal function
• Damage can be permanent if the obstruction is not treated promptly
• Can occur anywhere from the renal calyces to the urethral meatus
• May be partial, complete, unilateral or bilateral
• Obstructing lesions may be;
  • Luminal;
    • Stones
    • Blood clot
    • Sloughed papilla
    • Tumour – renal, ureteric, bladder
  • Mural;
    • Congenital or acquired stricture
    • Neuromuscular dysfunction
  • Extra-mural
    • Abdominal or pelvic mass
    • Retroperitoneal fibrosis
    • Unilateral obstruction may be clinically silent if the other kidney is functioning

Clinical features

• Acute upper tract obstruction;
• Loin pain radiating to the groin
• There may be superimposed infection +/- loin tenderness or an enlarged kidney
• Chronic upper tract obstruction;
• Flank pain, renal failure, superimposed infection
• There may be polyuria due to impaired concentrating capacity
• Acute lower tract obstruction;
• Urinary frequency, hesitancy, poor stream, terminal dribbling, overflow incontinence
• There may be a distended bladder and large prostate on PR

Tests

• Blood – U7Es, creatine
• Urine – microscopy and culture
• Ultrasound
• Antegrade or retrograde ureterograms

Treatment

• Upper tract obstruction
• Nephrostomy and ureteric stent
• Lower tract obstruction
• Catheter – beware of large diuresis after relief of obstruction – a temporatory salt losing nephropathy may occur resulting in loss of several litres of fluid a day
• Monitor weight, fluid balance and U&Es closely