Renal Tract Obstruction

Renal Tract Obstruction Key Info upper urinary tract obstruction is usually unilateral lower urinary tract obstruction is more common Upper Tract Obstruction Renal Ureteral Intraluminal Nephrolithiasis Blood clots Intramural Stricture For malignancy or iatrogenic trauma Nephrolithiasis Ureteral carcinoma Most common Accidental surgical ligation Carcinoma of the renal pelvis Extraluminal Ureteropelvic obstruction Pregnancy Renal papillary necrosis Neoplasia Iliac artery aneurysm Crohn’s disease Diverticulitis Tubo-ovarian mass Ectopic ureter Ureterocele Lower Urinary Tract Obstruction Bladder Urethral Prostatic enlargement Bladder carcinoma BPH – most common Neurogenic bladder Prostate cancer Urinary bladder tamponade Posterior urethral valves Bladder calculi Urethral stricture Bladder neck dysfunction Secondary to trauma, instrumentation or infection Kinked or plugged indwelling catheter Clinical Features Ix Renal and urinary tract U/S Best initial test Modality of choice for pregnant individuals and children CT abdomen and pelvis Preferred modality for patients with suspected nephrolithiasis Indicated when U/S is inconclusive X-ray Not usually indicated Not usually helpful May show some hydronephrosis or urolithiasis MRI If CT is contradicted Specialised studies IV pyelography to determine degree of hydronephrosis Retrograde pyelography confirm a diagnosis of ureteropelvic junction obstruction Renal scintigraphy to evaluate kidney function Cystoscopy gold standard for bladder cancer Voiding cystourethrography to evaluate vesicoureteral reflux Urodynamic studies to evaluate for neurogenic bladder Management Supportive cate Analgesia NSAIDS Opioids morphine Abx prophylaxis Upper UTO Ureteral stenting fluid drains from renal pelvis into the bladder Percutaneous nephrostomy if stent cannot be placed or there is a complete UTO and concomitant infection Lower UTO Urinary catheterisation Management as per cause Nephrolithiasis see kidney stone notes Urinary bladder tamponade Three-way Foley catheter Continuous bladder irrigation to dissolve blood clots Ureteral stricture Stricture length is predictive of the outcomes Transluminal balloon dilation +/- stent placement for short non-ischemic strictures Endarterectomy After unsuccessful balloon dilation For all types of strictures expect short and nonischemic strictures Urothelial carcinoma Meatal stenosis Dilatation or meatoplasty Pregnancy If asymptomatic with no infection most will resolve spontaneously after delivery If there is infection manage as UTI in pregnancy Complications Pyelonephritis Most common Perinephric abscess Obstructive nephropathy Bladder trabeculation AKI Urosepsis Most serious Urethral stricture Narrowing of the urethral may have restriction of urinary flow Causes Traumatic Iatrogenic instrumentation/catheterisation Congenital Post infectious e.g. urethritis Clinical features May not have symptoms until acute urinary retention Features of bladder outlet obstruction Weak stream Feeling incomplete bladder emptying Straining to urinate Genitourinary pain UTI Ejaculatory dysfunction Ix Uroflowmetry Retrograde urethrography – to visualise urethral strictures Cystourethroscopy – measure extent of stenosis Management Internal urethrotomy: endoscopic transurethral approach – incision at 12 o’clock position releases stricture/scar tissue Urethroplasty open reconstruction with excision of the fibrotic urethral and reanastomosis Permanent stent placement Ureteropelvic Junction Obstruction Ureteral stenosis at the junction of the renal pelvis and ureter Causes Congenial malformation of the SM Aberrant renal pole artery Clinical features Neonates and infants Palpable upper abdominal mass Failure to thrive Recurrent pyelonephritis Children and adults Flank pain or upper abdominal pain May be worsened in states of increased diuresis after caffeine or alcohol consumption Nausea/vomit Recurrent pyelonephritis Haematuria Investigations U/S hydronephrosis IV urography to exclude vesicoureteral reflux and assess ureteral patency Functional renal scintigraphy Management Asymptomatic and mild cases observation Anderson-Hynes pyeloplasty open or laparoscopy resection of the obstructed segment and anastomosis of the upper to the remaining renal pelvis