Urinary Tract Obstruction

Question 1

Causes of urinary tract obstruction (3)

Answer 1

1. Congenital Anomalies
   - urethral valves/strictures
   - bladder neck obstruction
   - uretero-pelvic junction narrowing/obstruction
2. Acquired Obstruction
   - BPH
   - calculi, urolithiasis
   - tumours - prostate, bladder, cervix, uterus
   - inflammation - prostate, ureter, urethra
   - sloughed papillae or blood clots
   - pregnancy, uterine prolapse (kinks ureters)
3. Functional Disorder
   - neurogenic - spinal cord damage, diabetic autonomic neuropathy
   - functional obstruction along urinary tract

Question 2

Associated changes of urinary tract obstruction (3)

Answer 2

1. Hydronephrosis
   - dilation of renal pelvis & calyces w progressive enlargement of the kidney w parenchymal atrophy due to obstruction of urine outflow
2. Pyonephrosis
   - infected hydronephrosis w frank pus in the dilated calyces & pelvis
3. Pyoureter
   - infected hydroureter, contains pus

Question 3

Morphology of hydronephrosis

Answer 3

G:

• enlarged kidney, changes begin in the pelvis with dilation
• later renal cortex is thinned & atrophic

M:

• tubules & Bowman’s spaces are dilated, tubular epithelium is flattened
• later tubular atrophy w fibrosis & eventually glomeruli disappear

Question 4

Effects & complications of urinary tract obstruction

Answer 4

1. Unilateral: typically clinically silent (compensation)

2. Bilateral: oliguria, anuria, after relief of obstruction - post obstructive diuresis