Urinary tract obstruction

Question 1

Describe examples of ureteric blockage. (6)

Answer 1

Intraluminal - stones, sloughed papillae (necrosis of the lumen, often in diabetes), clots.
Intramural - pelvic ureteric junction obstruction (PUJO), upper tract transitional cell carcinoma, benign strictures (TB, surgery).
Extraluminal - retroperitoneal malignancy, direct obstruction due to malignancy, retroperitoneal fibrosis.

Question 2

Describe examples of acute ureteric obstruction. (4)

Answer 2

Renal colic - flank pain that can radiate to the groin, unilateral and intermittent. Stones or clots or sloughed papillae.
Pyonephrosis - infection of the urine trapped by renal colic, presents like renal colic with infective symptoms.

Question 3

Describe examples of chronic ureteric obstructions.

Answer 3

Generally painless (except PUJO), can be uni- or bilateral. Often presents incidentally, or with renal failure or pyonephrosis (can progress to sepsis).

Question 4

Describe obstructive uropathy. (4)

Answer 4

Renal impairment due to bilateral ureteric (or unilateral in a single kidney), high pressure in the bladder leads to chronic retention. Leads to post-Renal AKI and hyperkalaemia.

Question 5

Describe the diagnostic process of upper tract obstruction. (5)

Answer 5

Ultrasound and CT to look for blockage, but static so can’t to diagnose obstruction.
Diuretic renograph is a functional test that shows how a kidney can be blocked when the radiation count rises in one kidney (as it’s filtered from blood but cannot be excreted).
Can see blockages, vesicles-ureteric reflux (hydronephrosis without obstruction), or pregnancy (progesterone smooth muscle relaxation causes dilation and compression of the ureters).

Question 6

Describe the two types of drainage for renal failure. (4)

Answer 6

JJ stent - drains urine into bladder through an internal method with no kidney injury.
Nephrostomy - external bag of urine drained directly from the renal pelvis. External and with kidney injury.

Question 7

Describe PUJO. (4)

Answer 7

A congenital condition that can present at any age with dilation of renal pelvis but no dilation of ureter. Drinking lots and diuretics (eg alcohol) causes intermittent pain. As the renal pelvis expands and kinks over a blood vessel.

Question 8

Describe retroperitoneal fibrosis. (3)

Answer 8

Idiopathic, malignant, autoimmune or AAA - causing scarring which draws ureters medially, interfering with peristalsis. Stents, steroids, immunosuppresion, uretolysis.

Question 9

Describe acute urinary retention.
Definition (2)
Causes (3)
Treatments (2)

Answer 9

Painful inability to avoid, high residual volume.
Men: BPH, CaP, urethral strictures.
Women: pelvic masses (uterine fibroids)
Both: UTI, constipation, neurological difficulties (eg cauda equina), drugs, anaesthesia.
Treatments: catheterise and record residual volume, history, kidney function, examinations of abdominal, genitals, prostate.
In men: give alpha blockers to relax prostate immediately.

Question 10

Describe chronic urinary retention.
Definition (4)
Treatments (2)
Monitoring (2)

Answer 10

Painless, can void, smaller residual volume.
High pressure - hydronephrosis and renal failure.
Low pressure - normal renal function, no hydronephrosis, big + floppy bladder.
Treatments: catheterise and record residual volume, exam, history.
Monitor for post-obstructive diuresis - pt will be water and salt overloaded following obstruction, so can cause dehydration when diuresis becomes pathological.