Urinary Tract Obstruction

Question 1

What are the general causes of urinary tract obstruction?

Answer 1

1. BPH, stones

2. Blood clot, tumour, strictures, iatrogenic post-surgery (haemorrhoid, hip, hernia).

Question 2

What is this a presentation of?

Pain with a tense distended lower abdomen and inability to pass urine. >300ml urine retention on USS.

Answer 2

Urinary tract obstruction

Question 3

What causes unilateral acute upper urinary tract obstruction?

Answer 3

Renal stones

Question 4

What causes acute lower urinary tract obstruction?

Answer 4

BPH (bilateral), urethral strictures, malignancy, anticholinergics, blood clots, alcohol, post-operative, cauda equina.

Question 5

How is a suspected urinary tract obstruction investigated?

Answer 5

1. Urinalysis
2. U&Es - raised creatinine
3. FBC - WCC
4. CT KUB - stones
5. Renal USS - failure to determine cause

Question 6

What is the management for urinary tract obstruction?

Answer 6

1. Evidence of sepsis, hydronephrosis, hydroureter - straight to nephrostomy to relieve obstruction and antibiotics.
2. Upper tract - nephrostomy or ureteric stent
3. Lower - urethral (CI in strictures/large prostate) or suprapubic catheter (used for severe BPH, strictures)

Question 7

What should you always check for before inserting a suprapubic catheter?

Answer 7

Palpable large bladder, otherwise there is a risk of bowel perforation.

Question 8

What are the complications of a urinary tract obstruction?

Answer 8

1. Hyperkalaemia
2. Metabolic acidosis
3. Post-obstructive distress - after relief, large production of urine, provide IV fluids to match.
4. Sodium/bicarbonate losing nephropathy
5. Infection