Urinary tract obstruction Flashcards
Where might obstructing lesions lie in urinary tract obstruciton?
- Lumen
- Wall of the urinary tract
- Outside the wall of the urinary tract
What are causes of urnary obstruction within the lumen of the urinary tract?
- Calculi
- Blood clot
- Cloughed papilla
- Tumour - renal pelvis, ureter, bladder
What are causes of urinary tract obstruction that originate from in the wall of the lumen?
- Ureteric/Uterovesical stricture
- Congenital bladder neck obstruction
- Urethral stricture
- Congenital urethral valve
- Neuopathic bladder
What are causes of urinary obstruction that originate from outside the ureter?
- Tumours
- Diverticulitis
- Aortic aneurysm
- Retroperitoneal fibrosis
- Accidental ligation
- Retrocaval ureter
- Prostatic obstruction
- Phimosis
What is the pathophysiology of urinary tract obstruction?
Obstruction with continuing urine formation results in:
- Progressive rise in intraluminal pressure
- Dilatation proximal to the site of obstruction
- Compression and thinning of the renal parenchyma
What are features of acute upper urinary tract obstruction?
- Loin to groin pain
- Loin tenderness
- Signs of cause - superimposed infection/enlarged kidney
What are features of chronic upper urinary tract obstruction?
- Flank pain
- Renal failure
- Superimposed infection
- Can have polyuria
What are symptoms of acute urinary retention/acute lower tract obstruction?
- Severe suprapubic pain
- Acute confusion (elderly)
What are signs of acute urinary retention?
- Distended, palpable bladder
- Dull to percussion
What residual volumes might someone have if in acute urinary retention?
400ml - 2L
What are causes of acute urinary retention?
- Prostatic obstruction
- Urethral strictures
- Anticholinergics
- Blood clots
- Alcohol
- Contipation
- Post-op
- Infection
- Neurological
What are complications of chronic urinary retention?
- Overflow incontinence
- Renal failure
- UTI
What are symptoms of chronic urinary retention?
- Urinary frequency
- Hesitancy
- Poor stream
- Terminal dribbling
- Overflow incontinence
What a signs of chronic lower tract obstruction?
- Distended, palpable bladder
- May have nelarged prostate
What are causes of chronic urinary retention?
- Prostatic enlargement
- Pelvic malignancy
- Rectal surgery
- DM
- CNS disease - transverse myelitis, MS
- Zoster - S2-S4
What investigations would you consider performing if you suspected someone had a urinary tract obstruction?
Confirm they are in retention
- Bladder scan
Investigate cause
- Bloods - U+Es, FBC, PSA
- USS KUB
- Consider X-ray/CT KUB
- Consider radionucletide studies
- Consider cystoscopy
What might you find on investgation of FBC and U+E’s in someone with a urinary tract obstruction?
- Raised urea
- Raised creatinine
- Hyperkalaemia
- Anaemia of chronic disease
What might you be looking for on USS when investigating someone with urinary tract obstruction?
Can rule out upper urinary tract dilatation. Ultrasound cannot distinguish a baggy, low-pressure unobstructed system from a tense, high-pressure obstructed one, so that false-positive scans are seen.
When would you consider radionucelotide studies?
Longstanding obstruction - to differentiate true obstructive nephropathy from retention of tracer in a baggy, low-pressure, unobstructed pelvicalyceal system.
How would you manage someone with upper urinary tract obstruction?
Consider following options
- Nephrostomy
- Ureteric stent +/- alpha blockers
- Pyeloplasty - PUJ obstruction
How would you manage acute urinary retention?
- Insert urinary catheter
- Treat cause
- Remove catheter after 2-3 days and trial output
How would you manage someone in chronic urinary retention?
- Asymptomatic - Do not catheterise
- If pain/UTI/Renal impairment - intermittent self-catheterisation
If someone was in clot retention, how would you manage them?
3-way catheter and bladder washout
What are complications that can arise with catheterisation?
- UTI
- Post-decompression haematuria
- Post-obstructive diuresis
- Renal failure
- Electrolyte abnormalities
