Urinary Tract Obstruction Flashcards
Causes of obstruction
Luminal:
• Stones
• Blood clots
• Sloughed papilla
Mural:
• Stricture
• Tumour: renal, ureteric, bladder
• Neuromuscular dysfunction
Extramural:
• Prostatic enlargement
• Abdo / pelvic mass / tumour
• Retroperitoneal fibrosis
Presentation of acute obstruction
• Upper Urinary Tract
- Loin to groin pain
• Lower Urinary Tract
- Bladder outflow obstruction
- Suprapubic pain with distended palpable bladder
Presentation of chronic obstruction
• Upper Urinary Tract
- Flank pain
- Renal failure
• Lower Urinary Tract - Frequency, hesitancy, poor stream, terminal dribbling, overflow incontinence - Distended, palpable bladder - ± large prostate PR
Investigations for urinary obstruction
• Bloods: FBC, U+E • Urine: dip, MC+S • Imaging - US: hydronephrosis or hydroureter - Anterograde / retrograde ureterograms - Radionucleotide imaging: renal function - CT / MRI • DRE - BPH
Mx of obstruction
Upper Urinary Tract:
• Nephrostomy
• Ureteric stent
Lower Urinary Tract
• Urethral or suprapubic catheter
- May be a large post-obstructive diuresis
Causes of urinary retention
Obstructive: • Mechanical • Dynamic: ↑ smooth muscle tone (α-adrenergic) - Post-operative pain - Drugs
Neurological: • Interruption of sensory or motor innervation - Pelvic surgery - MS - DM - Spinal injury/ compression
Myogenic:
• Over-distension of the bladder
- Post-anaesthesia
- High EtOH intake
Clinical feature of urinary retention
- Suprapubic tenderness
- Palpable bladder
- Dull to percussion
- Can’t get beneath it
• Large prostate on PR
- Check anal tone and sacral sensation
• <1L drained on catheterisation
Investigations for urinary retention
• Blood: FBC, U+E, PSA (prior to PR) • Urine: dip, MC+S • Imaging - USS: bladder volume, hydronephrosis - Pelvic XR
Mx of urinary retention
Conservative: • Analgesia • Privacy • Walking • Running water or hot bath
Catheterise:
• Hrly urine output monitoring
• Tamsulosin: ↓ risk of recatheterisation after retention
• TWOC after 24-72h
Chronic urinary retention classification
• High Pressure
- High detrusor pressure at end of micturition
- Typically bladder outflow obstruction
- bilateral hydronephrosis and ↓ renal function
• Low Pressure
- Low detrusor pressure at end of micturition
- Large volume retention with very compliant bladder
- Kidney able to excrete urine
- No hydronephrosis \ normal renal function
Mx of high pressure chronic urinary retention
• Catheterise if - Renal impairment - Pain - Infection • Hrly UO + replace: post-obstruction diuresis • Consider TURP before TWOC
TURP
Trans urethral resection of prostate
Mx of low pressure chronic urinary retention
Avoid catheterisation if possible - risk of infection
• Early TURP
Suprapubic Catheterisation
Advantages • ↓ UTIs • Avoids risk of urethral stricture formation • TWOC w/o catheter removal • Pt. preference: ↑ comfort • Maintain sexual function
Disadvantages
• More complex
• Serious complications can occur
CI
• Known or suspected bladder carcinoma
• Undiagnosed haematuria
• Previous lower abdominal surgery - adhesion of small bowel to abdo wall
