Chapter 24 · Acute lower urinary tract conditions
Acute urinary retention
Definition
Acute urinary retention (AUR) is the inability to void spontaneously despite a distended bladder.
Causes: BPH, urethral stricture, stones, clots, neurogenic dysfunction, postoperative conditions, medications.
Clinical assessment
- Severe lower abdominal pain, restlessness.
- Prolonged retention may cause overflow incontinence (involuntary urinary leakage).
- Assess bladder urine volume by percussion, palpation, and ultrasonography.
- History: previous urological disease, surgery, medication use.
Danger signs
- Fever, rigors.
- Hypotension.
- Oliguria/anuria (postrenal AKI).
- Rising creatinine.
Diagnosis
- Ultrasonography to assess bladder urine volume and hydronephrosis.
- Laboratory tests: creatinine, electrolytes, CBC, urinalysis, and culture if infection is suspected.
- Renal ultrasonography if upper tract obstruction is suspected.
Emergency management
- Bladder catheterization is the main method.
- Select catheter diameter according to the clinical situation. When a stricture is suspected, do not make repeated blind attempts with a curved-tip catheter.
- If catheterization is not possible, perform suprapubic cystostomy under ultrasound guidance.
Once the catheter has been safely inserted, allow free and complete bladder drainage. Routine catheter clamping and staged emptying do not prevent postobstructive diuresis.
After drainage
- Monitor hemodynamics, hematuria, and hourly urine output.
- Monitor creatinine and electrolytes; individualize fluid and electrolyte replacement in marked postobstructive diuresis.
- Assess the cause of retention.
- Plan definitive treatment (TURP, urethrotomy, etc.).
Algorithm
| Step | Action |
|---|---|
| 1 | Confirm retention (examination, ultrasonography) |
| 2 | Assess infection and kidney function |
| 3 | Bladder catheterization |
| 4 | If catheterization is not possible → cystostomy |
| 5 | Monitor for postobstructive diuresis |
| 6 | Plan definitive treatment |
Neurological red flags
In acute urinary retention, rule out cauda equina syndrome if there is new leg weakness or numbness, saddle anesthesia, bilateral radicular pain, bowel dysfunction, sexual dysfunction, or rapidly progressive neurological deficits.
- Perform and document a neurological examination of the lower limbs and perineal sensation.
- Arrange urgent lumbosacral MRI and immediate neurosurgical or relevant specialist consultation.
- Catheterization relieves urinary retention but does not replace urgent investigation and decompression of neural structures.