MKSAP Quiz: 6-month history of incontinence
A 68-year-old woman is evaluated for a 6-month history of incontinence typified by continuous leakage and dribbling. Following a physical exam and urinalysis, what is the most appropriate management?
A 68-year-old woman is evaluated for a 6-month history of incontinence typified by continuous leakage and dribbling. She reports no back pain, dysuria, or fever. Medical history is significant for a 30-year history of type 2 diabetes mellitus and a 10-year history of hypertension and hyperlipidemia. Medications include benazepril, metformin, and rosuvastatin.
On physical examination, blood pressure is 147/76 mm Hg, and pulse rate is 92/min. On abdominal examination, the bladder is palpable just above the pubic symphysis. Foot examination demonstrates dry feet, loss of sensation to monofilament testing, and vibration up to the ankles. Lower extremity tendon reflexes are absent.
Urinalysis results are normal.
Which of the following is the most appropriate management?
A. Botulinum toxin injection
B. Oxybutynin
C. Postvoid residual urine volume measurement
D. Urodynamic testing
MKSAP Answer and Critique
The correct answer is C. Postvoid residual urine volume measurement. This content is available to MKSAP 18 subscribers as Question 73 in the General Internal Medicine section. More information about MKSAP is available online.
Obtaining a postvoid residual urine volume is the most appropriate next step in the management of this patient. This patient likely has neurogenic bladder with overflow incontinence, characterized by constant urine leaking and dribbling and a palpable bladder. Overflow incontinence is more commonly found in men with prostatic hyperplasia and bladder outlet obstruction. However, this patient has long-standing diabetes mellitus and evidence of autonomic neuropathy (resting tachycardia, dry feet, distended bladder) on physical examination. Postvoid residual bladder volume measurement with ultrasonography can confirm the presence of large volumes of urine in the bladder, supporting the clinical diagnosis.
Botulinum toxin injection is used in the treatment of urgency urinary incontinence that persists despite behavioral and pharmacologic therapies. A systematic review concluded that botulinum toxin injection was superior to placebo in reducing incontinence in patients with urgency incontinence unresponsive to more conservative measures. Symptoms are typically reduced for 3 to 6 months, and then reinjection is required. Such injections can worsen overflow incontinence and would be contraindicated in this patient.
Oxybutynin is an anticholinergic agent used in the treatment of urgency incontinence. Anticholinergic drugs (oxybutynin, darifenacin, fesoterodine, solifenacin, tolterodine, trospium) block the muscarinic cholinergic receptors and decrease bladder contractility. The use of oxybutynin would worsen overflow incontinence due to neurogenic bladder and would be contraindicated in this patient.
Urodynamic testing is not recommended in the initial evaluation of urinary incontinence. Urodynamic testing consists of measuring bladder pressure during bladder filling, urine flow rate, and pressure-flow correlations and testing for sphincter deficiency. Urodynamic studies are required only for complex cases in which neurologic disease is suspected or surgical intervention is being considered.
Key Point
- A postvoid residual urine volume, determined by ultrasonography, can confirm a suspected case of overflow urinary incontinence.