A 73-year-old man comes to the emergency department saying, "I can't pee!" The patient has not been able to produce any urine over the past 24 hours and has had lower abdominal discomfort. He reports that his urine flow has been weak for the past year. He has had no fever, weakness, numbness, dysuria, back pain, or hematuria. The patient's other medical conditions include myelodysplastic syndrome, hypertension, and lumbar strain. He does not use tobacco, alcohol, or illicit drugs. Temperature is 36.9 C (98.4 F), blood pressure is 150/110 mm Hg, pulse is 94/min, and respirations are 16/min. The abdomen is soft with lower abdominal tenderness and dullness to percussion. Neurologic examination shows absent Achilles tendon reflexes bilaterally but is otherwise unremarkable. Straight catheterization of the bladder produces 800 mL of urine. Which of the following is most likely responsible for this patient's current condition?
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This patient with a history of a weakened urinary stream now has acute urinary retention, characterized by the inability to voluntarily micturate, with resulting bladder distension and suprapubic pain. Although the differential for acute urinary retention is broad (eg, neurologic disorder, medications, infection), the most common etiology is bladder outflow obstruction (BOO).
In men, BOO is most often due to benign prostatic hyperplasia (BPH); other etiologies include malignancy (eg, prostate, rectal), urethral stricture, and urolithiasis. BPH is more common with increasing age; up to 70% of men age >70 have lower urinary tract symptoms attributable to the disorder. Common symptoms include slow urinary stream, postvoid dribbling, hesitancy, urgency, and nocturia. Physical examination reveals an enlarged, nontender prostate. Management of BPH causing BOO includes acute decompression with urethral or suprapubic catheterization. Definitive therapies include alpha blockers (eg, terazosin, tamsulosin) and 5-alpha reductase inhibitors (eg, finasteride); surgical intervention (eg, transurethral resection of the prostate [TURP]) may be indicated.
Although spinal cord compression can cause acute urinary retention (or bowel or bladder incontinence) and, occasionally, decreased reflexes (although hyperreflexia can also be seen), patients typically have severe back pain, decreased rectal tone, and reduced strength or sensation in the lower extremities. Achilles tendon reflex decreases with age, and its absence is common in older individuals (Choice E).
(Choice A) Acute prostatitis can cause abdominal pain and acute urinary retention, but patients are typically acutely ill with signs of systemic illness (eg, fever, chills). In addition, they typically have dysuria and urinary urgency.
(Choice C) Detrusor sphincter dyssynergia results from simultaneous activation of the detrusor muscle and the urethral sphincter, resulting in BOO. It typically occurs in patients with neurologic disorders (eg, spinal cord injury, multiple sclerosis) and would be unexpected in this patient.
(Choice D) Poor urethral sphincter function would result in stress incontinence with urinary leakage, not urinary retention. Stress incontinence is most frequently seen in men after prostate surgeries (eg, TURP).
Educational objective:
Benign prostatic hyperplasia causes slow voiding, postvoid dribbling, hesitancy, urgency, or nocturia; complications include bladder outlet obstruction with acute urinary retention. Management of acute retention includes bladder decompression with urethral or suprapubic catheterization; definitive treatment includes alpha blockers (eg, terazosin, tamsulosin), 5-alpha reductase inhibitors (eg, finasteride), and possibly surgery.