Urinary retention can be either acute or chronic. The most common cause of retention is outlet obstruction secondary to benign prostatic hypertrophy in men although medication use, acute neurologic dysfunction, urinary tract bleeding or calculi, and other anatomic obstruction are also common causes in both sexes. Acute syndromes typically present with rapid onset of lower abdominal pain occasionally radiating to the lower back. Patients typically complain of difficulty voiding but some may not volunteer this information. Chronic obstruction usually presents with lower abdominal pain and the patient may note incomplete voiding or the need to void frequently.
The history should address previous episodes of obstruction, recent medication changes and over-the-counter medicine use. Assess for any history of trauma or neurologic disability or symptoms of infection. It is critical to know if any recent urologic procedures or urinary catheterizations have been performed. The duration of symptoms is also important as it is associated with the development of postobstructive diuresis and renal dysfunction.
Physical examination should address the functional and anatomic assessment of the lower urinary tract. Palpate the abdomen for a suprapubic mass corresponding to the distended urinary bladder. The penis should be examined for stricture at the meatus or palpable abnormalities of the penile urethra. The female lower urinary tract should be evaluated for bladder prolapse or stricture of the urethral meatus. In men the prostate should be assessed for size, texture, and tenderness. Perineal sensation and anal sphincter tone should be documented. A comprehensive neurologic examination should be performed.
Bedside ultrasound can be very helpful in distinguishing both the degree of obstruction and in discriminating obstruction from the sensation of fullness associated with bladder spasm in conditions like inflammatory or infectious cystitis. The patient should first be encouraged to attempt to void. After a voiding attempt the bladder is imaged with a low-frequency sector format probe in both the transverse and sagittal views (Fig. 54-1). Many manufacturers have a calculation package available to estimate the retained urine volume. Residual volumes > 50 to 150 cc are consistent with urinary retention, however, volumes are typically greater than 300 cc.
Transverse and sagittal views of the urinary bladder. The prostate is visualized as a medium echogenicity structure posterior and caudal to the bladder. Anterior-posterior, cradio-caudal, and transverse measurements of the bladder are obtained for calculation of the bladder volume. (Reproduced with permission from Casey Glass, MD.)
The goals of emergency department care are relieving the discomfort of retention, assessing for any secondary injury to the renal system, and treatment of the primary cause of retention.
Most patients with bladder outlet obstruction are in distress, and passage of a urethral catheter alleviates their pain and their urinary retention. Copious intraurethral lubrication including a topical anesthetic (2% lidocaine jelly) should be used, and a 16-French Coudé catheter is recommended ...