Merck Manual

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Urinary Retention


Patrick J. Shenot

, MD, Thomas Jefferson University Hospital

Reviewed/Revised Sep 2023

Urinary retention is incomplete emptying of the bladder or cessation of urination.

Urinary retention may be

  • Acute

  • Chronic

Retention is most common among men, in whom prostate abnormalities or urethral strictures Urethral Stricture Urethral stricture is scarring that obstructs the anterior urethral lumen. Urethral stricture can be Congenital Acquired Anything that damages the urethral epithelium or corpus spongiosum can... read more cause outlet obstruction. In either sex, retention may be due to medications (particularly those with anticholinergic effects, including many over-the-counter drugs), severe fecal impaction Fecal impaction Constipation is difficult or infrequent passage of stool, hardness of stool, or a feeling of incomplete evacuation. (See also Constipation in Children.) No bodily function is more variable and... read more (which increases pressure on the bladder trigone), or neurogenic bladder Neurogenic Bladder Neurogenic bladder is bladder dysfunction (flaccid or spastic) caused by neurologic damage. Symptoms can include overflow incontinence, frequency, urgency, urge incontinence, and retention.... read more in patients with diabetes Diabetes Mellitus (DM) Diabetes mellitus is impaired insulin secretion and variable degrees of peripheral insulin resistance leading to hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia... read more , multiple sclerosis Multiple Sclerosis (MS) Multiple sclerosis (MS) is characterized by disseminated patches of demyelination in the brain and spinal cord. Common symptoms include visual and oculomotor abnormalities, paresthesias, weakness... read more Multiple Sclerosis (MS) , Parkinson disease Parkinson Disease Parkinson disease is a slowly progressive, degenerative disorder characterized by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and eventually gait and/or... read more , or prior pelvic surgery resulting in bladder denervation.

Diagnosis of Urinary Retention

  • Measurement of postvoid residual volume

Diagnosis is obvious in patients who cannot void. In those who can void, incomplete bladder emptying is diagnosed by postvoid catheterization or ultrasonography Ultrasonography Imaging tests are often used to evaluate patients with renal and urologic disorders. Abdominal x-rays without radiopaque contrast agents may be done to check for positioning of ureteral stents... read more showing an elevated residual urine volume. A volume < 50 mL is normal; < 100 mL is usually acceptable in patients > 65 but abnormal in younger patients. Other tests (eg, urinalysis, blood tests, ultrasonography, urodynamic testing, cystoscopy Cystoscopy Cystoscopy is insertion of a rigid or flexible fiberoptic instrument into the bladder. Indications include the following: Helping diagnose urologic disorders (eg, bladder tumors, calculi in... read more Cystoscopy , cystography) are done based on clinical findings.

Treatment of Urinary Retention

  • Urethral catheterization and treatment of cause

No treatment is effective for impaired bladder contractility; however, reducing outlet resistance with alpha-adrenergic blockers may increase bladder emptying.

Intermittent self-catheterization or indwelling catheterization is often required. An indwelling suprapubic tube or urinary diversion is a last resort.

Key Points

  • Mechanisms include impaired bladder contractility, bladder outlet obstruction, and detrusor-sphincter dyssynergia.

  • Incomplete retention is diagnosed by a postvoid residual volume > 50 mL (> 100 mL in patients > 65).

  • Prescribe urethral catheterization and treat the cause of retention.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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