Causes of Urinary Retention in the Elderly
Benign prostatic hyperplasia (BPH) is the most common cause of urinary retention in elderly patients, accounting for 53% of cases, particularly in men aged 60 and older where BPH prevalence reaches 60% by age 60 and 80% by age 80. 1, 2, 3
Primary Obstructive Causes
In Men
- BPH causes urinary retention through two mechanisms: the static component (direct bladder outlet obstruction from enlarged prostatic tissue) and the dynamic component (increased smooth muscle tone and resistance within the enlarged gland) 1, 4
- Acute urinary retention from BPH increases dramatically with age: from 6.8 episodes per 1,000 patient-years in the general population to 34.7 episodes in men aged 70 and older 1
- Prostatitis can cause acute inflammatory obstruction leading to retention 2
In Women
- Pelvic organ prolapse, cystoceles, and other pelvic organ abnormalities frequently cause obstructive retention 5, 2
Medication-Induced Causes
Up to 10% of urinary retention episodes are attributable to medications, with elderly patients at particularly high risk due to polypharmacy and existing comorbidities. 6
High-Risk Medication Classes
- Anticholinergic medications (antipsychotics like risperidone, antidepressants, anticholinergic respiratory agents) impair detrusor contractility 7, 6
- Alpha-adrenergic agonists increase bladder outlet resistance 6
- Opioids and anesthetics depress detrusor function 6
- Benzodiazepines affect central nervous system control of micturition 6
- NSAIDs and calcium channel antagonists can impair bladder contractility 6
Neurogenic Causes
Detrusor Underactivity (DU)
- Detrusor underactivity affects nearly two-thirds of incontinent nursing home residents urodynamically and represents a major underdiagnosed geriatric condition 8
- DU results from axonal degeneration, muscle loss, and fibrosis in the detrusor muscle 8
- Multiple risk factors contribute: chronic retention itself, estrogen deficiency, infection, inflammation, and aging 8
Neurologic Lesions
- Cortical, spinal, or peripheral nerve lesions disrupt the complex micturition pathway 2
- Autonomic insufficiency from diabetes causes neurogenic bladder and overflow retention 5
Infectious and Inflammatory Causes
- Urinary tract infections can cause acute retention through inflammatory edema and pain 5
- Cystitis and urethritis create inflammatory obstruction 2
- Vulvovaginitis and candida vaginitis (particularly in diabetic elderly women) contribute to retention 5
Functional and Metabolic Causes
- Fecal impaction from autonomic insufficiency mechanically obstructs the bladder outlet 5
- Restricted mobility prevents timely voiding and leads to chronic retention 5
- Polyuria from uncontrolled diabetes (glycosuria) overwhelms bladder capacity 5
Mixed Pathology: Detrusor Hyperactivity with Impaired Contractility (DHIC)
- DHIC represents a particularly challenging geriatric syndrome where detrusor overactivity coexists with impaired contractility, making treatment difficult since anticholinergics worsen retention while bethanechol fails to improve emptying 8
Critical Clinical Pitfalls
- Do not assume infection based solely on urinary symptoms in the elderly—atypical presentations (confusion, functional decline, falls) are common, and asymptomatic bacteriuria is highly prevalent 5
- Do not overlook medication review—polypharmacy potentiates anticholinergic burden and drug interactions that impair micturition 7, 6
- Do not miss chronic retention presenting as overflow incontinence—post-void residual measurement is essential to differentiate true incontinence from retention with overflow 5, 8
- In men, always perform digital rectal examination to assess prostate size and exclude prostate cancer as a cause of obstruction 1