Why a 55-Year-Old Female Develops Overactive Bladder
A 55-year-old woman develops overactive bladder primarily due to age-related changes in bladder function, though the exact cause in most cases remains idiopathic after excluding identifiable pathology. 1, 2
Primary Mechanisms
Idiopathic OAB (Most Common)
- When no identifiable neurological, obstructive, or other pathological cause is found after appropriate evaluation, the diagnosis is idiopathic OAB, which represents the majority of OAB cases in clinical practice. 2
- This is fundamentally a diagnosis of exclusion requiring systematic evaluation to rule out other conditions. 1, 2
Myogenic Dysfunction
- Detrusor muscle instability leading to spontaneous contractions is a primary myogenic cause of OAB. 2
- The bladder muscle develops involuntary contractions during the filling phase, creating the hallmark urgency symptom. 3
Neurogenic Factors
- Neurological diseases or injuries affecting central or peripheral nervous system control of the bladder can contribute to OAB. 2
- The micturition cycle is under complex neural control involving both sympathetic and parasympathetic nervous systems, and disruption at any level can manifest as OAB. 3
Contributing Factors Specific to This Age Group
Hormonal Changes
- Genitourinary syndrome of menopause is a recognized comorbidity that can worsen OAB symptoms and should be optimized. 1
- Estrogen deficiency in postmenopausal women affects bladder and urethral tissue function. 4
Age-Related Bladder Changes
- Although the prevalence of OAB increases with age, it is not a normal consequence of aging. 3
- Age-related changes in bladder receptors and neural pathways may contribute to symptom development. 3
Bladder Outlet Obstruction
- While more common in men with prostatic enlargement, bladder outlet obstruction from pelvic organ prolapse can contribute to OAB in women. 1, 2
Essential Conditions That Must Be Excluded
Before attributing symptoms to idiopathic OAB, clinicians must systematically rule out: 1, 2
- Urinary tract infection - requires urinalysis and culture if indicated 1
- Hematuria not associated with infection - mandates urologic evaluation 1
- Nocturnal polyuria - distinguished by normal or large volume nocturnal voids, unlike the small volume voids in OAB 2
- Neurological disorders - through targeted history and examination 2
- Medication side effects - comprehensive medication review 2
- Urinary retention - post-void residual measurement in patients with emptying symptoms, history of retention, or long-standing diabetes 1
Comorbidities That Exacerbate OAB
The following conditions are known to affect OAB severity and should be addressed: 1
- Constipation 1
- Obesity (weight loss of 8% reduced urgency incontinence episodes by 42% vs. 26% in controls) 1
- Diabetes mellitus 1
- Pelvic organ prolapse 1
- Diuretic use 1
Critical Diagnostic Pitfall
Failure to measure post-void residual in appropriate patients can lead to misdiagnosing overflow incontinence as OAB, resulting in inappropriate antimuscarinic treatment that worsens the underlying condition. 5
- PVR should be performed in patients with concomitant emptying symptoms, history of urinary retention, prior incontinence surgery, or long-standing diabetes. 1
- Antimuscarinics should be used with caution in patients with PVR 250-300 mL. 1, 6
The Multifactorial Nature
The causes of OAB are multifactorial and not completely understood, involving complex interactions between: 3