Overactive Bladder

Overactive bladder (OAB) is a clinical syndrome characterized by urinary urgency, usually accompanied by frequency and nocturia, with or without urge incontinence, in the absence of infection or other obvious pathology.

Definition

Epidemiology

Prevalence increases with age, affecting up to 16–30% of adults globally
Both men and women are affected, though women may report higher prevalence
Significant impact on quality of life, sleep, and daily activities
Underreported due to embarrassment or normalization of symptoms with aging
Associated with comorbidities such as obesity, diabetes, and neurological disorders
Increases risk of falls in elderly due to urgency and nocturia
Economic burden due to healthcare costs and reduced productivity

Etiology

Idiopathic (most common in older adults)
Neurogenic: Parkinson's disease, multiple sclerosis, spinal cord injury
Bladder outlet obstruction (e.g., benign prostatic hyperplasia in men)
Medication-induced (diuretics, caffeine, alpha-adrenergic antagonists)
Infections or inflammation (excluding active UTI in diagnosis)
Metabolic conditions: diabetes mellitus, obesity
Age-related changes in detrusor muscle function and bladder compliance

Pathophysiology

Detrusor overactivity: involuntary bladder contractions during filling
Altered afferent signaling from bladder to central nervous system
Reduced bladder capacity or compliance
Neurogenic disruption of inhibitory pathways leading to hyperreflexia
Increased urgency sensation with minor bladder filling
Changes in urothelial signaling and neurotransmitter release
Chronic overactivity can lead to remodeling of bladder smooth muscle