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Overactive bladder syndrome (OAB-S)

Urinary urgency, with or without urgency incontinence, usually with urinary frequency and nocturia (the need to wake and pass urine at night), in the absence of a urinary tract infection or other obvious pathology.

Urinary urgency, with or without urgency incontinence, usually with urinary frequency and nocturia (the need to wake and pass urine at night), in the absence of a urinary tract infection or other obvious pathology.

International Continence Society (2010)

Pathophysiology

  • Neurogenic theory: Reduction in inhibitory neural impulses and increase in afferent impulses from bladder triggering the voiding reflex
  • Myogenic theory: Detrusor muscle becomes more sensitive to cholinergic stimulation leading to increased spontaneous activity
  • Autonomous bladder theory: Alteration/exacerbation of phasic activity is generated by muscarinic stimulation
  • Afferent signaling theory: Spontaneous bladder contractions during filling result in increased afferent output and hence the awareness of bladder filling

Clinical features

  • OAB dry (⅔ cases): OAB without urinary incontinence (UI)
  • OAB wet (⅓ cases): OAB with urge urinary incontinence (UUI)
Overlap in lower urinary tract (LUT) conditions | Dr Anthony Pdw. (2020) Urinary troubles for more than the ageing – Drug Discovery World (DDW). Retrieved November 09, 2020, from https://www.ddw-online.com/urinary-troubles-for-more-than-the-ageing-944-200310/
Prevalence of different OAB symptoms, from a European population-based prevalence study. | Milsom I, Abrams P, Cardoza L, et al. How widespread are the symptoms of overactive bladder and how are they managed? A population-based prevalence study. BJU Int. 2001;87:760–766.

Diagnosis

Diagnosis of OAB is considered in the absence of urinary tract infection (UTI), metabolic disorders (affecting urination), or urinary stress incontinence (generated by effort or overexertion).

Overactive bladder syndrome: Management and treatment options – Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/investigations-for-overactive-bladder-syndrome_tbl1_233397551 [accessed 8 Nov, 2020]

Management

Life style changes:

Lifestyle modification includes a variety of behavioral changes that can reduce and even eliminate OAB symptoms
  • Weight loss and exercise
  • Fluid restriction
  • Bowel regulation
  • Cessation of smoking
  • Bladder training (habit-training schedules)

Pelvic floor exercises:

  • Kegel exercises
  • Vaginal weight training
  • Pelvic floor exercise with biofeedback
  • Pelvic-floor electrical stimulation

Anticholinergic (antimuscarinics) drugs

Pharmacological management for relaxation of the detrusor muscle and consequently to improve patient symptoms.
  • Fesoterodine, oxybutynin, solifenacin, tolterodine, trospium, darifenacin
  • Adverse effects:
    • Dry mouth & constipation (M/C and bothersome)
    • Other adverse effects: Blurred vision, and somnolence
    • Serious adverse effects: Confusion, cognitive, and cardiac effects (prolongation of QT interval)
  • Contraindications: Closed angle glaucoma, myasthenia gravis, severe ulcerative colitis, toxic megacolon, or intestinal obstruction

Resilient OAB

Cases that received full dose of 1-2 antimuscarinic drugs without a sufficient clinical improvement or in those who stopped medical therapy due to adverse effects
  • Mirabegron 3 agonist): Similar efficacy to most antimuscarinics with a lower incidence of dry mouth, the most common adverse event reported with antimuscarinics and one of the main causes of discontinuation of treatment.
  • Botulinum neurotoxin: Direct cystoscopic multiple injections of the detrusor muscle to selectively block presynaptic release of acetylcholine from nerve endings and as a result decrease contractility, and muscular atrophy at the injection site
  • Posterior tibial nerve neuromodulation: External electrical signal sent through tibial nerve retrograde to sacral plexus, through a small needle inserted into the lower leg near the ankle
  • Sacral neuromodulation: S3 nerve root stimulation by an implanted electrical pulse generator

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