Introduction

Overactive bladder (also known as OAB or OAB Syndrome) is defined as a medical condition having the symptoms of urinary frequency (>8 micturitions/24 hours), urgency with a difficulty to defer and nocturia with or without urge incontinence, in the absence of local pathological or metabolic factors that would account for these symptoms.¹ These symptoms even in the absence of incontinence can have profound and stigmatizing effect on quality of life. However, they are under-reported by a majority of patients in lieu of the mis-beliefs such as incontinence is normal post-partum and with elderly age.²

The international continence society (ICS) has suggested OAB to be a urodynamic diagnosis of Detrusor Over activity (DO).  ICS defines this as an involuntary rise in detrusor pressure during filling of the bladder in a laboratory situation in a conscious co-operative patient.

Urinary frequency can be reliably measured by the maintenance of a voiding diary. Conventionally, up to seven micturition episodes during waking hours has been considered normal,⁴ but this number isn’t a constant and varies based upon hours of sleep, fluid intake, comorbid medical conditions and several other factors.

Urgency is defined by International Continence Society as the "complaint of a sudden, compelling desire to pass urine which is difficult to defer."⁵ It is considered to be the hallmark symptom of OAB, however it is difficult to define it for research or clinical purposes.

Nocturia is the complaint of interruption of sleep one or more times because of the need to void.⁵ 

Urge incontinence is defined as the involuntary leakage of urine, associated with a sudden compelling desire to void.⁶ Incontinence episodes can be measured reliably with a diary, and the quantity of urine leakage can be measured with pad tests.

1. Nitti VW. Clinical Impact of Overactive Bladder. Rev Urol. 2002;4(Suppl 4):S2–6.
2. Allison SJ, Gibson W. Mirabegron, alone and in combination, in the treatment of overactive bladder: real-world evidence and experience. Ther Adv Urol. 2018 Sep 26;10(12):411–9.
3. Irwin DE, Milsom I, Hunskaar S, Reilly K, Kopp Z, Herschorn S, et al. Population-based survey of urinary incontinence, overactive bladder, and other lower urinary tract symptoms in five countries: results of the EPIC study. Eur Urol. 2006 Dec;50(6):1306–14; discussion 1314-1315.
4. Fitzgerald MP, Brubaker L. Variability of 24-hour voiding diary variables among asymptomatic women. J Urol. 2003 Jan;169(1):207–9.
5. Haylen BT, de Ridder D, Freeman RM, Swift SE, Berghmans B, Lee J, et al. An International Urogynecological Association (IUGA)/International Continence Society (ICS) joint report on the terminology for female pelvic floor dysfunction. Neurourol Urodyn. 2010;29(1):4–20.
6. Abrams P, Cardozo L, Fall M, Griffiths D, Rosier P, Ulmsten U, et al. The standardisation of terminology in lower urinary tract function: report from the standardisation sub-committee of the International Continence Society. Urology. 2003 Jan;61(1):37–49.
7. Chapple CR, Cardozo L, Nitti VW, Siddiqui E, Michel MC. Mirabegron in overactive bladder: a review of efficacy, safety, and tolerability. Neurourol Urodyn. 2014 Jan;33(1):17–30.
8. Warren K, Burden H, Abrams P. Mirabegron in overactive bladder patients: efficacy review and update on drug safety. Ther Adv Drug Saf. 2016 Oct;7(5):204–16.
9. Tyagi P, Tyagi V. Mirabegron, a β₃-adrenoceptor agonist for the potential treatment of urinary frequency, urinary incontinence or urgency associated with overactive bladder. IDrugs Investig Drugs J. 2010 Oct;13(10):713–22.
10. Scheife R, Takeda M. Central nervous system safety of anticholinergic drugs for the treatment of overactive bladder in the elderly. Clin Ther. 2005 Feb;27(2):144–53.
11. Sexton CC, Coyne KS, Thompson C, Bavendam T, Chen C-I, Markland A. Prevalence and effect on health-related quality of life of overactive bladder in older americans: results from the epidemiology of lower urinary tract symptoms study. J Am Geriatr Soc. 2011 Aug;59(8):1465–70.
12. Willis-Gray MG, Dieter AA, Geller EJ. Evaluation and management of overactive bladder: strategies for optimizing care. Res Rep Urol. 2016 Jul 27;8:113–22.
13. Eapen RS, Radomski SB. Review of the epidemiology of overactive bladder. Res Rep Urol. 2016 Jun 6;8:71–6.
14. Khullar V, Amarenco G, Angulo JC, Cambronero J, Høye K, Milsom I, et al. Efficacy and tolerability of mirabegron, a β(3)-adrenoceptor agonist, in patients with overactive bladder: results from a randomised European-Australian phase 3 trial. Eur Urol. 2013 Feb;63(2):283–95.
15. Hesch K. Agents for treatment of overactive bladder: a therapeutic class review. Proc Bayl Univ Med Cent. 2007 Jul;20(3):307–14.
16. Andersson K-E, Van Kerrebroeck P. Pharmacotherapy for Nocturia. Curr Urol Rep [Internet]. 2018 [cited 2019 Oct 19];19(1). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5807446/
17. Herschorn S, Staskin D, Tu LM, Fialkov J, Walsh T, Gooch K, et al. Patient-reported outcomes in patients with overactive bladder treated with mirabegron and tolterodine in a prospective, double-blind, randomized, two-period crossover, multicenter study (PREFER). Health Qual Life Outcomes [Internet]. 2018 Apr 19 [cited 2019 Oct 20];16. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5909214/

Dr Darpan Bansal

Department of General Surgery, Sri Guru Ram Das Institute of Health Sciences and Research, Amritsar