Lysanne Campeau, MD, CM, PhD, FRCSC
Victor W. Nitti, MD, FACS
BASICS
DESCRIPTION
• Detrusor overactivity (DO) is occurrence of involuntary detrusor contractions during filling cystometry
– Spontaneous or provoked
– Contractions produce a wave form on cystometrogram of variable duration and amplitude
– Phasic or terminal
– Can be associated with symptoms
– Neurogenic DO: DO with evidence of a relevant neurologic disorder
– Idiopathic DO: DO without a neurologic cause
EPIDEMIOLOGY (1,2)
• DO is a common cause of symptoms of overactive bladder (OAB) syndrome, however since it is defined by urodynamics, it may not be documented if urodynamics are not preformed
• Symptoms associated with DO (urgency, frequency, and urgency incontinence) are more commonly treated rather than DO per se
• OAB is a symptom complex and is diagnosed without urodynamics and therefore may be diagnosed in the presence or absence of DO
• Approximately one-third of patients with OAB have incontinence
– OAB is defined as urinary urgency, usually accompanied by frequency and nocturia, with or without incontinence, in the absence of urinary tract infection (UTI) or other obvious pathology
– Urinary incontinence accounts for 2% of healthcare cost in the United States
Prevalence
• OAB present in 17% of women and 16% of men
– Increases with age
• DO present in 33% of women with OAB
• DO is present in 36% of patients with no OAB symptoms
RISK FACTORS
• Neurogenic and idiopathic DO
– Most neurologic disorders are risk factors for DO (ie, stroke, neurodegenerative disorders, multiple sclerosis)
– Pelvic surgeries, metabolic syndrome, diabetes, pelvic floor disorders, bladder outlet obstruction
PATHOPHYSIOLOGY
• Increased connectivity and excitability between detrusor muscle and nerves
• Inflammation
• Increased afferent activity
• Neurologic lesions of the CNS above the sacral micturition center
ASSOCIATED CONDITIONS
OAB, pelvic floor disorders, urinary incontinence, bladder outlet obstruction, neurologic lesions above the sacral micturition center, detrusor external sphincter dyssynergia
GENERAL PREVENTION
• Avoiding large fluid intake or the consumption of “bladder irritants” such as caffeine.
• Timed voiding and avoiding bladder overdistension
DIAGNOSIS
ALERT
DO, by definition can only be diagnosed by urodynamics. Therefore it is more practical to talk in terms of diagnosing OAB.
HISTORY (3)
• Past medical and surgical history
• Medications (diuretics, psychoactive drugs)
• Lower urinary tract symptoms survey
• Women with DO and OAB:
– Are twice as likely to have urge urinary incontinence.
– Have a higher symptom score on questionnaires
– Higher episodes of daytime voiding and nocturia
– Have lower functional bladder capacities
PHYSICAL EXAM
• Rule out the presence of exacerbating conditions
– Pelvic and vaginal exam
– Neurologic exam: Peripheral sensation and motor assessment
– Postvoid residual
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• Urinalysis: Determine presence of infection, hematuria, glycosuria
• Urine culture: Rule out infection
• Urine cytology: Rule out malignancy
Diagnostic Procedures/Surgery
• Urodynamic testing
– Filling cystometry: Measurement of the pressure/volume relationship of the bladder during filling
Imaging
• Can involve videourodynamics with cystogram and voiding cystourethrogram
– Renal ultrasound can also rule out the presence of hydronephrosis caused by high bladder pressures
Pathologic Findings
DO is characterized by the presence of contractions that produce a wave form on cystometrogram of variable duration and amplitude
DIFFERENTIAL DIAGNOSIS
• Bladder calculi
• Bladder cancer/carcinoma in situ
• Bladder outlet obstruction/Prostatic hypertrophy
• Congestive heart failure
• Detrusor external sphincter dyssynergia
• Diabetes
• Interstitial cystitis/Painful bladder syndrome
• Pelvic pain syndrome
• Medications
• Neurogenic bladder
• Pelvic organ prolapse
• Polyuria/polydipsia
• Sexually transmitted infection
• Stress incontinence
• Testing artifact during UDS evaluation (false positive)
• Urethral diverticulum
• UTI
TREATMENT
GENERAL MEASURES
• Treatment aimed at inhibiting involuntary detrusor contractions and decreasing intravesical pressures
• There are a number of options used to treat symptoms associated with DO. Only antimuscarinics, botulinum toxin, and augmentation cystoplasy have been proven to actually reduce or eliminate DO
• Behavioral modifications: Timed voiding, decrease fluid intake, avoid caffeine
– Pelvic floor exercises (Kegel): With or without biofeedback
MEDICATION
• Antimuscarinics: Inhibit the effect of acetylcholine at postjunctional muscarinic receptors on detrusor muscle cells
– Tolterodine (2–4 mg/d)
– Trospium XR (60 mg/d)
– Darifenacin (7.5–15 mg/d)
– Solifenacin (5–10 mg/d)
– Oxybutynin (IR 7.5–20 mg/d, XL 5–30 mg/d, patch twice weekly),
– Fesoterodine (4–8 mg/d)
• β3-adrenergic receptor agonist: Promotes detrusor muscle relaxation
SURGERY/OTHER PROCEDURES
• Intravesical botulinum toxin (OnabotulinumtoxinA) injection:
– Approved for treatment of neurogenic detrusor overactivity and OAB
• Sacral neuromodulation: Stimulation of S3 nerve root (InterStim)
• Posterior tibial nerve stimulation (PTNS): Urgent PCTM
• Augmentation cystoplatsy/Urinary diversion: Increase functional bladder capacity and reduce intravesical pressure
• Pelvic floor reconstruction: If concomitant pelvic floor disorder
Additional Therapies
• Infection prophylaxis
• Clean intermittent catheterization
– Decrease bladder pressure if urinary retention present
ONGOING CARE
PROGNOSIS
• Stepwise approach to treatment with least invasive pharmacologic options as first line
– Patient may develop refractory OAB that may require second- or third-line treatment
COMPLICATIONS
• Urinary incontinence: Social and hygienic issues
• UTIs
• Renal deterioration
– High economic burden
FOLLOW-UP
Patient Monitoring
• Periodic patient follow-up
– Symptom assessment
– Treatment compliance
– Minimize medication side effects
– Repeat urodynamic evaluation
Patient Resources
• National Association For Continence: www.nafc.org/bladder-health
• National Kidney and Urologic Diseases Information Clearing House: http://kidney.niddk.nih.gov/kudiseases/pubs/urodynamic/
REFERENCES
1. Garnett S, Abrams P. The natural history of the overactive bladder and detrusor overactivity. A review of the evidence regarding the long-term outcome of the overactive bladder. J Urol. 2003;169:843–849.
2. Haylen B, de Ridder D, Freeman RM, et al. An International Urogynecological Association (IUGA)/International Continence Society (ICS) joint report on the terminology for female pelvic floor dysfunction. Neurourol Urodyn.2010;29:4–20.
3. Abrams P, Chapple CR, Jünemann KP, et al. Urinary urgency: A review of its assessment as the key symptom of the overactive bladder syndrome. World J Urol. 2012;30:385–392.
ADDITIONAL READING
• Abrams P, Cardozo L, Fall M, et al. The standardization of terminology of lower urinary tract function: Report from the standardization sub-committee of the International Continence Society. Neurourol Urodyn. 2002;21(2):167–178.
• Gormley EA, Lightner DJ, Burgio KL, et al. Diagnosis and treatment of overactive bladder (non-neurogenic) in adults: AUA/SUFU guideline. J Urol. 2012;188(suppl 6):2455–2463.
• Kanai A, Zabbarova I, Oefelein M, et al. Mechanisms of action of botulinum neurotoxins, β3-adrenergic receptor agonists, and PDE5 inhibitors in modulating detrusor function in overactive bladders: ICI-RS 2011. Neurourol Urodyn. 2012;31(3):300–308.
• Winters JC, Dmochowski RR, Goldman HB, et al. Urodynamic studies in adults: AUA/SUFU guideline. J Urol. 2012;188(6 suppl):2464–2472.
See Also (Topic, Algorithm, Media)
• Detrusor Overactivity Image 
• Incontinence, Urinary, Adult Female
• Incontinence, Urinary, Adult Male
• Overactive Bladder (OAB)
• Urgency, Urinary (Frequency and Urgency)
• Sacral Neuromodulation
CODES
ICD9
• 596.51 Hypertonicity of bladder
• 788.41 Urinary frequency
• 788.63 Urgency of urination
ICD10
• N32.81 Overactive bladder
• R35.0 Frequency of micturition
• R39.15 Urgency of urination
CLINICAL/SURGICAL PEARLS
• OAB is not synonymous with detrusor overactivity; the key symptom of OAB is urinary urgency.
• DO demonstrated on cystometry needs to be correlated with patient’s symptoms.
• Treatment indicated if potential complications or patient driven.
• Only antimuscarinics, botulinum toxin, and augmentation cystoplasy have been proven to actually reduce or eliminate DO.