Nima Baradaran, MD
Samuel Walker Nickles
Eric S. Rovner, MD, FACS
BASICS
DESCRIPTION
• OAB is defined as a symptom syndrome consisting of urinary urgency, with or without incontinence usually with urinary frequency and nocturia in the absence of causative factors or other identified pathologic conditions causing such symptoms.
• Urinary urgency is the key symptom.
ALERT
OAB is not synonymous with detrusor overactivity (DO, strictly a urodynamic term) and should be distinguished from bladder pain syndrome.
EPIDEMIOLOGY
Incidence
Overall 10.2–17.4% in adult males and 7.7–31.3% in adult females.
Prevalence
∼16% of men and women over 40 suffer from OAB and the prevalence increases to 31% and 42%, respectively in patients >75 yr. OAB wet is more common in females.
RISK FACTORS
• Neurogenic: Stroke, Parkinson disease, multiple sclerosis, spinal injury, etc.
• Nonneurogenic: Caucasian, Insulin-dependent diabetes mellitus, Female gender, Depression, Aging associated with estrogen deficiency, Outflow obstruction, Arthritis, Increased BMI.
Genetics
For OAB a definite genetic link is not well established.
PATHOPHYSIOLOGY
• Not well established or understood.
• DO is found in some but not all patients with OAB.
• Urothelial afferent and efferent innervation, connective tissue, smooth muscle, pharmacologic (receptors, neurotransmitters, peptides, etc.), hormones, and other factors may contribute to OAB in individual patients.
• Ultimately, OAB results from either an afferent mechanism (underlying urgency), or a neurogenic or myogenic source or a combination of these.
ASSOCIATED CONDITIONS
• Pelvic floor disorders
• IBS
• High caffeine intake
• Depression/anxiety
• DM
• Smoking
• ADHD
• Obesity
GENERAL PREVENTION
Currently there are no known preventative measures to reduce the potential for development of OAB.
DIAGNOSIS
HISTORY
• Duration of symptoms
• Quantitative assessment of urinary frequency, nocturia, and incontinence (pad use)
• Documentation of urgency
• Quantitation of daily fluid intake
• Aggravating factors (caffeine, stress, etc.)
• Presence of dysuria, hematuria
• Response to prior therapy
• GU history including childhood voiding dysfunction, prior surgery (BPH, urethral stricture, dilation, etc.)
• History should include assessment of the impact of the disorder on daily life (I-QOL (1) and ICIQ (2) for urinary incontinence and OAB-q (3) for men and women with OAB specifically)
• Medical/surgical/OB-GYN history (especially if associated with the initial symptom onset):
– Prior pelvic surgery: Prolapse, hysterectomy, anti-incontinence surgery, history of radiation therapy, etc.
– Pregnancy especially vaginal delivery/episiotomy
– UTI (frequency, urgency, dysuria)
– Bowel function: Constipation
– Neurologic history or events (eg, CVA/TIA, MS, Parkinson disease, trauma, back surgery, etc.)
– Sexual function: Dyspareunia
– Medical comorbidities: Congestive heart failure (CHF), diabetes, obesity, venous insufficiency, BPH, sleep apnea, etc.
– Medications (diuretics, prescription, OTC)
– Menopausal status and hormonal replacement: Contributes to atrophic vaginitis/urethritis
• Use of tobacco, alcohol, fluid intake, caffeine, etc.
PHYSICAL EXAM
• General exam:
– Abdominal masses, bladder distention
– Mental status/cognitive function
– Neurologic exam including perineal sensation, anal wink, resting, and volitional sphincter tone, bulbocavernous reflex
– Knee/ankle deep tendon reflexes: Sacral nerve compromise/injury
• Pelvic exam:
– Condition of vaginal mucosa: Atrophy (thinning, pallor), narrowing of introitus, inflammation
– Pelvic organ prolapse
– Pelvic floor tone
– Bimanual exam for mass or tenderness
– Cough stress test: Stress incontinence
– Rectal exam: Constipation and prostate evaluation for men
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• Urinalysis, urine cultures:
– Infection, Glycosuria: Possible diabetes, Hematuria: Possible kidney/bladder pathology, Proteinuria: Kidney/chronic disease, Cytology: Atypia, urothelial carcinoma
– The diagnosis and initial management of OAB does not require more than a history, physical exam, and urine analysis. Other diagnostic studies should be utilized selectively
Imaging
• These are optional studies usually reserved for complex patients or patients who have failed initial therapy
– VCUG/Cystography/video urodynamic
– Renal/bladder US
Diagnostic Procedures/Surgery
• 1–3-day frequency–volume chart (FVC) and/or bladder diary are helpful in documenting presence and severity of OAB
• Post-void residual volume (PVR) (catheterized or ultrasound)
– PVR >100 is found in 10–19% women with OAB, 15.9% women with SUI, and 5% of asymptomatic women
– Elevated PVR may be associated with urgency/frequency and nocturia
• Pressure flow urodynamics:
– Provides functional information about bladder and urethral function
– Assesses bladder filling and urinary storage as well as bladder emptying, contractility, voiding efficacy, and outlet obstruction
– Can document presence of DO which is associated with OAB but is NOT required for the diagnosis
• Cystoscopy identifies lesions, tumors, trabeculation, and foreign bodies
ALERT
OAB is a clinical diagnosis and does not require UDS confirmation.
Pathologic Findings
N/A
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
• Urethral diverticulum
• Urinary tract infection
TREATMENT
GENERAL MEASURES
• Lifestyle modifications and bladder/pelvic floor training in conjunction with pharmacotherapy are 1st-line therapy and are mainstays of treatment.
• Behavioral therapy:
– Dietary and lifestyle modification (weight loss, reduce caffeine intake, EtOH, and nicotine cessation)
– Bladder retraining (education, diaries, self-monitoring)
• Pelvic floor physiotherapy: To reestablish inhibitory control over bladder storage
– Pelvic floor exercises (Kegel)
– Adjunctive measures include biofeedback, electrical stimulation, vaginal weights/cones, magnetic therapy, etc.
MEDICATION
First Line
• Antimuscarinics: Inhibits the effect of acetylcholine at postjunctional muscarinic receptors on detrusor muscle cells. All used to treat OAB and all have level 1 evidence.
– 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 agonist agent: Promotes detrusor muscle relaxation
– Mirabegron (25–50 mg/d)
Second Line
• Urgent PC (PTNS): Tibial nerve stimulation: Office-based therapy requiring repetitive weekly therapy sessions over 3–4 mo and then periodic treatments thereafter
• InterStim (sacral neuromodulation): Implanted neurostimulation of sacral nerves: Modulates activities of bladder, sphincter, and pelvic floor muscles
• Intravesical botulinum toxin (onabotulinumtoxinA) injection:
– Addresses both motor efferent innervation and sensory afferent nerves that contribute to OAB. It is a transient effect requiring periodic retreatment at intervals of 4–12 mo.
surgery/other procedures (4)
• Augmentation enterocystoplasty: Using a portion of GI tract to increase bladder capacity. Usually involves use of ileum or colon
– Auto-augmentation: Incision of detrusor muscle creating a pseudodiverticulum (most commonly performed in pediatric age group)
• Urinary diversion such as Bricker bilateral ureteroileostomy, rarely needed
• Clinical use of endoscopic bladder transection, bladder overdistension, or transvesical phenol injection is no longer recommended for nonneurogenic OAB
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
• Non-FDA approved:
– Estrogens for females (topical or oral)
– Tricyclic antidepressants (imipramine, etc.)
• For intractable OAB, options are appliances, catheters (urethral), and pads with careful attention to skin care
Complementary & Alternative Therapies
• Acupuncture
• Cognitive therapy
ONGOING CARE
PROGNOSIS
• Varies according to severity of disorder and compliance of the patient
• 50–80% of patients respond to combination of behavioral modification, pelvic floor therapy, and pharmacotherapy
COMPLICATIONS
• Antimuscarinic agents are contraindicated in narrow angle glaucoma and patients should be aware of side effects (dry mouth, constipation, etc.)
• Augmentation cystoplasty may lead to metabolic abnormalities and short bowel syndrome.
• SNS implant site complications include infection and pain.
• Botulinum toxin is associated with UTI, and urinary retention.
FOLLOW-UP
Patient Monitoring
Depending on treatment modality close follow-up with urologist or primary care physician is necessary
Patient Resources
• National Association for Continence 1-800-BLADDER (www.nafc.org)
• Simon Foundation (www.simonfoundation.org)
• National Institute of Diabetes and Digestive and Kidney Diseases (http://kidney.niddk.nih.gov/kudiseases/pubs/uiwomen/)
REFERENCES
1. 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.
2. Abrams P, Cardozo L, Khoury S, et al. Incontinence. 4th International consultation on incontinence, Paris July 5–8, 2008.
3. Voelzke BB. Overactive bladder; prevalence, pathophysiology, and pharmacotherapy. Urol Rep. 2007;1:16–22.
4. Wein AJ, Rackley RR. Overactive bladder: A better understanding of pathophysiology, diagnosis, and management. J Urol. 2006;175:S5–S10.
ADDITIONAL READING
• Avery K, Donovan J, Peters TJ, et al. ICIQ: A brief and robust measure for evaluating the symptoms and impact of urinary incontinence. Neurourol Urodyn. 2004;23:322.
• Coyne K, Revicki D, Hunt T, et al. Psychometric validation of an overactive bladder symptom and health-related quality of life questionnaire: The OAB-q. Qual Life Res. 2002;11:563.
• Patrick DL, Martin ML, Bushnell DM, et al. Quality of life of women with urinary incontinence: Further development of the incontinence quality of life instrument (I-QOL). Urology. 1999;53:71.
See Also (Topic, Algorithm, Media)
• Detrusor Overactivity
• Incontinence, Urinary, Adult Female
• Incontinence, Urinary, Adult Male
• Nocturia
• Overactive Bladder (OAB) Image 
• Posterior Tibial Nerve Stimulation (PTNS)
• Sacral Neuromodulation
• Urgency, Urinary (Frequency and Urgency)
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.
• The diagnosis and initial management of OAB require only a history, physical exam, and normal urinalysis.