Michael J. Amirian, MD
Leonard G. Gomella, MD, FACS
BASICS
DESCRIPTION
• Detrusor underactivity (DU) often referred to as underactive bladder is a bladder contraction of reduced strength and/or duration
– Results in prolonged bladder emptying
– Failure to complete bladder emptying within a normal time span
– Observed in many neurologic conditions and myogenic failure
• DU is a common cause of lower urinary tract symptoms (LUTS) in both men and women
• A wide range of terminology is currently applied in the literature
– The only formal definition was from the International Continence Society (ICS) in 2002 was the urodynamic definition of DU along with detrusor acontractility
• Underactive Bladder Syndrome is characterized by urinary symptoms including hesitancy, straining, and incomplete bladder emptying in the absence of anatomic obstruction.
EPIDEMIOLOGY
Incidence
Present in 9–48% of men and 12–45% of older women undergoing urodynamic evaluation for non-neurogenic LUTS (1)
Prevalence
N/A
RISK FACTORS (2)
• Overactive bladder (OAB) may lead to underactive bladder (UAB)
• Diabetes mellitus
• Aging
• Acute Cerebrovascular accident (CVA)
• Multiple sclerosis (MS)
• Parkinson disease
• Injury to spinal cord, cauda equine, and pelvic plexus
– Pelvic surgery
– Pelvic and sacral fractures
– Herniated disc
– Lesions of pudendal nerve
• Infectious neurologic problems
– AIDS
– Neurosyphilis
– Herpes zoster and herpes simplex
– Guillain–Barre syndrome
• Medications
– Antimuscarinics, α-receptor antagonists
Genetics
N/A
PATHOPHYSIOLOGY
• Diabetic mellitus leading to diabetic cystopathy
– Metabolic derangement of Schwann cells
Altered metabolism of glucose
Ischemia
Superoxide-induced, free-radical formation
Impaired axonal transport
– Alteration in physiology of detrusor smooth muscle cell
• Aging
– Reduction in acetylcholinesterase-positive nerve
Reduced parasympathetic innervation
• CVA
– Cerebellar infarct leading to detrusor areflexia
ASSOCIATED CONDITIONS
OAB syndrome
GENERAL PREVENTION
• Diabetic patients
– Control blood glucose levels
• Hypertension and hyperlipidemia control
• Smoking cessation
DIAGNOSIS
HISTORY
• History of neurologic injury or medical disorder
• Recurrent episodes of urinary retention
• Lower urinary tract symptoms
– Straining to urinate
– Sensation of incomplete bladder emptying
– Diminished and interrupted urinary stream
– Urinary hesitancy
– Rely on abdominal straining to urinate
• Incontinence
– Overflow, urge, or stress
• Recurrent urinary tract infections
PHYSICAL EXAM
• May reveal a distended bladder
• Suspected or known neurologic injury due to pelvic or sacral injury
– Testing of sacral dermatomes
Assessing perianal sensation
Anal sphincter tone
Bulbocavernosus reflex
• Neurologic testing
– Deep tendon reflexes in the lower extremities
– Clonus
– Plantar responses
DIAGNOSTIC TESTS & INTERPRETATION
Lab
Beyond routine urinalysis and culture, none specific
Imaging
Upper tract screening if obstruction suspected.
Diagnostic Procedures/Surgery
• Urodynamic evaluation (basis of current ICS definition of UAB)
– Cystometry
Long curve with lack of sensation
Low detrusor pressure
– Electromyography
Usually normal
May show sphincter denervation and uninhibited sphincter relaxation
• Uroflowmetry
– Low peak flow
– Prolonged duration of flow
– Increased residual urine
Pathologic Findings
N/A
DIFFERENTIAL DIAGNOSIS
• Bladder outlet obstruction
• Detrusor overactivity
TREATMENT
GENERAL MEASURES
• Limited management available (3)
– No validated, effective oral drugs, no FDA approved medications. All used off label.
• Double void or straining to void
• Avoidance of bladder overdistention
– Indwelling urinary catheter
– Intermittent catheterization (preferred)
MEDICATION
First Line
• α-Adrenergic blockers
– Alfuzosin
– Doxazosin
– Terazosin
• Muscarinic receptor agonists
– Bethanechol, carbachol
• Choline esterase inhibitors
– Distigmine (Approved outside of US)
Second Line
• Potential therapy
– Prostaglandin E2
– Acting on four types of EP receptors
Increase detrusor contraction
Relax the urethra
SURGERY/OTHER PROCEDURES
• Sacral nerve stimulation and intravesical electrical stimulation
– Potentially beneficial in select patients
• Invasive surgical reconstruction
– Latissimus dorsi muscle transposition to restore bladder function
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
• Experimental therapeutics:
– Stem cell therapy
Allow weak detrusor to improve contractility
– Targeted gene therapy
Complementary & Alternative Therapies
N/A
ONGOING CARE
PROGNOSIS
Good prognosis with appropriate bladder management
COMPLICATIONS
• Urinary retention
• Urinary tract infections
• Damage to upper urinary tract
FOLLOW-UP
Patient Monitoring
• Post-void residual
• Uroflowmetry
• Urinalysis and urine culture
Patient Resources
• Underactive Bladder Foundation
– www.underactivebladder.org
REFERENCES
1. Osman N, Chapple CR, Abrams P, et al. Detrusor underactivity and the underactive bladder: a new clinical entity? A review of current terminology, definitions, epidemiology, aetiology, and diagnosis. Eur Urol. 2014;65(2):389–398.
2. Miyazato M, Yoshimura N, Chancellor MB. The other bladder syndrome: Underactive bladder. Rev Urol. 2013;15(1):11–22.
3. van Koevering GA, Vahabi B, Andersson KE, et al. Detrusor underactivity: A plea for new approaches to a common bladder dysfunction. Neurol Urodyn. 2011;30:723–728.
ADDITIONAL READING
Chancellor MB, Blaivas JG. Classification of neurogenic bladder disease. In: Chancellor MB, ed. Practical Neuro-urology. Boston, MA: Butterworth Heinemann; 1995.
See Also (Topic, Algorithm, Media)
• Lower Urinary Tract Symptoms (LUTS)
• Neurogenic Bladder, General Considerations
• Overactive Bladder (OAB)
CODES
ICD9
• 596.59 Other functional disorder of bladder
• 788.21 Incomplete bladder emptying
• 788.99 Other symptoms involving urinary system
ICD10
• N31.8 Other neuromuscular dysfunction of bladder
• R33.8 Other retention of urine
• R39.19 Other difficulties with micturition
CLINICAL/SURGICAL PEARLS
The term DU remains surrounded by ambiguity and confusion with a lack of accepted terminology, definition, and diagnostic methods and criteria.