H. Henry Lai, MD, FACS
Gerald L. Andriole, MD, FACS
BASICS
DESCRIPTION
• Bladder areflexia (detrusor areflexia) is the inability of the bladder to contract to empty.
• Requires urodynamics study for diagnosis.
• Presentation may include urinary retention, incomplete emptying, and overflow incontinence.
EPIDEMIOLOGY
Incidence
No incidence study has been reported. The risk of urinary retention may increase with aging.
Prevalence
• No prevalence study has been reported in US.
– 40% of men and 13% of women over the age of 65 have detrusor underactivity during urodynamics in a Korean cohort (1,179 patients).
– 48% of men and 12% of women over the age of 70 have underactivity in a study from Israel.
RISK FACTORS
• Diabetes mellitus
• Longstanding bladder outlet obstruction
• Neurologic diseases
• Recent radical pelvic surgery
Genetics
• Genetic diseases predisposing to bladder dysfunction include:
– Muscular dystrophy
– Neurofibromatosis
PATHOPHYSIOLOGY
• May result from primary detrusor muscle failure (myogenic causes) and/or neurologic causes (eg, from lower motor neuron lesions, injury to sacral spinal cord, multiple sclerosis).
• Patients often attempt to void by valsalva.
• Success of emptying depends on resistance of smooth and striated sphincter mechanisms.
• Continence depends on sphincter competence.
ASSOCIATED CONDITIONS
• Cauda equina syndrome
• Diabetes mellitus
• Fowler syndrome (“nonneurogenic, neurogenic bladder”)
• Intervertebral disc diseases
• Longstanding bladder outlet obstruction with detrusor decompensation (myogenic failure)
• Lumbosacral spinal surgery
• Lyme disease
• Multiple sclerosis
• Myelodysplasia, spina bifida
• Radical pelvic surgery
• Recent spinal or brain trauma (“spinal shock”)
• Sacral spinal cord injury
GENERAL PREVENTION
N/A
DIAGNOSIS
HISTORY
• Symptoms may include: Incomplete bladder emptying, frequency, urgency, incontinence (urge or stress), weak urine stream, straining to empty.
• History of any risk factors listed in the section entitled “Associated Conditions.”
• Medication: Recent use of anticholinergic medications or over-the-counter cold medicine.
• Recurrent bladder infections.
PHYSICAL EXAM
• Palpable suprapubic mass (distended bladder)
• Stress incontinence on pelvic exam (overflow)
• High post-void residual volumes
• Abnormal neurologic exam:
– Perianal and perineal sensation
– Anal sphincter tone
– Bulbocavernous reflex
• Enlarged prostate on rectal exam
• Sacral abnormalities:
– Sacral dimple
– Tuft of hair
– Sacral agenesis
– Spinal surgical scar
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• Blood: Creatinine to assess renal function.
• Urine: Urinalysis to assess urinary infection.
Imaging
Renal and bladder ultrasound (to assess renal stones, bladder stones, hydronephrosis).
Diagnostic Procedures/Surgery
• Bladder scanner
– High post-void residuals may be identified to support the diagnosis
• Multi-channel urodynamics study:
– No or minimal detrusor contraction (Pdet line)
– Urodynamics criteria:
Bladder contractility index (BCI) <100
Maximal flow rate (Qmax) <12 mL/s
Detrusor pressure Pdet at Qmax <10 cm water
– To distinguish detrusor areflexia from bladder outlet obstruction (benign prostatic hyperplasia).
– To assess detrusor compliance and storage pressure. Detrusor leak point pressure >40 cm of water poses risk to the upper urinary tract.
– To identify the etiology of incontinence.
– To guide rational, safe management strategy.
Pathologic Findings
Bladder wall thickening and fibrosis may be found in decompensated bladder from obstruction.
DIFFERENTIAL DIAGNOSIS
• Bladder outlet obstruction causing retention:
– Benign prostatic hyperplasia
– Urethral stricture disease
• Functional outlet obstruction (eg, detrusor external sphincter dyssynergia)
• Potential reversible causes of areflexia:
– Recent spinal shock or stroke
– Recent radical pelvic surgery
– Medication use (eg, anticholinergics)
– Fowler syndrome
TREATMENT
GENERAL MEASURES
• Intermittent catheterization is preferred over chronic indwelling catheters (Foley or suprapubic catheter) to reduce the risks of infection and stones.
• Sacral neuromodulation (InterStim) may be considered for nonobstructive urinary retention (eg, good results in Fowler syndrome).
MEDICATION
First Line
• Bethanechol was ineffective in reducing residual volumes in a randomized, placebo trial (1)[C].
– Bethanechol may decrease the duration of transient urinary retention in patients who underwent radical hysterectomy or anorectal surgery in randomized, controlled trials (1)[C].
– Typical dosage: 10–50 mg PO BID–TID.
Second Line
N/A
SURGERY/OTHER PROCEDURES
• Sacral neuromodulation (InterStim) in selected patients who do not have contraindications.
– Effective in restoring voiding in patients with Fowler syndrome (1)[C].
– May be selectively considered in patients with nonobstructive urinary retention (2)[C].
• Bladder augmentation may be considered in patients with poor detrusor compliance, and high detrusor leak point pressure and storage pressure.
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
N/A
Complementary & Alternative Therapies
N/A
ONGOING CARE
PROGNOSIS
• Most cases are irreversible, except the few circumstances described in “Differential Diagnosis”
• However with proper urologic management, secondary complications may be minimized.
COMPLICATIONS
• Bladder neoplasm from indwelling catheter
• Hydronephrosis and hydroureters
• Recurrent urinary tract infections
• Renal and bladder stones
• Renal insufficiency, failure, and dialysis
• Urethral erosion from chronic Foley catheter
• Urinary incontinence
• Urosepsis and death
FOLLOW-UP
Patient Monitoring
• Patients with poor detrusor compliance need periodic urodynamics studies, upper tract imaging, and creatinine lab work to minimize complications.
• Patients who refuse to catheterize should be monitored closely.
• Patients with chronic indwelling catheter should undergo cystoscopy periodically due to the increased risk of bladder neoplasm.
Patient Resources
N/A
REFERENCES
1. Kessler TM, Fowler CJ. Sacral neuromodulation for urinary retention. Nat Clin Pract Urol. 2008;5(12):657–666.
2. van Kerrebroeck PE, van Voskuilen AC, Heesakkers JP, et al. Results of sacral neuromodulation therapy for urinary voiding dysfunction: Outcomes of a prospective, worldwide clinical study. J Urol. 2007;178(5):2029–2034.
ADDITIONAL READING
Cruz CD, Cruz F. Spinal cord injury and bladder dysfunction: New ideas about an old problem. Scientific World J. 2011;11:214–234.
See Also (Topic, Algorithm, Media)
• Bladder Areflexia (Detrusor Areflexia) Image 
• Neurogenic Bladder, General Considerations
• Sacral Neuromodulation
• Spinal Cord Injury, Urologic Considerations
• Urodynamics, Indications, and Normal Values
CODES
ICD9
• 596.55 Detrusor sphincter dyssynergia
• 788.29 Other specified retention of urine
• 788.38 Overflow incontinence
ICD10
• R33.8 Other retention of urine
• N36.44 Muscular disorders of urethra
• N39.490 Overflow incontinence
CLINICAL/SURGICAL PEARLS
• Detrusor areflexia requires urodynamics for diagnosis.
• Urodynamics can distinguish detrusor areflexia from bladder outlet obstruction.
• Intermittent catheterization is preferred over chronic indwelling catheters.
• Sacral neuromodulation (InterStim) may be selectively considered in patients with nonobstructive urinary retention or Fowler syndrome.
• Patients with chronic indwelling catheter should undergo cystoscopy and urine cytology periodically due to the increased risk of bladder neoplasm.