Neurogenic lower-urinary-tract dysfunction is classified by lesion location, which predicts the storage/emptying pattern. The overriding management goal is low-pressure storage and emptying to protect the upper tracts.
Classification by Lesion Location
| Lesion | History | PVR | Urodynamics | Sphincter |
|---|---|---|---|---|
| Suprapontine | Predominantly storage | Insignificant | Detrusor overactivity | Normal (synergic) |
| Spinal (infrapontine–suprasacral) | Storage + voiding | Usually elevated | DO + DSD (lesions above T6 may have autonomic dysreflexia and smooth-sphincter dyssynergia) | Overactive |
| Sacral / infrasacral (below S2) | Predominantly voiding | Usually elevated | Underactive/acontractile detrusor | Normal or underactive |
Suprapontine lesions give DO with coordinated (synergic) sphincters; complete suprasacral cord lesions give DO with striated-sphincter dyssynergia; sacral lesions give detrusor areflexia with a fixed, non-voluntary striated sphincter tone.
Diseases at or Above the Brainstem
- CVA — acute retention (areflexia) initially; the most common long-term pattern is phasic detrusor overactivity with intact sensation and a synergic sphincter (no true DSD); UI within 7 days of stroke predicts poor outcome. Manage by reducing contractility and increasing capacity.
- Dementia — usually incontinence; antimuscarinics may be contraindicated in Alzheimer's (cortical cholinergic loss).
- Traumatic brain injury / brain tumor — usually DO with synergic sphincters (retention with frontal/posterior-fossa lesions).
- Cerebellar ataxia / normal-pressure hydrocephalus / cerebral palsy — usually DO with synergy (most CP patients have normal control).
- Parkinson disease — LUT dysfunction in 35–70%; DO is the most common UDS finding, smooth sphincter synergic; pseudodyssynergia/bradykinesia can mimic DSD; areflexia is uncommon; TURP is not contraindicated but warrants caution and full UDS.
- Multiple system atrophy (MSA) — earlier, more severe bladder symptoms with erectile dysfunction; DO common; VUDS shows an open bladder neck (unlike PD) and striated-sphincter denervation; both sphincters often insufficient → avoid outlet-reducing procedures in males.
Diseases Primarily Involving the Spinal Cord
- Multiple sclerosis — 2× more common in women; DO is the most common UDS finding, sphincter usually synergic, striated-sphincter dyssynergia in 30–65%, impaired contractility in 12–38%; rarely causes upper-tract damage. Avoid irreversible therapies (the urodynamic picture changes over time).
- Spinal cord injury —
- Spinal shock: acontractile/areflexic bladder with a competent bladder neck and urinary retention; usually 6–12 weeks in complete suprasacral injury (sacral SCI → persistent areflexia); resolution begins with return of the bulbocavernosus reflex. Initial UDS within 3 months; VUDS with fluoroscopy is the gold standard.
- Suprasacral SCI: DO + striated-sphincter dyssynergia + absent sensation (lesions above T6–T8 may add smooth-sphincter dyssynergia and autonomic dysreflexia) → both storage and emptying failure.
- Sacral SCI: detrusor areflexia, a competent non-relaxing smooth sphincter, and fixed striated tone.
- Management: keep storage pressures low; CIC ± antimuscarinics; for indwelling drainage a suprapubic catheter is preferred over a urethral catheter (less erosion/epididymo-orchitis). Routine follow-up for high pressures, VUR, stones, and infection.
- Autonomic dysreflexia — a potentially fatal emergency in lesions above T6–T8: an exaggerated sympathetic response to a stimulus below the lesion (commonly bladder/rectal distention) → pounding headache, hypertension, flushing/sweating above the lesion, bradycardia. Do endoscopy under spinal/monitored anesthesia; sublingual nifedipine 10–20 mg can treat or prevent it.
- VUR (17–25%, more in suprasacral SCI) — best initial treatment is to normalize urodynamics; UTI — treat only symptomatic disease; bladder cancer (SCC) is strongly associated with long-term indwelling catheters.
- Transverse myelitis — acute urinary retention (areflexia) is most common; after spinal shock, DO/DSD/low compliance.
- Neurospinal dysraphism — LUT dysfunction in 90%; the typical pattern is an areflexic bladder with an open bladder neck; the main goal is to avoid high storage pressures (CIC, intradetrusor onabotulinumtoxinA; augmentation if these fail). Tethered cord syndrome — stretch-induced dysfunction; UDS improves after detethering.
- Tabes dorsalis / pernicious anemia — "sensory" bladder (loss of sensation, large PVR). Poliomyelitis — "motor" bladder (retention, areflexia, intact sensation).
Diseases Distal to the Spinal Cord
- Disk disease — the sacral cord begins at T12–L1 and ends as the cauda equina at L2; central disk prolapse (15%) can compress the cauda equina (most protrusions at L4–L5/L5–S1). DESD does not occur (infrasacral); detrusor areflexia in ~27%; cauda equina syndrome = perineal sensory loss + loss of voluntary sphincter control + an acontractile, insensate bladder. Pre-laminectomy UDS is prudent.
- Radical pelvic surgery (APR, radical hysterectomy) — pelvic-plexus injury; ~1/3 have dysfunction (impaired contractility/failure of voluntary contraction, decreased compliance, a fixed non-relaxing striated sphincter); goal is low-pressure storage with periodic emptying (often CIC for 6–12 months); avoid prostatectomy in men unless clear BOO (worsens sphincteric UI).
- Diabetes — the most common cause of peripheral neuropathy; "diabetic cystopathy" classically progresses from impaired sensation to decreased contractility, but DO is the most common recent UDS finding; sphincter dyssynergia is not typical; early timed voiding helps.
- Guillain-Barré — usually reversible dysfunction (↑ PVR, ↓ sensation, DO, ↓ compliance); manage with reversible therapy. Herpes zoster — sacral ganglion invasion → retention/areflexia, usually resolving in 1–2 months.
- Miscellaneous: SLE, schistosomal myelopathy (bladder-neck obstruction), AIDS, and TB can cause storage or voiding symptoms.
Other Conditions
- DSD — true DSD requires a lesion between the sacral cord and PMC (SCI, MS, transverse myelitis); be skeptical otherwise and distinguish from pseudodyssynergia. Untreated, >50% of men develop complications (VUR, upper-tract deterioration, stones, sepsis); treat with CIC, sphincterotomy, a stent, intrasphincteric onabotulinumtoxinA, or diversion.
- Dysfunctional voiding — involuntary striated-sphincter obstruction without neurologic disease (hard to prove; needs EMG evidence without abdominal straining).
- Bladder-neck dysfunction (smooth-sphincter dyssynergia) — incomplete bladder-neck opening, almost exclusively in young/middle-aged men with longstanding symptoms; diagnosed on VUDS; α-blockers help, and bladder-neck incision is the definitive male treatment.
- Female BOO — uncommon; from dysfunctional voiding, cystocele, prior incontinence surgery, stricture, prolapse, or diverticulum; operate cautiously (sphincteric-incontinence risk).
- Fowler syndrome — urinary retention in young women without overt neurologic disease, bladder capacity >1 L without urgency, impaired sphincter relaxation on EMG, detrusor acontractility; treat with neuromodulation.
- Postoperative retention (4–25%), radiation (early storage symptoms peaking at 4–6 weeks, usually recovering by 6 months), and the defunctionalized bladder (decreased capacity/compliance, rehabilitated by cycling).
- Aging-related changes: decreased afferent activity, efferent activity, detrusor contractility, and urethral pressure.
Goals of treating neurogenic dysfunction: preserve the upper tracts, control infection, adequate low-pressure storage and emptying, continence, no catheter/stoma, and social/vocational adaptability.
Self-Test
1. How is neurogenic LUT dysfunction classified, and what is the pattern at each level? Suprapontine — DO with synergic sphincter (storage symptoms); spinal (infrapontine–suprasacral) — DO + DSD (storage and voiding); sacral/infrasacral — underactive/areflexic detrusor (voiding symptoms).
2. What is the most common long-term LUT finding after CVA, and in MS and Parkinson disease? Detrusor overactivity in all three (CVA and Parkinson have a synergic sphincter; MS has DSD in 30–65%).
3. In which SCI lesions does autonomic dysreflexia occur, and how is it managed acutely? Lesions above T6–T8; sublingual nifedipine 10–20 mg can treat or prevent it (remove the triggering stimulus).
4. What is Fowler syndrome and its treatment? Urinary retention in young women with bladder capacity >1 L without urgency and impaired sphincter relaxation; treated with neuromodulation.