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Neurogenic bladder
The site of the neural lesion sets the picture: above the brainstem — coordinated overactivity; in the spinal cord above S2 — overactivity with detrusor-sphincter dyssynergia (DSD) and high pressure that endangers the kidneys; in the conus, cauda equina or peripheral nerves — a weak bladder and retention. The first goal is protecting the kidneys.
Why it matters in the exam
The exam shows a patient with spinal cord injury, multiple sclerosis, spina bifida, Parkinson disease or diabetes, and asks about the bladder type, treatment or a complication. After acute spinal cord injury there is a period of "spinal shock" in which the bladder is flaccid and catheterisation is needed. Detrusor pressure kept below 40 cm water during filling protects the kidneys. Evaluation includes video-urodynamics, renal ultrasound and renal function, with yearly follow-up in high-risk patients.
The basic treatment is clean intermittent self-catheterisation 4 to 6 times a day, with volumes not exceeding 400 to 500 mL, together with an antimuscarinic to lower pressure. On failure — onabotulinumtoxinA 200 units into the detrusor in spinal cord injury or multiple sclerosis. At an advanced stage — bladder augmentation with a bowel segment, sometimes with an abdominal catheterisable channel (Mitrofanoff). Asymptomatic bacteriuria in a self-catheterising patient is not treated.
Autonomic dysreflexia occurs with injury at T6 or above: a sharp rise in blood pressure, bradycardia, headache and flushing above the level of injury, usually because of a full bladder. Sit the patient up, empty the bladder or unblock the catheter, and if blood pressure stays high give nifedipine or a nitrate. After bladder augmentation there is a risk of hyperchloraemic metabolic acidosis, mucus, stones, late malignancy and bladder rupture — an augmented patient who arrives with fever, abdominal pain and confusion has a rupture until proved otherwise. In MSA, urinary symptoms and erectile dysfunction sometimes precede the motor symptoms, with a large residual and an open bladder neck.
Key points
- Protect the kidneys: detrusor pressure below 40.
- Intermittent self-catheterisation is the basis of treatment.
- DSD with lesions between the brainstem and S2.
- Autonomic dysreflexia from T6 and above.
- Augmentation: acidosis, mucus, stones, rupture.
Summary table
| Lesion level | Examples | Urodynamic finding | Risk |
|---|---|---|---|
| Above the brainstem | Stroke, Parkinson disease, dementia | Coordinated overactivity | Leakage, low pressure |
| Spinal cord above S2 | Spinal cord injury, multiple sclerosis | Overactivity with DSD | High pressure and renal damage |
| Conus, cauda equina, peripheral nerves | Disc, diabetes, pelvic surgery | Weak or acontractile detrusor | Retention and infections |
| Spina bifida | Congenital malformation | Mixed, low compliance | Renal damage in childhood |
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Sources
- EAU Guidelines on Neuro-Urology, 2025 edition — Classification, diagnostic evaluation and management
- AUA/SUFU Guideline: Adult Neurogenic Lower Urinary Tract Dysfunction, 2021 — Risk stratification and surveillance
- Campbell-Walsh-Wein Urology, 12th edition (2020) — Neuromuscular Dysfunction of the Lower Urinary Tract
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.