Renal and Genito-Urinary
Neurogenic Bladder
The bladder can no longer function properly if its nerve supply is damaged (neurogenic bladder).
Nerve injury causes:
- Impaired bladder storage
- Inability to void and/or incontinence
Nerve injury can be at the level of the:
- Brain
- Spinal cord
- Peripheral nerves
Damage can be due to:
- Tumor growth (causing pressure or normal tissue erosion)
- Surgery
- Radiation Therapy (RT)
The effect on bladder function depends on the level of the
injury:
Brain tumors:
- Produce centrally mediated bladder dysfunction
- Urinary incontinence
- Loss of inhibition of the bladder and the patient is unable to prevent voiding
- Associated with:
- Detrusor over-activity
- Uninhibited bladder contractions
- Lesions above the pons do not affect the voiding reflex
Spinal cord injury (SCI)
This can be complete or incomplete
Complete Injury:
- Bladder and external sphincter disconnected from central control and inhibition
- Decentralization of the bladder causes detrusor over-activity and poor storage of urine
- Acutely: Usually a period of spinal shock with detrusor underactivity or areflexia and impairment of bladder emptying
- When bladder contractility returns there is discoordination between the bladder and the external sphincter leading to high voiding pressures
- Untreated elevated bladder pressures lead to hydronephrosis and deterioration of renal function
Peripheral nerve damage:
- The usual cause is extensive pelvic surgery during resection of a pelvic tumor (but can occur as a consequence of less radical surgery such as ureteral reimplantation)
- Causes impaired bladder contractility
- Bladder storage affected if there is complete denervation, much like that noted with
SCI - High doses of RT (>50 Gy) to the lumbar or sacral spine or to the cauda equina may also cause nerve damage that results in neurogenic bladder
