Editing Urinary retention (section)

== Acute neuropathic bladder ==

* Associated with spinal shock which occurs immediately after spinal cord injury. The detrusor cannot contract, the bladder distends and overflow incontinence occurs. If neglected, over-distension will lead to damage and ultimately renal failure.
* Need either long-term IDC or intermittent drainage
* Neurologic examination to assess level of injury - incomplete lesions may recover somatic and bladder function
* Demonstration of intact bulbocavernosus and anal reflexes indicate that the sacral cord and nerves are intact and that reflex bladder contractions are likely to develop to some extent
* If there is persistent total loss of reflexes and perineal sensation then either the sacral cord or cauda equina is damaged. In such circumstances an acontractile bladder is likely.
* Full urodynamic assessment of bladder function should be undertaken when the injury is stable. Prime aim is to prevent upper tract injury by maintaining good bladder emptying.

Lesions above T10, or those involving sympathetic outflow (T11, T12, L1, L2)

* Usually leads to 'upper motor neuron' bladder with reflexes intact but isolated from higher control mechanisms. Such patients are at risk of autonomic dysreflexia.
* Bladder contractions are high pressure and ineffective in emptying the bladder. Bladder capacity is usually decreased. Can lead to upper tract damage. 
* Some patients with low-pressure bladders that empty may be managed with condom drainage. Others will require ISC.
* Patients with poor emptying, low bladder capacity and upper tract dilatation require treatment with endoscopic sphincterotomy and condom drainage, and some may require bladder reconstruction.

Damage to sacral centre S2, S3, S4 and cauda equina lesions

* Usually leads to 'lower motor neuron' bladder; acontractile detrusor. Abdominal straining can produce reasonable emptying but the mainstay is ISC.
* Some may have sensation of filling if T11 and T12 are intact
* The bladder capacity may be good, but still high pressure system, with risk of damage to upper tract
* Patients who can achieve satisfactory bladder emptying by means of ISC usually have reasonable continence.

Damage to inferior hypogastric plexus

* Occurs in 10-15% of patients having radical rectal excisions
* Leads to impotence and neurogenic bladder dysfunction
* Similar bladder dysfunction to cauda equina lesion
* If retention occurs in the post-op period, best to catheterise, then carry out urodynamic investigation to determine the appropriate treatment.