Cerebral insult

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					VOIDING DYSFUNCTION IN
CEREBRAL AND CEREBELLAR

LESIONS

G.A. Ali

Mechanism of CVA
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It is ischemia and infarction of the brain secondary to a vascular insult.

Stroke

Prognosis of CVA
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10% no residual effects. 40% mild disability. 40% significant disability. 10% require nursing home care. Although complete recovery from the cerebral insult often occurs, fixed deficits may persist within areas governing voluntary bladder control resulting in loss of cortical inhibition and lead to OAD.

The role of cerebral cortex in micturition.

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Voluntary control of voiding: During filling there is inhibitory discharge to the pontine micturition center to relax the bladder and sphincters are tightened (guard reflex). During emptying the sphincters relax followed by bladder contraction.

Mechanism of voiding dysfunction
Cerebral shock: urine retention during the initial phase (detrusor areflexia). This usually takes few days up to few weeks.  In 96% resolve in 2 months.  Prolonged areflexia occurs if:
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1. A lesion in an area that facilitates voiding. 2. Detrusor decompensation 2ry to BOO.
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Irritative symptoms occur after recovery.

Cause of retention in cerebral shock

1. 2. 3.

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Impaired consciousness. Immobility. Inability to communicate the need to void leading to bladder over-distension. Premorbid detrusor dysfunction or concomitant medication.

Presentation
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Frequency, urgency and incontinence. Incontinence is due to bladder over-activity or incomplete emptying and overflow incontinence. The incidence of incontinence decreases with time but still significant number of patients suffer. Incontinence is indication of more severe CVA Incontinence in the first few days of CVA is a major predictive factor of mortality. The relative risk of death is 3.9 in incontinent patients.

Presentation
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When a patient does not sense that the bladder is full until sudden onset of voiding. This is described as urge but may reflect lack of recognition by the patient (severe CVA).

Urodynamic findings
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Detrusor hyperreflexia. 21% of patients with OAD have poor detrusor contractility. There is no affection of the sphincters. But pseudodyssynergia may be encountered. Heavy affection of frontal cortex and internal capsule lesions may result in uninhibited sphincteric relaxation. DESD occurs with basal ganglia lesions.

Associated LUT obstruction

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Obstruction due to BPH is easily diagnosed if there is low flow and increased residual urine as there is no affection of the urethral sphincters by CVA . Difficulty only in patients with impaired contractility. Some authors state that removal of obstruction makes control of OAD easier.

Summary of UDs findings

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Overactive Bladder with normal contractility. Overactive bladder with impaired contractility. Normal external sphincter. Pseudodyssynergia. Uninhibited sphincter relaxation. DESD (rare).

Voiding dysfunction in dementia

Dementia and urinary incontinence are common in geriatric population.  Incontinence is more common in multiple cerebral infarction than in Alzheimer.  Alzheimer is more common in females.  Incontinence is more common in males 2:1.
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Prerequisites for continence in elderly

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Normal LUT with intact innervation. Proper motivation to urinate in toilet. Cognitive ability to get to toilet and adjust clothing. Physical ability. Absence of medications that affect LUT. Proper environment including access to toilet.

Voiding dysfunction

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Functional incontinence is more common. Functional incontinence = normal LUT but incontinence due to immobility, cognitive disability or decreased motivation.

Urodynamic findings

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Normal LUT. Overactive bladder due to other causes as CV insufficiency. DO and impaired contractility with high residual.

Head injury

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Coma is associated with incontinence due to spontaneous micturition (loss of cerebral control). Temporary retention in some patients (unknown cause), may be pontine shock.

Cerebral palsy

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The most common manifestation is muscle spasticity (70%-80%) plus disorders of motor function as hypotonia or ataxia. 96% of patients with normal intelligence are continent. Low intelligence and spasticity are responsible for incontinence. Irritative or obstructive symptoms can occur due to pelvic floor spasticity.

Urodynamic findings

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Hyper-reflexic bladder may occur. Reduced bladder capacity and hypocompliance. DESD or Acontractile bladder due to affection of other areas in the spinal cord.


				
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