from the Onuf’s nucleus. Acetylcholine acts on

initiates low-level afferent activity in the pelvic

nicotinic receptors located at the motor end

nerve. Afferent firing originating from the ure-

plate and causes muscle contraction. Botulinum

thra stimulates sympathetic efferent outflow to

toxin and its various serotypes prevent acetyl-

the bladder base and urethra as well as somatic

choline-containing vesicles from fusing to the

outflow to the EUS. The storage reflexes are

prejunctional terminal membrane interfering

organized at spinal level, whereas the spinal

with the release process. Botulinum toxin A

reflex pathways are under influence by a lateral

(BoTNA) injections into the EUS have been used

pontine area designated the urine storage

for treating DSD.10 Intravesical BoTNA injec-

center.

tions have been useful to treat urinary inconti-

During bladder filling, the intravesical pres-

nence due to neurogenic DO.11

sure remains low and constant (5–10 cm H O)

2

until the threshold for inducing voiding is

reached. Once this threshold is achieved, the

Central Control of Urine Storage

central and peripheral parasympathetic efferent

pathways are activated, whereas sympathetic

and Release and the Pontine

and somatic pathways are inhibited. SCI, MS,

cervical disk disease, tumors, or inflammatory

Micturition Center (PMC)

processes that interrupt these pathways are

associated with loss of coordination between

The central regulation of the micturition reflex

the bladder and its outlet and DSD.

involves the cerebral cortex, diencephalon, and

In predicting the impact of neurological con-

pons. The command and control center for the

ditions on urinary control, it is helpful to envi-

bladder is the pons. Stimulation of the dorsome-

sion a hierarchical scheme divided into brain,

dial pontine center causes urinary bladder con-

spine, and periphery, and consider whether

traction and simultaneous EUS inhibition.12

pathology exists rostral or caudal to the SPN.

Stimulation of the dorsolateral pons increases

However, urodynamic findings and clinical

activity of EUS while inhibiting the bladder.

expression of disease do not always clearly fit

Neurons in the dorsomedial pons send axons to

into known pathophysiological mechanisms.

the sacral spinal. Onuf’s nucleus also receives

For example, although only lesions between the

projections from the dorsolateral pons and the

pons and sacral cord should lead to DSD, some-

medial hypothalamus as well as axons from a

times DSD is seen in other conditions either

lateral region of the PMC. Other brain regions

because of multiple levels of pathology or

implicated in bladder control include the central

because of erroneous interpretations of UDS.

nucleus of the amygdala, bed nucleus stria ter-

Neuropathology effects both voiding and stor-

minalis, paraventricular nucleus, and locus

age reflexes. Changes in neural connections and

coeruleus suggesting that stress and alertness

transmitter following disease or injury, termed

could impact on bladder function.13 Many pro-

neuroplasticity, alter these pathways sometimes

jections in these pathways contain corticotropin

in unpredictable ways.

releasing factor (CRF) that when released from

the hypothalamus causes ACTH release.14 Thus

Brain Lesions

it is not surprising that conditions associated

with severe stress (posttraumatic stress disor-

der, abuse) are associated with OAB.15

Cerebrovascular Accident (CVA)

Ascending pathways from neurons arising in

the dorsal horn of the spinal cord are involved in

LUTS are prevalent in the stroke victim with up

transmission of sensory information from the

to 94% of patients describing at least one uri-

lower urinary tract to the dorsolateral pons

nary symptom with nocturia being the most

including the periaqueductal gray.

common complaint.16 Acute urinary retention is

To promote bladder distension and urethral

common immediately after a CVA. Bothersome

sphincter contraction during urine storage, the

urinary incontinence is seen in 25% of patients

micturition reflex is inhibited, whereas sympa-

at 12 months with a range of UI in the early

thetic and somatic pathways are activated

period of 57–83%. UI following a CVA is the best

(Fig. 33.2). During storage, bladder distension

predictor of future disability.17

examination reveals lax anal tone or absent

Dementias

voluntary anal contraction further suspicion of

MSA is raised. Nearly a third of MSA patients

There is wide variation in UI (11–90%) reported

complain of difficulty voiding, 44% have SUI, a

with dementia. UI is more common with

third note urinary frequency, and a third dem-

Alzheimer’s than multi-infarct dementia. Incon-

onstrate urge UI.21

tinence in patients with dementia is multi-facto-

Video UDS can differentiate MSA from PD.

rial with social factors; such unwillingness to

While up to a third of PD may show an open

hold urine after first sensation of fullness, cog-

bladder neck, 46–100% of patients with MSA

nitive inability to get to toilet, physical inability

have this finding.22 UDS show that more than

to reach a toilet, impact of medications, and

half the patients lack EUS responses to cough or

access are operative. Underlying these limita-

Valsalva. Sixty-seven percent show DA, a third

tions are studies demonstrating DO. One study

neurogenic DO, and more than half reduced

showed that DO was present on CMG in 58% of

compliance.21 Indeed, residual urines greater

patients with Alzheimer’s disease, 91% with

than 100 cm3 should lead the clinician to suspect

multi-infarct dementia,and 50% who had both.26

MSA rather than PD. Motor unit responses of

Half of UI patients had DO, whereas none of the

the EUS consistent with denervation include

continent patients had this urodynamic finding.

polyphasic potentials and increased duration of

Another finding in dementia patients is unin-

responses.23

hibited sphincter relaxation. Of particular

For the urologist, the most important reason

importance is avoiding the use of nonselective

to differentiate MSA from PD is for the manage-

antimuscarinics to treat UI in these patients

ment of a patient in whom bladder outlet

which may exert adverse effects on cognitive

obstruction is suspected. Since retention and

function.

residuals are common in MSA, these patients

more likely to under prostatic surgery to relieve

Normal Pressure Hydrocephalus (NPH)

obstruction. Stress urinary incontinence (SUI)

occurs either more commonly or exclusively in

Dilated cerebral ventricles and normal cerebro-

MSA relative to PD.24

spinal fluid pressure, termed NPH, is associated

with gait disturbance, memory defects, and UI.

Multiple Sclerosis

Up to 93% of NPH patients have OAB symptoms

with 63–100% demonstrating DO.27 Some

MS is a demyelinating disorder of axons in the

patients demonstrate a PVR urine as well poten-

brain and spinal cord. Eighty to ninety percent

tially due to aging-related impaired contractile

of MS patients will develop urologic complaints.

function. In a substantial proportion of patients

In a systemic review of UDS in MS patients neu-

shunting improves or eliminates LUTS.28 Care in

rogenic DO was found in 62%, DSD in 25%, and

the use of antimuscarinics is advised due to

hypocontractility in 20%.25

memory defects.29

Although upper tract deterioration is unusual

in MS, men with lower extremity involvement

Cerebral Palsy, Cerebellar Ataxia,

may be the one group at greater risk and require

close monitoring, if not with UDS, than with fre-

Epilepsy

quent upper tract imaging.

DO has been demonstrated in 31–100% of

patients with CP.30,31 DSD is uncommon(3–19%).

Huntington’s Disease

UI may be related to underlying bladder dys-

function or social limitations imposed by lim-

This autosomal dominant neurodegenerative

ited mobility or cognitive function.

disorder causes neuronal loss in the cerebral

Cerebellar ataxia is usually not associated

cortex and caudate nucleus. In the rare studies

with LUTS unless other neurodegenerative con-

examining urinary complaints, DO was the only

ditions coexist. When present, UI and urgency

finding. In large surveys, LUTS occurred only in

are typical symptoms. DO in symptomatic

late stages (>10 years) of the disease.

patients has been described in 25–53%.32,33 One