INERVATION OF BLADDER AND ITS

DYSFUNCTION

OVERVIEW

Anatomy and physiology CNS centers Arcs and loops Spinal tracts Basic concepts of neurourological

function Reflexes Dysfunction Pharmacological management

Anatomy and physiology

Upper urinary tract dysfunction is rare due to neurological disease

Lower urinary tract is richly supplied with both autonomic and somatic nervous system

Bladder anatomy

Three anatomical layersInner mucosal layerMuscular middle layer

○ Outer and inner longitudinal layer○ Middle circular layer

Outer adventitial layer Functinally bladder is divided in to parts

Body Trigone

Receptors of the bladder

Parasympathetic (musacrinic) Sympathetic

Dual actionBeta adrenargicAlpha adrenergic

CNS centers

PONSPontomesencephalic reticular formationAfferents from bladder receptors of

distensionSphincter detrusor synergesiaReticulospinal tracts spincter and detrusor

centers of the spinal cord

Cortex, basal ganglia and cerebellumParacentral lobule involved in voluntary

initiation of micturition and inhibition of reflex voiding

Lesions results in frequency and urgencyDirect control of voluntary micturition

influencing the onufs nucleus through CSTPontine micturition center

Spinal cord centersSympathetic anteriomediolateral gray

column thoracolumbar cord T9-L1Parasympathetic nuclei intermediolateral

region of sacral cord S2-S4Onuf’s nucleus anterior horn of sacral cord

Arcs and Loops

Supra spinal arcParasympathetic afferent input from tension

receptor in the bladder wall to pontine micturition centers

Reticulospinal tracts to centers to sacral cord

3 to 4 yrs of age voiding is a reflex processLesions above the brain stem manifested

clinically by frequency and urgency with preserved detrusor sphincter synergesia

Sympathetic nervous system arcEfferent sympathetic innervation T9-L1

through ventral routes, sympathetic ganglia in the para vertebral chain preaortic and parvertebral chains

Touch, pain, and temperature from bladder through spinothalamic tract

Parasympathetic nervous system arcEfferents originate in the sacral cord travels

throgh ventral spinal roots and pelvic nerves and joins with sympathetic nerves to create a large autonomic plexus

Proprioceptive information of bladder sensation and pain through posterior columns and spinothalamic centers to PMC and supraspinal centers

Pudendal system arcsEfferent somatic innervation of ext sphincter

from the onufs nucleus through pudendal nerves

Afferent carry exteroceptive and proprioceptive sensation from pelvic floor

Afferent fibers from the ext sphincter and pelvic floor synapse with pudendal motor neurons in ventral horns of the spinal cord and helps in voluntary and reflex activity

LOOPS

Loop 1Pathways between frontal cortex, basal ganglia,

thalamic nuclei, cerebellum and pontomesencephalic reticular formation

Predominantly inhibitoryInterruption leads to loss of volitional control of

micturition reflex – uninhibited detrusor CVA, brain tumor, head injury, multiple sclerosis,

Parkinson’s disease.

LOOP 2Sensory afferent neurons from detrusor –

posterior and lateral columns, ‘’long routing’’ in spinal cord - pontomesencephalic portion in brain stem

Efferent neurons from micturition center travel down in reticulospinal tract ‘’long routing’’ to detrusor without any synapse in spinal cord

Required to establish an adequate magnitude and duration of detrusor reflex to accomplish complete bladder emptying

contdInterruption – hyper-reflexic detrusor –

unable to produce a voluntary voiding contraction

Spinal cord trauma, multiple sclerosis, spinal cord tumor, arachnoiditis

LOOP 3Detrusor and pudendal motor nuclei and

their interneurons in sacral cordCoordination between detrusor contraction

and striated urethral sphincter relaxation during voiding

LOOP 4Motor cortex in frontal lobe – traverse via

pyramidal tract in lateral columns of spinal cord, synapse on pudendal sphicter nucleus.

Voluntary control over striated muscle of the urethral sphincter during bladder storage and voiding

Spinal tracts

Corticospinal tract Reticulospinal tract Spinothalamic tract Posterior columns

Basic concepts of neurourological function Two phases

Low pressure insensanate filling and storage of urine

Efficient evacuation under voluntary control Filling and storage of urine

Passive filling phase initial phase occurs till proxim al urethral pressure > exceeds the bladder

Continence reflex phase bladder pressure > urethral pressure

Frontal micturition center by bladder distension enhances sympathetic activity and external sphincter

MicturitionNormal urinary voiding is voluntary

disinhibition of pontine and sacral reflex activity in response to bladder distension

REFLEXES

Superficial anal reflexAnal reflex or anal wink consists contraction

of anal sphincter in response to stroking or pricking the skin of perianal region

Inferior haemarhoidal nerve (S2-S5)Caudaequina or conus medullaris lesions

Bulbocavernosus reflexStimulating the skin of glans or penis

response is felt by placing a gloved finger in rectum

Neurogenic bladder dysfunction

5 types (2 UMN; 3LMN) Uninhibited Reflex Autonomous Motor paralytic Sensory paralytic

Nomenclature Urgency is the complaint of a sudden and

compelling desire to pass urine that is difficult to defer.

Urge incontinence is the complaint of involuntary leakage accompanied by urgency. Leakage may range from drops to soaking

Retention bladder is unable to empty itself to a point that there is over 100 cc's (3.5 ounces) of urine left over in the bladder after urinating*

Uninhibited bladder

Lesion affecting the second frontal gyrus and the pathways leading from it down to the pontine centre

Frontal lobe tumours, parasagittal meningiomas, anterior communicating artery aneurysms, normal perssure hydrocephalus, Parkinson’s disease and multisystem atrophy

Uninhibited bladder

Features are: Urgency at low bladder volumes

(detrusor hyperreflexia) Sudden uncontrollable evacuation No residual urine - little risk of infection If severe intellectual deterioration occurs

urine may be passed at random, without appropriate concern.

Spinal bladder Damage to spinal cord by trauma, tumor, multiple sclerosis Fullness is not appreciated Intravesical pressure may only be indicated by sweating,

pallor, flexor spasms, dramatic rise in blood pressure Reflex emptying without warning Incomplete evacuation may improve with practice and may

be performed at will if massaged and suprapubic pressure applied

Detrusor – sphincter dyssynergia . Evidence of bilateral pyramidal lesion – enhanced reflexes

and extensor plantar response Bladder is small and contracted, can hold maximum of 250ml

Autonomous bladder(subsacral lesions)

Damage to sensory and motor components in cauda equina or pelvis

Cauda equina lesions, Pelvic surgery, pelvic malignant lesions, spina bifida and high lumbar disc lesions

MRI or myelogram is obligatory to exclude high disc lesions

Autonomous bladder(subsacral lesions) contd

Features Continual dribbling incontinence Considerable residual urine with high

infection risk No sensation of bladder fullness- large

atonic bladder May be associated with perineal

numbness and loss of sexual function

Sensory bladder

Similar to autonomous bladder Anatomical explanation is uncertain Primary problem is sensory denervation Ultimately overdistension, myogenic

damage and contractile failure Rare disorders : Tabes dorsalis, SACD

and Multiple sclerosis, Diabetes mellitus

Sensory bladder contd..

Features : Massive retention of urine in litres – high

risk of infection Dribbling incontinence of sufficiently

large volumes Voiding possible with considerable

straining but evacuation is incomplete

Motor paralytic

Areflexic detrusorMarked by painful distention

Inability to initiate urination

Difficulty initiating urination, straining, decreased size and force of stream, interrupted stream, and recurrent urinary tract infection.

Pharmacological methods Urinary retention

Cholinergic agents to increase detrusor motor function○ Bathnechol improves detrusor funtion

particularly in denervation and selectively affects bladder and gut

Alpha adrenergic blockers such as prazosin

Urinary incontinenceInhibition of detrusor activity and

increase functional capacity of bladderAnticholinergics such as propanthalineAnticholinergic with smooth muscle

relaxing properties such as oxybutininTCA such as imipramine with

anticholinergic activity

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