Bladder Anatomy and Dysfunction

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Bladder Anatomy and Dysfunction

• Suzanne L. Groah, MD, MSPH

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Neuroanatomy of MicturitionFrom the Top Down
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Micturition - Anatomy

• Micturition center is located where in the brain?
• Frontal lobe
• Function of micturition center (excitatory or
  inhibitory?)
• Send tonically inhibitory signals to the detrusor
  muscle to prevent the bladder from emptying
  (contracting) until a socially acceptable time
  and place to urinate is available.

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Next stop is the..

• Pons

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Pons

• The major relay center between the brain and the
  bladder
• What is the function of the pons?
• Coordinating the activities of the urinary
  sphincters and the bladder so that they work in
  synergy
• What is the specific anatomic location?
• Pontine micturition center
• The PMC coordinates the urethral sphincter
  relaxation and detrusor contraction to facilitate
  urination

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Pontine Micturition Center

• Bladder filling ? detrusor muscle stretch
  receptors ? signal to the pons ? brain
• Perception of this signal (bladder fullness) as a
  sudden desire to go to the bathroom
• Normally, the brain sends an inhibitory signal to
  the pons to inhibit the bladder from contracting
  until a bathroom is found.
• Brain ? deactivating signal to PMC
• Urge to urinate disappears
• When urination appropriate, brain sends
  excitatory signals to the pons, allowing voiding

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Pontine Micturition Center

• Excitatory or inhibitory?
• Excitatory
• Stimulation of the PMC causes what actions of
  the
• Urethral sphincter?
• Open
• Detrusor?
• Contract
• The PMC is affected by emotions
• Hence, some urinate when they are excited or
  scared
• The brains control of the PMC is part of the
  social training that children experience during
  growth and development
• Brain takes over the control of the pons at age
• 2 - 4 years

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Next Stop After the PMC.

• Spinal cord

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Normal Micturition Spinal Cord

• Function
• Long communication pathway between the brainstem
  and the sacral spinal cord
• Sensory information from bladder ? Sacral cord ?
  Pons ? Brain ? Pons ? Spinal cord ? Sacral cord ?
  Bladder
• Normal bladder filling/emptying
• Spinal cord acts as an important intermediary
  between the pons and the sacral cord
• Intact spinal cord is critical for normal
  micturition

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Normal Micturition Spinal Cord

• Sacral spinal cord what is the significance?
• Sacral reflex center
• Responsible for bladder contractions
• Primitive voiding center
• In infants, the brain is not mature enough to
  command the bladder
• SRC controls urination in infants and young
  children
• When urine fills the infant bladder, an
  excitatory signal ? sacral cord ? spinal reflex
  center ? detrusor contraction ? involuntary
  detrusor contractions with coordinated voiding

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Bladder Normal Neuroanatomy
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Bladder - Anatomy
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Neuroanatomy - Peripheral Nervous System

• 3 components
• Somatic nervous system via _________nerve
• Autonomic nervous system
• Sympathetics via ________________ nerve
• Parasympathetics via _____________ nerve

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Bladder Neuroanatomy

• Sympathetic receptors their locations
• _____________________
• _____________________

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Bladder NeuroAnatomy

• Sympathetic receptors
• Adrenergic
• _ ?1
• Trigone, bladder neck, urethra
• Maintain continence by contraction of bladder
  neck smooth muscle
• ?2-Adrenergics
• Bladder neck and body of bladder
• Inhibitory when active to
• Relax bladder neck on void
• Relax bladder body for storage (minor)

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Bladder Neuroanatomy Parasympathetic receptor

• Parasympathetic receptors
• Muscarinic
• Type
• Cholinergic
• Anatomic location
• Bladder, trigone, bladder neck, urethra

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Normal Micturition - ANS

• Normally, bladder and the internal urethral
  sphincter primarily are under sympathetic vs.
  parasympathetic nervous system control?
• Sympathetic
• SNS activity
• Bladder can increase capacity without increasing
  detrusor resting pressure
• Stimulates the internal urinary sphincter to
  remain tightly closed
• Inhibits parasympathetic stimulation
• Micturition reflex is inhibited

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Normal Micturition Autonomic Nervous System

• Parasympathetic nervous system
• Stimulates detrusor to _______________
• Immediately preceding parasympathetic
  stimulation, sympathetic influence on the
  internal urethral sphincter becomes suppressed so
  that the internal sphincter relaxes and opens
• Pudendal nerve is inhibited ? external sphincter
  opens ? facilitation of voluntary urination

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Normal Micturition Somatics

• Regulates the actions of voluntary muscles
• External urinary sphincter
• Pelvic diaphragm
• Innervation is via the.
• ______________________________
• Originates from the nucleus of Onuf
• Activation of the pudendal nerve causes ?
  contraction of the external sphincter and the
  pelvic floor muscles
• Neuropraxia of pudendal may occur with.
• Difficult or prolonged vaginal delivery, causing
  stress urinary incontinence

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Normal Micturition - Physiology

• 2 phases
• Filling and emptying
• Normal micturition cycle requires that the
  urinary bladder and the urethral sphincter work
  together as a coordinated unit to store and empty
  urine
• Storage
• Bladder is a low-pressure receptacle
• Urinary sphincter closed with high resistance
  to urinary flow
• Emptying
• Bladder contracts to expel urine
• Urinary sphincter opens to allow urinary flow

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Normal Micturition - Physiology

• Filling phase
• Bladder
• Accumulates increasing volumes of urine
• Pressure inside the bladder remains low
• Pressure within the bladder must be __________
  than the urethral pressure during the filling
  phase
• Bladder filling dependent on
• Intrinsic viscoelastic properties of the bladder
• Inhibition of the parasympathetic nerves
• Bladder filling primarily is a passive or active
  event?

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Normal Micturition - Physiology

• Bladder filling
• Sympathetic nerves also facilitate urine storage
• Inhibition of the parasympathetic nerves from
  triggering bladder contractions
• Directly cause relaxation and expansion of the
  detrusor muscle.
• Close the bladder neck by constricting the
  internal urethral sphincter
• Thus, sympathetic input to the lower urinary
  tract is constantly active during bladder filling.

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Normal Micturition

• During bladder filling - pudendal nerve becomes
  excited.
• Pudendal nerve stimulation ? contraction of the
  external urethral sphincter
• Urethral pressure maintained by the continence
  mechanism, which is composed of ??
• Contraction of the external sphincter
• Contraction of the internal sphincter
• Pressure gradients
• Continence urethral pressure gt or lt bladder
  pressure
• Incontinence urethral pressure lt or gt
  intravesical pressure is abnormally high

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Normal Micturition - Physiology

• Pressure Gradients
• During bladder filling
• Small ? in intravesical pressure
• When the urethral sphincter is closed, the
  intraurethral pressure gt the intravesical
  pressure
• With ? intraabdominal pressure (cough, sneeze,
  laugh, physical activity), some pressure
  transmitted to both the bladder and urethra
• If the pressure is evenly transmitted to both the
  bladder and urethra, Ø incontinence
• If pressure transmitted to the bladder is gt
  urethra, stress incontinence results

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Normal Micturition - Emptying

• Involuntary (reflex) or voluntary
• Infants involuntarily reflex void when the volume
  of urine exceeds the voiding threshold
• Bladder wall stretch receptors ? sacral cord ?
  pudendal nerve ?
• relaxation of the levator ani ?relaxation of
  pelvic floor muscle
• Opens external sphincter
• Also, sympathetic nerves ? relaxation of internal
  sphincter
• Parasympathetic nerves ? detrusor contraction
• Bladder pressure gt urethral pressure ? urinary
  flow

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Normal Micturition - Emptying

• A repetitious cycle of bladder filling and
  emptying occurs in newborn infants
• As the infant brain develops, the PMC also
  matures and gradually assumes voiding control
• During childhood, primitive voiding reflex
  becomes suppressed and the brain dominates
  bladder function
• Toilet training usually is successful at age 2-4
  years
• Primitive voiding reflex may reappear in people
  with SCI

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Delayed/Voluntary Voiding

• Healthy adults are aware of bladder filling and
  can willfully initiate or delay voiding
• Normally, the PMC functions as an on-off switch
  that is activated by stretch receptors in the
  bladder wall and is modulated by inhibitory and
  excitatory neurologic influences from the brain.
• When voiding must be delayed
• Brain bombards the PMC with inhibitory signals to
  prevent detrusor contractions
• Individual actively contracts the levator muscles
  to keep the external sphincter closed

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Normal Micturition Delayed Emptying

• Voiding coordination of both the ANS and
  somatic nervous system, which are in turn
  controlled by the PMC located in the brainstem
  and regulated by the brain

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Work-Up

• U/a and c s
• BUN Cr
• if compromised renal function is suspected
• Postvoid residual urine
• If high, the bladder may be contractile or the
  bladder outlet may be obstructed

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Work-Up

• Filling cystogram
• Bladder capacity
• Bladder compliance
• Presence of phasic contractions (detrusor
  instability)

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Work-Up - Cystogram

• Static Cystogram
• Confirm the presence of stress incontinence
• Degree of urethral motion
• Presence of a cystocele
• Intrinsic sphincter deficiency
• Vesicovaginal fistula
• Bladder diverticulum

• Voiding cystogram
• Bladder neck and urethral function (internal and
  external sphincter) during filling and voiding
  phases
• Urethral diverticulum
• Urethral obstruction
• Vesicoureteral reflux

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Work-Up - Cystometrogram

• Volume vs pressure graph
• Evaluates
• Detrusor compliance
• Stability of detrusor

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Pressures

• Rectal pressure abdominal pressure
• True detrusor pressure intravesical pressure
  rectal (abdominal) pressure
• Normal bladder resting pressure
• 8 40 cm H20
• Nl compliance is lt 15 cm H20 increase in
  pressure during filling
• Avg urethral closure pressure is
• 60 cm H20
• 80 cm H20

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Work-Up - Urodynamics

• Filling cystometry
• Flow/pressure study
• Detrusor pressure at maximum flow
• Obstruction to passage of urine (high pressure,
  low flow) can be distinguished from a lack of
  tone in the detrusor muscle (low pressure, low
  flow)
• Electromyography
• Coordinated or uncoordinated voiding
• Detrusor sphincter dyssynergia
• Videocystourethography
• Combined x-ray or ultrasound

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Normal Cystometry
Rectal P
Intravesical P
Detrusor P
Infused volume
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Stable Bladder with Rectal Cancellation
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Stable Bladder
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Detrusor Hyperactivity
The normal detrusor if filled slowly accepts 300
- 600 ml without rise in pressure. If the bladder
undergoes phasic contraction while the patient is
trying to inhibit voiding this is called Detrusor
overactivity. Note the low bladder capacity
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Low Compliance Bladder
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Neurogenic Detrusor Hyperactivity
Cystometry Neurogenic detrusor overactivity is
overactivity in the presence of confirmed
neuropathy in this case Multiple Sclerosis. Often
the detrusor is unstable without sensation and
the pressure involved tend to be higher than
idiopathic instability
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Work-Up - Cystoscopy

• Cystoscopy
• Bladder cancer
• Bladder stone
• Indicated in persistent irritative voiding
  symptoms or hematuria

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Problems and Treatment

• Classification
• Failure to store because of the bladder
• Failure to store because of the outlet
• Failure to empty because of the bladder
• Failure to empty because of the outlet

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Medications

• Alpha-adrenergic drugs
• Location - Bladder neck receptors
• Function - Increase bladder outlet resistance by
  contracting the bladder neck
• Example - pseudoephedrine

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Medications

• Estrogen derivatives
• Mechanism - Increases the tone of urethral muscle
  by up-regulating the alpha-adrenergic receptors
  in the surrounding area
• Mechanism - Enhances alpha-adrenergic contractile
  response to strengthen pelvic muscles
• Use inStress incontinence

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Medications

• Anticholinergic drugs
• Function - Inhibit involuntary bladder
  contractions
• Adverse effects
• Blurred vision
• Dry mouth
• Heart palpitations
• Drowsiness
• Facial flushing
• Ex. Pro-banthine, Levsin

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Medications

• Antispasmodic drugs
• Function - Relax the smooth muscles of the
  urinary bladder
• Function - Direct spasmolytic action on the
  smooth muscle of the bladder
• Adverse effects similar to anticholinergic agent
• Impaired mental alertness and physical
  coordination
• Ex. Ditropan, Detrol

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Medications

• Tricyclic antidepressant drugs
• Mechanism - Increase norepinephrine and
  serotonin levels
• Mechanism - Anticholinergic and direct muscle
  relaxant effects on the urinary bladder
• Ex. elavil

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Pathophysiology

• Brain Lesions stroke, tumor, CP, Parkinsons
  disease, hydrocephalus
• Above the pons
• Destroys the master control center, causing a
  complete loss of voiding control
• Primitive voiding reflex remains intact
• S/Sx
• Urge incontinence or spastic bladder
• Bladder empties too often with relatively low
  quantities
• Storing urine in the bladder is difficult

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Pathophysiology

• SCI (after resolution of spinal shock)
• Urge incontinence
• External sphincter may have paradoxical
  contractions
• Detrusor-sphincter dyssynergia

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Pathophysiology

• Peripheral nerve injury - Diabetes mellitus,
  severe genitoanal herpes, pernicious anemia,
  neurosyphilis, and AIDS
• Result in silent/painless urinary retention
• DM - lose the sensation of bladder filling first,
  then difficulty urinating

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CVA

• Brain may enter into a temporary acute cerebral
  shock phase
• Bladder retention with detrusor areflexia
• Then detrusor hyperreflexia with coordinated
  urethral sphincter activity
• PMC released from the cerebral inhibitory center
• S/Sx
• Urinary frequency, urgency, and urge
  incontinence
• Treatment
• Early indwelling catheter or CIC
• Hyperreflexia Timed void anticholinergics

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Brain Tumor

• Detrusor hyperreflexia with coordinated urethral
  sphincter
• S/Sx
• Urinary frequency
• Urgency
• Urge incontinence
• Treatment
• Anticholinergics

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Parkinsons Disease

• Characterized by detrusor hyperreflexia and
  urethral sphincter bradykinesia
• S/Sx
• Urinary frequency
• Urgency
• Nocturia
• Urge incontinence
• Treatment
• Anticholinergic agents

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Multiple Sclerosis

• Focal demyelinating lesions of the CNS often
  involve the posterior and lateral columns of the
  C spinal cord
• Poor correlation between the clinical symptoms
  and urodynamic findings
• UD
• Detrusor hyperflexia (50-90 with MS)
• Approx 50 demonstrate DSD-DH
• 20-30 have detrusor areflexia
• Treatment individualized

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Diabetic cystopathy

• Usually, 10 years after the onset of DM
• Autonomic and peripheral neuropathy
• Segmental demyelination
• Impaired nerve conduction
• S/Sx
• Loss of sensation of bladder filling
• Loss of motor function
• Urodynamics
• Elevated residual urine
• Decreased bladder sensation
• Impaired detrusor contractility
• Detrusor areflexia.

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Herniated Disc

• Lumbar disc herniation ? irritation of the sacral
  nerves ? detrusor hyperreflexia
• Acute compression of sacral roots (trauma) ?
  detrusor areflexia.
• Urodynamics
• Sacral nerve injury
• Detrusor areflexia with intact bladder sensation
• ? internal sphincter denervation may occur
• Striated sphincter is preserved