Urodynamics Flashcards
What are the two phases of bladder function?
Filling (storage)
Emptying (voiding)
What three things are required for bladder filling?
Absence of involuntary contractions
Accommodation
Closed bladder outlet
What are the three components of bladder accommodation?
Compliance SNS stimulation (reduces detrusor tone) PNS inhibition (reduces detrusor tone)
What two things are required to keep the bladder outlet closed during the filling stage?
SNS stimulation (increases smooth sphincter tone) Onuf's nucleus stimulation (increases striated tone)
What 3 factors are required for normal emptying?
Absence of obstruction
Open bladder outlet
coordinated detrusor contraction
What two factors are involved in opening the bladder outlet during the emptying phase?
SNS inhibition (decreases smooth sphincter tone) Onuf's nucleus inhibition (decreases striated tone)
What two factors are involved in coordinated detrusor contraction?
PNS stimulation (Increases detrusor tone) SNS inhibition (decreases detrusor inhibition)
What are the two major determinants of urine flow rate?
Detrusor function
Outlet resistance
What is the guarding reflex?
Inhibition of PNS
Stimulation by SNS
Activation of Onuf’s nucleus
What is the voiding reflex?
Bladder volume reaches critical level leading to:
Activation of PNS
Inhibition of SNS
Inhibition of Onuf’s nucleus
Can be suppressed and controlled by the cerebral cortex.
What structure allows the CNS to allow voluntary voiding?
Barrington’s nucleus in the Pons.
What are the seven components of a urodynamic study?
Cystometry Uroflowmetry Pressure flow studies Electromyography Urethral pressure profilometry Cystogram Post void residual
What does uroflowmetry measure?
Flow rate
voided volume
voiding duration
What is required for an adequate uroflometry study?
At least 150ml
What does the graph of a normal flow profile look like?
Bell shaped curve
What are the normal peak flow rates for men and women?
Men: 20-25 ml/sec
Female: 25-30 ml/sec
What flow rates suggest obstruction?
Suspected obstruction: 10-15 ml/sec
Probable obstruction: < 10 ml/sec
What is a normal PVR?
< 50-100cc
What does an increased PVR indicate?
Bladder outlet obstruction
Decreased detrusor function
Both of the above.
What 5 things does a CMG measure?
Detrusor pressure Bladder capacity Bladder compliance Voluntary sphincter function Leak point pressure
What is a normal bladder compliance?
< 6 cm water rise in detrusor pressure with filling
What is a normal volume for first sensation of filling?
100-200ml
What is a normal volume for sensation of fullness?
350-450ml
What is a normal volume for first desire to void?
350-450ml
What is volume of imminent void?
Unable to inhibit voiding any longer
What else should the patient be asked to do during a cystometrogram?
cough or valsalva
What is abdominal leak point pressure/valsalva leak point pressue?
The lowest intravesical pressure at which urine leaks around the catheter with an increase in abdominal pressure but no detrusor contraction.
What values are diagnostic for ALPP/VLPP?
ALPP < 60 indicates SUI caused by ISD
ALPP 60-100 is indeterminant
ALPP > 100 indicates that SUI is not from ISD
What is detrusor leak point pressure?
The lowest pressure at which urine leaks around the catheter without detrusor contraction and with no increase in abdominal pressure.
What values are important for detrusor leak point pressure?
DLPP > 40cm water can cause ureteral obstruction, hydronephrosis, and renal damage.
In what order should the phases of the UDS be read?
- Filling phase
- Voiding phase
- Flow
- Video cystogram
What should be evaluated when reading the filling phase?
Compliance Capacity Sensation Detrusor overactivity Urine leak
What is the equation of bladder capacity in kids?
(Age in years + 2) x 30 = bladder capacity in ml
What indicates significant detrusor overactivity?
If they are sensed
If they cause leakage
If they increase pressure > 15ml of water
What should be evaluated in the voiding phase?
Max flow Voided volume Max detrusor pressure (Pdet max) PVR EMG
What is normal Pdet max?
40-60cm water
Less for females
What is the impact of a suprapontine lesion on voiding?
Detrusor overactivity
Bladder sphincter synergy
Normal sensation
Adequate emptying
What is the impact of a lesion in the pons to the spinal cord above S2?
Detrusor overactivity
Spastic sphincter
Detrusor sphincter dyssynergia
Spastic paresis of lower limbs
What is the impact of a lesion from S2-S4?
Acontractile flaccid detrusor
Flaccid striated sphincter
Flaccid paralysis of the lower limbs
What is the impact of a lesion to the peripheral pelvic nerves?
Acontractile detrusor
Absent bladder sensation
What are the typical UDS findings of Multiple sclerosis?
Detrusor overactivity
What are the typical UDS findings of normal pressure hydrocephalus?
Detrusor overactivity
Dementia (wacky)
Gait disturbances (wobbly)
Urge incontinence (wet)
What are the typical UDS findings for stroke patients?
Detrusor overactivity
Synergic sphincter
What are the typical UDS findings for Parkinson’s disease?
Detrusor overactivity
Usually no DSD but sometimes cogwheeling can cause DSD.
What are the typical UDS findings associated with Cauda equina syndrome?
Acontractile detrusor
Flaccid sphincter
What are the typical findings for a patient with spinal shock from a suprasacral spinal cord injury?
Acontractile detrusor
Increased tone in urethral sphincter and bladder neck
Absent bulbocavernosus and deep tendon reflexes
How long does spinal shock usually last?
6-12 weeks
What are the typical UDS findings for a patient with tethered cord?
Detrusor underactivity
