A guide to indications, components and interpretation of urodynamic investigations TOG 2019

Question 1

3 main components of urodynamics

Answer 1

representative uroflowmetry with post-void residual (PVR)

transurethral cystometry

pressure-flow study.

Question 2

According to NICE when is urodynamic testing required?

Answer 2

Urge, mixed urge predominant: After failure of Cx measure, before considering surgery

Stress: Only if voiding dysfunction, anterior compartment prolapse or previous surgical management

Neurological: Video urodynamics for substantial risk renal complication (SB, spinal cord injury), before surgery

Children: no guidance

Question 3

When test should be performed prior to urodynamic testing

Answer 3

Urine dip for infection/haematruia
Urodynamic testing postposed until UTI treated.

Question 4

How is uroflowmerty measured?

Answer 4

Void by relaxing not straining onto commode with flowmeter. Volume of urine passed per unit ofttimes ml/s and volume passed.

Post-void residual by USS or catheter

Question 5

What does diagram of normal uroflowmetry look like?

Answer 5

Bell curve of normal flow with voided volume 250mls.
Q max 20-36mls

Question 6

What are the 3 main categories of voiding dysfunction?

Answer 6

a) Detrusor contractility dysfunction
b) urethral dysfunction
c) bladder outflow resistance

Question 7

A Uroflow like this, can indicated what?

Answer 7

Question 8

A Uroflow like this, can indicated what?

Answer 8

Question 9

A Uroflow like this, can indicated what?

Answer 9

Question 10

Causes of high PVR

Answer 10

Anticholinergics (Detrusor under activity)
Detrusor failure
Outlet obstruction

Question 11

What is cystometry?

Answer 11

Test to assess bladder’s storage ability
Artificially and continuously filling the bladder with fluid via Cather to measure the pressure within the bladder/intravesicle

Rectal catheter used to measure abdominal pressure

Detrusor pressure - abdo pressure - intravesicle pressure

Question 12

Normal values for intravesicle and intra abdominal pressure

Answer 12

5-50cm H2O

Question 13

Normal values for intravesicle pressure

Answer 13

-5-15H2O

Question 14

Normal cystogram with filling and voiding phase. Not Cg - patient cough, FSF first sensation to void, SD strong desire to void

Answer 14

No change in Pet throughout filling despite provocation (cough)

Question 15

Cystogram showing detrusor overactivity

Answer 15

Unprovoked rises in detrusor pressure associated with sensations of urgency.

Question 16

What findings on cystogram, if low or poor detrusor compliance e.g. post radiotherapy

Answer 16

Steep rise in detrusor pressure during filling that persists after filling is stopped. Usually <30 ml/cm H2O. Associated with reduced bladder capacity

Question 17

What findings on cystogram, if high detrusor compliance e.g. neurological causes

Answer 17

Generally, compliance will be >100 ml/cm H2O and can have capacities of > 1 L.

Question 18

What findings on cystogram, if Poor detrusor accommodation

Answer 18

Rise in detrusor pressure during filling, but the pressure falls to normal when filling is stopped.

Question 19

What findings on cystogram, if detrusor overactivity

Answer 19

Phasic – waves of detrusor contractions that may or may not be associated with incontinence

Terminal – single involuntary detrusor contraction at cystometric capacity resulting in incontinence, usually bladder emptying

Cough-associated DO – onset of DO is immediately following cough pressure peak

Question 20

What findings on cystogram for urodynamic stress incontience

Answer 20

Urinary leakage during filling, in presence of raised abdominal pressure but in absence of detrusor contraction

Question 21

If urodynamics have not answered you questions, what other tests could be considered?

Answer 21

pad test
videocystometry (NICE recommended6)
ambulatory urodynamics (NICE recommended6)
urethral pressure profile tests.