Urodynamic tests

Question 1

What does uroflowmetry measure?

Answer 1

volume of urine passed in ml per second

Question 2

In uroflowmetry what is normal maximum flow rate?

Answer 2

> 15ml/second

Question 3

In uroflowmetry, what is the minimum total volume voided for the test to be valid?

Answer 3

> 200ml otherwise the test needs to be repeated

Question 4

In uroflowmetry, what does a normal graph look like?

Answer 4

A bell curve with a the maximal flow rate (Q max) of more than 15ml/second

Question 5

In uroflowmetry, what is the possible diagnosis if the curve prolonged into a plateau?

Answer 5

Bladder outlet obstruction e.g. prolapse or urethral stricture
Or
Hypocontractile bladder

Question 6

In uroflowmetry, what is the possible diagnosis if the graph shows intermittent bladder voiding, with several peaks?

Answer 6

Could be bladder outlet obstruction (abdomin straining to overcome) or bladder hypocontractility

Question 7

What are the risks of cystometry?

Answer 7

Haematuria and UTI

Question 8

What are the diagnoses that can be made by cystometry?

Answer 8

1) detrusor overactivity

2) urodynamic stress incontinence

Question 9

In cystometry, where are the transducers placed?

Answer 9

1) pressure transducer in the bladder (intravesical)

2) pressure transducer in the rectum (intraabdominal)

Question 10

In cystometry, how is detrusor pressure assessed?

Answer 10

Intravesical pressure -intrabdominal pressure

Question 11

In a cystometry trace - if there is an increase in intrabdominal pressure and intravesical pressure but no increase in detrusor pressure and the patient leaks, what is the diagnosis?

Answer 11

urodynamic stress incontinence

Question 12

How is voiding cystometry useful for interpreting uroflowmetry results?

Answer 12

If there is poor flow and low contraction then the consequence is a hypocontractile bladder, if there is poor flow by high level of abdominal straining and or detrusor activity then the problem is bladder outflow obstruction

Question 13

What is a normal max contraction pressure of detrusor during voiding?

Answer 13

50cmH20

Question 14

In urethral profilometry, what pressure range suggests the underlying pathology for stress incotinence?

Answer 14

<25cmH20 = intrinsic urethral deficiency
>25cmH20 = weak suburethral support

Question 15

When do NICE recommend ambulatory urodynamics?

Answer 15

If conventional urodynamic tests are unclear

Question 16

When would you recommend postvoid residual volume for a first line investigation for LUTs?

Answer 16

For patients describing voiding symptoms