[12] Urinary Tract Obstruction

Question 1

What are the categories of causes of urinary tract obstruction?

Answer 1

Luminal
Mural
Extramural

Question 2

What are the luminal causes of urinary tract obstruction?

Answer 2

Stones
Blood clots
Sloughed papilla

Question 3

What are the mural causes of urinary tract obstructions?

Answer 3

Congential or acquired stricture
Tumour
Neuromuscular dysfunction

Question 4

What tumours can cause urinary tract obstructions?

Answer 4

Renal
Ureteric
Bladder

Question 5

What are the extramural causes of urinary tract obstruction?

Answer 5

Prostatic enlargement
Abdominal/pelvis mass or tumour
Retroperitoneal fibrosis

Question 6

How does acute upper urinary tract obstruction present?

Answer 6

Loin to groin pain

Question 7

How does acute lower urinary tract obstruction present?

Answer 7

Severe suprapubic pain with distended, palpable bladder

Question 8

What causes suprapubic pain and palpable bladder in acute lower urinary tract obstruction?

Answer 8

Bladder outflow obstruction

Question 9

How does chronic upper urinary tract obstruction present?

Answer 9

Flank pain

Renal failure

Question 10

How does chronic lower urinary tract obstruction present?

Answer 10

Frequency
Hesitancy
Poor stream
Terminal drippling
Overflow incontinence

Question 11

What may be found on examination in chroinc lower urinary tract obstruction?

Answer 11

Distended, palpable bladder

Sometimes large prostate on PR

Question 12

What investigations are done in urinary tract obstruction?

Answer 12

Bloods
Urine dip and MC&S
Imaging

Question 13

What imaging is done in urinary tract obstruction?

Answer 13

Ultrasound
Anterograde/retrograde ureterograms
Radionucleotide imaging
CT/MRI

Question 14

What might be found on US in urinary tract obstruction?

Answer 14

Hydronephrosis or hydroureter

Question 15

What do anterograde/retrograde ureterograms allow in urinary tract obstruction?

Answer 15

Therapeutic drainage

Question 16

What is the purpose of radionucleotide imaging in urinary tract obstruction?

Answer 16

Check renal function

Question 17

How is an upper urinary tract obstruction managed?

Answer 17

Nephrostomy

Ureteric stent

Question 18

How is a lower urinary tract obstruction managed?

Answer 18

Urethral or supra-pubic catheter

Question 19

What might happen following catheterisation in a lower urinary tract obstruction?

Answer 19

May be a large post-obstructive diuresis

Question 20

What are the common complications of ureteric stents?

Answer 20

Infection
Haematuria
Trigonal irritation
Encrustation

Question 21

What are the rare complications of ureteric stents?

Answer 21

Obstruction
Ureteric rupture
Stent migration

Question 22

What are the causes of urethral stricture?

Answer 22

Trauma
Infection
Chemotherapy
Balantitis xerotica obliterans

Question 23

Give two examples of urethral trauma that can cause strictures

Answer 23

Instrumentation

Pelvic fractures

Question 24

Give an example of an infection that can cause urethral strictures

Answer 24

Gonorrhoea

Question 25

How do urethral strictures present?

Answer 25

``` Hesitancy Strangury Poor stream Terminal dribbling Pis en deux ```

Question 26

What is done on examination in urethral stricture?

Answer 26

PR to exclude prostatic cause Palpate urethra through penis Examine meatus

Question 27

What investigations are done in urethral stricture?

Answer 27

Urodynamics Urethroscopy and cystoscopy Retrograde urethrogram

Question 28

What is found on urodynamics in urethral strictures?

Answer 28

Decreased peak flow rate | Increased micturition rate

Question 29

How are urethral strictures managed?

Answer 29

Internal urethrotomy Dilatation Stent

Question 30

Why might obstructive uropathy go unnoticed for days?

Answer 30

Because acute retention on a chronic background may not produce pain

Question 31

What might serum creatinine be in obstructive uropathy?

Answer 31

Up to 1500uM

Question 32

What is the long-term outcome of obstructive uropathy?

Answer 32

Renal function should return to normal over days, but some background impairment may remain

Question 33

What are the complications of obstructive uropathy?

Answer 33

``` Hyperkalaemia Metabolic acidosis Post-obstructive diuresis Na and HCO3 losing nephropathy Infection ```

Question 34

What causes post-obstructive diuresis?

Answer 34

Kidneys produce a lot of urine in the acute phase after relief of obstruction

Question 35

What do you need to ensure with post-obstructive diuresis?

Answer 35

Need to ensure you keep up with loses to avoid dehydration

Question 36

What might cause Na and HCO3 losing nephopathy in obstructive uropathy?

Answer 36

Post-obstructive diuresis might cause loss of Na and HCO3

Question 37

What management might Na and HCO3- losing nephropathy require?

Answer 37

Replacement with 1.26% NaHCO3