Obstructed Urinary Tract Disorders

Question 1

What is the diameter of a normal feline ureter?

Answer 1

0.44 mm

Question 2

What is the diameter of a normal canine ureter?

Answer 2

1-3 mm

Question 3

What is Acute Unilateral Ureteral Obstruction characterized by?

Answer 3

• clinically silent
• NOT associated with azotemia
• evidence may be detected in cats presented for signs of acute abdominal pain, erratic or elusive behavior, hematuria or on routine abdominal imaging

Question 4

What is Acute Bilateral Uretearl Obstruction characterized by?

Answer 4

• uncommon
• associated with severe acute signs including bilaterally enlarged and painful kidneys, severe progressive azotemia, and oliguria or anuria
• prognosis good if obstruction alleviated but reoccurrence common

Question 5

What is “Big Kidney- Little Kidney” Syndrome characterized by?

Answer 5

• common presentation seen in cats with a past unilateral ureteral obstruction that has caused the kidney to progress to a fibrotic end stage
• subsequently, the contralateral hypertrophied kidney becomes acutely obstructed by a ureterolith causing further enlargement and characteristic renal asymmetry, abdominal pain, progressive severe azotemia, and variable urine production
• prognosis good if obstruction alleviated but reoccurrence in big kidney common

Question 6

What is Bilateral Chronic Kidney Disease and Concomitant Ureteral Obstruction characterized by?

Answer 6

• presentation is common
• carries the most guarded prognosis bc even with resolution of the ureteral obstruction, global renal function is several compromised
• the sudden obstruction (uni or bi) causes decompensation of the tenuous residual renal fxn and promotes the onset of overt uremia

Question 7

What is the presenting complaint with ureteral obstruction?

Answer 7

• severe acute uremia which includes anorexia, depression, intermittent vomiting, uremic odor, lethargy, oligo/anuria
• prevalent in cats >7 YO
• ureterocolic signs
• incidental on US

Question 8

What stones can be identified on radiographs?

Answer 8

Calcium oxalate stones bc radiodense

Question 9

What can we see on US with regards to ureteral obstruction?

Answer 9

hydronephrosis and dilatation of proximal ureter- principle feature of ureteral obstruction

however, only 7080% sensitive in the dx of ureteral obstruction bc only demonstrable for 4-7 days following complete obstruction

Question 10

What can we see on a unilateral, bilateral or unilateral on CKD for an acutely obstructed ureter?

Answer 10

Unilateral: pain
Bilateral: uremia
Unilateral on CKD: uremia

Question 11

What is the preferred imaging modality at specialist hospitals to confirm mineralization and non mineralization uroliths?

Answer 11

Computed tomography with contrast bc less invasive than ante grade pyelography

Question 12

What do ante grade pyelography and computed tomography do?

Answer 12

help define the indication and location for surgical intervention

Question 13

How do we medically manage ureteral obstructions?

Answer 13

• 20-30% spontaneously resolve within 3-4 days
• stabilize the uremia
• if sx contraindicated (d/t fluid overload/hyperkalemia)-hemodialysis
• if oliguric- Mannitol!
• Prazosin and amitryptilline-ureteral relaxants!
• pain management

Question 14

T/F Lithotripsy is an excellent choice in cats.

Answer 14

False! Lithotrispy is an excellent choice for dogs! Poor choice for cats bc resistant to fragmentation and particles tend to be too large to pass through their 0.4 mm ureter

Question 15

What is our standard of care?

Answer 15

Ureteral stents!

Placed by:
Cytoscopy: dog (retrograde)
Surgically: cat (ante grade)

Question 16

Did you know a SUB isn’t just a sandwich?

Answer 16

SUB= subcutaneous ureteral bypass system

-the development of an indwelling ureteral bypass using a combination locking-loop nephrotomy/ cystotomy tube

Question 17

Which of the following is not part of how we diagnose ureteral obstruction?

A. small bladder
B. signs of urine urgency
C. difficultly in manually expressing urine
D. resistance encountered during passage of a ureteral catheter

Answer 17

A. we see an ENLARGED bladder (in a male cat) with ureteral obstruction

Question 18

How do we treat an emergency case of hyperkalemia in a cat?

Answer 18

Fluids: calculate shock rate for cats: 45 ml/kg so if have 4 kg dog then = 180 ml, give 1/4 immediately so 45 ml

Then Calcium Gluconate to protect the heart

IV insulin then dextrose

Bicarb

Question 19

What is the most common way to relieve the obstruction in an obstructed cat?

Answer 19

Retrograde

Question 20

What if the owner cannot afford tx?

Answer 20

Euthanize or no indwelling catheter -just unblock cat, anti spasmolytics and repeated cystocentesis and anti-spasmotics

Question 21

What are the anti spasmostic drugz that have zero evidence based medicine but Christie likes them so we gotta know them?

Answer 21

Prazosin and phenoxybenzamine

Question 22

What are the most common causes of urethral rupture in dogs and cats?

Answer 22

Dogs: MVA: motor vehicle accident. Asshole.
Cats: urethral obstruction and traumatic catheterization

Question 23

What is associated with urethral rupture?

Answer 23

1. HYPERK
2. HYPONa
3. Acidosis

Question 24

What can we expect to see with a uroabdomen?

Answer 24

1. Abdominal fluid
2. Subcu bruising
3. Measure abdominal fluid for creatinine, urea, potassium
4. Medical mgmt and urinary catheterization
5. Sx later on once stable