Obstructive Urinary Tract Dz Flashcards
What is the most common cause of renal disease and acute uremia in cats?
Urethral obstruction from calcium oxalate ureteroliths
What is the diameter of a normal feline utter?
0.4mm
What is the diameter of a normal canine ureter?
1-3mm
What are the 4 outcomes of ureteral obstruction?
Acute unilateral obstruction
Acute bilateral obstruction
Big kidney -little kidney
Bilateral chronic kidney disease with concomitant ureteral obstruction
What do you see clinin acute unilateral ureteral obstruction?
Generally, unilateral ureteral obstruction is clinically silent, potentially transient, and not associated with azotemia.
Abdominal pain, erratic/elusive behavior, or hematuria
How does acute bilateral ureteral obstruction present clinically?
Severe acute signs with bilaterally enlarged and painful kidney
Azotemia, oliguria, or anuria
What do you see clinically in a patient with big kidney- little kidney?
Past unilateral ureteral obstruction that has caused the kidney to progress to a fibrotic end-stage
Contralateral kidney is acutely obstructed —> hypertrophy
Abdominal pain, severe azotemia, variable urine production
What do you see clinically in a patient with bilateral chronic kidney disease with concomitant ureteral obstruction?
Most guarded prognosis even with resolution of obstruction
Underlying kidney dz may be secondary to fibrotic changes from previous ureteral obstruction or other intrinsic kidney dz that can predisposed to uroliths formation.
Overt uremia
What are the presenting complains in patients with ureteral obstrucion?
Severe acute uremia Anorexia Depression Intermittent vomiting Uremic odor Lethargy Weight Oligo/anuria
Uterocolic signs (generalized pain, ureter run just dorsal to colon in retroperitoneal space)
T/F: ureteral obstruction is more common in older cats
True
What might you see on a radiograph of a patient with ureteral obstruction?
Barely perceptible radiodensities in retroperitoneal space
Expansion of retroperitoneal space
Presence of marked renal asymmetry
- can be superimposed on colon-> difficult to determine if mineral opacities are in the colon or the ureter
What are the principle features of ureteral obstruction seen on ultrasound?
Hydronephrosis
Dilatation of the proximal ureter
What is the preferred imaging modality to confirm mineralization/mon-mineralized urothliths in the ureters?
CT
What method of imaging provides reliable information of presence, degree, and proximal location of ureteral obstruction in cats?
Antegrade pyelography
—> incorporates US guided pyelocentesis and antegrade injection of positive contrast media in the renal pelvis
How are ureteral obstructions managed?
Benign neglect Extracorporeal shock wave lithotripsy Nephrectomy Ureteral stent Subcutaneous ureteral bypass Pyelostomy tube
How would you medically manage ureteral obstruction??
Stabilize uremia
If surgery contraindicated (fluid overload/hyperkalemia) —> hemodialysis
Oliguria —> mannitol
Ureteral relaxants —> prazosin and amitryptilline
Pain management
T/F: lithotripsy is a good potion for managing ureteral obstruction in cats
False
Good for dog
Poor for cat -> resistant to fragmentation, particles too large for 0.4mm diameter lumen to pass
What is the best standard of care for ureteral obstruction ?
Ureteral stent
-made of soft polyurethane type catheters with double pigtail design with multiple fenestrations along their length
How are ureteral stents placed in dogs and cats?
Dog - Cystoscopy (retrograde)
Cat - surgically (antegrade)
What is a subcutaneous ureteral bypass system?
Indwelling ureteral bypass using locking-loop nephrotomy/cystotomy tube
How can you diagnose urethral obstruction?
Enlarged bladder (male cat)
Signs of urinary urgency
Difficulty manually expressing urine
Resistance in passage of a urethral catheter
An obstructed cat comes into your clinic, what do you do immediately?
IV line —> correct dyhydration and volume expansion
Therapeutic cysto -> pass urethral catheter -> collect urine/monitor output
ECG —> hyperkalemia or hypocalcemia
Stat bloods
What is your emergency treatment of hyperkalemia??
Fluids
-shock rate -45ml/kg (NaCL)
-calcium gluconate (cardioprotective)
IV insulin with dextrose
Bicarb
What do you do for ongoing management of a blocked cat?
Indwelling U-cath placement
Monitor urine production/urine sediment
Analgesia
Lab parameters
Exam parameters
Anti-spasm optics
Post obstructive diuresis
