a. Provide analgesia, typically an opioid
b. Consider decompressive cystocentesis
c. Establish IV access
i. Balanced electrolyte solution, avoid normal saline
ii. Treat shock if necessary: weight (kg)x10=½ of shock dose
iii. Replace fluid deficit (80% over 24 hours): (% dehydration)x(1000 mL)x(weight [kg])
iv. Calculate maintenance fluid requirement: (weight [kg]x30)+70
b. Cardiac function: evaluate ECG for arrhythmia induced by hyperkalemia
i. Slow rate, absent P waves, short QRS complexes, tall spiked T waves
c. Minimum database: hematocrit, total protein, electrolytes, ionized calcium, BUN, creatinine
d. Survey radiographs: include entire urinary tract
3. Treat electrolyte disturbances
i. Mild-moderate: may resolve with fluid therapy
ii. Dextrose 50%: 1 mL/kg
iii. Sodium bicarbonate: 1–2 mEq/kg IV over 10–15 minutes
iv. Calcium gluconate 10%: 0.5 mL/kg IV over 5–10 minutes, monitor ECG
v. Regular insulin + dextrose infusion
4. Relieve urethral obstruction once stable
a. Consider sedation + sacrococcygeal epidural
i. Lidocaine 2%: 0.1–0.2 mL/kg with 25 G x 1-inch needle, sacrococcygeal space or coccygeal space 1–2
b. Clip hair around prepuce, surgical prep of area, wear gloves
c. Use the least traumatic catheter possible
i. Stainless steel olive tip catheters for distal obstructions
ii. Soft catheters for proximal obstructions and indwelling (e.g., MILA tomcat)
d. Check catheter position with radiograph, ensure tip is inside bladder
e. Use a closed collection system; keep catheter clean
f. Avoid antibiotics unless clinical signs of infection
5. Ongoing management and catheter removal
a. Monitor hydration, electrolytes, renal function, bladder condition, urine output & characteristics
b. When to remove catheter: resolution of clinical signs, diminishing or resolving hematuria, resolution of lab abnormalities, small firmly contracting bladder
c. Discharge patient with analgesia, appropriate long-term therapy, schedule for re-evaluation
1. VETgirl. Treating the hyperkalemic obstructed cat. https://vetgirlontherun.com/how-to-treat-the-hyperkalemic-feline-urethral-obstruction-vetgirl-veterinary-continuing-education-blog/.
2. VETgirl. Urethral obstruction & unblocking cats. https://vetgirlontherun.com/feline-urethral-obstruction-part-1-vetgirl-veterinary-continuing-education-blog/.
3. VETgirl. Coccygeal epidurals. https://vetgirlontherun.com/veterinary-continuing-education-coccygeal-epidurals-feline-urethral-obstruction-vetgirl-blog/.
4. Hall J, et al. Outcome of male cats managed for urethral obstruction with decompressive cystocentesis and urinary catheterization: 47 cats (2009–2012). J Vet Emerg Crit Care. 2015;25(2):256–262.
5. O’Hearn AK, Wright BD. Coccygeal epidural with local anesthetic for catheterization and pain management in the treatment of feline urethral obstruction. J Vet Emerg Crit Care. 2011;21:50–52.
6. Performing a coccygeal epidural video. www.youtube.com/watch?v=_oruduRgYkU.
7. Weese S, et al. International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Vet J. 2019.