Presentation: Straining to urinate (often reported by pet parents as constipated), yowling, extreme lethargy and vomiting; bladder will be distended and firm on palpation; typically male cats sometimes associated with environmental stressor; bradycardia and collapse due to hyperkalemia; hypothermia; azotemia and subsequent nausea/vomiting
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Diagnostics
- A young male cat will almost never have a UTI at presentation. Incidence of UTI in cats under 10-years-old is quite low, while FIC is much more common.
Treatments
- 1/4 shock dose of 60 ml/kg = 0 mL
- LRS is preferred as this will correct acidosis more quickly than 0.9% NaCl.1 LRS only has 4 mEq K+ (physiologic is 20 mEq), so this is not reason to use 0.9% NaCl.
- Calcium gluconate counteracts the effect of hyperkalemia at the sino-atrial node. Give 0.5 to 1.5 mL/kg = 0.00 mL to 0.00 mL of 10% Calcium gluconate I.V. over 5-10 minutes while monitoring EKG
- Dextrose & Insulin will shift plasma K+ into cells. Give 0.5 U/kg = 0.0 U regular insulin I.V. and 2 mL/U of insulin = 0.0 mL 50% Dextrose I.V. and add 2 mL/U of Insulin = 0.0 mL 50% Dextrose to 1 L fluid bag. Check BG in 2-3 hours.
- Terbutaline will shift K+ into cells and is used instead of Dextrose & Insulin by some clinicians. Give 0.01 mg/kg = 0.00 mL Terbutaline (1 mg/mL) I.V. slowly over 5-10 minutes. Inhaled Albuterol may have a similar effect.
| Drug (concentration; dose) | Volume (mL) |
|---|
| Midazolam (5 mg/mL; 0.3 mg/kg) | 0.00 |
| Ketamine (100 mg/mL; 5 mg/kg) | 0.00 |
| Buprenorphine (0.3 mg/mL; 0.02 mg/kg) | 0.00 |
| Drug (concentration; dose) | Volume (mL) |
|---|
| Acepromazine (1 mg/mL; 0.03 mg/kg) | 0.00 |
| Buprenorphine (0.3 mg/mL; 0.02 mg/kg) | 0.00 |
| Drug (concentration; dose) | Volume (mL) |
|---|
| Alfaxalone (10 mg/mL; 2 mg/kg) | 0.00 |
| Butorphanol (10 mg/mL; 0.1 mg/kg) | 0.00 |
| Midazolam (5 mg/mL; 0.05 mg/kg) | 0.00 |
- Additonal Propofol or Alfaxalone can be used for induction
- 1 - 4 mg/kg Propofol (10 mg/mL) or Alfaxalone (10 mg/mL) = 0.00 mL to 0.00 mL
- Decompressive cystocentesis at presentation or prior to catheter placement is considered by some clinicians to be helpful.
- Many feline patients with UO present with abdominal effusion; the incidence of abdominal effusion following decompressive cystocentesis is higher (from 33% at presentation to 49% following single cystocentesis).2 This same study suggests that there is minimal risk of clinically relevant complications associated with decompressive cystocentesis.
- Slippery Sam style preferred. 3.5F polyvinyl catheter is alternative and is associated with lower short-term recurrence of obstruction compared to larger 5F.4 In some challenging cases, a semi-rigid polypropylene open end tom cat catheter may be used for the initial unblock, but this should be replaced with a softer catheter that will not further traumatize the urethra and bladder.
- Fully extrude the penis. Attempt to gently massage any lodged grit at the tip. Grasp the extruded penis at the base and pull caudally and dorsally to straighten the urethra. Some clinicians prefer to shift their grip to the prepuce once the catheter reaches the base of the penis.
- Sterile saline or sterile saline mixed with sterile lubricant can be used to pulse flush the urethra as you advance the urinary catheter. Lidocaine can be added to this flush. Be patient. Retrograde hydropulsion—where digital pressure is applied to the urethra per rectum and then released while flushing through the catheter—may be helpful in some challenging cases.
- Bladder lavage may have no significant effect on recurrence, duration of catheter retention, or duration of hospitalization.5
- Catheter should be sutured to prepuce and taped to tail. A closed collection system should be kept clean (and off the ground). Hard E-collar is necessary to prevent premature removal by patient.
- Duration of catheterization is typically 24-48 hours based on difficulty unblocking, appearance of urine in line/bag, and resolution of azotemia. There is no association between re-obstruction and duration of catheterization beyond 24 hours.6
- Buprenorphine 0.3 mg/mL I.V.: 0.01 to 0.03 mg/kg = 0.00 mL to 0.00 mL
- Maropitant (Cerenia) 10 mg/mL I.V.: 1 mg/kg I.V. = 0.00 mL
- I.V. Fluid Therapy: LRS preferred over 0.9% NaCl; typically start at 35-50 mL/hr. Quantify urine output every 2-6 hours and adjust fluid rate accordingly. Be aware of post-obstructive diuresis; some patients will require significantly higher fluid rates.
- Empirical antibiotic administration is not indicated.7 If finances allow for multiple urine cultures, consider submitting the sample collected at presentation and a second sample collected from the urinary catheter line (after alcohol wiping the port) just prior to removal of the catheter. If finances are limited, consider a single sample just prior to removal of the port or from a sample collected by cystocentesis at a follow up appointment 7 days post-discharge.
- Some clinicians will not routinely submit urine for culture on the front end if no evidence of bacteriuria on urine sediment. In these cases, urine sediment should be evaluated daily and urine submitted for culture if any suggestion of bacteriuria.
Medications for long-term management:
Buprenorphine, 0.3 mg/mL
Give 0.2 mL (contents of 1 syringe) into the mouth onto the gums every 6-12 hours to reduce pain. Absorbed through the gums. May cause sedation, wobbly walking, or odd behavior.
- 0.01 to 0.03 mg/kg = 0.00 mL to 0.00 mL
- Use with acepromazine at first sign of difficult urination and may be able to prevent recurrence/hospitalization if patient is able to urinate on their own.
Acepromazine, 10 mg tablet
At first sign of difficult urination, give 1/4 tablet by mouth every 8 hours for 3 days. Then give 1/4 tablet by mouth every 12 hours for 3 days.
- Alpha antagonist (overlapping MOA with Prazosin, so avoid using both) that may promote urethral muscle relaxation
- The 2010 Cooper paper lends some evidence for acepromazine/buprenorphine combination therapy.8
Gabapentin
Give by mouth every 8 hours for 5-7 days. Give 1-2 hours before veterinary visits or other potentially stressful events.
- Anxiolytic, pain medication, mild appetite stimulant
Amitriptyline, 10 mg tablet
Give 1/2 tablet by mouth every evening. This is an anti-depressant that helps promote bladder relaxation. Do not discontinue abruptly. If any sign of difficult urination, increase dose to 1 full tablet.
- May be appropriate for some cats that are easily medicated
Maropitant (Cerenia)
At first sign of difficult urination, give INPUT tablet by mouth every 24 hours for 4-7 days. This medication has broad anti-inflammatory properties and may help your pet feel better. Next dose due INPUT.
- No data and off-label, but theoretically a great application of a very safe drug
Dantrolene, 25 mg capsules
At first sign of difficult urination, give INPUT capsule by mouth every 12 hours for 5-7 days. This drug may help prevent skeletal muscle spasm of the urethra that would cause your cat to become blocked.
- 0.5 to 2 mg/kg = 0.00 to 0.00 of a 25 mg capsule PO q12h
Adequan
Give 0.00 mL subcutaneously (under the skin) twice each week for 4 weeks. Then once each week for 4 weeks. Then once every 4 weeks.
- Glycosaminoglycans (GAGs) have a role in treatment of human women with cystitis. GAGs are important for covering the bladder epithelium. May work similarly to Pentosan (Elmiron) which is labeled for humans with cystitis.
- This is off-label with no sufficient evidence
NSAIDs
- Do not give Onsior (Robenacoxib) or Meloxicam to these cats which often have some degree of renal compromise.
- There is no COX2 in the feline uroepithelium.9
Prazosin
- Prazosin may help relax smooth muscle associated with internal urethral sphincter.
- This medication is falling out of favor. A recent study showed prazosin to increase the rate of recurrent urethral obstruction.10
Informational Handouts:
Discharge Note (Key Points):
- Most cats that have experienced urethral obstruction are at increased risk for recurrence of this life-threatening condition. Any signs of urinary tract problems are an emergency. These may include: bloody urine, straining to urinate, urinating outside the litter box, licking the urinary opening, crying/yowling, loss of appetite, vomiting. Recheck promptly if your cat is showing any of these signs or you are concerned.
- A prescription urinary diet (wet food is best) is one of the most important parts of your cat's management and may help prevent recurrence of this problem.
- Reducing environmental stress, vertical climbing areas/perches, Feliway pheromone diffusers, and other stress-reducing supplements may help prevent recurrence of this problem.
- We have recommended sending out a urine culture. If this was approved, we will call with the results when they are available from the lab. Your cat may need antibiotic treatment and/or recheck evaluation if there is evidence of a urinary tract infection.
1 Cunha, et al. Renal and cardiorespiratory effects of treatment with lactated Ringer’s solution or physiologic saline (0.9% NaCl) solution in cats with experimentally induced urethral obstruction. AJVR 2010.
2 Gerken, Cooper, et al. Association of abdominal effusion with a single decompressive cystocentesis prior to catheterization in male cats with urethral obstruction. JVECC 2020.
3 Pratt, et al. A prospective randomized, double-blinded clinical study evaluating the eefficacy and safety of bupivacaine versus morphine-bupivacaine in caudal epidurals in cats with urethral obstruction. JVECC 2020.
4 Hetrick, et al. Initial treatment factors associated with feline urethral obstruction recurrence rate: 192 cases (2004–2010). JAVMA 2013.
5 Dorsey, et al. Effect of urinary bladder lavage on in-hospital recurrence of urethral obstruction and durations of urinary catheter retention and hospitalization for male cats. JAVMA 2019.
6 Hetrick, Davidow. Initial treatment factors associated with feline urethral obstruction recurrence rate: 192 cases (2004-2010). JAVMA 2013.
7 Cooper, et al. Incidence of bacteriuria at presentation and resulting from urinary catheterization in feline urethral obstruction. JVECC 2019.
8 Cooper, et al. A protocol for managing urethral obstruction in male cats without urethral catheterization. JAVMA 2010.
9 Singer, et al. ACVIM Forum 2013.
10 Conway, et al. Prazosin administration increases the rate of recurrent urethral obstruction in cats: 388 cases. JAVMA 2022.
This guideline reflects opinion and experience that is not necessarily applicable to all institutions, situations, or patients. It is intended as a reference for veterinarians caring for patients, but is not intended to replace their clinical judgement.
All calculators are meant to double check your math. They are not a substitute for calculating your patient's dose. Always double check drug dosages and concentrations.