CVC Highlight: How to think outside the litter box: Managing cats with nonobstructive idiopathic interstitial cystitis
Current evidence suggests that some cases of idiopathic cystitis represent a systemic disorder variably affecting the bladder and other organ systems rather than a primary bladder disease. Idiopathic cystitis may account for clinical signs related to the urinary system of irritative voiding (dysuria, stranguria, pollakiuria, gross hematuria, periuria) in up to 70% of cats that are less than 10 years old. In contrast, only about 5% of cats older than 10 years with such signs have idiopathic cystitis—instead, more than half of the cats in this age group have bacterial urinary tract infections with or without urolithiasis.2
DIAGNOSISAbdominal palpation sometimes reveals pelvic organ pain, bladder wall thickening, and a small bladder. In cats with recurrent signs of lower urinary tract disease, we recommend survey abdominal radiography and double-contrast cystography or abdominal ultrasonography to rule out calculi and anatomic defects and identify bladder wall abnormalities.
Urinalysis in affected cats may reveal hematuria, proteinuria, crystalluria (which is likely secondary to sterile neurogenic inflammation that leads to proteinuria and increases urine pH so that struvite crystals precipitate), and high specific gravity. In cats with lower urinary tract signs and a urine specific gravity < 1.025, investigate a systemic problem such as renal disease, diabetes mellitus, or hyperthyroidism.
Increased noradrenergic outflow (catecholamine secretion) in response to activation of the stress response system may increase epithelial permeability and activate local neurogenic inflammation in the bladder and elsewhere.3 Thus, it is crucial to decrease noradrenergic outflow by identifying and reducing factors that may contribute to a cat's stress and epithelial compromise, such as living indoors with people, poor welfare, and inferior husbandry. In addition, providing systemic analgesia helps break the bladder pain-inflammation cycle.
Clinical signs of a first or a recurrent episode of idiopathic cystitis usually resolve in about 85% of affected cats within a week with or without treatment, but about 50% of cats have another episode within a year. The signs of idiopathic cystitis are distressing to owners, and irritative voiding is presumably stressful for affected cats. Thus, we recommend the following treatment regimen.
We treat the distress and pain associated with acute flares of idiopathic cystitis with acepromazine and buprenorphine. The injectable form of acepromazine may be given orally (2.5 mg b.i.d. to t.i.d.), although some cats will exhibit hypersalivation. In these cats, the oral form may be used—1/4 of a 10-mg tablet in a Greenies Pill Pocket (Nutro Products) or made up as a suspension and administered with an oral syringe. The injectable form of buprenorphine is given orally at 5 to 20 µg/kg two to four times a day for three to five days—buprenorphine is absorbed across the buccal mucosa.
We also recommend enriching the environment of indoor cats, because captivity and housing with people and other cats or other environmental challenges may elicit stress responses in some cats. Although extensive indoor housing in an unenriched environment doesn't cause idiopathic cystitis, it may contribute to its development and ongoing occurrence. We have found that about 80% of cats with recurrent idiopathic cystitis respond to successful implementation of environmental modification.