This brief overview of Idiopathic Human Intersitial Cystitis is taken from the publication Infect. Urol. 10 (3) 75-79,80,1997. I have downloaded and for a variety of reasons edited a version of that publication, which you may read, realizing that the original article has been adulterated. This information should be of use to veterinarians as a similar--possibly identical--syndrome (Feline Idiopathic Cystitis) has been documented in cats--some of whom have been erroneously diagnosed with a behavioral inappropriate urination problem.

Interstitial Cystitis (IC) primarily affects women (approximately 90% of cases) though a related condition, Prostatodynia, occurs in men. Symptoms include chronic dysuria, pollakauria,pelvic pain/bladder discomfort, reduced bladder capacity, and the absence of documented urinary tract infection. A large numner of victims complain of concurrent musculoskeletal pain and of fatigue. Men may also experience rectal or pelvic pain without laboratory evidence of infection or of inflammation in urine or prostatic fluids. About 20% of effected people will experience spontaneous remission.


Theories regarding the cause of human IC include autoimmune, infection, toxin, ischemia and defect in the bladder glycosaminoglycan protective layer synthesis.

This appears to be the most popular theory. An antinuclear antibody has been found in the sera of patients with IC that matches one found in patients with suspected immune-mediated arthralgia/myalgia-- raising the issue of a possible common autoantigen. It is most interesting that a large portion of IC patients complain of concurrent musculoskeletal/ joint stiffness!


There is no consistent correlation of urinary tract infection with IC, based upon cultures of urine and of bladder itself. A theory that perhaps a non-specific , or specific (and extremely fastidious-impossible to culture) low-level, persistent bacterial infection is present in IC has been suggested --but is only weakly supported. Some believe that prolongued antibiotic therapy reduces clinical signs, but the issue is unresolved.

Though considered possible causes of IC, evidence supporting each of these is theoretical only and, in some instances, loosely inferred by therapeutic response.


Treatment Options

  1. Conservative Medical

    In people, several interesting medical treatment regimens have been tried, to various levels of success. These include hydrodistension and/or intravesicular drug therapy, tricycyclic antidepressants, calcium channel blockade (nifedipine), polysacharosulfated glycoseaminoglycans, prolongued antibiotic therapy (rationale?)...and a few others. Analgesics are utilized where medical therapeutics do not provide acceptable levels of comfort and functionality.

    1. Hydrodistension of the bladder provided symptomatic relief in about 15%-30% of patients. Intravesicular dimethylsulfoxide (DMSO) and intravesicular sodium oxychlorosone have also been tried. The latter require repeated anesthesia AND there is risk of subsequent urethral fibrosis!

    2. Several of the tricyclic antidepressants are strong antihistaminergics; it is believed that large numbers of mast cells line the bladder wall and that clinical signs result, in part, from release by mast cells of histamine as an important inflammatory mediator. Other antihistamines have also been utilized, in people with various degrees of success. The significance of effect antihistamines in the treatment of feline idiopathic cystitis has extrapolated from studies like this, and , as discussed below, may play an important role in the treatment of afflicted cats.

    3. Vasoactive substances, for example nifedamine, are assumed to improve local circulation via vasodilator activity, which allows local dilution of and movement of focal inflammatory intermediates away from the bladder.

    Surgical Options

I don't think the surgical options ("supratrigonal substitution cystoplasty", "cystectomy with neobladderization from bowel segment") are practical options in veterinary medicine at this time.



Interstitial Cystitis in Veterinary Medicine

Clinical Signs

A syndrome similar to human interstitial cystitis is now recognized in veterinary medicine (Current Veterinary Therapy, XII,pp1009; JAVMA,January'97, pp46). Feline Idiopathic Interstitial Cystitis is characterized by either chronic-intermittent irritative voiding (stranguria, pollakiuria), and/or just (a prominent feature is) "inappropriate urination" (frequently misdiagnosed as behavioral urination, or "marking"). Urinalysis is frequently normal and, based on culture results, urine is sterile.

Cystoscopy reveals diffuse glomerulation, increased vascularity and denuding of superficial bladder (glycosaminoglycan) layer. Occasionally, crystals are seen adherent to exposed epithelium. Histologically, an inflammatory infiltrate is present which often includes a sizable mast cell population.

In the JAVMA study, about 20% of cats did not show stranguria or pollakiuria.. Urines were normal and sterile. In the absence of further diagnostics, these would be treated for "behavioral urination". However:

"....idiopathic cystitis is the most common cause of clinical signs in non-obstructive lower urinary disorders....(and)...urination in inappropriate places was reported in neary all cats with idiopathic cystitis..."

One more interesting tidbit: the exclusive consumption of dry food--regardless of composition or effect on urine pH--is a common historical finding in cats with idiopathic cystitis.


Treatment Options

The use of canned/moist food must be considered in treating these cats.
Other recommendation are amitriptylline or other antihistamine (e.g. hydroxazine); Probably these act to limit mast cell degranulation as well as pain/discomfort-induced anxiety (in the case of amitriptylline) Whether neutraceuticals (e.g.Cosequin®) or other medications may be of benefit is presently an unknown.

Corticosteroids, intravesicular DMSO and "bladder stripping" do not appear to be effective in the cat.

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