Feline Idiopathic Cystitis (FIC)
FIC is diagnosed when no specific cause can be determined for inappropriate
urination. Lower urinary tract diseases in cats are as varied as those in any other
species.
Causes
Infectious agents have been investigated without identifying a culprit. Thus, there
is no definitive evidence that idiopathic cystitis is a contagious disease. There is
no evidence of a relationship with FeLV or FIV. Struvite crystalluria (urine
crystals) has been proposed as a causative factor. However, struvite crystals are
commonly noted in urine of normal cats. Use of acidifying diets has not
prevented recurrence of clinical signs in some cats affected with FIC.
The effect of early age neutering (younger than 10-14 weeks old) on urethral
characteristics and predisposition to obstruction has been evaluated. Several
studies have found no effect of early age neutering on urethral diameter in male
cats. No association has been found between age of neutering and occurrence of
FIC or urethral obstruction.
Most recently, idiopathic cystitis has been compared to interstitial cystitis in
women. Interstitial cystitis is a painful, progressive disease of unknown cause,
characterized by dysuria. Histologically, the lesion is characterized by
inflammation and edema. Because of the similarity of clinical signs, urine
biochemical findings and histologic appearance, it has been theorized that FIC
might be similar to interstitial cystitis. Qualitative and quantitative changes in the
glycosaminoglycan (GAG) layer of the bladder have been found in affected
women and cats. This is associated with an increased permeability, allowing
substances in urine to pass through the urothelium to the bladder wall, where
they may cause inflammation. It is not known what causes the alteration in the
GAG layer. However, one important difference in the two conditions is that the
frequency of recurrence of acute signs in cats declines as the cat ages.
Cats with FIC tend to be fed significantly more dry food than cats without this
problem. Although this does not show that dry food causes idiopathic cystitis, it
implies a relationship. Stress has been considered as a possible causative factor.
Cats with idiopathic cystitis more likely live in multiple-cat households or with
another cat with which there is conflict.
Urinalysis
It is essential that a complete urinalysis including microscopic examination of the
urine sediment be performed on all cats with lower urinary tract problems.
Whenever possible, urine should be collected prior to treatment. It is also
important to note how the urine sample was obtained because the technique may
affect interpretation of the results.
Ultrasonography
Ultrasonography is a useful tool for evaluating the urinary bladder of cats with
dysuria/hematuria as long as the bladder contains urine. Ultrasound is so
sensitive that occasionally calculi diagnosed by ultrasound cannot be found at
surgery. Bladder-wall thickening is the primary finding in FIC.
Management of cystitis
Most cats improve, regardless of therapy, within five days. If the signs do not
abate within seven days, a diagnostic plan to rule out other causes of hematuria
and dysuria should be instituted. Antibiotic and other therapy is not indicated in
cats with FIC as it has been shown to be no more effective than placebo and has
a high incidence of adverse effects. Drugs to relieve pain may be useful. If the
cat becomes dehydrated sub Q fluids may be necessary.
Change of diet to one that increases water intake (canned food) is often the
approach recommended.
Prevention
Recurrence rates for FIC have been 40-65 percent, depending perhaps on how
closely the owner observes the cat. Only three prospective studies have been
done to evaluate the efficacy of treatment regimens to prevent recurrence of FIC.
One study compared the efficacy of a dry versus a wet acidifying diet (diets
identical except for water content). Incidence of recurrence was lower on the wet
diet (11 percent versus 39 percent), indicating the importance of increasing water
intake. Methods to increase water intake include feeding canned food, dry food
mixed with water, providing water the cat likes (such as fresh water), and
providing bouillon, soups or broths from cooking. The second study evaluated
oral glucosamine versus a placebo. Recurrence rates were the same in both
groups, although there were four cats of 20 in the glucosamine group that
relapsed whenever the drug was discontinued and improved again when it was
reinstituted, suggesting some cats may be responsive. Interestingly, owners of
cats in this study changed the cats' diets. Prior to the study, 95 percent of the
cats were fed at least 50 percent dry food; within one month of starting the sixmonth course of therapy, more than 80 percent were fed solely wet food, and
their urine specific gravity dropped accordingly. Cats in both groups improved
during the six-month study, providing further support that the most effective
treatment option may be to change from dry to wet food. The third study
compared the use of feline facial pheromone in the environment versus placebo
for two months. No significant difference was found, although the study involved
only nine cats.