Feline Idiopathic Cystitis
World Small Animal Veterinary Association World Congress Proceedings, 2013
Larry G. Adams, DVM, PhD, DACVIM (SAIM)
Purdue University, West Lafayette, IN, USA

Feline idiopathic cystitis (FIC) is a lower urinary tract disease (LUTD) of undetermined etiology characterized by hematuria and/or dysuria (with or without urethral plug formation in male cats).1-7 Idiopathic cystitis is one of the causes for dysuria/pollakiuria in cats with LUTD. The danger in assuming all cats with LUTD have FIC is that other diseases with similar signs will be misdiagnosed as FIC and not treated effectively.

Diagnosis of FIC is based on ruling out other known causes of LUTD, thus FIC is an exclusion diagnosis.1,7,8 The minimum work-up consists of a urinalysis, urine culture, and abdominal radiographs, although these do not rule out all possible causes. Cats with persistent clinical signs (more than 7 days) should be evaluated by ultrasound or contrast radiographs to rule out radiolucent uroliths or neoplasia.1 Cystoscopy may be used to confirm a diagnosis of FIC and to exclude other causes of LUTD.1,2,5,9

There are two clinical forms of FIC: nonobstructive and obstructive FIC.1-4 Cats with nonobstructive FIC present with a history of hematuria, dysuria, and pollakiuria. It occurs in males and females, and tends to be episodic with acute onset. Nonobstructive FIC usually resolves spontaneously within 5 to 7 days regardless of treatment. Recurrence is common but unpredictable; cats can be normal from days to years between episodes. Obstructive FIC is seen almost exclusively in males, and is caused by urethral "plugs." Urethral plugs are not uroliths. Urethral plugs differ from uroliths in that they lack organized internal structure.10 They are semi-solid plugs composed of matrix and crystals (usually struvite). The matrix consists of varying quantities of protein and cellular debris. If obstruction is due to true uroliths, the disease is urolithiasis, not idiopathic cystitis. Urethral obstruction may occur abruptly without prior clinical signs. Urethral matrix plugs may begin to form in female cats and non-obstructed male cats, but they pass out the urethra without becoming obstructed. Increased crystals in plugs may solidify the plug causing obstruction. Urethral spasms contribute to obstruction. Urethral obstruction also tends to be recurrent similar to nonobstructive FIC.

The etiology of idiopathic cystitis is unknown. Some authors have suggested that FIC is "feline interstitial cystitis," similar to interstitial cystitis, which occurs in humans (mainly women).2,3,14 Recent observations by Drs. Westropp and Buffington are that cats with FIC have abnormal size and function of their adrenal glands.1,15 Cats with FIC also have elevated catecholamine levels that normalize after periods of environmental enrichment. The exact clinical relevance of these observations is not clear.

There is no proven effective therapy for treatment of idiopathic cystitis.1,16,17 The disease resolves spontaneously over 5–7 days in non-obstructed cats. Antibiotics are only indicated for documented UTI or prophylaxis following urethral catheterization. While several treatments have been suggested for idiopathic cystitis, none are more proven to be more effective than a placebo. Antibiotics are not effective in treatment of idiopathic cystitis.18,19 Methylene blue-containing products and phenazopyridine are contraindicated in cats, because they may cause Heinz body hemolytic anemia and methemoglobinemia. Corticosteroids have been suggested to reduce inflammation in idiopathic cystitis, but a double-blind clinical trial showed no improvement with steroids compared to a placebo. Prednisone did not reduce inflammation in an experimental model of idiopathic cystitis and predisposed the cats to pyelonephritis. Steroids can also predispose cats to UTI.18 Meloxicam was also not beneficial compared to a placebo in cats with FIC. Propantheline is an antispasmodic that may reduce the severity and frequency of "urge" incontinence in cats with non-obstructed idiopathic cystitis. However, this is symptomatic only and does not affect the rate of recovery. Intravesical DMSO (instillation of dimethyl sulfoxide within the bladder) does not help, and it may predispose the cat to UTI and pyelonephritis.18 Treatment with sublingual buprenorphine (0.01–0.03 mg/kg PO q 6–12h) may reduce clinical discomfort from FIC while waiting for the disease to spontaneously resolve.

There is also no proven preventative therapy for idiopathic cystitis. Uncontrolled clinical trials suggest that dietary therapy designed to prevent crystalluria, such as a canned dietary therapy, may reduce the incidence of recurrent FIC episodes and urethral obstruction.20,21 Adding water to the diet and/or feeding canned diets is the main treatment that appears to reduce recurrence of idiopathic cystitis.1

Amitriptyline (5–10 mg per cat q24h) may prevent recurrence of FIC based on a non-controlled study, but this is not consistently effective.22 Perineal urethrostomy (PU) has been advocated for prevention of recurrent urethral obstruction. Perineal urethrostomy surgery reduces the risk of obstruction; however, it does not address the underlying disease process. PU can also predispose to UTI, which can lead to infection-induced struvite urolithiasis, along with potential complications including urethral stricture.23-25 Although glucosamine has been recommended for treatment of idiopathic cystitis, one published study did not demonstrate any benefit over placebo-treated cats.21 In this study, most cats were fed more canned food during the study and both glucosamine-treated and placebo-treated cats improved to a similar degree.21 In a multicenter clinical trial of GAG therapy, ELMIRON® (pentosan polysulfate sodium) had a small beneficial effect on cystoscopic scores in cats with idiopathic cystitis, but no difference in clinical signs. In this study there was a large placebo effect that prevented any measurable benefit on clinical signs. Similarly, a placebo-controlled study of pheromone therapy also failed to demonstrate any benefit.26 A recent uncontrolled observational study suggested that environmental enrichment along with other behavioral modifications (so-called multimodal environmental modification) resulted in significant improvement of the clinical signs of LUTD and warrants further study.27

The incidence of lower urinary tract disease in geriatric cats is very different than young adult cats: 46% had UTI (2/3 with concurrent CKD), 17% had UTI and uroliths, 10% had uroliths, 7% had urethral plugs, 7% were due to trauma, 5% had idiopathic cystitis, and 3% had neoplasia.28


1.  Westropp JL, Buffington CAT. Feline lower urinary tract diseases. In: Textbook of Veterinary Internal Medicine: Diseases of The Dog and Cat. Ettinger SJ and Feldman EC (eds.), Saunders Elsevier, St. Louis; 2010:2069–2086.

2.  Buffington CA, et al. Feline interstitial cystitis. J Am Vet Med Assoc. 1999;215:682–687.

3.  Buffington CA, et al. Interstitial cystitis in cats. Vet Clin North Am Small Anim Pract. 1996;26:317–326.

4.  Osborne CA, et al. Feline urologic syndrome, feline lower urinary tract disease, feline interstitial cystitis: what's in a name? J Am Vet Med Assoc. 1999;214:1470–1480.

5.  Westropp JL, Buffington CA. In vivo models of interstitial cystitis. J Urol. 2002;167:694–702.

6.  Buffington CA, Chew DJ. Idiopathic, lower urinary tract disease. J Am Anim Hosp Assoc. 1995;31:455–456.

7.  Kruger JM, et al. Clinical evaluation of cats with lower urinary tract disease. J Am Vet Med Assoc. 1991;199:211–216.

8.  Buffington CA, et al. Clinical evaluation of cats with nonobstructive urinary tract diseases. J Am Vet Med Assoc. 1997;210:46–50.

9.  Chew DJ, et al. Urethroscopy, cystoscopy, and biopsy of the feline lower urinary tract. Vet Clin North Am Small Anim Pract. 1996;26:441–462.

10. Osborne CA, et al. Feline matrix-crystalline urethral plugs: A unifying hypothesis of causes. J Small Anim Pract. 1992;33:172–177.

11. Kruger JM, Osborne CA. The role of uropathogens in feline lower urinary tract disease. Clinical implications. Vet Clin North Am Small Anim Pract. 1993;23:101–123.

12. Kruger JM, Osborne CA. The role of viruses in feline lower urinary tract disease. J Vet Intern Med. 1990;4:71–78.

13. Kruger JM, et al. Clinicopathologic and pathologic findings of herpesvirus-induced urinary tract infection in conventionally reared cats. Am J Vet Res. 1990;51:1649–1655.

14. Buffington CA, Chew DJ. Does interstitial cystitis occur in cats? In: Bonagura JD, editor. Current Veterinary Therapy XII. Philadelphia: W.B. Saunders; 1995:1009.

15. Westropp JL, Buffington CA. Uncoupling of the noradrenergic-hypothalamic-pituitary-adrenal axis in stressed cats with interstitial cystitis. J Vet Intern Med. 2002(A);16:379.

16. Lane IF. Pharmacologic management of feline lower urinary tract disorders. Vet Clin North Am Small Anim Pract. 1996;26:515.

17. Lane IF, Bartges JW. Treating refractory idiopathic lower urinary tract disease in cats. Vet Med. 1999;94:633–642.

18. Barsanti JA, et al. Effect of therapy on susceptibility to urinary tract infection in male cats with indwelling urethral catheters. J Vet Intern Med. 1992;6:64–70.

19. Barsanti JA, et al. Feline urologic syndrome: further investigation into therapy. J Am Anim Hosp Assoc. 1982;18:387–390.

20. Markwell PJ, et al. Clinical evaluation of commercially available urinary acidification diets in the management of idiopathic cystitis in cats. J Am Vet Med Assoc. 1999;214:361–365.

21. Gunn-Moore DA, Shenoy CM. Oral glucosamine and the management of feline idiopathic cystitis. J Feline Med Surg. 2004;6:219–225.

22. Chew DJ, et al. Amitriptyline treatment for severe recurrent idiopathic cystitis in cats. J Am Vet Med Assoc. 1998;213:1282–1286.

23. Griffin DW, Gregory CR. Prevalence of bacterial urinary tract infection after perineal urethrostomy in cats. J Am Vet Med Assoc. 1992;200:681–684.

24. Osborne CA, et al. Feline perineal urethrostomy: a potential cause of feline lower urinary tract disease. Vet Clin North Am Small Anim Pract. 1996;26:535–549.

25. Osborne CA, et al. Perineal urethrostomy versus dietary management in prevention of recurrent lower urinary tract disease. J Small Anim Pract. 1991;32:296–305.

26. Gunn-Moore DA, Cameron ME. A pilot study using synthetic feline facial pheromone for the management of feline idiopathic cystitis. J Feline Med Surg. 2004;6:133–138.

27. Buffington CAT, Westropp. JL, et al. Clinical evaluation of multimodal environmental modification (MEMO) in the management of cats with idiopathic cystitis. J Feline Med Surg. 2006;8:261–268.

28. Bartges JW, Barsanti JA. Bacterial urinary tract infections in cats. In: Bonagura JD, editor. Current Veterinary Therapy XIII. Philadelphia: W.B. Saunders Co.; 2000:880–883.


Speaker Information
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Larry G. Adams, DVM, PhD, DACVIM (SAIM)
Purdue University
West Lafayette, IN, USA

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