1. Definition: What Are We Talking About?
Feline chronic gingivostomatitis (FCGS) is a syndrome clinically characterized by pain on eating and/or opening the mouth, pawing at the mouth, dysphagia, weight loss, bad general condition, grooming deficiency, ptyalism, and sometimes bleeding from the mouth.1,2 Typically, cats show ulcerative and/or ulcero-proliferative mucosal lesions located around the teeth (alveolar/labiobuccal stomatitis or caudally to the dental arch and lateral to the glossopalatine arches (caudal stomatitis). Cats presenting with the most severe and frustrating condition show caudal stomatitis which may extend more caudally in the oropharyngeal area (oropharyngitis).
2. Hypothetical Cause
FCGS is considered a multifactorial condition resulting from an inadequate individual response towards oral-located antigens of bacterial and viral origins. Chronic oral carriage of calicivirus is thought to play a role in cats presenting with caudal stomatitis. Other factors acting on the host's immune response may exacerbate the expression of clinical lesions.3
Dental-related conditions including periodontal disease and, possibly, dental resorptions are chronic inflammatory processes which may play a role. However, no specific bacterium is associated with this condition. Several viruses may affect cats' oral and upper respiratory cavities. The prevalence of chronic carriage of calicivirus in a random cat population is estimated between 20–30% according to various studies, whereas the prevalence of Herpesvirus carriage seems lower (5%). Calicivirus has been known for a long time to cause acute focal or multifocal ulcerative glossitis and palatitis as well as acute upper respiratory disorders. The prevalence of calicivirus carriage associated with "chronic gingivitis/stomatitis" has also been reported to be higher than in the random population. More specifically, it has been shown that acute caudal stomatitis (sometimes wrongly called "faucitis") can be experimentally induced with calicivirus strains sampled from the oropharynx of cats suffering from chronic stomatitis. However, this experimentally induced acute caudal stomatitis did not result in a chronic disease in the experiment setting.
Recently, it has been shown using PCR technology that almost all cats presenting with caudal stomatitis were chronic oral calicivirus carriers, whereas only 30% of cats with chronic gingivitis/stomatitis but without caudal stomatitis were. No specific biotype of calicivirus has been identified to be responsible for acute respiratory disorders, joint disease (lameness), oral vesicular disease or feline chronic gingivostomatitis. The same strain can induce different clinical signs. However, there are antigenic differences between "stomatitis"-related calicivirus and acute respiratory disorders-related calicivirus. Chronic infections isolates are antigenically more distant from the other isolates than the acute/respiratory isolates. The reason for this seems to be that antigenic changes occur during chronic infection. This may cause progressive mergence of isolates, which are antigenically more distant from other isolates. Antigenic variations (resulting from a series of mutations) are induced by the immunologic pressure during chronic infection and constitute an escape mechanism for the virus.4
Clinical diagnosis through a thorough examination of the oral cavity is aimed at recognizing different clinical entities that may affect the mouth. Precise terminology should be used to avoid placing under the same headline all inflammatory processes. Gingivitis and periodontitis might be severe and develop rapidly (aggressive periodontitis) but are well known conditions associated with dental plaque accumulation. Extension of the inflammatory process on the alveolar mucosa beyond the mucogingival line may sometimes occur associated with aggressive periodontal disease. However, so-called chronic gingivitis/stomatitis (FCGS) is only a therapeutic challenge when chronic caudal stomatitis is present. Chronic caudal stomatitis is most of the time associated with alveolar/buccal mucositis and all the time associated with some extent of periodontal disease.
The term chronic gingivitis/stomatitis should not be used to designate any of these inflammatory conditions. Clinical diagnosis must be completed, under general anaesthesia, by radiographic identification of the extent of periodontitis and of the presence of dental resorptions. Biopsy of the mucosa should be performed when the aspect, the extent or the severity of the lesion is unusual (for example, severe unilateral inflammatory process) to rule out a neoplasia (e.g., carcinoma). A biopsy report concluding to a lympho-plasmocytic infiltrate is totally nonspecific and only indicates a chronic inflammation in the mouth. PCR technology can be used to identify oral calicivirus carriage.
Various treatments have been advocated for this condition. Most of them have been aimed at reducing the inflammatory process, decreasing discomfort and allowing better nutrition. An 80% improvement has been reported with the use of long-acting steroids, megestrol acetate and Gold salt. However, no publication has shown that cats could be cured, and side effects with these drugs are important. The current therapeutic approach to chronic gingivitis/stomatitis with chronic caudal stomatitis is to eliminate all sources of infection and of chronic inflammatory processes from the mouth in order to facilitate the action of the body's defence system against calicivirus. There is still some debate on which teeth need to be extracted as some practitioners advocate full-mouth extractions instead of a more selective approach, which mostly result in extraction of premolar and molar teeth. The results of dental extraction in calicivirus-positive cats with chronic caudal stomatitis can be globalized as such: 50–60% of cats are cured, 25–30% are markedly improved, and about 15% are totally nonresponsive.2,5
Adjunct medical treatments are used both in the postoperative phase after dental extraction and for cats which are insufficiently improved after extractions. Choice of the protocol is individually based and depends on clinical signs (bacterial surinfection within oral cavity and pain) more than on appearance of the lesions. Appearance of the lesion is, however, recorded to correlate it with clinical signs in order to evaluate improvement and cure. Various drugs can be used to improve the cat clinically.
Most commonly used drugs include amoxicillin-clavulanic acid, clindamycin, doxycycline and spiramycin-metronidazole. A three-week course is prescribed in addition to specific dental treatments in order to decrease the oral bacterial load over a significant period of time and to improve the oral comfort. Additionally, refractory cases may be partially improved by courses of several weeks of antibiotics in order to decrease oral surinfection. Azithromycin has been suggested in Bartonella-positive cats with FCGS, though recent studies6 failed to find any correlation between FCGS and Bartonella sp., and treatment with such a drug is reported unrewarding.
Opioids and nonsteroidal antiinflammatory drugs (NSAIDs) are used in the peri- and postoperative periods. Other drugs such as gabapentin and amantadine may also be used in the postoperative period and for refractory cases. Antiinflammatory drugs: glucocorticoids can be used, but high dosage are best avoided in calicivirus-positive or herpes-positive cats. A tapering three-week course can be prescribed. As far as possible, NSAIDs are better used inflammation control in calicivirus-positive cats. When insufficient effect is observed, minimum dose (to effect) of corticosteroids can be used and, in our experience, has not been shown to negatively affect the outcome.
Vitamins, fatty acids and specific food for critical-care patients are used as necessary. Tube feeding can be done through an oesophageal tube after surgery for the most debilitated cats but is rarely necessary in our experience. A recent study has shown that changes in omega 6/omega 3 fatty acid ratio did not result in less inflammation or improvement of the healing.7
Recent randomized double-blind controlled studies have shown that a daily oral administration of a diluted dose of feline recombinant interferon omega (Virbagen omega® - Virbac) and daily administration of ciclosporin had a significant effect on cats with refractory cases of chronic caudal stomatitis (not improved after extraction) compared to control.8,9
1. Healey KA, Dawson S, Burrow R, Cripps P, Gaskell CJ, Hart CA, Pinchbeck GL, Radford AD, Gaskell RM. Prevalence of feline chronic gingiva-stomatitis in first opinion veterinary practice. J Feline Med Surg. 2007;9(5):373–381.
2. Bellei E, Dalla F, Masetti L, Pisoni L, Joechler M. Surgical therapy in chronic feline gingivostomatitis (FCGS). Vet Res Commun. 2008;32 Suppl 1:S231–234.
3. Harley R, Gruffydd-Jones TJ, Day MJ. Immunohistochemical characterization of oral mucosal lesions in cats with chronic gingivostomatitis. J Comp Pathol. 2011;144(4):239–250.
4. Poulet H, Brunet S, et al. Comparison between acute/respiratory and chronic stomatitis/gingivitis isolates of feline calicivirus: pathogenicity, antigenic profile and cross-neutralisation studies. Arch Virol. 2000;145:243–261.
5. Hennet PH. Chronic gingivo-stomatitis in cats: long-term follow-up of 30 cases treated by dental extractions. J Vet Dent. 1997;14:15–21.
6. Dowers KL, Hawley JR, Brewer MM, Morris AK, Radecki SV, Lappin MR. Association of Bartonella species, feline calicivirus, and feline herpesvirus 1 infection with gingivostomatitis in cats. J Feline Med Surg. 2010;12(4):314–321.
7. Corbee RJ, Booij-Vrieling HE, van de Lest CH, Penning LC, Tryfonidou MA, Riemers FM, Hazewinkel HA. Inflammation and wound healing in cats with chronic gingivitis/stomatitis after extraction of all premolars and molars were not affected by feeding of two diets with different omega-6/omega-3 polyunsaturated fatty acid ratios. J Anim Physiol Anim Nutr (Berl). 2012;96(4):671–680.
8. Hennet PR, Camy GA, McGahie DM, Albouy MV. Comparative efficacy of a recombinant feline interferon omega in refractory cases of calicivirus-positive cats with caudal stomatitis: a randomised, multi-centre, controlled, double-blind study in 39 cats. J Feline Med Surg. 2011;13(8):577–587.
9. Lommer MJ. Efficacy of cyclosporine for chronic, refractory stomatitis in cats: a randomized, placebo-controlled, double-blinded clinical study. J Vet Dent. 2013;30(1):8–17.