QUARTERLY BEAT / DECEMBER 2023 ///
/// QUARTERLY BEAT / DECEMBER 2023
TREATMENT Treatment of feline URT disease depends on the underlying cause, whether signs of disease are acute or chronic, and the extent and severity of systemic illness. Chronic URT disease can be frustrating to treat, and often for cats with chronic idiopathic rhinitis there is no cure. Please see recommendations for bacterial infections in cats with URT above (Table 1). Cats infected with FHV-1 can be treated with famciclovir 90 mg/kg TID for 21 days or with cidofovir topically if only ocular signs are present. For cats with chronic rhinitis, the treatment is not always successful and individual cats might respond to different therapy. Anti-inflammatory doses of systemic corticosteroids may help in cases of lymphoplasmacytic inflammation. Some cats may respond to antihistamines but further research with new immune modulatory drugs in this field is needed. Nasopharyngeal polyps can be removed by simple traction and is considered first-line treatment, but a ventral bulla osteotomy can be considered if clinical signs recur, however there is a risk of development of Horner’s syndrome after removal, which is mainly transient but may be permanent in some cats. Nasopharyngeal stenosis can be treated with balloon dilation and stent placement. Anti-inflammatory medications such as corticosteroids can also be considered in cats with nasopharyngeal polyps or stenosis. Foreign bodies might require endoscopic removal or nasal flushing (post visualization with endoscopy). PROGNOSIS The prognosis for cats with URT signs depends on the nature of the underlying disease. Feline URT infections are generally associated with high morbidity (especially in at-risk populations) but low mortality. Most infections are typically self-limiting in young adult immunocompetent cats. Poorer prognosis is seen in kittens and cats with systemic clinical signs, such as viral pneumonia, and concurrent infectious disease, such as panleukopenia. Cats with chronic rhinitis will likely always have some clinical signs.
References
oral ulcers etc.) but additional diagnostic tests might be needed, especially for cats with chronic URT signs. All cats should be tested for FIV/FeLV as URT disease can be associated with immunosuppression. Complete blood cell count and serum biochemistry are indicated in cats that are systemically unwell or have chronic clinical signs. Please see the above discussion on PCR testing for infectious agents. Diagnostics for cats with chronic URT signs and/or localizing signs should be more thorough given the broad range of differential diagnoses. Oral examination under sedation or anesthesia should be performed to fully assess the extent of dental disease and its potential contribution to URT signs. Diagnostic imaging should be performed in cats with chronic respiratory signs or in cats that are not responding to treatment. Computed tomography (CT) is now used instead of traditional skull radiographs to assess nasal passages and bullae for potential masses, lytic lesions, or polyps. Rhinoscopy is used to assess the nasal cavity and nasopharynx for possible masses, foreign bodies, and stenosis. Antegrade rhinoscopy is challenging and can be performed with narrow rigid scopes (Figure 2). Retroflex rhinoscopy is commonly performed to assess the nasopharynx (Figure 3). A biopsy is indicated in cases of a mass in the nasal passages and can be done blind or guided during rhinoscopy.
OTHER CAUSES Nasopharyngeal polyps and nasal tumors can cause chronic URT signs in cats. These polyps originate in the Eustachian tube or middle ear and are a source of upper airway obstruction. The exact etiology of these polyps is not known but are benign masses. Polyps are generally found in young cats, while nasopharyngeal masses of neoplastic origin (e.g., lymphoma or adenocarcinoma) are seen in older cats. Nasal tumors are a less common cause of URT signs. These tumors tend to be locally invasive without distant metastases. Nasal/nasopharyngeal foreign bodies are less common in cats than in dogs, and most of them are plant material. Nasopharyngeal stenosis is not common in cats but can be seen in young cats as a congenital disease or be acquired secondary to chronic infection/ inflammation. Dental disease can be the cause of URT signs in cats; tooth root abscesses and fistulas should be considered a differential diagnosis for cats with URT signs, particularly unilateral discharge with other evidence of dental disease. DIAGNOSTICS The diagnosis of feline URT infection often is based on history and physical examination (ocular and nasal discharge, ocular/
1. Bannasch MJ, Foley JE (2005). Epidemiologic evaluation of multiple respiratory pathogens in cats in animal shelters. J Feline Med Surg, 7: 109-19. 2. Coyne KP, Dawson S, Radford AD, Cripps PJ, Porter CJ, McCracken CM, Gaskell RM (2006). Long term analysis of FCV prevalence and viral shedding patterns in naturally infected colonies of domestic cats. Vet Microbiol, in press. 3. Radford AD, Addie D, Belak S, et al. Feline calicivirus infection. ABCD guidelines on prevention and management. J Feline Med Surg2009; 11:556-564. 4. Schorr-Evans EM, Poland A, Pedersen NC (2003). An epizootic of highly virulent feline calicivirus disease in a hospital setting in New England. J Fel Med Surg, 5: 217-226. 5. Hurley KF, Sykes JE (2003): Update on feline calicivirus: new trends. Vet Clin North Am Small Anim Pract 33(4), 759-772. 6. Ruch-Gallie RA, Veir JK, Hawley JR, Lappin MR (2011): Results of molecular diagnostic assays targeting feline herpesvirus-1 and feline calicivirus in adult cats administered modified live vaccines. J Feline Med Surg 13(8), 541-545. 7. Sykes JE, Studdert VP, Browning GF (1998): Detection and strain differentiation of feline calicivirus in conjunctival swabs by RT-PCR of the hypervariable region of the capsid protein gene. Archives of Virology 143(7), 1321-1334. 8. Quimby J, Lappin MR. Update on feline upper respiratory diseases: Introduction and diagnostics. Compend Cont Ed Pract Vet2009; 31:554-564. 9. Scherk M. Snots and snuffles: Rational approach to chronic feline upper respiratory syndromes. J Feline Med Surg2010; 12:548-557. 10. Burns RE, Wagner DC, Leutenegger CM, et al. Histologic and molecular correlation in shelter cats with acute upper respiratory infection. J Clin Microbiol 2011; 49:2454-2460. 11. Helps CR, Lait P, Damhuis A, et al. Factors associated with upper respiratory tract disease caused by feline herpesvirus, feline calicivirus, Chlamydophila felis, and Bordetella bronchiseptica in cats: Experience from 218 European catteries. Vet Rec2005; 156:669-673. 12. Thiry E, Addie D, Belak S, et al. Feline herpesvirus infection. ABCD guidelines on prevention and management. J Feline Med Surg 2009; 11:547-555.
Figure 3: Visualization of normal nasopharynx with flexible endoscopy in a cat. Photo courtesy of Dr. Petra Cerna, PhD, MRCVS, CertAVP, AFHEA, AdvCertFB.
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Figure 2: Normal nasal turbinates in a cat during rigid rhinoscopy. Photo courtesy of Dr. Petra Cerna, PhD, MRCVS, CertAVP, AFHEA, AdvCertFB.
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