Chronic Rhinitis in Cats
Chronic rhinitis is a common and important problem in cats potentially resulting from a number of intranasal or systemic disorders. Idiopathic chronic rhinosinusitis and nasal neoplasia are the most common causes of chronic nasal disease in cats. For most cats with chronic rhinitis, diagnostic imaging and endoscopic studies and nasal biopsy will be required to establish a diagnosis. A discussion of some of the more common causes of chronic nasal disease is presented.
Clinical Signs of Nasal Disease
Nasal discharge, sneezing, stertorous respiration, and open-mouth breathing (rare) are typical signs associated with chronic nasal disease in cats. Chronic sneezing is a common clinical sign in cats and often is accompanied by nasal discharge.
Epiphora (tearing) may be seen with obstruction of the nasolacrimal duct.
Gagging, dysphagia, or halitosis may occur when disease involves the oral or pharyngeal cavities.
Chronic nasal disease may be seen concurrent with otitis externa or vestibular disease in cats with nasopharyngeal polyps.
Facial deformity may occur in advanced stages of nasal, extraocular, or oral neoplasia or fungal rhinitis.
Behavior changes, seizures, or obtundation in cats with a chronic history of nasal disease may occur with neoplasia or fungal rhinitis resulting from compromise of the cribriform plate with extension of disease into the brain.
The type and location of the nasal discharge may help limit differential diagnoses. Unilateral nasal discharge may be seen with nasal foreign bodies, early nasal neoplasia, and dental disease. Bilateral nasal discharge is most commonly seen and does not further define the cause for the rhinitis.
Mucopurulent nasal discharge is most common type results from secondary bacterial infection from a large number of primary causes for the rhinitis.
Serous (watery) nasal discharge is uncommon and typically seen with allergic rhinitis or early viral infection. Serous discharges are often modified to mucoid or mucopurulent types with persistence of the underlying cause for the nasal disease.
Blood may be seen intermittently in mucopurulent discharges from a wide variety of underlying nasal diseases due to erosion of blood vessels and sneezing.
Epistaxis (bleeding from the nose) is not commonly seen in cats, as compared to dogs, with chronic nasal disease. Epistaxis is seen with aggressive intranasal diseases causing erosion of blood vessels (e.g. neoplasia, inflammation) or coagulopathies.
Oronasal fistula in adult cats or cleft palate in kittens may be associated with food material appearing in the discharge from the nose.
Causes for Chronic Nasal Disease in Cats
Chronic rhinitis is a common and important problem in cats that may result from a number of intranasal or systemic disorders. A list of the many known causes for chronic nasal disease in cats is provided on the following page.
Viral infection, idiopathic chronic rhinosinusitis, and nasal neoplasia are the most common causes of chronic nasal disease in cats. Nasopharyngeal polyps, fungal rhinitis, nasal foreign bodies, dental disease, and nasopharyngeal stenosis are less frequent, but important causes of chronic rhinitis in cats.
Primary nasal and paranasal sinus disorders causing nasal discharge
- Viral infection
- Feline rhinotracheitis virus
- Feline calicivirus
- Idiopathic chronic rhinosinusitis
- Neoplasia (nasal, oral, extraocular)
- Lymphoplasmacytic rhinitis
- Bacterial infection
- Chlamydia felis
- Mycoplasma spp
- Pasteurella multocida
- Bordetella bronchiseptica
- Anaerobic bacteria
- Foreign body
- Nasopharyngeal polyp
- Dental disease
- Palatine defects
- Allergic rhinitis
- Stenotic nares
- Fungal infection
- Cryptococcus spp
- Aspergillus spp
- Nasopharyngeal stenosis
- Nasopharyngeal turbinates
- Parasitic infection
- Eucoleus (Capillaria) boehmi
Systemic or extranasal disorders associated with nasal discharge
Coagulopathies Esophageal stricture Cricopharyngeal disease Hypertension Environmental agents (dusts, smoke) Hyperviscosity syndrome Megaesophagus Thrombocytopenia Oropharyngeal diseases Vasculitis Pneumonia Vomiting Polycythemia
Diagnosis of Chronic Nasal Disease in Cats
Age, breed, and lifestyle may help to narrow the list of potential causes for chronic rhinitis. Young to middle aged cats will not likely have neoplastic disease as opposed to older cats (>8 years of age). Nasopharyngeal polyps are typically seen in cats < 8 years of age. Brachycephalic breeds (e.g., Persians), cats coming from a high density housing situations (e.g., multi-cat households, poorly maintained catteries or pet stores), or stray and barn cats may be more likely to develop idiopathic chronic rhinosinusitis secondary to previous upper respiratory viral infections. Outdoor cats have a higher occurrence of nasal foreign bodies, nasal trauma, nasal parasites (especially Cuterebra), and fungal rhinitis.
Prior vaccination history is important for the affected cat as well as other cats in the household. Vaccination will not prevent viral upper respiratory infection, but may diminish the severity of clinical signs. Viral infection should be suspected when acute upper respiratory infection is present in multiple cats within a household. The preceding history of a cat obtained at a later age should be obtained (if possible) in regard to former lifestyle, housing, and vaccination status.
Many cats with prior viral upper respiratory infection will have recurrent bouts of rhinitis throughout their lives. Any sudden change in the nature or severity of nasal disease should prompt investigation into other causes for chronic rhinitis (e.g., neoplasia, fungal rhinitis). Acute onset of sneezing and nasal discharge should prompt investigation into nasal foreign bodies, nasal trauma, and coagulopathies. Chronic nasal discharge is more often associated with idiopathic chronic rhinosinusitis, neoplasia, lymphoplasmacytic rhinitis, fungal rhinitis, and nasopharyngeal polyps.
A thorough physical examination with particular attention to orofacial structures is important in the evaluation of cats with chronic rhinitis. The maxillary and frontal sinus regions need to be visualized and palpated for evidence of asymmetry or swellings. The eyes need to be examined for any evidence of exophthalmia. The external nares need to be studied for patency, symmetry, and visible occlusions (such as a mass protruding through the openings).
Facial asymmetry or exophthalmia would suggest an underlying neoplastic process or the presence of fungal rhinitis. Approximately 35% of cats with nasal cryptococcosis have prominent swellings over the bridge of the nose. Some cats with nasal cryptococcosis will have a polypoid mass protruding through the nostril. Lack of airflow through one or both nostrils indicates presence of obstructive disease, but does not define an underlying cause. Plugs of inspissated mucopurulent debris are as likely to obstruct airflow as a space occupying mass (e.g., neoplasia, fungal granuloma).
A complete ophthalmic examination may be recommended to discover signs suggestive of systemic or fungal disease (e.g., anterior uveitis, chorioretinitis, optic neuritis) or for indications of hypertension or hyperviscosity syndrome (e.g., retinal hemorrhage, tortuous vessels, retinal detachment).
For most cats with chronic rhinitis, diagnostic imaging and endoscopic studies and nasal biopsy will be required to establish a diagnosis. A complete blood count, chemistry profile, and urinalysis will be recommended to rule out extranasal systemic causes for the nasal discharge (e.g., hyperviscosity syndrome, polycythemia, or thrombocytopenia). A coagulation profile is indicated if epistaxis is present and a coagulopathy is suspected. Blood pressure determination is advised if hypertension is suspected. Serum titer for cryptococcal antigen is a very specific and sensitive test for cryptococcosis and will be recommended if clinical findings are suggestive of this disease. Culturing of nasal discharge for bacterial or fungal organisms are not recommended as secondary bacterial contaminates are typically isolated. Deep culture of nasal tissue, performed with the patient under anesthesia, is of potential value in those patients where idiopathic chronic rhinosinusitis is suspected.
All diagnostic imaging studies require that the patient be under general anesthesia. Imaging studies are essential in most cats with chronic rhinitis to help achieve a diagnosis. It is critical that imaging studies are completed prior to rhinoscopy or collection of intranasal samples so that secondary hemorrhage does not obscure subtle lesions or affect the quality of diagnostic images. If dental disease is suspected, dental films may be recommended to evaluate the questionable teeth and surrounding structures. Radiographic images of the nose and sinuses may provide some insight but often do not reveal a specific cause for the nasal disease. Due to the complexity of the nose and overlying boney structures, conventional radiography rarely offers the detailed information required to determine an accurate cause for chronic nasal disease in cats. Radiographs also suffer from lack of sufficient resolution to identify or localize early nasal disease.
Nasal Computed Tomography
Computed tomography (CT) is the diagnostic imaging study of choice for evaluation of the nasal cavity, paranasal sinuses, tympanic bulla, periorbital region, and skull. Nasal CT is superior to conventional radiography for detecting subtle changes within the nasal cavity, determining the extent and severity of disease processes, and differentiation of infectious or inflammatory disease from nasal neoplasia.
Conventional radiographs have poor sensitivity for differentiating inflammatory rhinitis from neoplasia and fungal rhinitis. Image acquisition time (time spent under anesthesia) for nasal CT is also considerably less than that for routine nasal and skull radiographs. Rhinoscopy is not recommended in lieu of nasal CT in that rhinoscopy alone frequently affords limited information about the extent of the disease because of the internal complexity of the nasal cavity. The presence of mucopurulent or hemorrhagic nasal discharge also prevents satisfactory visualization within the nasal cavity. The nasal sinuses also cannot be routinely visualized with rhinoscopy.
Nasal CT is a rapid imaging modality that utilizes x-rays and complex computers to construct cross-sectional images of the nose, paranasal sinuses, and skull. The ability to obtain cross-sectional images allows for evaluation of internal structures and anatomical relationships that cannot be seen on conventional radiographs. Because x-rays are used to construct the tomographic images, the interpretation of computed tomography studies is comparable to basic radiographic principles.
Computed axial tomography images are made by rotating an x-ray tube head around the patient in the area of interest. When image slices are collected in an axial fashion, the computed tomography table supporting the patient is held stationary during the time required to complete one revolution of the x-ray tube head. The computed tomography table then advances the patient a predetermined slice interval through the gantry and the next acquisition takes place.
The images acquired by CT provide a thorough assessment of the nasal cavities and paranasal sinuses, extent of disease present and superior insight to the nature of the disease. Nasal CT studies often can differentiate neoplastic nasal disease from fungal rhinitis and inflammatory rhinitis. Contrast-enhanced CT images are occasionally used and may be useful to distinguish between vascularized soft tissues versus mucous accumulation. Because nasal CT will clearly demonstrate the location and extent of nasal disease, it is often used to help guide post-imaging rhinoscopic and biopsy procedures.
Rhinoscopy should be performed only after all imaging studies are completed with the patient remaining under anesthesia. This is so that endoscopy-induced hemorrhage does not obscure the imaging studies. The nasopharynx is examined before the nasal cavity because if hemorrhage is induced by examination of the nasal cavities, blood will frequently pool in the nasopharynx and obscure visualization of abnormalities in this area. Retroflex nasopharyngoscopy is performed by turning a small flexible scope 180 degrees around the caudal margin of the soft palate for visualization and evaluation of the caudal nares, dorsal soft palate, and nasopharynx. Tumors or foreign bodies lodged within the caudal nares or within the nasopharynx occasionally cause chronic rhinitis in cats and are readily visualized with this procedure.
Anterior rhinoscopy is performed by direct passage of a scope through the rostral nares, which allows for direct visualization of structures within the nasal cavity. Evaluation of the nasal cavity is often limited by the size of size of the scope in relation to the size of the nasal cavity, lesion location, and impeded visualization of intranasal structures by mucous or hemorrhage. The convoluted nature of the nasal passages will not allow for evaluation of the entire nasal cavity, so foreign bodies and neoplastic masses may be overlooked. Although rhinoscopy has utility in the diagnosis of chronic nasal disease, the various limitations outlined above severely limit its use as a sole or preferred diagnostic test procedure. When available, nasal computed tomography is a vastly superior method for evaluation of the entire nasal cavity.
During rhinoscopy, the nasal mucosa is evaluated for color, vascularity, friability, edema, and presence of parasites or fungal plaques. The nasal passages should be evaluated for obstruction by tissue masses, foreign bodies, or secretions. A loss of normal nasal turbinates would indicate the presence of a destructive rhinitis secondary to fungal infection or severe idiopathic lymphoplasmacytic rhinitis. Rhinoscopy is especially helpful to aid in the diagnosis of fungal rhinitis and rostrally positioned nasal foreign bodies. Fungal rhinitis is associated with widespread turbinate destruction. Rhinoscopy reveals a cavernous nasal cavity, frequently with white to grey fungal plaques scattered within the surface of the nasal mucosa.
Procurement of nasal specimens and biopsies of nasal tissue should only be performed after all imaging studies are completed with the patient remaining under anesthesia. Cytology of nasal secretions is rarely useful. Brush cytology from masses or fungal plaques may be useful in establishing a diagnosis. Stained direct smears of nasal tissue specimens also can be useful for identifying fungal organisms. Tissue from lesions visualized during rhinoscopy may be obtained either by direct biopsy with forceps passed either adjacent to or through the endoscope. Rhinoscopic-directed biopsies of masses may be limited by the small size of tissue samples obtained and confounded by inflammation surrounding the mass. Lymphoplasmacytic inflammation often is concurrent with intranasal neoplasia, whereas idiopathic lymphoplasmacytic rhinitis is not associated with mass lesions in the nose. It is often preferable to use nasal CT images to provide a guide for procurement of biopsy samples. Specialized biopsy forceps are advanced to the site of disease as identified from CT images with multiple biopsies being obtained.
Nasal Tissue Culture
Deep nasal tissue samples are submitted for aerobic and anaerobic bacterial culture when idiopathic chronic rhinitis is suspected. Occasionally samples will be submitted for fungal culture if fungal rhinitis is suspected. Nasal fungal and bacterial tissue cultures must be interpreted cautiously because fungal and bacterial isolates may be a consequence of nasal passage colonization rather than the cause of a given disease process. Primary or secondary bacterial rhinitis may play a role in idiopathic chronic rhinosinusitis of cats.
Nasal lavage may be required to dislodge foreign material identified or suspected to be present within the nose. Nasal lavage may also be performed to flush accumulated secretions out of the nose. This may help provide temporary relief in cats having difficulty breathing due to the accumulation of large amounts of mucous within the nose.
Common Causes of Chronic Rhinitis in Cats
Idiopathic Chronic Rhinosinusitis
Chronic rhinosinusitis is an extremely significant cause of chronic rhinitis, representing one of the two most common causes of sneezing and nasal discharge in cats. Chronic rhinosinusitis may follow severe acute upper respiratory tract infection, particularly in kittens or adults cats exposed to an infected cat. Acute upper respiratory tract disease is presumed to be caused by infection with feline herpesvirus type 1, feline calicivirus, Chlamydia felis, or some combination of these agents. Although viral (especially feline herpesvirus type 1) or chlamydia infection is often implicated as the initiating cause of acute rhinitis, the pathogenesis of events leading to idiopathic chronic rhinosinusitis remains largely unknown. It also remains unclear whether acute infectious rhinitis is associated with the chronic syndrome.
Even though cats with idiopathic chronic rhinosinusitis have similar clinical signs, the disease syndrome appears heterogeneous among the population perhaps due to individual susceptibility to microbial pathogens, genetic characteristics of the inflammatory response, and environmental factors (e.g., stress) effecting the development of clinical signs. A more thorough understanding of the influence of these characteristics would likely help to facilitate treatment recommendations for patients so affected.
Feline herpesvirus type 1 is estimated to account for the majority of cases of acute severe upper respiratory disease in cats, although calicivirus may be more prevalent in some populations. Feline herpesvirus type 1 is possibly an important pathogen for initiating chronic rhinitis. Experimental infection of germ-free cats with feline herpesvirus type 1 can cause severe upper respiratory disease in the absence of microbial flora. In the natural cat population, it is likely that some interrelationship between herpesvirus type 1 and various bacterial organisms are important factors determining the severity and duration of upper respiratory disease.
Clinical signs of chronic rhinosinusitis may be perpetuated by: 1) chronic or recurrent bacterial infection within the nasal cavities and paranasal sinuses, 2) an disproportionate inflammatory response to the presence of bacteria or virus, 3) permanent destruction of nasal epithelium and boney turbinates following a bout of acute severe viral rhinitis, or 4) cumulative destruction of nasal epithelium and boney turbinates following paroxysmal reactivation of virus from the trigeminal ganglia. The role any one or combination of microbial agents plays in the pathogenesis of chronic rhinosinusitis is ultimately not understood.
The difficulty at hand in our understanding of this disease is that the mere identification of bacterial or viral organisms via culture, antibody titers, or molecular techniques does not necessarily imply that the organism or organisms found are responsible for the clinical signs. In summary, a complex progression of microbial, physiological, anatomical, and immunological interactions appears to be responsible for development of chronic rhinosinusitis.
Idiopathic chronic rhinosinusitis may be seen in cats of any age, although younger cats are most often afflicted. Affected cats with this disease syndrome typically have a recurrent history of chronic intermittent or progressive sneezing, stertor, and nasal discharge. The nasal discharge is usually copious, bilateral, and mucopurulent to purulent, although occasionally the discharge can be unilateral or intermittently contain blood. Systemic or ocular disease is generally not present. Older cats may develop anorexia due to loss of smell, which may exacerbate other underlying disease conditions (i.e., chronic renal failure, liver, or gastrointestinal disease). Physical examination findings are generally unremarkable other than abnormalities confined to the upper respiratory tract.
Diagnostic studies should be undertaken once it is established that chronic refractory rhinosinusitis is present so that other treatable conditions may be excluded from consideration. In general, computed tomography will initially be recommended over routing nasal radiographs as CT provides for exact localization of lesions and complete determination of extent of disease within the nasal cavity, paranasal sinuses, and tympanic bulla. Findings often seen with computed tomography include soft tissue opacification of the nasal cavity and frontal or sphenopalatine sinuses, lysis of nasal and frontal bones, turbinate destruction, and asymmetry of the cribriform plate. Computed tomography is also superior for differentiation of chronic rhinitis from neoplastic or fungal diseases.
Selected computed tomography (CT) images from a cat with idiopathic chronic rhinosinusitis
The CT image on the left shows scattered soft tissue attenuating densities (representing mucous) between nasal turbinates within both sides of the nasal cavity. The CT image on the right is further back within the nose at the level of the eyes showing similar changes.
Rhinoscopy may be performed once diagnostic imaging procedures are completed. Cats with idiopathic chronic rhinitis have mild to severe hyperemia of nasal mucosa, moderate to large amounts of mucoid to purulent discharge between turbinates, and varying severity of turbinate destruction (although in some cats the turbinates may be normal). The degree of observed abnormalities may vary between either sides of the nasal cavity. Histopathology is of critical importance and both sides of the nose should be biopsied. There may be considerable discordance between visualized abnormalities and those detected histologically, as cats with relatively normal appearing nasal tissue may have moderate to severe histological inflammation.
Histopathology findings may include moderate to severe neutrophilic, lymphocytic, or pleiocellular inflammation with epithelial ulceration, turbinate destruction and remodeling, fibrosis, necrosis, and glandular hyperplasia. Histologic changes may be predominately unilateral rather than bilateral. Nasal biopsy samples or material cultivated from deep nasal aspiration may be submitted for microbial culture and sensitivity. Aerobic, anaerobic, and Mycoplasma cultures may be requested. Following visualization of the nasal cavity and collection of biopsy materials, the nasal cavities will often be suctioned and flushed with copious amounts of warm isotonic solution to remove secretions and provide temporary improvement in clinical signs.
Cats with idiopathic chronic rhinosinusitis frequently prove to be very refractory to treatment. Broad spectrum antibiotics are often used for treatment of secondary bacterial colonization or infection within the nasal and paranasal sinus cavities. As compared to normal cats, those with chronic rhinosinusitis have a larger numbers of potentially pathogenic bacteria and a wider variety of bacterial species isolated from within the nose. Antibiotic therapy may initially be based on culture results from nasal biopsy tissue or specimens collected from a deep nasal flush. Antibiotics often used include doxycycline, clindamycin, amoxicillin-clavulanic acid, cefpodoxime, Enrofloxacin, marbofloxacin, and azithromycin. Cats with idiopathic chronic rhinitis demonstrating an initial response to antibiotic therapy will likely have treatment continued for 6-8 weeks or longer.
Antiviral therapy is not routinely recommended as the role of chronic viral infection in cats with idiopathic chronic rhinosinusitis has not proven. However, it is likely that feline herpesvirus type 1 may play a have paroxysmal recurrence causing exacerbation of disease in some cats. Lysine (500 mg PO q12h) therapy may benefit some of these cats. Lysine replaces arginine in viral proteins rendering them nonfunctional and thereby reducing viral replication. For those cats demonstrating response to lysine, therapy may be continued indefinitely as it is safe to use in young or older cats.
The role of immunosuppressant agents in management of idiopathic chronic rhinosinusitis is poorly understood, although there are antidotal reports suggesting some cats may benefit from such therapy. However, immunosuppressive drugs may worsen disease in certain patients via exacerbation of viral or bacterial infections, cause recrudescence of viral shedding, or suppress host immune response to viral or bacterial infections.
Piroxicam is a non-steroidal antiinflammatory agent that can ameliorate clinical signs in some cats with idiopathic chronic rhinosinusitis. Piroxicam is generally well tolerated at a dose of 0.3 mg/kg orally daily or every other day. Side effects may include anorexia, diarrhea, or vomiting. Piroxicam may also be combined with antibiotic therapy.
Moisturization of nasal secretions promotes sneezing and evacuation of mucous from the nasal cavity. Some cats will tolerate the instillation of saline drops within the nasal cavity.
Immune stimulators are generally not recommended as there are no prospective, randomized clinical studies with evidence to support the use of these drugs in the management of this disease.
A number of surgical techniques have been described but are attended with generally disappointing results and not recommended. Frontal sinus ablation may be effective in controlling clinical signs, although sneezing and nasal discharge will not be resolved with this procedure and an especially troubling potentially complication of this procedure is persistent anorexia due to loss of smell.
In summary, the prognosis for a cure of clinical signs in cats with idiopathic chronic rhinosinusitis is extremely guarded. The chronic nasal discharge and sneezing are very difficult to control, and once controlled is achieve it is often temporary with recurrence expected.
Nasal neoplasia is the second most common cause of chronic rhinitis in cats. Although there are exceptions, neoplasia is of greatest concern in cats > 8 years of age. Nasal lymphoma is most common with various carcinomas occasionally seen and other neoplasms encountered much less frequently. Nasal tumors are primarily locally invasive with local to widespread destruction of nasal turbinates seen initially and invasion of septal, cribriform, or facial bones later in the course of disease. Metastasis to regional lymph nodes or lung may occur, but this is rare and generally occurring in the very late stage of disease.
Clinical signs are primarily related to obstruction of air flow through the nasal cavities, mucopurulent nasal discharge, epistaxis, sneezing, and reverse sneeze. Facial deformity or swelling, exophthalmia, or neurological signs may be seen as a result of tumor destruction of facial bones or cribriform plate. In some patients, initial clinical signs may be very subtle with unexplained onset of snoring, occasional reverse sneeze, and difficulty breathing through the nose reported.
Nasal radiographs are frequently limited in their ability to distinguish subtle lesions or changes seen with nasal tumors that overlap with chronic and fungal rhinitis. Nasal CT is a vastly superior imaging modality for differentiating neoplastic from nonneoplastic disease and detection of bone destruction and neoplastic extension into surrounding structures. Nasal CT also is needed for staging, to delineate tumor boundaries, and to plan for radiation therapy.
Selected computed tomography (CT) images from a cat with nasal lymphoma
The CT image on the left shows a uniform soft tissue attenuating density (representing cancer) within the left nasal cavity. There is destruction of the nasal septum with extension into the right nasal cavity and destruction of the left dorsal maxillary bone with extension out of the nose causing facial deformity. The CT image on the right is further back within the nose. There is destruction of the orbital wall on the left side with extension of lymphoma into the orbital region causing rostral and lateral displacement of the left eye.
Radiation therapy is the treatment of choice for most feline nasal tumors. Some cats with nasal lymphoma will show good response to chemotherapy and not require radiation therapy. Thoracic radiographs may be recommended prior to radiation therapy to rule out metastatic lung disease.
Lymphoplasmacytic rhinitis is a relatively uncommon disease of unknown etiology in cats. These cats generally do not have a history of a preceding acute episode of feline upper respiratory tract infection. The evolution of the disease is progressive with minimal signs of nasal disease early on. Lymphoplasmacytic rhinitis should only be considered when all other causes for the chronic rhinitis are excluded. Lymphoplasmacytic inflammation may accompany other diseases, especially neoplasia.
If nasal CT findings are highly suggestive of neoplasia, the diagnosis of lymphoplasmacytic rhinitis will be considered highly provisional and repeat biopsies or rhinotomy will likely be recommended. Severe lymphoplasmacytic inflammation may be associated with underlying nasal lymphoma. Special immunohistochemical stains for B-cell and T-cell markers may be requested in cats with severe lymphoplasmacytic inflammation in order to rule out lymphoma.
Fungal rhinitis is an uncommon cause of chronic rhinitis in cats, although in some geographic areas the disease is seen frequently.
Nasal cryptococcosis is most common and nasal aspergillosis is only occasionally encountered. Facial deformity of the rostral aspect of the nose is often striking in cats with cryptococcosis. Occasionally granulomatous tissue may be seen projecting through the external nares. The clinical signs of cryptococcosis are that of an obstructive rhinitis associated with mucopurulent nasal discharge. Mucopurulent conjunctivitis may develop in some cats. Cytology and serum titers for cryptococcal antigen can be highly diagnostic for nasal cryptococcosis.
Primary nasal aspergillosis (initially involving the nose only) is relatively uncommon in cats. The clinical signs are initially copious unilateral mucopurulent nasal discharge. Bilateral mucopurulent nasal discharge can be seen later in disease. Intermittent bleeding is not uncommon. Nasal pain is often present. Anorexia and depression may develop as the disease progresses, especially with frontal sinus involvement or with destruction of maxillary bones. Extensive turbinate destruction is present. The extent of destruction and determination of sinus or maxillary bone involvement is best demonstrated with computed tomography. The diagnosis of nasal aspergillosis is made by direct observation of fungal plaques or attempted by identification of fungal elements in biopsy specimens or direct cytology obtained from affected tissue or positive fungal culture of affected tissue. Diagnosis of nasal aspergillosis may be very difficult in some circumstances. Treatment decision may need to be based on changes observed on nasal CT that are highly suggestive of fungal rhinitis. Treatment is challenging and antifungal therapies that may be considered include triazole drugs (itraconazole, posaconazole, voriconazole) either alone or in combination with terbinafine. Nasal infusion of clotrimazole is another option.
Sino-orbital aspergillosis (involving the frontal sinus and region of the eye) is comparatively rare in cats, although reports on this condition are increasing. Both Aspergillus spp and Neosartorya spp are fungal pathogens implicated in feline sino-orbital fungal infection. The clinical signs are initially sneezing and copious unilateral or bilateral mucopurulent nasal discharge. Intermittent epistaxis is not uncommon. Sinonasal pain is often present. Anorexia and depression may develop as the disease progresses, especially with frontal sinus involvement or with bony lysis of the sinus, orbital wall, maxilla, or hard palate. Extensive turbinate destruction is present. Late in disease facial deformity or exophthalmia may be seen. The magnitude of bone lysis and determination of sinus, orbital, or maxillary bone involvement, and integrity of the cribriform plate is best demonstrated with computed tomography.
The diagnosis of sino-orbital aspergillosis is made by direct observation of fungal plaques, identification of fungal elements in biopsy specimens or direct cytology obtained from affected tissue, or positive fungal culture of affected tissue. Treatment is very challenging and antifungal therapies that may be considered include triazole drugs (itraconazole, posaconazole, voriconazole) either alone or in combination with terbinafine. Sinonasal infusion of clotrimazole is another option.
Nasopharyngeal polyps occur predominately in young cats or kittens. Nasopharyngeal polyps usually arise within the middle ear and grow down the eustachian tube to the nasopharyngeal region. Polyps occasionally may be visible in the external ear canal. Clinical signs are caused by direct obstruction of either the oropharynx or nasopharynx. Chronic rhinitis develops secondary to bacterial overgrowth due to the lack of clearance
of nasal secretions. Clinical signs observed in the early stage of disease include stertorous respiration (snuffling sound), gagging, and minimal sneezing or nasal discharge. As the polyps attain greater size, obstructive breathing and increased nasal discharge with sneezing are seen. These signs may be indistinguishable from those of idiopathic chronic rhinitis, especially in a young cat with a prior history of acute upper respiratory infection. For this reason, any cat with chronic rhinitis (especially those of young age) should be carefully evaluated for the presence of polyps.
The diagnosis of nasopharyngeal polyp is relatively straight forward. Oropharyngeal examination and palpation of the area above the soft palate for a mass or direct visualization of the nasopharyngeal region is diagnostic. Once the diagnosis of nasopharyngeal poly is made, skull radiographs or computed tomography of the bulla region should be performed for evidence of middle ear infection or inflammation. This is characterized by osseous bulla thickening, soft tissue densities within the tympanic cavity, or sclerosis of the petrous temporal bone. Radiographic evidence of middle ear inflammation or infection may not always be present, whereas computed tomography offers enhanced discrimination of middle ear involvement.
Nasopharyngeal polyps may be removed by traction avulsion, however recurrence is common. Bulla osteotomy is definitely indicated if there is recurrence, and should probably be performed in all cats with radiography or tomographic evidence of middle ear involvement being present.
Foreign Body Rhinitis
Nasal or nasopharyngeal foreign bodies are infrequent in cats and are usually due to blades of grass lodged within the nasal cavity. Seeds and grass awns are less frequently encountered. Clinical signs associated with foreign bodies within the nasopharyngeal region are often peracute with coughing, gagging, and hard swallowing response usually observed. With time, stertorous respiration, phonation changes, nasal discharge, and sneeze may develop with nasopharyngeal foreign bodies.
Clinical signs associated with foreign bodies confined within the nasal passages may be acute or chronic and often consists solely of sneezing and nasal discharge. Cats having nasal foreign bodies not immediately expelled from the nose will develop progressively increasing nasal discharge, often attended by occasional hemorrhage. Severe granuloma tissue response may occur with long-term foreign bodies. Foreign bodies usually wind up within the nasal cavity by entry through the caudal nares. Foreign material is ingested and then either gagged or vomited, inadvertently transferring the foreign material into the nasopharynx and then through the caudal nares into the caudal nasal cavity.
Grass blades and similar material can usually be removed under direct examination of the nasopharynx or nasal cavities. Retroflex nasopharyngoscopy is diagnostic for nasopharyngeal foreign bodies. Flushing the nose with copious amounts of warm saline may dislodge smaller particles (e.g., seeds) within the nasal cavity. Rhinotomy may be required for longstanding cases with excessive granulation tissue or foreign bodies resistant to direct removal (e.g., grass awns).
Nasopharyngeal stenosis is a rare complication of acute upper respiratory tract infections or following episodes of severe vomiting (e.g., aspiration rhinitis). Initially progressively worsening stertor is present with absence of nasal discharge. With severe stenosis, nasal discharge and extreme difficulty with nasal breathing is observed. Retroflex nasopharyngoscopy will often reveal circumferential stricturing or narrowing of a focal region of the nasopharynx. Early stenosis may be managed by stretching the affected region followed by corticosteroid therapy to reduce scar tissue and reformation of the stricture. Recurrence unfortunately is very common necessitating the placement of a stent to maintain an opening over the affected region.
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