| Inflammation of the mucous membranes of the nose and sinuses may be acute or chronic. |
| Etiology: |
| Viral infection is the most common cause of acute rhinitis or sinusitis in dogs and cats. Feline viral rhinotracheitis (FVR), feline calicivirus (FCV), canine distemper, canine adenovirus types 1 and 2, and canine parainfluenza are most frequently incriminated. Chronic states exist for FVR and FCV, with intermittent shedding associated with stress. Bacterial rhinitis or sinusitis frequently is a secondary complication. Primary bacterial rhinitis is extremely rare in dogs and
cats. It may result from infection with
Bordetella
bronchiseptica
in dogs. Allergic rhinitis or sinusitis is a poorly defined atopy that occurs seasonally in association with pollen production, and perennially, probably in association with house dusts and molds. Smoke aspiration, inhalation of irritant gases, or foreign bodies lodged in the nasal passages also may cause acute rhinitis. |
| Chronic rhinitis is commonly complicated by secondary bacterial infection because the primary nasal disease results in increased mucus production and altered mucociliary clearance of debris within the nose. Underlying causes of chronic rhinitis include chronic inflammatory disease (lymphoplasmacytic rhinitis), trauma, parasites (
Cuterebra
), foreign bodies, neoplasia, or mycotic infection. In cats, chronic rhinosinusitis is a frequent sequela of acute viral infections of the nasal and sinus mucosa that result in hyperplastic glandular and epithelial changes. Rhinitis or sinusitis may result when an apical tooth root abscess extends into the maxillary recess. Mycotic rhinosinusitis may be caused by
Cryptococcus
neoformans
,
Aspergillus
spp
, and
Penicillium
spp
. Cats are more often affected with
Cryptococcus
spp
than dogs, whereas aspergillosis is frequent in dogs but rare in cats. |
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| Clinical Findings: |
| Acute rhinitis is characterized by nasal discharge, sneezing, pawing at the face, respiratory stertor, open-mouth breathing, and/or inspiratory dyspnea. Lacrimation and conjunctivitis often accompany inflammation of the upper respiratory passages. Affected tissues are often hyperemic and edematous. The nasal discharge is serous but becomes mucoid as a result of secondary bacterial infection. If inflammatory cells infiltrate the mucosa, the discharge may become mucopurulent.
Sneezing, in an attempt to clear the upper airways of discharge or exudate, is seen most frequently in acute rhinitis and tends to be intermittent in chronic rhinitis. Aspiration reflex (“reverse sneeze”), a short paroxysmal episode of inspiratory effort in an attempt to clear the nasopharynx of obstructing material, may also be seen. Respiratory stertor, open-mouth breathing, and
inspiratory dyspnea occur when the nasal passages are narrowed from inflamed mucosa, glandular elements, and secretions. An acute unilateral nasal discharge, possibly accompanied by pawing at the face, suggests a foreign body. Neoplastic or mycotic disease is suggested by a chronic nasal discharge that was initially unilateral but becomes bilateral or that changes in character from mucopurulent to serosanguineous or hemorrhagic.
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| Diagnosis: |
| Diagnosis is based on history, physical examination, radiographic findings, (especially computed tomography), rhinoscopy, nasal biopsy, and elimination of other causes of nasal discharge and sneezing.
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| Treatment: |
| In mild or acute cases, supportive treatment may be effective. Severe cases of rhinosinusitis in kittens or adult cats may require parenteral fluids to prevent dehydration, and nutritional support via a nasogastric tube to maintain weight. Chronic secondary bacterial rhinosinusitis may be treated with antimicrobial chemotherapy for 3-6 wk. Intranasal feline herpesvirus vaccine may help shorten and minimize recurrence of clinical signs. Intermittent use of vasoconstrictive nasal
decongestants usually provides only temporary relief of congestion. Mycotic rhinosinusitis requires antifungal therapy based on identification of a fungal etiologic agent. Animals that do not respond to medical therapy may require surgery consisting of sinusotomy or rhinotomy, lavage, and biopsy. Cobalt radiation therapy is the most viable treatment for intranasal neoplasia. |
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