Canine Rhinitis

13 Canine Rhinitis

Phase 1

A complete history and physical examination are essential in the initial evaluation of rhinitis. Placing a feather, cotton fibers, or other lightweight material in front of the nasal openings and watching for signs of airflow can be used to identify complete or partial nasal obstruction. Examination of the external nasal cavity and oral cavity, as much as possible, is a critical step. Obtaining specimens of the nasal discharge for cytologic examination is also helpful. Either a direct impression of the nasal discharge or a swab of the rostral nares may help identify nasal mites (Pneumonyssoides caninum). Microbiological cultures are unlikely to yield reliable information, are difficult to interpret, and can be expensive at this point. If the animal has recently received an antibiotic medication, however, bacteria may not be present. A complete blood count, biochemistry profile, and urinalysis are necessary when a specific cause cannot be identified from the initial examination.

Phase 2

A complete oral and nasal examination, including radiography, under anesthesia, is necessary to identify tooth root infections or fractures (periodontal probing), neoplasms, or foreign bodies. A dental mirror may help with examination of deep oral tissues. A rigid otoscope can be used for initial examination of the external nares and nasal area. Rhinoscopy, with a flexible endoscope, is an effective procedure to examine the mucosa and collect specimens of nasal tissues to culture for bacterial and fungal pathogens, if an infection is suspected. Another option is nasal flushing with sterile saline. Flushing saline from the pharyngeal region toward the nares will allow cellular material and debris to be collected on cotton gauze squares from which a specimen for culture can be taken. This procedure, which does not usually cause hemorrhage, is best performed after complete nasal examination but before tissue collection.

When tissue biopsy specimens are necessary they should be collected from both nasal passages. Taking a biopsy specimen from the nasal mucosa often causes hemorrhage because of the extreme vascularity of the submucosa, and the bleeding makes subsequent examination of the mucosa impossible. Therefore both nasal cavities must be examined completely before biopsy specimens are obtained. Cold saline infusion can be used to decrease the amount of bleeding during acquisition of biopsy specimens. When a “blind” biopsy is performed, it must be stressed that the biopsy instrument must not pass beyond the medial canthus of the eye, to avoid penetrating the cribiform plate during this procedure. Skull radiographs are critical to the success of this procedure, to measure distances for obtaining “blind” biopsies.

Phase 3

Computed tomography (CT) and magnetic resonance imaging (MRI) can be used to diagnose nasal cavity disease. CT and MRI are much more expensive than plain radiography; however, they offer a more complete assessment. CT and MRI may help localize lesions before rhinoscopy is performed but often cannot provide a definitive diagnosis. Previous trauma may have caused a sequestrum with a subsequent secondary bacterial infection. This may be identified on radiograph examination, CT, or MRI.

Rickettsial infections such as Ehrlichia, Anaplasma, Rocky Mountain spotted fever (RMSF), or Bartonella may cause rhinitis. Testing for these pathogens can be performed in any phase of the examination.

Stay updated, free articles. Join our Telegram channel

Jul 31, 2016 | Posted by in INTERNAL MEDICINE | Comments Off on Canine Rhinitis

Full access? Get Clinical Tree

Get Clinical Tree app for offline access