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Nasal disorders in the dog and cat (Proceedings)

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Nov 01, 2010

Lymphocytic-Plasmacytic Rhinitis

Lymphocytic-plasmacytic rhinitis (L-PR) is a nonspecific inflammatory condition associated with antigenic and irritant stimulation. This disorder is most commonly found in dogs. and has a predisposition for Dachshunds. The clinical signs are those commonly seen with nasal diseases, including sneezing and nasal discharge of varying character. Although the origin of this disorder is typically idiopathic, fungal, parasitic, and neoplastic diseases are sometimes associated with the chronic inflammatory infiltrates observed with L-PR. One theory concerning the origin of L-PR speculates that some affected individuals may not have actual fungal infection but acquire this disorder as a result of a hypersensitivity to fungal organisms, including commensal fungal organisms residing within the nose. Rhinoscopy in patients with L-PR generally reveals evidence of nonspecific inflammation. Diagnostic imaging often shows fluid density In the nasal cavity and frontal sinuses and may show mild to moderate lysis of the turbinates, especially rostrally. Histopathology of the nasal mucosa most commonly reveals mixed inflammatory cells with lymphocytes and plasma cells predominating. Immunohistochemical staining for B- and T- cell markers should be considered in patients, especially cats, with marked lymphoplasmacytic inflammation to rule out lymphoma. Therapeutic options for L-PR of idiopathic origin include:

     1. Trial therapy with ivermectin (0.2 mg/kg subQ or PO, 2 treatments 3 weeks apart) for nasal mites

     2. Trial therapy with itraconazole (5 mg/kg PO q12hrs for a minimum of 3-6 months) for possible low grade fungal infection or fungal-triggered hypersensitivity reactions

     3. Immunosuppressive steroid therapy (prednisone, 1 mg/kg q12 hours PO initially) or topical steroid administration with nasal drops or aerosolized preparations via metered dose inhaler

     4. Alternative immunosuppressive therapy with azathioprine (1 - 2 mg/kg/day PO)

     5. Antiinflammatory therapy with piroxicam (0.3 mg/kg/day PO)

     6. Immunomodulating antibiotics such as doxycycline (3 – 5 mg/kg q12 hrs) or azithromycin (5 mg/kg q24 hrs PO) in combination with daily piroxicam; if improvement is noted,combination therapy is continued but with a reduction in frequency of antibiotic administration (doxycycline – SID or azithromycin – twice weekly)

     7. Ancillary therapy with humidification of airways, elimination of environmental irritants, and intranasal saline

Most dogs with L-PR have some degree of persistent clinical signs although the majority of patients can be managed successfully long-term with medical treatment.

Foreign Bodies

Nasal foreign bodies should be suspected with the following circumstances:

     1. Known opportunity for foreign body inhalation with a sudden onset of compatible signs

     2. Sudden onset of paroxysmal sneezing

     3. Pawing at the nose

     4. Unilateral nasal discharge, especially mucopurulent discharge with occasional hemorrhage

     5. Persistent gagging, retching, or reverse sneezing

     6. Persistent nasal discharge which follows an acute onset of sneezing

It should be remembered that acute and persistent sneezing in the cat is more often associated with viral upper respiratory infection than with foreign body inhalation.

Foreign bodies within the nasal cavity usually enter via the caudal nares following gagging or vomiting episodes. Plant material is the most common type of foreign body usually encountered. Patients with appropriate history and clinical signs for nasal foreign body should undergo rhinoscopy, including examination of the caudal nasopharynx, as an initial diagnostic procedure and are an exception to the general rule of performing imaging prior to rhinoscopy. If a nasal foreign body is suspected but not seen with rhinoscopy or cannot be removed with a grasping instrument, extensive nasal flushing should be performed to try to dislodge any hidden foreign material. When flushing, the patient's nose should be directed downward with the endotracheal tube cuff inflated and the caudal oropharynx packed with gauze to prevent tracheal aspiration. If a foreign body is removed, the remainder of the nasal cavity and caudal nasopharynx should be examined to be sure that all foreign material has been eliminated. Granulomas may develop when foreign material has been present for an extended period of time, making identification and nonsurgical removal of the foreign matter difficult.