FELINE CHRONIC IDIOPATHIC RHINOSINUSITIS
THE PROBLEM AND IT'S CAUSE(S)
"Chronic" means long-term, "idiopathic" means of unknown cause, and "rhinosinusitis" means inflammation of the nasal passageways and sinuses. The most popular theory among veterinarians is that feline chronic rhinosinusitis begins with a kittenhood infection with feline herpes and/or calIcivirus. The patient's immune system eliminates or suppresses the viral infection, but the inflammation remains.
Inflammation is not a steady state and it does not dwindle or "just go away"; it progresses. Even if there are no complicating or perpetuating factors, inflammation will get worse as time goes by. Possible complicating and perpetuating factors include inflammatory tissue changes, the presence of mucus in the nasal passages and sinuses, relapse of chronic viral infections, bacterial infections (due to bacteria normally present in the nasal passages taking advantage of the inflammation), and environmental irritants.
SIGNS AND DIAGNOSIS
Sneezing, mild or severe, persistent or occasional, with or without mucus or blood, is the primary sign. Infrequently a cat with rhinosinusitis will have signs associated with pharyngitis (inflammation in the back of the throat), including halitosis, gagging, and exaggerated swallowing motions. A small number of cats with this problem snore.
It is possible for rhinosinusitis to be caused by: infection (viral, bacterial, fungal, protozoal, mycoplasmal), parasites, polyps, cancer, allergy, anatomical deformity, or dental disease. Only when all of these potential problems are ruled out can we reliably call the patient's problem "idiopathic rhinosinusitis". The patient's history and physical exam often allow us to lower our level of suspicion for many of these problems. Usually, though, additional diagnostic tests are needed. Some of the tests we consider are:
- general blood and urine profiles
- specific blood tests for infectious diseases
- x-rays: whole body, nasal and dental
- anesthetized dental exam
- rhinoscopy (exam of the nasal passages with an endoscope)
- cytology and histopathology (microscopic exam of swabs, surgical biopsies, and other samples)
- culture and sensitivity (attempts to grow infectious organisms)
- trial therapies
Idiopathic rhinosinusitis is very manageable but not curable. Treatments that we have to choose from include:
- facilitate drainage of mucus: vaporizers, nasal saline drops, nasal flushes under anesthesia
- decrease irritants in the enviroment: cigarette smoke, dusty or perfumed cat litter, the American Lung Association has recommendations for improving indoor air quality at www.lung.org
- control secondary bacterial and mycoplasmal infections with long term antibiotic therapy
- control possible herpesvirus infections with oral lysine
- reduce inflammation: oral, injectable, and topical cortisone, oral omega-3 fatty acids, oral substance p inhibitors (note: antihistamines are not usually effective at providing antiinflammatory effect for feline problems)
Successful management of rhinosinusitis requires a patient-by-patient approach, use of multiple therapies for each patient, and periodic re-evaluations to direct adjustments in treatment.
To repeat: idiopathic rhinosinusitis is not curable. However, it does not usually shorten an affected cat's lifespan, and management usually allows us to help our patients maintain a very high quality of life.