The chronic feline sneezer or snuffler is an exasperating patient for veterinarians and clients to treat. With so many possible causes and diagnostic options, it is a challenge to find the path that provides the answers you seek. Margie Scherk, DVM, DABVP (feline practice), offers several tips for helping these runny-nosed kitties.*
The ins and outs of chronic rhinosinusitis
Chronic rhinosinusitis can occur in cats of any age. These patients may have serous, mucoid, purulent or sanguineous nasal discharge that is unilateral or bilateral, and sneezing with noisy breathing. Dr. Scherk says be sure to ask clients about the timing, onset, duration and frequency of the sneezing and whether the cat's nasal discharge has changed. Chronic inflammatory changes reduce irritant receptor sensitivity in the nasal and sinus subepithelium and decrease the sneezing response, which allows the discharge to accumulate.
Respiratory sounds and patterns may also be abnormal. Clients sometimes mention that their cats sound hoarse or have a silent meow or different purr. If clients report that breathing seems worse at night, it could indicate bronchitis—but keep in mind that this is also the time when the client is most likely to observe the cat. And seasonal flare-ups can be associated with an allergic cause. "Inevitably, the cat in the clinic will be completely fine," says Dr. Scherk. "So try to get the client to pay attention to whether the sounds occur on inspiration or expiration." Your questions for the owner are critical to isolating the location of the abnormal respiratory sounds and the cause. And clients may be able to obtain a video of an episode with their smartphone and email or text it to you.
What does inspiration vs. expiration tell you? Dr. Scherk says abnormal inspiratory sounds are generally associated with the larger airways, whereas expiratory sounds typically stem from smaller, lower airways. Congestion can occur because discharge accumulates in the nasal passages or can be associated with proximal upper respiratory occlusion, such as a polyp or foreign body. Stridor (an inspiratory wheeze) reflects changes in the larynx. An expiratory wheeze (crackles and rales) can reflect lower airway involvement.
Underlying factors that may contribute to chronic upper respiratory infections can include trauma, a congenital or conformational predisposition, polyps, periodontal disease and foreign bodies. It has been suggested that chronic inflammation may predispose affected patients to nasal lymphoma. Neoplasia further alters nasal function, and cancerous lesions usually result in sneezing and unilateral nasal discharge. Most nasal tumors are malignant and locally invasive.
*This article is based on Dr. Scherk's presentation "Snots and snuffles: The cat with chronic upper respiratory disease" at CVC Washington, D.C. on April 27, 2012. Dr. Scherk reviewed and updated this article on July 21, 2016.
Dr. Scherk's diagnostic tip
Perform a complete physical examination. Be sure to assess the cat's facial symmetry, looking directly face-to-face as well as above the head. Palpate the entire face to assess for swelling or discomfort. Evaluate the oral cavity for periodontal disease, oronasal fistulae, masses or ulcers. You can assess some cranial nerve (CN) function by opening the mouth and checking jaw tone (CV N, motor); tongue position, movement, and symmetry (CN XII); and the gag reflex (CN IX, X). Check air movement through the nasal passages by using a dental mirror or glass slide that has been kept in the freezer (Figure 1).
Palpate the trachea to see if a cough is easily elicited, and auscultate the trachea bilaterally along its length. Auscult the frontal sinuses with a pediatric (small bell) stethoscope. Include a fundus examination to rule out cryptococcosis or other signs of systemic disease, and assess the size of regional lymph nodes.
Keep in mind that an inadequate immune response may play a role in chronic upper respiratory infections. Feline herpesvirus (FHV) infection can be a common denominator, creating unchecked inflammation and allowing secondary bacterial infections. This is especially problematic in brachycephalic patient because they "have alteration of form and function," says Dr. Scherk, "with a shortened and tortuous upper tract that has even more little nooks and crannies that things can grow in."
Irreversible destruction of the turbinates may be present, and reactivation of FHV can result in recurrent issues, says Dr. Scherk. Calicivirus and FHV infections can be involved in these cases. Herpesvirus can enter a latent state and recur later. About 80% of cats infected with FHV can be carriers. Periods of stress often elicit a recurrence of clinical signs.
Primary bacterial agents including Bordetella bronchiseptica and Mycoplasma and Chlamydia species are sometimes isolated, and Bartonella species may be detected on serologic tests, but there is no definitive proof of their roles in this disease, says Dr. Scherk.
A note on response-to-antibiotic trials. Patients may improve clinically with antibiotics, but if signs recur, we can suspect that bacteria are only part of the cause. "Often antibiotic therapy results in improvement, but when it doesn't or when signs recur, we need to look further," says Dr. Scherk.
If appropriate antibiotic therapy of seven to 10 days' duration fails to result in resolution, a diagnostic workup is recommended, including a complete blood count, serum chemistry profile, retroviral serologic tests, urinalysis and blood pressure measurement. If rhinoscopy is possible or if epistaxis is a presenting complaint, a coagulation panel is indicated. Consider measuring serologic titer for Aspergillus and Cryptococcus species where regionally appropriate. Skull radiography requires general anesthesia but allows a thorough examination of the mouth and dental structures as well.
Biopsies and aspirates. While the cat is anesthetized, collect samples, although one retrospective study indicates that cytology may not be a reliable means to determine causes of chronic rhinitis in cats,1 says Dr. Scherk. Anaerobic and aerobic cultures can be performed, but because of the large numbers of normal flora in the nasal cavity, results can be deceptive. Calicivirus requires virus isolation, and some of the other causes may be determined by polymerase chain reaction (PCR) testing. These tests vary in sensitivity and may not be definitive, says Dr. Scherk.
Rhinoscopy. Rhinoscopy can be challenging in cats, and clients should be cautioned that it may not yield definitive results. Use a cuffed endotracheal tube and pack the oropharynx (count the swabs to ensure retrieval!) to prevent aspiration. If the disease appears to be unilateral, examine the unaffected side first. Note any abnormalities and obtain biopsy samples of fungal plaques. Even if the tissue looks normal, obtain biopsy samples because the appearance can be misleading in patients with chronic disease, says Dr. Scherk.
Be sure you examine the entire cavity before performing a biopsy because bleeding will interfere with your examination. Also gently and thoroughly flush the nasal cavity with sterile saline and suction it to remove exudate and other material to facilitate the cat's comfort during and after anesthetic recovery.
Dr. Scherk's treatment tips
- Antibiotics are a reasonable choice to treat cats with chronic upper respiratory disease, but if multiple organisms are identified on culture, their clinical relevance is questionable. If a species is identified on culture that is not a commensal bacterium, the antimicrobial sensitivity results for that organism may be reliable. Therapy should be continued for six to eight weeks without changing the antibiotic (if there is an initial positive response), and the antibiotic should reach the site of infection at effective therapeutic concentrations, thus it should penetrate cartilage and bone.
- For fungal infections, follow antifungal protocols tailored for the patient's local or systemic disease.
- Address allergic disease with antihistamines and allergen avoidance when possible.
- FHV infection might necessitate administering a herpesvirus and calicivirus vaccine intranasally two or three times a year to stimulate local immunity. L-lysine may help reduce the frequency of snuffling in cats with FHV by competing with arginine (which is needed for viral replication), and interferon-alpha may also help. The antiviral famciclovir may also be considered.
- Remove any polyps or foreign bodies.
- For neoplastic disease, consult with a veterinary oncologist about radiation, chemotherapeutic, or surgical treatment options.
- Affected cats benefit from humidified air in the home and possibly oral and nasal decongestants.
- Anti-inflammatories could also play a key role in reducing the cycle of inflammation, and by doing so may also help reduce the potential for reinfection with secondary bacteria.
- Appetite stimulants may also be helpful if needed.
Manage clients' expectations
It is critical that pet owners understand that feline chronic rhinitis will never be cured. But Dr. Scherk emphasizes that with ongoing, diligent management, the cat's quality of life can be improved and the clinical signs can be reduced.
1. Michiels L, DayMJ, Snaps F, et al. A retrospective study of non-specific rhinitis in 22 cats and the value of nasal cytology and histopathology. J. Feline Med Surg 2003;5:279-285.