Chronic Upper Respiratory Tract Disease in Cats

What is the upper respiratory tract?

The upper respiratory tract includes the nose (nasal sinuses, nasal cavity) and throat (pharynx and larynx). Its surface is lined with a mucous membrane that produces a protective mucus coating.

The eyes are closely connected to the upper respiratory tract. The inner surfaces of the eyelids are covered by conjunctiva, a tissue similar to the respiratory mucous membranes. Tears drain from the eyes through a lacrimal duct into the back of the nose and throat. Because of this connection, the conjunctiva is often included as part of the upper respiratory tract and may be affected by upper respiratory disease.

What is chronic upper respiratory tract disease?

Chronic upper respiratory disease refers to long-lasting conditions affecting the upper respiratory tract. When clinical signs of upper respiratory tract inflammation, such as sneezing or nasal and eye discharge, persist over weeks or months or when they tend to recur at intervals of a few weeks, the condition is referred to as chronic upper respiratory tract disease. This disease is a relatively common problem in unvaccinated cats.

What are the signs of chronic upper respiratory tract disease?

Common signs include:

• Runny or stuffed-up nose
• Nasal discharge that is often thick and may be clear, yellow to green, red-tinged (fresh blood) or brown (older blood). One or both nostrils may be involved.
• Noisy breathing
• Reduced appetite and weight loss
• Drooling or gagging while eating
• Chronic discharge from one or both eyes

Signs of more severe disease may include:

• Facial swelling and soreness 
• Facial pain and sensitivity to touch 

In milder cases, cats may have intermittent sneezing and clear nasal or ocular (eye) discharge while otherwise acting normally. Cats with mild symptoms usually retain a normal appetite.

What are the leading causes of chronic upper respiratory tract disease?

There are many causes of this relatively common problem in cats.

Viral infection

Feline viral rhinotracheitis (feline herpesvirus) and calicivirus were the primary causes of chronic upper respiratory tract disease before the development of vaccines in the 1970s. These viral infections caused severe mucous membrane damage in some cats. Healing was incomplete, leaving the membranes susceptible to secondary bacterial infection.

These upper respiratory viruses persist in some cats, known as carrier cats, for weeks, months, or even years. In some of these carriers, the chronic viral infection damages the protective mucous membranes and allows bacteria to invade the damaged tissues, causing persistent clinical signs. 

Vaccinated cats that have not been given the appropriate booster vaccines (especially against feline herpesvirus) or have been exposed to virulent strains of herpesvirus may still become infected with one or more of these viruses and later in life exhibit chronic post-viral rhinitis and conjunctivitis.

Bacterial infection

Chlamydophila felis and Bordetella are bacteria that can cause primary respiratory infections in cats. A group of organisms called Mycoplasma can cause primary respiratory and eye infections or play a secondary role, along with bacteria such as Pasteurella, Streptococci, Staphylococci, and many others. 

There are no feline vaccines for these organisms except for C. felis and Bordetella. The immunity from the C. felis vaccine is relatively short-lived, and boosters are required annually. Vaccination against C. felis and Bordetella is recommended only in certain circumstances.

Chronic post-viral (idiopathic) rhinitis

The most common form of chronic upper respiratory tract disease is chronic post-viral or idiopathic rhinitis. With this condition, a viral infection (e.g., feline herpesvirus or feline calicivirus) causes the initial mucosal damage. The chronic signs that follow are caused by a secondary bacterial infection of the damaged nasal passages. 

This infection may lead to a bacterial infection of the delicate bones within the nasal sinuses (osteomyelitis of the nasal turbinate bones). This chronic inflammation can cause distortion or destruction of these structures.

Are there other possible causes?

• Some fungal infections, like Cryptococcus, can cause chronic upper respiratory tract disease. These infections are more likely to occur in specific geographic regions. 
• Cancer (neoplasia) affecting the upper respiratory tract is rare, but may need to be ruled out in some instances. 
• Non-cancerous nasal polyps may occasionally cause chronic sneezing and discharge. 
• Your veterinarian may need to rule out other causes, such as trauma, foreign bodies trapped in the nose, or even dental disease.

How is the cause of chronic upper respiratory tract disease diagnosed?

Your veterinarian will start by gathering a detailed medical history and performing a thorough physical examination. For the history, tell your veterinarian about:

• When the problem began and how it has progressed
• The color and consistency of any discharge
• Past respiratory or eye infections
• Previous trauma, such as an accident or fight
• Any dental disease

Tests may include blood work, swab samples for microscope examination and culture, radiographs (X-rays), and tissue biopsy. Culturing the discharge may reveal a variety of bacteria, but these are often secondary invaders. Anesthesia may be necessary for a thorough nasal examination or to acquire specific diagnostic samples.

How is chronic upper respiratory tract disease treated?

Treatment depends on test results and diagnosis. In many cases, no specific cause can be found. 

• Antibiotics typically give an initial dramatic improvement that is often short-lived. 
• Nutritional supplements that promote a strong immune system can be helpful, especially in chronic viral infections. 
• Anti-viral and immune-stimulating medications may be beneficial in some cases. 
• Nebulization therapy may provide relief in some cases.

What is the long-term outlook?

Some cases remain chronic or recurrent despite treatment. In these cases, the goal is to reduce discomfort and maintain quality of life through regular monitoring, supportive care, and medication when needed  New treatments may be discovered, so keep in contact with your veterinary team regularly.