Cat Specialist Services veterinary investigations

Causes and diagnosis of nasal disease.

Nasal disease in cats will show with various clinical signs such as sneezing and nasal discharge (ie snot!), crusting around the nose and sometimes even swelling over and around the nose and bleeding. Bleeding from the nose is always of significant concern in cats and may be due to more widespread medical disorders.

There are various diseases that cause these symptoms including infections (e.g. cat flu (feline calicivirus, feline herpes virus), fungal disease (e.g. cryptococcus, aspergillus)), inflammatory disease (e.g. chronic rhinitis or allergic rhinitis) and unfortunately cancers (e.g. lymphoma or carcinoma).

Dental disease can cause nasal signs if there is communication between the tooth and the nose (tooth root abscess).

Chronic rhinitis is a fancy term for long term nasal inflammation of the nose. It is similar to irritable bowel syndrome, but in the nose! It is a very common cause of long term nasal signs in cats.

Young cats are more likely affected with upper respiratory infections such as cat flu, foreign bodies, nasopharyngeal polyps and nasopharyngeal stenosis. Older cats are more likely affected with cancer or chronic rhinosinusitis.

Finding out the cause of the nasal signs (definitive diagnosis) may require a variety of tests including blood tests and imaging such as CT scanning and rhinoscopy (insertion of a camera into the nose) and biopsies are often required.

This image shows a severely infected tooth where the infection has extended up into the nose causing nasal discharge.

Possible causes of nasal disease include the following:

Infectious

Viral e.g. Feline Herpesvirus & chronic rhinosinusitis
Fungal e.g. Cryptococcus, Aspergillus
Mycobacteria - rare form of infection that often causes disfigurement and swelling of the nose Tooth root abscess

Inflammatory

Nasopharyngeal polyp - tissue that grows in the back of throat and the nose
Chronic lymphocytic plasmocytic rhinitis “irritable nose disease - like irritable bowel syndrome
Foreign body

Cancer

Lymphoma
Adenocarcinoma
Squamous cell carcinoma

Congenital

Choanal atresia
Nasopharyngeal stenosis - narrowing of the tissues at the back of the nose

This image is a CT scan from a patient with chronic rhinitis. The black colour is normal gas in the frontal sinus. The grey colour is mucous or possibly tissue with the sinus and nasal cavity.

Computed tomography (CT) provides extensive detail of the nasal cavity and sinuses and is the gold standard for evaluation of nasal disease, particularly early lesions. It is also superior for evaluating the extent of invasive nasal disease e.g.involving the bones around the nose and eyes and can facilitate guidance for biopsy.

Magnetic resonance imaging (MRI) provides a sensitive test and can readily distinguish between soft tissue structures and fluid or mucous accumulations. If brain involvement is suspected (e.g. a patient has neurological signs which can be seen with some fungal infections) then MRI is often better. Limitations of both CT and MRI include cost, technical skill and availability of equipment.

This is an MRI scan showing a patient that has a fungal infection of the nasal cavity that has caused loss of the bone and extension through to behind the eye. This is a type of fungal infection called Aspergillosis.

This image shows a scope tower. The large black scope is inserted into the back of the throat and looks at the "back of the nose".

Rhinoscopy is when we place highly specialised cameras up into the nose and back of the throat. This allows direct visualisation of the nasal cavity and nasopharynx. This silver scope is placed inside the nose and can allow flushing and biopsy.

This is a rhinoscopy image of a cat with a grass seed (arrow) stuck at the back of it’s nose (choanae). The seed was pulled out and the cat made a complete recovery.

Rhinoscopy can be limited in cats due to their size, availability of appropriately sized scoping equipment and technical skill.

Rhinoscopy alone can identify large growths or diffuse inflammatory disease and some infectious diseases, however it cannot evaluate the entire nasal and sinus cavities by itself and lesions may be missed. When combined with CT or MRI, rhinoscopy allows complete evaluation of the nasal cavity however rhinoscopy alone cannot evaluate the entire nasal cavity and sinuses.

Nasal flushing is often performed when cats are under anaesthesia and can provided relief for very thick secretions. Nasal flushing may also dislodged fragments of friable cancer or infections.

Diagnosis of nasal disease in cats requires working through the above investigations or trialling treatments to see what works for each individual patient.

Unfortunately for some diseases such as nasal adenocarcinomas, long term survival is poor and treatment options are limited. For other diseases such as a foreign body, removal can result in complete recovery. For diseases such as cryptococcosis, patients can also have good long term survival. Chronic rhinitis often requires life long management but cats can still have a good quality of life with simple treatments.