Nasopharyngeal disease

Diseases of the nasopharyngeal region are often seen in many of the animals we treat. Some species and breeds are more prone to problems than others, such as long nosed or brachycephalic dogs and cats, as well as all animals living in dusty or dry surroundings.

Posted: 14 January 2020

Nasopharyngeal disease

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Typically, chronic conditions of the nasal cavity tend to be noticed by their owners early in the disease process. They’ll be aware of sneezing, noisy breathing or a nasal discharge, all of which are the result of irritation and inflammation to the nasal mucosa.

What are the causes?

  1. Allergies – like humans, dogs, cats and some rabbits are also prone to developing allergic reactions as a result of grass and tree pollens. Dust and fomites can also trigger the same response.
  2. Nasal mass – tumours within the nasal cavity aren’t particularly common, but when they occur, they can cause intense irritation and discomfort.
  3. Lymphocytic-plasmocytic rhinitis – this is a nonspecific inflammatory condition associated with chemical and biological irritants and antigens.
  4. Nasal foreign body – dogs running through long grass in the summer are particularly at risk of grass seed foreign bodies.
  5. Fungal infections – long nosed dogs living around farms and riding stables can sniff old hay contaminated with aspergillus spores.
  6. Tooth root abscess – all species can develop these, including rabbits.
  7. Secondary bacterial infections – chronic Pasteurellosis causes significant problems in rabbits.
  8. Environmental irritants – animals living in a house undergoing building work may develop chronic sneezing, as plaster and concrete dust is extremely irritating.
  9. Vasomotor rhinitis – look for a clear discharge. This can occur with household aerosols, cleaners and cigarette smoke.

Check the nasal discharge

With nasopharyngeal disease, you can get a significant amount of information from any discharge which is produced. Examine the quantity and appearance both grossly and microscopically. The frequency of sneezing and periods of discharge are also important.

A. Clear discharge

This is usually produced with;

  • Allergic rhinitis
  • Viral infections
  • Environmental irritants
  • Vasomotor rhinitis

B. Cloudy Discharge

This is often present with;

  • Nasal mass
  • Allergic rhinitis
  • Viral infections
  • Environmental irritants
  • Lymphocytic-plasmocytic rhinitis
  • Vasomotor rhinitis

C. Green/Yellow Discharge

As most nasopharyngeal conditions progress, the nature of the discharge becomes more distinct. When a thick, purulent and coloured (green/yellow) discharge is seen, you need to start considering a bacterial involvement, which is typically secondary to;

  • Fungal infections
  • Nasal tumours
  • Foreign material
  • Tooth root abscess
  • Lymphocytic-plasmocytic rhinitis

Most secondary bacterial infections tend to respond well to antibiotics, but the underlying condition needs to be found otherwise the infection will recur once the antibiotics are stopped.

Making a diagnosis

Most cases of chronic nasal discharge and sneezing are treated for many weeks and months with variable results. You may be restricted by the owner’s expectations and finances, or maybe the nature of the pet and willingness of the patient to have treatment administered. Many of us will choose a combination of antibiotics, NSAID’s, antihistamines or steroids.

The reality of these cases is that if the sneezing and discharge have been present for more than a few weeks, then you need to be persuasive and go for an aggressive investigation. The more information you have the more likely you are that you’ll get a diagnosis.

Some of the procedures you should consider include;

  • Radiography – intra-oral, oblique and lateral views of the maxilla should all be taken.
  • Rhinoscopy – most dogs and some of the larger cats are big enough for this to be performed. When introducing the rhinoscope, take care not to damage the delicate mucosa.
  • Flexible endoscope – these can be used to check behind the soft palate and examine the caudal choanae. In middle and large breeds of dog, these can also be used to check the cranial nasal passages.
  • Biopsy – a variety of biopsy methods can be used, but the tissues are usually very vascular and heavy bleeding may occur. Pinch and full core thickness biopsies will usually give you a diagnosis.
  • Culture – always take a swab and submit for culture and sensitivity.
  • Blood tests – these can be used to check for Aspergillus titres

What treatments are available?

With an accurate diagnosis, you’ll be in a good position to discuss and offer treatment. Some of the options available include;

1. Allergic Rhinitis 

  • Antihistamines – these are usually given orally, once or twice a day.
  • Steroids – these tend to be particularly effective, though do have side effects which need to be discussed.

2. Nasal tumours

Surgery is not an option and if attempted, is unlikely to increase the animal’s quality of life or life expectancy.

  • Chemotherapy – this tends to be offered with reasonable success for nasal lymphoma.
  • Radiotherapy - radiation therapy is available at a few veterinary centres in the UK. For example, Liverpool University has a particularly active and successful oncology department, where they offer a variety of different protocols for dogs, cats and rabbits.

Have a look at the University of Liverpool Oncology department >

The main problem with radiotherapy is that it’s expensive and usually requires a number of treatments over several weeks, where the animal will typically have to be anaesthetised. The owner will need to be dedicated and either have comprehensive insurance or deep pockets.

For most non-lymphoma nasal tumours, radiotherapy carries a variable prognosis of anything between a few months to a couple of years.

3. Lymphocytic plasmocytic rhinitis

The aetiology of this condition is not fully understood. It’s known that the nasopharyngeal cavity develops recurring secondary infections, so the first approach is to use antibiotics. There is thought to be a response to allergens triggering the condition, so inhalant steroids are also used.

4. Foreign body

Grass seeds and soil are probably the most common foreign bodies in small animals, and in most cases, these can be removed during rhinoscopy by flushing. Use warm saline to flush, and make sure the back of the throat is packed to prevent inhalation into the trachea.

5. Fungal infections

Aspergillosis is the most frequently diagnosed fungal infection and is usually identified in dogs. The most effective treatment involves the use of antifungals into the nasal cavity and sinuses. This needs to be done with the animal anaesthetised, and the antifungal needs to be left in place for around an hour during each treatment.

6. Tooth root abscess 

In all species, the affected tooth needs to be identified and removed.

7. Secondary bacterial infections

Primary bacterial infections are not common, but secondary infections are. Common pathogens found include;

  • Staphylococcus infections
  • Streptococcal infections
  • E. coli
  • Pasteurella spp.
  • Pseudomonas spp.

8. Vasomotor Rhinitis

This is a common cause of a clear nasal discharge and is often the result of a reaction to benign household substances, such as perfumes, cleaners, washing powders and aerosols. You’ll need to take a detailed history and find a pattern of when the reaction occurs. The aim is to remove all access to the substance causing the rhinitis.

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