1.1.1: Canine and feline nasal disease Flashcards
Signs of nasal disease
- Sneezing
- Snorting
- Nasal discharge
- Epistaxis
- Nasal pain (common with neoplasia)
- Nasal ulceration / loss of pigment around the nostrils
- Reverse sneezing is not usually a sign of severe disease
If nasal discharge (e.g. mucoid, bloody) starts unilateral and then becomes bilateral, what does this tell you about the disease process?
- If it starts unilateral and then goes bilateral, the disease is getting worse
- Crossing the midline means destruction is occurring
What history questions could you ask when investigating nasal disease?
- When was the animal last seen normal? (Classify disease as acute vs chronic)
- Is it one or both nares affected?
- Nature of discharge? Presence of blood?
- Any pain?
- Any difficulty eating?
- Any halitosis?
What aspects of the clinical exam will you pay particular attention to in the animal with nasal disease?
- Symmetry
- Eyes
- Pain (palpate over the dorsum of the nose and sinuses)
- Air flow
- Teeth
- Nasal planum depigmentation
- Lymph nodes
Differential diagnoses for chronic nasal disease
- Foreign body
- Neoplasia (±epistaxis, esp if unilateral)
- Aspergillosis (±epistaxis)
- Rhinitis e.g. allergic rhinitis is a diagnosis of exclusion. Primary bacterial rhinitis is rare!
- Dental disease
- Chronic post-viral disease in cats (e.g. kittens infected with herpes developing chronic issues)
Common in bold.
What should you consider if there is epistaxis and blood in any other body system?
Clotting disorders are always a possibility. Epistaxis could be an early sign.
Describe the cause and pathogenesis of chronic rhinitis in cats
- Feline herpesvirus 1 is suspected to play a role in chronic nasal inflammation resulting in destructive rhinitis (turbinates can be destroyed)
- There is inflammation and swelling of the conchae -> increased mucus production and secondary infection
- Mucopurulent secretion may contain blood -> sometimes disease is severe enough to result in loss of conchae
Diagnosis of chronic rhinitis in cats
- Noticeable on rhinoscopy as loss of conchae / turbinates means there is lots of room to move the rhinoscope
- Appearance of chronic post-viral rhinitis in cats appears similar endoscopically to aspergillosis of nasal passages in dogs
- May have history of respiratory disease / viral infection as a kitten
3 most common causes of chronic nasal disease in cats
- Tumours
- Foreign bodies e.g. grass blades
- Rhinitis
Polyps are also a possibility. Other causes are miscellaneous or undiagnosed.
Which fungi most commonly causes fungal rhinitis in dogs?
A. fumigatus (causes aspergillosis)
Which species is fungal rhinitis more common in?
- Mainly seen in dogs, especially in medium to long-nosed breeds
- Rare in cats
Describe the pathogenesis of aspergillosis / fungal rhinitis
- A. fumigatus often causes fungal rhinitis
- Disease is generally restricted to the nasal cavity and sinuses but is markedly destructive to the turbinates
- It can erode the frontal bones and cribiform plate, even getting into the brain
Clinical signs of fungal rhinitis / aspergillosis
- Nasal discharge: may be mucopurulent with intermittent epistaxis
- Discharge may progress from unilateral to bilateral.
- Discharge often smells dank (like a cellar)
- Ulceration / depigmentation of the nasal planum
- Pain on palpation
- Sneezing
- Facial deformity
- Neuro signs
Diagnosis of fungal rhinitis / aspergillosis
- History and clinical signs
- Imaging: radiography of nose and sinuses / CT or MRI if available
- Rhinoscopy: rigid or flexible endoscope. Flexible allows anterograde sinuscopy. Can take guided biopsy.
- Cytology
- Serology
- Best method: visualise the plaque or culture the fungus from a sample
What are the disadvantages of using serology to diagnose aspergillosis?
- Sensitivity and specificity not great
- Can produce false negatives commonly
- Can produce false positives if the animal has previously had and cleared the infection
What are the advantages of using rhinoscopy for diagnosis of aspergillosis?
- Can take a guided biopsy at the same time -> this is important as a swab would be insufficient for diagnosis; you need to be in the lesion
- Can visualise plaques and remove them at the same time (this is treatment)
Treatment of aspergillosis
- Challenging
- Topical therapy: enicoazole, clotrimazole
- Delivery can be surgical or minimally invasive
- Minimally invasive: catheter placement under GA
- Surgical: drill hole into frontal sinuses and place catheter. Treat second time 7-14 days post initial surgery. 80% success rate. Usually done at same time as rhinoscopy if highly suspicious of aspergillosis.
- Oral antifungal agents no longer recommended due to long course and severe side effects.
This is Squamous cell carcinomas on the nasal planum of white cats due to solar exposure
Describe the development of squamous cell carcinomas in white cats
- Seen on nasal planum of white cats with solar exposure; rare in dogs
- Carcinoma in situ -> superficial squamous cell carcinoma -> infiltrative squamous cell carcinoma (locally invasive, mets rare)
Treatment of nasal squamous cell carcinomas in cats
Options:
* Photodynamic therapy (PDT) - may need repeat sessions
* Planectomy - good prognosis with nose off
* Immunomodulators e.g. imiquimod
* Can affected ears as well. If caught early, respond well to surgery.
* Generally referral for surgery is done.
Which kinds of neoplasia are most common in nasal cavities of dogs?
- Carcinomas
- Rarely squamous cell carcinomas
- Lymphoma, fibrosarcoma, chondrosarcomas, osteosarcomas
What kinds of neoplasia are most common in nasal cavities of cats?
- Adenocarcinomas or lymphoma most likely
- (Squamous cell carcinomas on surface of nasal planum)
Lymphoma is usually a safe bet in cats.
Investigation and treatment of nasal cavity neoplasia
- CT / MRI then rhinoscopy and biopsy
- Therapy: radiotherapy ± chemo ± NSAIDs
- Cannot achieve good margins with surgery
- Prognosis guarded even with radiotherapy
- There are no good oral and nasal tumours in dogs and cats
Nasal tumour that has crossed the midline
Causes and presentation of pharyngeal disease
Common presentation: dysphagia (client may report difficulty eating so need to confirm that it is swallowing that is the problem).
Possible causes
* Foreign body
* Neoplasia
* Nasopharyngeal polyps (cats)
* BOAS
Presentation of nasopharyngeal polyps in cats
- Laboure and noisy breathing
- Nasal discharge
- Head shaking
- Sneezing
- Difficulty swallowing
True/false: neoplasia of the larynx and trachea is common in dogs and cats.
False
It is rare but on the list of differentials for URT dyspnoea.
* Dogs: oncocytoma, rhabdomyosarcoma, tracheal cartilagenous tumours, OSA, fibrosarcoma, SCC all possible
* Cats: laryngeal lymphoma recognised but rare
* Usually diagnosed on exam under GA, then biopsy if possible.
* Tracheal masses may be benign and resectable but refer for surgery
Optimal diagnostic plan for nasal cavity disease
- CT = optimal. Cost ~£2000
- Rhinoscopy
- Nasal radiography
- Serology for aspergillosis
- Nasal flush
This list is ordered in terms of gold standard/ preference - you would not be aiming to do all of these for the given case.
How would aspergillosis appear on rhinoscopy
- White plaques
- Blood - very easy to make the nose bleed
What does the arrow indicate?
Area of soft tissue density = foreign body (in this case a grass seed)
This shows advanced neoplasia which has crossed the midline
Where should you check for foreign bodies especially grass blades in cats?
- Behind the soft palate
- Hard if you don’t have a flexible endoscope; try to look with a dental mirror
Describe how you would attempt nasal radiography and its advantages and disadvantages
- Opt for open-mouth, intraoral view where the film is in the animal’s mouth and radiograph dorsoventrally
✅ Can identify/ potentially rule out destructive diseases
❌ Difficult to generate
❌ Teeth get in the way
❌ Limited use, CT is better
Describe how to perform a nasal flush, and its advantages and disadvantages
- Anaesthetise the animal, pack the pharynx with swabs in order to not push saline into the lungs
- Collect what is blown to the back of the pharynx
✅ Cheap especially if animal under GA
✅ Can sometimes be lucky e.g. if a chunk of tumour comes out
❌ Not sensitive, may yield nothing
