Chronic Nasal Disease in Dogs: Nothing to Sneeze at! Veterinary Specialty & Emergency Center - VSEC

Chronic Nasal Disease in Dogs:
               Nothing to Sneeze at!
    Alan R. Klag, DVM, DACVIM, Chief of Internal Medicine
Peter Chapman, BVetMed (Hons), DECVIM-CA, DACVIM, MRCVS

         Veterinary Specialty & Emergency Center

Overview
•   Introduction
•   Anatomy
•   History and Presentation
•   Equipment
•   Diagnostic Workup
•   Differential Diagnoses
•   Treatment and Prognosis by Etiology
•   Clinical Cases

Introduction
• Challenges in obtaining diagnosis

• Incidence

• Need for advanced imaging
  studies

Anatomy
• Nasal passage extends caudally from external
  nares to cribiforme plate and nasopharynx
• Divided in half by septum-cartilage cranially
  and bone caudally
• Contains thin scrolls of cartilage and bone
  called conchae or turbinates
  – Serve to warm, humidify and filter air as it passes
    through the nasal cavity

Anatomy Cont.
• Ventral, middle and dorsal nasal meatus
  – ventral meatus communicates with nasopharynx
    via choanae or internal nostrils
• Nasopharynx is delineated ventrally by soft
  palate and dorsally by vomer bone.
• Cribiforme plate separates caudal nasal cavity
  from rostral olfactory bulbs of brain hence a
  major problem if breached

Anatomy Cont.
• Frontal sinuses, lateral maxillary recesses and
  sphenoidal sinuses all communicate with nasal
  cavity
  – not able to be visualized routinely during
    endoscopy
  – importance of combining CT scanning with
    endoscopic procedure.

History/Presentation

• Sneezing, nasal discharge, epistaxis, nasal
  congestion/stertor, gagging, reverse sneezing,
  coughing

• Unilateral vs bilateral

• Chronic vs acute

History/Presentation Cont.

• Signalment-tumors in older dogs, fungal
  rhinitis in German Shepherds and other
  dolichocephalic larger breeds
• History/presentation can be very helpful in
  determining location (nasal cavity vs
  nasopharyx) as well as most likely diagnoses

Equipment
• Camera adaptor, Processor, Xenon light source
  – Olympus

Equipment Cont.

• Rigid endoscopes
  – Stortz (rhinoscopy)
• Flexible endoscope
  – Olympus (nasopharyngeal endoscopy)

Equipment Cont.

Equipment Cont.

Equipment Cont.
• CT scanner
  – Siemens Somatom Esprit+

Diagnostic Workup
• Baseline
   – CBC/chem-rule out thrombocytopenia, severe metabolic
     issues (complicating factors), anemia (not common even
     with epistaxis), helps assess as candidate for anesthesia.
• PT/PTT (if epistaxis)
• Nasal rads
   –   limited value,
   –    must be anesthetized in most cases to obtain good films
   –   Much less informative than CT
   –   If CT declined, nasal radiographs at time of endoscopy.

Diagnostic Workup Cont.
• Rhinoscopy/NP endoscopy + CT of skull and sinuses +/-
  chest cavity=gold standard
   – CT can image areas where rhinoscopy cannot( i.e. frontal and
     accessory sinuses, bone, caudal nasal cavity)
       • Helps localize problem and determine extent of invasiveness
   – CT of chest much more sensitive in detecting metastatic disease
     compared to chest rads
       • additional cost to image chest no more expensive than 3 view chest
         rads
   – Pulmonary metastasis of nasal tumors is uncommon (10% or
     less) but implications are important, especially if aggressive
     therapy such as radiation therapy will be considered
       •     Therefore, CT of chest typically done where suspicion for nasal tumor
           is high or if nasal tumor found on nasal CT

Diagnostic Workup Cont.
• Why not CT alone (without rhinoscopy)?
   –   CT identifies tumor but will not allow for histopath diagnosis
       • important for treatment planning and prognosis
       • In most cases does not help establish cause of non neoplastic disease
• Rhinoscopy/NP endoscopy
   – allows for detailed evaluation of nasal cavity and nasopharynx
     for tumor, foreign body
   – allows for careful assessment of mucosal changes/allows for
     tissue biopsy
       • is critical in establishing specific tumor diagnoses as well as nature of
         non neoplastic disease
• Oral/dental exam if oronasal fistula on differential list

Differential Diagnoses
• Neoplasia
  – nasal cavity, frontal sinus, nasopharyngeal,
    extension of bone/maxillary
• Nasal polyps
  – extremely rare in dogs
• Nasal foreign body
• Fungal rhinitis
• Lymphoplasmacytic rhinitis

Differential Diagnoses Cont.
• Allergic rhinitis
• Bacterial rhinitis/sinusitis
   – usually secondary/opportunistic
• Tooth root abscess
• Nasal mites
• Diseases of the rhinarium
   – can be confused with nasal cavity disease if
     bleeding or crusting

Differential Diagnoses Cont.
                Unilateral Bilateral   Age        Breed/size   Discharge   Epistaxis
Neoplasia           +         rare     older*     variable        0-4+     common
Polyps              +         rare     older      variable        0-4+     common
FB                  +           -      younger    variable        3-4+     rare
Fungal              +           +      younger    larger           4+      common
LP                  +           +      variable   variable        1-2+     occasional
Allergic             -          +      younger    variable        3-4+     no
Bacterial           +           +      variable   variable        3-4+     rare
Tooth abscess       +           -      older      variable        3-4+     rare
Mites               +           +      variable   variable        0-1+     no
Rhinarium           +           +      variable   variable        0-1+     variable

            *exception-lymphoma, fibrosarcoma

Treatment and Prognosis
• Neoplasia-Non lymphoma: Radiation therapy
  – Most common=carcinoma
  – Radiation therapy for carcinoma-median survival
    12-16 months with full course radiation.
  – If no radiation-NSAIDS?
  – With no treatment euthanasia typically necessary
    within 3-4 months of diagnosis due to
    uncontrollable epistaxis

Treatment and Prognosis Cont.
• Neoplasia-Lymphoma
  – Uncommon
  – typically focal and not part of systemic condition
  – Chemotherapy-full course sequential vs more
    conservative
  – benefit to radiation therapy + chemotherapy vs
    chemotherapy alone?
  – 6-12 months with chemotherapy is typical for those
    that show response (80+%)
  – 6-12 weeks with palliative prednisone

Treatment and Prognosis Cont.
• Nasal Polyps
  – Very rare in dogs
  – Can be extensive and cause remodeling/lysis in
    nasal cavity so caution in ruling out without
    biopsy!
  – Treatment is surgical (rhinotomy)
  – Low grade fibrosarcomas?

Treatment and Prognosis Cont.
• Nasal foreign body
  – Relatively uncommon
  – Usually plant material or food
  – Can trigger secondary bacterial rhinitis
  – Treatment consists of removal (usually able to
    remove endoscopically) along with appropriate
    antibiotic therapy (ideally guided by c/s results)
  – Prognosis is excellent until the next one.

Treatment and Prognosis Cont.
• Fungal rhinitis
   – Treatment consists of nasal infusion of clotrimazole
     under anesthesia
   – Can be combined with sinus trephanation for
     instillation of clotrimazole solution and cream if
     needed
   – Sinus trephanation alone if CT shows infection to be
     limited to frontal sinuses
   – Approximate 85% cure rate with 1-3 infusions
   – Oral antifungals are expensive
      • must be given long term and have lower cure rate.

Treatment and Prognosis Cont.
• Lymphoplasmacytic rhinitis
  – Difficult to treat/no uniformly effective treatment.
  – Make sure to rule out underlying disease with
    rhinoscopy and CT
  – Different cause in different individuals?
  – Typically try intranasal steroids (Rhinocort)
     • If not effective, can try oral steroids, or chlorambucil,
       antifungals?
  – Typically controlling condition, not curing it
  – Prognosis is excellent for survival but very guarded for
    resolution of signs

Treatment and Prognosis Cont.
• Allergic rhinitis
• Relatively uncommon
• Very responsive to high dose steroids
  – 0.75mg/kg Bid initially with slow taper
  – Will often relapse if weaned off steroids so usually
    maintain on low EOD dosing
  – Intranasal steroids?
  – Prognosis is excellent

Treatment and Prognosis Cont.
• Bacterial rhinosinusitis
  – Treat underlying condition!!
  – Rare cases of primary bacterial infection require 6-
    12 weeks of antibiotics selected based on c/s
  – Prognosis usually depends on underlying
    condition

Treatment and Prognosis Cont.
• Tooth root abscess
  – Extraction of affected teeth/ appropriate
    antibiotic therapy ideally based on c/s results
  – Warn client of possible ongoing concurrent nasal
    condition if signs do not resolve with dental
    treatment!
  – Prognosis is excellent if no concurrent primary
    nasal disease

Treatment and Prognosis Cont.
• Nasal mites
  – Uncommon
  – Pneumonyssoides caninum
  – 1mm length
  – Transmission probably through direct transmission
  – Diagnosis by direct visualization of yellow white mites at
    external nares or in nasal passage/nasal discharge
  – Rarely can be only in sinuses
  – Can be treated with Revolution q2 weeks x 3, Interceptor
    0.5-1.0mg/kg q1-2 weeks x3, Ivermectin 400mcg/kg SQ or
    PO q2 weeks x3
  – Treat all animals in household!

Treatment and Prognosis Cont.
• Diseases of rhinarium
  – Lupus, pemphigus, mucocutaneous pyoderma,
    vasculitis, trauma (chemical, thermal, physical)
    and other conditions of rhinarium that cause
    bleeding or crusting can be confused with
    intranasal disease.
     • Dr Spiegel!