Tracheobronchial diseases--dogs

Question 1

What signs are associated with disease in the following areas:

Larynx (voicebox)?

Trachea (windpipe)?

Bronchi?

Answer 1

• Larynx = hoarse bark, gagging, inspiratory difficulty
• Trachea = cough and resp distress
• Bronchi = cough and resp distress

Question 2

Clinical signs?

Answer 2

• Cough (most common)
  
  • +/- productive
• Retch/gag
• Wheezing
• Inspiratory sounds
• Tachypnea
• Resp distress
• Cyanosis if severe

Question 3

Canine etiology

Answer 3

• Brachycephalic airway syndrome and laryngeal paralysis–know hallmarks
• Canine infectious respiratory disease complex: kennel cough
• Canine influenze
• Oslerus osleri
• Collapsing trachea, bronchi
• Canine chronic bronchitis
• Bronchiectasis

Question 4

Canine infectious respiratory disease complex (CIRD): kennel cough

Pathogens responsible?

Answer 4

• Parainfluenza virus–mild clinical signs
• Canine adenovirus (CAV-2)
• Mycoplasma spp.–mild to severe clinical signs
• Bordetella spp.–mild to severe clinical signs
  
  • Attaches to cilia of bronchial epithelium and interferes with motility–resulting in mucous accumulation and inflammation
• Other viruses–canine distemper virus (CDV), canine respiratory coronavirus (CRCoV), canine herpes virus (CHV-1), and canine influenza virus (CIV)
• Secondary bac. invaders are comon

Question 5

CIRD: kennel cough

Contagious?

Spread?

Incubation?

Most common clinical sign?

Answer 5

• Very contagious–acquire pathogen from dog shows, kennels, vet clinics, etc.
• Spread through resp secretions and fomites
• Incubation 3-7 days
• Coughing is most common clinical sign

Question 6

CIRD: kennel cough

Clinical signs

Answer 6

• Usually develop 4-10 days post exposure
• Uncomplicated
  
  • Non-sick animals
  • Involves upper airways
  • Dry cough is elicited on tracheal palpation
  • Serous oculonasal discharge, gagging, and retching can be found
• Complicated
  
  • Sick animals
  • Upper and lower airways
  • Moist cough
  • Oculonasal discharge more mucopurulent
  • May develop into bronchopneumonia

Question 7

CIRD: kennel cough

Diagnosis

Answer 7

• History
  
  • Where has the dog been? Kennels?
  • Has the dog received bordetella vaccine recently?
• Clinical signs
• In uncomplicated cases further diagnostics may be included
  
  • Hemogram–left shift neutrophilia
  • Thoracic radiographs
  • Transtracheal wash, cytology and culture
  • PCR panels for upper resp viruses and bac.

Question 8

CIRD: kennel cough

Treatment: uncomplicated

Answer 8

• Uncomplicated
  
  • Restricted exercise
  • Use doxycycline if Bordetella spp is suspected
  • Usually resolves w/in 2 weeks
  • Cough suppressants
    
    • Butorphanol, hydrocodone, codeine derivative, dextromethorphan

Question 9

CIRD: kennel cough

Treatment: complicated

Answer 9

• Restrict exercise
• Systemic antibiotic for 2 wks
  
  • Doxycycline, tetracycline, sulphonamides, enrofloxacin
  • Penicillins are not a good choice for Bordetella spp as they reach poor concentrations in the respiratory secretions
• Nebulization w/ or w/o gentamycin (only antibiotic that can actually have an effect when added to nebulizer)
• Cough suppressants (avoid if bac. pneumonia is present)
• Bronchodilators
  
  • Albuterol, theophylline (avoid or reduce dose by 30% if using together w/ fluoroquinolones)

Question 10

CIRD: kennel cough

Prognosis?

Prevention?

Answer 10

• Prognosis = good to excellent
• Prevention
  
  • Avoid places where dog could get infected
  • Vaccination
  • Sanitation–household bleach dilated 1:32
  • Ventilation in kennels

Question 11

CIRD: kennel cough

Vaccination

Answer 11

• Parenteral vaccination
  
  • CAV-2, CPIV, CDV and Bordetella spp (dogs)
  • Blocked by maternal antibodies so repeat every 3-4wks until 16wks of age
• Intranasal vaccination
  
  • Bordetella spp and CPIV
  • Important for high- or at-risk animals
• New vaccinations against CIV
• Need vaccine 2-3 wks BEFORE going to kennels for protection

Question 12

Canine influenza

Influenza type A?

Spread?

Answer 12

• Type A
  
  • H3N8 (related to equine flu)
  • H3N2 (related to avian flu)
• Spread through direct contact (resp secretions) and fomites or indirect contact through kennel surfaces, water/food bowls, toys, collars and leashes

Question 13

Canine influenza

Clinical signs

Diagnosis

Answer 13

• Clinical signs
  
  • 2-5 days post exposure
  • Usually results in coughing, sneezing, nasal discharge and fever; may result in hemorrhagic pneumonia
  • Disease has high morbidity but low mortality
  • 20% don’t show clinical signs and just shed virus
  • Most animals dev. mild clinical signs, but some can dev. severe (2 forms)
• Diagnosis–PCR, serology (acute and convalescent titres) or viral isolation

Question 14

Canine influenza

2 forms?

Answer 14

• Mild/uncomplicated–typical mild uncomplicated kennel cough
• Severe/complicated
  
  • Pyrexia (104-106F)
  • Hemorrhagic pneumonia–dyspnea, tacypnea, hemoptysis
  • Rapid onset and animal can die w/in hours
  • 5-8% mortality

Question 15

Canine influenza

Treatment

Prevention

Answer 15

• Treatment
  
  • Supportive care, NSAIDs to reduce fever, and IV fluids
  • Systemic antibiotics in the severe form–may require ICU but extremely contagious and requires isolation
• Prevention
  
  • Vaccination
  • Isolate sick and exposed dogs
  • Change clothes/wash hands
  • Virus does not persist in environment >48hrs–good quality bleach/disinfectant solution

Question 16

Oslerus osleri

What is it?

Generally affects?

Life cycle?

Causes what?

Clinical signs?

Answer 16

• Canine parasite on resp. passages
• Generally affects younger dogs in kennels
• Direct life cycle–larvae ingested, molt in small bowel and migrate to lungs, bronchi, and trachea
• Cause cream-colored nodules in trachea
• Clinical signs: coughing, wheezing, dyspnea

Question 17

Oslerus osleri

Diagnosis

Answer 17

• Radiographs–may see tracheal mass
• Bronchoscopy–masses are found
• Tracheal/bronchial brushes or biopsies
• Fecal

Question 18

What parasite is this indicative of (white plaques)?

Answer 18

Oslerus osleri

Question 19

Oslerus osleri

Treatment

Answer 19

• Fenbendazole
• Ivermectin

Question 20

Tracheal collapse

Signalment?

Usually acquired reduction in what?

Pathophysiology?

Answer 20

• Signalment
  
  • Middle aged to older dogs (rarely cats–full cartilagenous rings in trachea)
  • Toy or small breed dogs–usually obese
• Usually acquired reduction in chondrocytes
  
  • Lack glycosaminoglycans and chondroitin sulfate in tracheal cartilage
• Pathophysiology
  
  • Weak cartilage w/ flattening of tracheal rings, resulting in mechanical irritation, edema, and inflammation
  • Tracheal rings lose their firmness and collapse

Question 21

Tracheal collapse

Clinical signs

Answer 21

• Goose honking cough
• Exacerbated by exercise, excitement and eating
• Elicited w/ tracheal palpation
• Causes cyanosis and collase/syncope
• Many dogs have hepatomegaly
  
  • Theory: O2 deprivation–> significant liver disease
• Many have cardiac murmur
• Variable breath sounds

Question 22

Tracheal collapse

Diagnosis

Answer 22

• Signalment, history, clinical signs
• Thoracic/cervical rads
  
  • Inspiratory AND expiratory films
  • May/may not be diagnostic
  • Often underestimate severity
  • Extra-thoracic and intra-thoracic collapse occurs
• Fluoroscopy
• Bronchoscopy
  
  • Best diagnostic tool
  • Assess dynamic change
  • Grade extent of collapse
  • Look for concurrent diseases

Question 23

Tracheal collapse

Grading scale?

Answer 23

Question 24

Tracheal collapse

Treatment: calm patient (/owner)

Answer 24

• Sedation often required
  
  • Acepromazine, butorphanol, diazepam
• O2-rich environment
  
  • O2 cage, nasal catheterization
• Use cough suppressant (antitussive)
  
  • Butorphanol injectable/oral
  • Oral hydrocodone
• Corticosteroid
  
  • Single dose for anti-inflammatory effects
  • 0.1mg/kg IV dexamethasone
• Intubation may be required

Question 25

Tracheal collapse

Treatment: break the cycle

Answer 25

• Weight loss
• Avoid neck collars
• Avoid excitement
  
  • Use sedative if required
  • Behavioral–reward quiet behavior
• Avoid dust, smoke, pollens, carpet powders, etc.
• Use cough suuppressants–butorphanol, codeine, hydrocodone
• Use corticosteroids–very short course if required
  
  • Too long–> suppress immune system–> secondary bac. pneumonia
• Antibiotics for secondary infection if suspected

Question 26

Tracheal collapse

Response to medical management?

Surgery?

Answer 26

• 30% of dogs do not respond to medical management
• Surgical intervention–referral
  
  • Extraluminal stents
    
    • For extrathoracic or cervical collapse
  • Endoluminal stents
    
    • For intrathoracic or entire tracheal collapse
    • Nitinol stents are used

Question 27

Canine chronic bronchitis

What is it?

Clinical signs?

Cause?

Long-term sequelae?

Not similar to what?

Answer 27

• Inflammation of bronchial walls–> thickened walls, increased mucous –> obstruction of small airways
  
  • Chronic obstructive pulmonary disease
• Clinical signs–daily cough > 2mo
• By the time it is diagnosed there is rarely a cause found for the underlying inflammation
  
  • Etiology is rarely determined
• Long term sequelae–emphysema, bronchiectasis, pneumonia
• Not similar to asthma in cats or people

Question 28

Canine chronic bronchitis

Signalment

Client complaint

Clinical signs

Diagnostics

Answer 28

• Signalment: small breeds, usually >6yrs
  
  • Often obese
• Client compliant: chronic cough, audible wheezes, exercise intolerance
  
  • Usually BAR, signs wax and wane
• Clinical signs–expiratory wheezes, crackles audible on inspiration and expiration
  
  • Dog can also have concurrent tracheal collapse or mitral valve insufficiency
• Diagnostics–exclude other causes of a cough
  
  • Rads, bronchoscopy, bronchial cytology and culture

Question 29

Canine chronic bronchitis

Treatment

Answer 29

• Eliminate triggers–smoke, excitement, allergens
• Keep hydrated–to aid mucociliary clearance
• Reduce weight if obese
• Prednisolone–reduce inflammation
• Bronchodilators–only in reversible stages, use only w/ corticosteroids
• Antibiotics–if secondary bac. infection found
• Avoid cough suppressants–unless a tracheal collapse is present or the cough is inconsistent and dry
• Metered dose inhalers (MDI)–inhalation steroids
  *

Question 30

Bronchiectasis

Secondary to?

Pathophysiology?

Answer 30

• Secondary to chronic conditions like chronic bronchitis
• Pathophysiology
  
  • Damage to bronchial structure–> thickened wall, dilation of structure
  • Mucous cannot be cleared–> builds up
  • Secondary infection –> recurrent bronchopneumonia –> more damage to airways
  • Dilation of bronchial tree is irreversible caused by the destruction of the muscle and elastic tissue

Question 31

What specific diseases in the various lung lobes can cause bronchiectasis?

Answer 31

• Upper lung lobe
  
  • Cystic fibrosis
  • Tuberculosis
• Central
  
  • Cystic fibrosis
  • ABPA
  • Congenital tracheobronchomegaly
• Lower
  
  • Childhood infection
  • Aspirations
  • Immunodeficiencies