Lower Airway Diseases in Small Animals Flashcards
Coughing Puppy Rule outs…
- Canine infectious tracheo-bronchitis > “Kennel cough”
- Tracheal foreign body
- Tracheal collapse
> Cons: usually older, seasonal - Bronchopneumonia
> Cons: usually anorexia, lethargy, history of aspiration or exposure
Canine Infectious Tracheobronchitis
- what is this?
Infectious “complex”
* Bordetella bronchiseptica
* Canine adenovirus-2
* Canine parainfluenza virus
* Canine respiratory coronavirus
* +/- other secondary organisms
Canine Infectious Tracheobronchitis
- spread?
- disease course?
- Highly contagious
> Usually, history of contact with other dogs - Usually mild & self-limiting (within 1-2 weeks)
> frustrating for client as dog is continuously coughing and may not be able to sleep
Canine Infectious Tracheobronchitis
* Clinical features
- Dry, hacking, paroxysmal cough most common sign
- May have nasal discharge (purulent)
- Usually healthy otherwise
Diagnosing ITB
- Diagnosis usually presumptive
> History & clinical signs
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Thoracic auscultation, radiographs, CBC - Usually normal
- Diagnostic tests beyond the physical examination usually not performed in routine cases
> Coughing induced on tracheal palpation
Treating ITB
- Antibiotics have limited benefit in uncomplicated cases
> Course of infection not shortened
> Self-limiting disease
<><><><> - Antibiotics rarely used
- Antibiotics warranted only if:
- Systemic signs or deeper respiratory involvement
> E.g., fever, productive cough - Or if neonates (<8 weeks)
- Empirical choices include Clavamox, doxycycline
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Antivirals? - Not recommended
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Glucocorticoids? - Not recommended
- Does not shorten course of disease
- May worsen illness if high dose used (immunosuppression)
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Antitussives for dogs with dry cough - Hydrocodone, butorphanol
- Contraindicated in cases of productive cough, systemic signs that may be reflective of pneumonia
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Bronchodilators can help decrease bronchospasm
Treating ITB Antitussives
- which ones?
- what is their use?
- when not to use?
Antitussives for dogs with dry cough
* Hydrocodone, butorphanol
* Contraindicated in cases of productive cough, systemic signs that may be reflective of pneumonia
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not recommended
- cough is cleaning the lungs, if we give this we can make things worse
- can give for the night if the puppy os not able to sleep, for example
ITB Prevention
- B. bronchiseptica & Parainfluenza vaccine
- ± Adenovirus
- Recommended for at-risk dogs
- Often required for boarding kennels
- May lessen severity or prevent infections
ITB Prognosis
- Excellent prognosis for recovery in uncomplicated cases
Complicated ITB
- what is this?
- what should we do?
- Persisting (>1-2 weeks) or progressive clinical signs warrant the following diagnostics:
- Thoracic radiographs
- Airway sampling (transtracheal wash)
- CBC
- ± infectious disease testing (e.g., canine influenza)
<><><><> - Pneumonia can result from ITB and requires further therapy
what radiographs do we need to diagnose tracheal collapse?
we need both inspiratory and expiratory views to see tracheal collapse - some are more visible in one view or the other
Tracheal Collapse, origins
- Tracheal cartilage malacia
> Dorsoventral collapse - Miniature and toy breeds
> Yorkshire Terrier and Pomeranian
Clinical Signs of tracheal collapse
- “Goose – honk” cough!!
- Wheezing
- Hacking
- Exercise intolerance
- Cyanosis +/- syncope
tracheal collapse dx? types and how to differentiate?
Radiography
* Dynamic condition
* Not overly sensitive
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* Inspiration > cervical collapse
* Expiration > thoracic collapse
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* also, fluoroscopy
Medical Management for tracheal collapse (broad, no drug names)
Initially
* Weight loss
* Environmental modifications
> Harness vs neck collar
> Removal of secondhand smoke
> Normal humidity
> Dental prophylaxis
* Pharmaceutical therapy
drugs we use for medical management of tracheal collapse
- Doxycycline for a week > when severe signs, also has antiinflammatory properties
- Corticosteroids > reduce inflammation
- Bronchodilators > Open small airways and anti-inflammatory effect
- Anti-tussives
- Tracheal collapse elixir (0.22-0.44 ml/kg q8hr)
> Phenobarbital, isoproterenol, theophylline, ephedrine
possible issue with bronchodilators for tracheal collapse
questionable, as it can increase negative pressure > collapse
Medical Management for tracheal collapse efficacy? when to go to surgery?
- Majority of dogs respond well
to medical management - However… progressive disease and still guarded long- term prognosis
- Surgery/stent is palliative, performed when medical treatment fails
Extra-luminal Tracheal Prosthesis - what is this? disadvantages?
- External rings around trachea
<><> - Disadvantages:
- Only for cervical collapse
- Collapse can occur beyond rings
- 40% complication rate
Endo-Luminal Tracheal Stent - when do we use this? what is it? complications?
more common, generally better
> for cases that are not improving with medical manamgement
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* Minimally-invasive insertion
> Fluoroscopy +/- scoping
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* Complications:
* Stent migration or fracture
* Granulation tissue formation
* Progressive collapse
* Costly
Endo-Luminal Tracheal Stent - at what point should we consider this treatment? goal? results? what else do we need?
- LAST RESORT ONLY
- Goal: allow breathing and better quality of life
- Dogs won’t stop coughing !!!!!
- 100% need medical management
Tracheal Collapse Prognosis
- Life-long condition, progressive
- Depends on grade of collapse
- More severe collapse = guarded prognosis
Bacterial Pneumonia Predisposing causes
Aspiration of GI contents
* Megaesophagus, recent anesthesia, chronic vomiting, seizures, force feeding, dysphagia, etc
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Systemic immunosuppression
* Drugs
* Endocrine dz (hyperadrenocorticism, diabetes mellitus)
* Infection (FeLV, FIV)
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Defective respiratory defenses/damage to
respiratory epithelium
* Bronchiectasia
* Smoke inhalation
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* Sepsis (hematogenous spread of bacteria)
Aspiration Pneumonia - pathogenesis?
- Low bacterial content of aspirated GI material
- Gastric pH kills most bacteria – contents may
be sterile - Material may be contaminated by oral bacteria
<><><><> - Acid injury to pulmonary parenchyma
- Induces lung inflammation, bronchoconstriction
- Predisposes to secondary (opportunistic) bacterial invaders
Aspiration and bacterial pneumonia share several historical & PE findings, and may include:
- **Anorexia
- Lethargy**
- Exercise intolerance
- Tachypnea
- Cough (more than 50% do not cough)!!!
- Dyspnea
- Cyanosis if severe lung involvement
- Fever
- Nasal discharge
- Inspiratory crackles
- Increased bronchovesicular sounds
Pneumonia Thoracic Radiographs
- Interstitial to alveolar radiographic pattern common * Typical distribution is ventral
- May only affect one lung lobe
> Often right middle lung lobe with aspiration pneumonia
> Right cranial or caudal portion of left cranial
Pneumonia CBC and pulse ox diagnostics?
- CBC – neutrophilia common
- Hypoxemia common
> Pulse oximetry, blood gas analysis
> Depends on how much lung is affected
Airway Sampling for pneumonia use?
* Most common bacterial pathogens in canine pneumonia:
- Culture & sensitivity helpful in guiding treatment
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Most common bacterial pathogens in canine pneumonia: - E. coli
- Pasteurella spp.
- Bordetella bronchiseptica (especially in young dogs)
- Streptococcus spp.
- Staphylococcus spp.
Empirical Antibiotic Selection for pneumonia?
mild vs severe cases
Dogs with mild to moderate clinical signs:
* Ampicillin, amoxicillin, amoxicillin-clavulanic
acid
* Cephalexin, cefazolin
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Dogs with severe clinical signs or sepsis:
* IV route
* Add a fluoroquinolone or aminoglycoside
pneumonia treatment, other than antibiotics
- Oxygen support (nasal canula)
- Maintain adequate airway hydration > IV fluids, nebulization with saline and coupage
should we monitor pneumonia with radiographs? what should we do?
how long should we treat?
- Paradigm shift in monitoring resolution: skip the x-rays, consider C-Reactive Protein to monitor resolution
- Shortest course of antimicrobials
<><><><> - Recurrent pneumonia is challenging
- Underlying causes often hard to treat
pneumonia prognosis? how can radiographs predict?
Prognosis for recovery is good
* Depends on underlying cause
* Relapse may occur if underlying cause not able to be corrected
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* Severity of radiographic involvement does not appear to predict prognosis
what should we do if there is pneumonia recurrence?
CT-scanner recommended to look for FB
