Lower Airway disease in small animals pt 2 Flashcards
Blastomycosis
- can affect what body systems
- Pulmonary infection is most common
- Can also affect:
- Lymph nodes (enlarged)
- Skin (draining tracts, wounds); nail beds
- Subcutaneous tissue (masses, wounds)
- Bone (fungal osteomyelitis)
- Eyes (uveitis, fundic abnormalities)
Fungal Pneumonia - common pathogens we see?
- Blastomyces spp. common in Ontario
- (esp Northern ON, cottage country)
<><><><> - Other fungal infections that affect lungs:
- Histoplasma capsulatum
- Coccidiodes immitis
Blastomycosis
- when does infection occur? how?
- Infection usually occurs after fungal spores are inhaled
- Or fungal spores invade a skin wound, etc
- Not contagious animal to animal
- May be disseminated through the body via blood
Diagnosing Blastomycosis? rule outs?
- Thoracic radiographs usually suggestive
- Nodular pattern
- Rule outs: Neoplasia (metastatic) a differential diagnosis
<><><><> - Definitive diagnosis requires visualization of the organism (cytology)
> Sample enlarged lymph nodes or cutaneous lesions first
> If only pulmonary involvement, need airway cytology
<><><><> - Blastomyces urine antigen EIA
> Highly sensitive and specific for infection
> May have utility in determining therapy duration
> Turn around time : 2 weeks
blastomycosis treatment, considerations
- Oral itraconazole
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Other treatment considerations: - Short-term anti-inflammatory corticosteroids (prednisone)
> Incases of high pulmonary fungal burden
> Massive fungal organism die-off leads to initial
worsening of pulmonary signs
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Long-term hepatoprotectants - S-adenosylmethionine (SAMe) on empty stomach
> because out treatments can be damaging to the liver
blastomycosis monitoring, treatment duration
- Expect long-term treatment (~3 months)
- Skin wound resolved in 5 weeks
- Radiographs normalized in 8 weeks
- Continued itraconazole for 4 weeks after resolution radiographic signs (average of 4 months total of txt)
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Other monitoring option: - Continue itraconazole until urine antigen titer becomes negative
Blastomycosis: Prognosis
- Clinical improvement expected in 70-75% of dogs
- Treatment failure more likely in severely affected dogs, and multiple organ involvement
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Relapse can occur - Approximately 15% of cases will relapse
- Usually within the first 6 months, but can occur at any time
<><> - Management is expensive
Canine Chronic Bronchitis - what is it? diagnosis?
- Defined as daily (or almost daily) coughing for ≥ 2 months
- Excluding other differentials – heart disease, infections, tracheal collapse
<><> - Diagnostic per exclusion
- No signs of cardiac disease
- No signs of infectious disease
Canine Chronic Bronchitis
* Pathophysiology
- Inflammatory cells infiltrate airway mucosa
- Increase mucus production
- Loss of ciliated epithelial cells
- End result is narrowed airways, build-up of mucus
- Leads to coughing
Canine Chronic Bronchitis
* Etiology, associations
- Usually unknown
- May be associated with:
- Tracheal collapse
- Chronic airway irritation secondary to parasites or microaspiration
- Smoke
- Foreign body presence
- Left atrial enlargement
Clinical Features of Chronic Bronchitis
- who gets it?
- primary clinical signs?
- presentation?
- thoracic auscultation?
- Usually middle-aged to older dogs
- Small sized dogs may be more frequently
affected - Small breeds also predisposed to other reasons for cough including tracheal collapse and mitral valve disease
<><> - Primary clinical signs:
- Harsh cough, may be productive
<><> - Cough often elicited on tracheal palpation
- Wheezing accompanies cough
- May have exercise intolerance, dyspnea, collapse
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Thoracic auscultation: - Inspiratory crackles, wheezing may be detected
- Increased breath sounds
Diagnosing Chronic Bronchitis, primary rule outs? how to make a preseumptive diagnosis?
Rule out:
* Heartworm (Antigen test)
* Lungworm (Baermann fecal test)
* Heart disease (radiographs; echocardiography may be indicated)
* Usually no changes on CBC/profile
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Radiographs
* +/- Bronchial pattern
* Nonspecific! also present in normal older dogs
* Normal radiographs
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Presumptive diagnosis can be made in some cases based on:
* Consistent history
* PE findings
* Radiographs
* Response to empirical therapy
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* Swallowing studies can be done
Diagnosis of Bronchitis - how to make a definitive diagnosis?
Definitive diagnosis requires direct visualization of airways
* Bronchoscopy
* Collect samples for cytology & culture
* Hyperemic airways, mucus
* Cytology – non-degenerate neutrophils,
eosinophils, mucus
* Culture usually negative
NT-proBNP assay for chronic bronchitis in dogs
- Elevated in some dogs with cardiac disease
<><> - Caution – some dogs may have asymptomatic cardiac disease and concurrent bronchitis
- Cough due to bronchitis but presence of cardiac disease may cause elevated BNP
ASPIRATION RELATED UPPER AIRWAY Diseases
* Tests, what they are for?
* Alternative to further investigation
Tests:
* Videofluoroscopy > Laryngeal dysfunction or paresis
* CT-scanner > Thickened soft palate
* Tracheoscopy > Hyperemia of the trachea
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Alternative to further investigation:
* Proton-pump inhibitor: omeprazole 1mg/kg BID
Treating Bronchitis
- Corticosteroids
> oral prednisone
> or inhaled fluticasone
<><> - Bronchodilators
> Theophylline
> β2-agonist (salbutamol)
<><> - ± Cough suppressants (if cough not productive)
> but dont want to stop a productive cough (protective mechanism)
<><> - Weight loss for overweight dogs
Prognosis for Bronchitis
- Disease can be managed but not cured
- Control coughing, minimize airway inflammation
- Cough frequency & severity may wax and wane despite appropriate therapy
Complications of chronic bronchitis
- Progression to bronchiectasis
> Permanent dilation of airways
> Damage to mucociliary clearance, other defense mechanisms
<><> - Secondary infections
- Pulmonary hypertension
cat presents to emergency clinic with acute dyspnea:
* Quick PE–RR is >60 breaths/min
* Mucous membranes appear gray in colour
- What should we do?
Need to stabilize cat before anything else
* Sedation
* !!! Hands off !!!
* Oxygen if needed
Differential Diagnoses for
* 5 yo FSDSH
* Acute dyspnea, open-mouthed breathing
- Heart disease (HCM with secondary congestive heart failure)
- Feline bronchial disease, aka “Asthma”
- Airway parasites, neoplasia, pneumonia
How do you tell asthma vs heart failure vs infectious vs pleural effusion?
Heart failure:
- History: Less active
- PE: +/- low T°c, Pulmonary crackles, Tachycardia, +/- Heart murmur
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Asthma:
- History: +/- coughing
- PE: Normal T°c, Expiratory wheeze
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Infectious
- History: Exposure, Systemic signs
- PE: High T°c, Pulmonary crackles
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Pleural effusion:
- History: Coughing, +/- cardiac disease
- PE: Normal T°c, Muffled heart and lung sounds
how to look for pleural effusion - diagnostic tests
- Auscultation
- Focused assessment with sonography in trauma (FAST)
> Bedside chest ultrasound - +/- thoracocentesis
Feline Bronchial Disease
* Etiology?
- Exact cause usually not identified
- Possible allergic component for asthma
- Noxious stimulus to airway > airway hypertrophy & ulceration, increased mucus secretion, inflammation, & edema
- Decreases airway lumen size
Feline Bronchial Disease
- presentation
Presentation can be variable
* Recurrent episodes of cough, dyspnea,
wheezing
* Respiratory effort with expiratory push
* Respiratory distress
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* All ages / breeds cats
> Siamese predisposed
Feline Bronchial Disease Diagnosis with thoracic radiographs
Thoracic radiographs
* Classic findings:
* Bronchial pattern, peribronchial cuffing > Airway secretions
* Pulmonary nodulesor infiltrates
* Collapse/atelectasis of lung lobe (usually right middle) > Mucus plugs
* Hyperlucent lungs > air trapping
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Thoracic Radiographs
* Not a perfect diagnostic test for feline bronchial disease
* Caution when restraining – limited ability to tolerate stress
* False positives and negatives
> May be normal in cats with bronchial disease
> Clinically normal cats can show a bronchial pattern on thoracic radiographs
diagnostics for feline bronchial disease other than radiographs
- what are we trying to rule out?
Rule out Parasites
* Baermann fecal test for lungworms
* Heartworm test (rare in cats)
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Rule out Infectious Pneumonia
* CBC (neutrophilia or neutropenia)
* PCR panel
* Thoracic radiographs
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Rule out cardiac disease
* Thoracic radiographs
* Pro-NT BNP
Rule out Cardiac diseases
* NT-pro BNP plasma test use? what does it do?
- Measures “plasma N-terminal pro-brain natriuretic peptide”
- ↑ if volume overload & pulmonary hypertension (=congestive heart failure)
<><><><> - Elevated in cats with heart disease
> Especially severe HCM - Cats can have both (HCM and Asthma)
Rule out Cardiac diseases
- what can we do for treatment trial?
- Treatment trial : Furosemide injection
- Observation….
To confirm Bronchitis or Asthma - indications and cytology
Indications:
* Recurrent/chronic unexplained cough
* Refractory to medical txt
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Cytology & bacterial culture
* Asthma: ↑ eosinophils
risks/ complications of bronchitis and asthma in cats with GA
Risk/General Anesthesia
* Laryngospasm
* Bronchoconstriction
To confirm Bronchitis or Asthma - CT-scanner
- indications? uses? drawbacks?
Indications
* Recurrent/chronic unexplained cough
* Refractory to medical txt
* Rule out foreign body
<><>
Drawbacks:
* $$$
* General Anesthesia
what tests are commonly vs rarely done for feline bronchitis or asthma?
COMMONLY DONE
* Lasix trial > if we think it could be cardiac
* Radiographs (once stabilized)
* Fecal: easy, cheap and safe( if out door)
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RARELY DONE
* Blood tests
> CBC
> NT-ProBNP snap test easy
> PCR panels for infectious diseases
> Heartworm tests
* Bronchoscopy + cytology
* CT-scanner
feline bronchitis / asthma treatment objectives
- Keep the cat alive
- Control clinical signs
> Cough, wheeze, dyspnea - Decrease airway inflammation
- Relax airway smooth muscles
Acute Treatment for bronchitis / asthma
- Handle gently
- Sedation with butorphanol
- +/- Bronchodilator (inhaler)
- Quick bedside ultrasound
- +/- Thoracocentesis
- Oxygen tent for ~10 minutes +/- immediately
- Placed an IV catheter +/- oxygen flow-by
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Note: If suspicion of heart disease, Lasix can be tried (before confirming heart disease)
long Treatment for bronchitis / asthma? response? prognosis?
Corticosteroids = mainstay of therapy
* ↓ airway inflammation
* Prednisolone
* Replaced by inhaled fluticasone
* Usually need daily corticosteroid treatment long-term or for life
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* Usually respond to corticosteroid & bronchodilator therapy within 5-7 days
* If no response, re-evaluate diagnosis
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Bronchodilators to relieve suspected chronic bronchoconstriction
* Salbutamol or albuterol
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* Weight loss
* No smoking
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* Prognosis: good but relies on proper medical
therapy
* Therapy for life usually required
* Cure is unlikely
aerosol therapy for bronchitis / feline asthma? what is its use? examples and how to use?
- ↓ systemic side effects compared to oral medications
<><>
Fluticasone MDI > inhaled corticosteroid, Local anti-inflammatory action - 7-14 days before peak efficacy achieved
- Start with oral prednisolone to control signs
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Salbutamol MDI (Ventolin) - Inhaler works more rapidly than injected salbutamol
- Initially used daily
- Only used for crises after
what bronchodilators can be used for emergency feline asthma situations?
- Salbutamol or albuterol
- Can be used in emergency situations every 30 minutes for up to 4 hours
