Tracheobronchial diseases--cats

Question 1

DDx for felines presenting with a cough, wheeze, or respiratory distress?

Answer 1

• Pulmonary parasites
• Heartworm
• Bac. or viral bronchitis
• Toxoplasmosis
• Idiopathic pulmonary fibrosis
• Neoplasia–carcinoma
• Aspiration pneumonia
• Idiopathic feline bronchitis/asthma
• Chronic bronchitis

Question 2

Idiopathic feline bronchitis

What is it?

Signalment?

Clinical signs?

Answer 2

• Asthma = bronchial constriction
• Signalment
  
  • Any age–commonly in young to middle aged cats (3-5yrs)
  • Siamese appear predisposed
• Clinical signs
  
  • Variable
  • Chronic or intermittent cough
  • Acute resp distress (more likely)
    
    • Open-mouth breathing
    • Audible wheezing
  • Auscultation–wheezes, crackles, inc. resp effort
  • Systemic signs are not found

Question 3

Idiopathic feline bronchitis

Diagnosis

Answer 3

• 1st tier
  
  • Radiographs–IF CAT IS STABLE ENOUGH
  • CBC–17-46% have eosinophilia
  • Fecal–Aelurostrongylus spp (lungworm)
• 2nd tier
  
  • Transtracheal wash/bronchoscopy/BAL
  • Cytology/culture

Question 4

Idiopathic feline bronchitis

Radiographs

Answer 4

• Normal lungs in 23% of cases
• Bronchial pattern predominates
• Reticular interstitial and patchy alveolar opacities can sometimes be found
• Hyperinflation of lungs is found
  
  • Air-trapping–constriction of small airways does not allow inspired air to be exhaled–>lungs overinflate
• 10% have collapsed right middle lung
• Flattening of diaphragm
• Clinical signs precede radiographic changes

Question 5

What’s wrong with these radiographs? What disease is most likely associated with them?

Answer 5

• Left: collapsed right middle lung lobe
• Right: patchy alveolar/interstitial alveolar pattern
• Idiopathic feline bronchitis

Question 6

Idiopathic feline bronchitis

Bronchoscopy

Answer 6

• Mucosal hyperaemia
• Increased mucous
• Perform broncho-alveolar lavage

Question 7

Idiopathic feline bronchitis

Point of transtracheal wash/BAL?

Cytology?

Culture/sensitivity?

Answer 7

• TTW/BAL may help differentiate asthma from other differentials
• Cytology
  
  • Asthma–inc. eos and neut and mixed inflammation
  • Infectious–degenerative neut and/or intracellular bac.
  • Parasitic–larvae or ova
• Culture/sensitive–if +, less likely to be feline asthma, but still think of poss secondary infection

Question 8

Idiopathic feline bronchitis

Treatment?

Answer 8

• Treat in acute life-threatening cases
• NO STRESS
• O2-rich environment
• Rapid-acting corticosteroid
  
  • Dexamethasone SC, IM (IV often too stressful)
• Bronchodilation choices
  
  1. Albuterol via metered-dose inhaler (MDI) or orally
  2. Terbutaline (0.01mg/kg SC)
     
     • Bronchodilation w/in 15-30min
     • Cats can become dazed/disoriented
     • Also comes as MDI

Question 9

Idiopathic feline bronchitis

Long-term management

Answer 9

1. Environmental management
   
   • Improve indoor air quality
   • Eliminate potential allergens/irritants
2. Anti-inflammatories–glucocorticoids
   
   • Prednisolone/prednisone–0.5-1mg/kg BID
     
     • Taper once clinical signs controlled
     • 7 day recheck
   • Depo-medrol for patients that cannot be medicated orally due to aggression (last resort)
     
     • 10-20mg/cat IM q4-8wk
     • Warn owners of potential side effects
   • Metered dose inhaler (MDI)
     
     • Fluticasone proprionate (flixotide or flovent)
     • Beclomethasone (Quar or becotide)

Question 10

Idiopathic feline bronchitis

Metered dose inhaler (MDI)

Answer 10

• “Aerocat” or “pediatric spacer”
• Advantages
  
  • Minimizes systemic corticosteroid side effects
  • Easier to treat–no pill-popping
  • Perhaps higher drug conc. delivered to lungs
• Disadvantages
  
  • Inc. risk of dental disease
  • Re-emergence of latent herpesvirus infection
  • Local dermatitis
• Recommended not to start on MDI until there is good control w/ systemic glucocorticoids

Question 11

Idiopathic feline bronchitis

Chronic clinical signs?

Answer 11

Intermittent coughing and wheezing

Question 12

Idiopathic feline bronchitis

Other possible long-term treatments?

Answer 12

1. Oral bronchodilator indications
   
   • Chronic management when large quantities of glucocorticoids required
   • When there is adverse reaction to glucocorticosteroids
   • When owner cannot use the MD I
   • Which bronchodilator
     
     • Oral theophylline–at night
     • Terbutaline–at night in crisis
     • Albuterol oral
2. Antibiotics
   
   • Therapeutic trial for mycoplasma
     
     • Doxycycline, chloramphenicol, azithromycin
   • Give bolus of water after doxycycline

Question 13

Idiopathic feline bronchitis

Prognosis

Answer 13

• Chronic disorder–some form of long-term glucocorticoids needed in most cases
• Long-term medically treated–good prognosis for control of clinical signs
• If untreated–develop permanent changes of chronic bronchitis w/ irreversible damage (fibrosis) and emphysema

Question 14

Feline chronic bronchitis

What is it?

Characterized by?

Answer 14

• Chronic airway inflammation, typically in older cats
• Char. by
  
  • Neutrophilic inflammation
  • Mucosal edema
  • Mucus gland hypertrophy
  • Excessive mucus production

Question 15

Feline chronic bronchitis

Clinical signs?

Management?

Answer 15

• Clinical signs indistinguishable from asthma
  
  • Rarely have life-threatening broncho-constriction
  • Coughing on daily or almost daily basis
  • Usually in older animals
• Management focuses on control of inflammation using glucocorticoids