Feline bronchial disease Flashcards
sympathetic innervation
stimulation of Beta2 receptors leads to smooth relaxation
Bronchodilation
parasympathetic innervation
responsible for baseline tone
ACh–>increased intracellular calcium
stimulation leads to bronchoconstriction, mucus, cough
serotonin
released from feline mast cells
leads to bronchoconstriction
alpha adrenergic stimluation
decrease in cAMP
contraction of smooth muscles
inhibition of phosphodiesterase
increase in cAMP, cGMP
relaxation of smooth muscle
nitric oxide
endothelium-derived vasodilator
promotes bronchodilation
Which class of drugs is used to relax bronchial smooth muscle?
phosphodiesterase inhibitor
airway obstruction of asthma
hyperreactivity of bronchial smooth muscle
airway inflammation (bronchitis)
luminal bronchial secretions-goblet cell hyperplasia, musuc accumulation
extraluminal obstruction-emphysema, contributes to airway collapse
intramural changes-hypertrophy, fibrosis, edema, hyperplasia
Feline asthma
spontaneous bronchoconstriction associated with airway inflammation
reversible constriction
young adults, females>males, Siamese
etiology of feline asthma
type 1 hypersensitivity reaction
inhaled allergens, infectious agents, eosinophilia
idiopathic
hx and clincial signs of feline asthma
historical cough, normal between episodes
wheezing
sneezing
vomiting
acute respiratory distress
PE findings for feline asthma
tachypnea
dyspnea
wheezes
crackles
cough
normal PE
DDx for feline asthma
feline bronchial disease
layngeal disease
tracheal disease
heart disease-dyspnea, no cough
heartworm infection
pleural effusion
neoplasia
parasitic disease
pneumonia
Heartworm associated respiratory disease (HARD)
cough and dyspnea
due to arrival of immature heartworms in pulmonary vasculature and death of adult heartworms
Dx of feline asthma
administration of beta agonist if wheezing
chest rads
CBC-eosinophilia
Chem-increased TP
heartworm testing
fecal float
Airway wash
Chest rad findings for feline asthma
bronchial pattern
interstitial to patchy alveolar poss
collapse of right middle lung lobe-10%
overinflation of lung-increased lucency, flat, caudally displaced diaphragm, ventral bowing of caudal vena cava, extension of lung past L1
Airway wash for feline asthma
endotracheal washe
BAL
reasons: to characterize the inflammatory response, ID infectious agents, ID neoplastic cells, atypical rads, don’t respond to tx
Increase total cell count, eos, neutrophils, macs, mixed, excessive mucus, culture + in 10-25%
airway wash cytology normal
alveolar macs and lymphocytes
<10% are neutrophils
total cell count<400/ul
eos present
epithelial cells, goblet cells, mast cells
+/- positive culture
Feline chronic bronchitis
airway inflammation
narrowing of airways is minimally reversible with bronchodilators
middle to old age
siamese
fibrosis, emphysema
BAL cytology variable
bacterial culture usually positive
rad changes severe
hx and clinical signs for feline bronchitis
Chronic (>2 months) daily cough
episodes of wheezing and dyspnea
vomiting, coughing spells
PE findings similar to asthma
dx of feline chronic bronchitis
Chem-increased TP
CBC-eosinophilia
Chest rads-bronchial patter, interstitial to patchy alveolar poss, emphysema, collapse of right middle lung lobe
airway wash-neutrophils, mucus, positive culture
tx of feline bronchial disease
remove any underlying etiology
provide anti-inflammatory therapy
provide bronchodilator therapy
tx of feline bronchial disease: environmental changes
unscented, dust free cat litter
remove hood for litterbox
change air filters
minimize exposure to smoke, aerosols, powder
Tx of feline bronchial disease: methylxanthines
PO, injection
aminophylline, theophylline
phosphodiesterase inhibitors
inhibits calcium influx into cells
blocks adenosine receptors
increase contractility of fatigued muscle
inhibit mast cell degranulation
increase mucociliary clearance
prevent microvascular leakage
improve strength of respiratory muscles
side effects: GI upset, neurologic signs
Tx of feline bronchial disease: Beta2 agonist
PO, inhalant, injection
terbutaline, albuterol
relax bronchial smooth muscle, decrease mucus viscosity, enhance mucociliary clearance
tx of feline bronchial disease: glucocorticoids
anti-inflammatory
PO, injection, inhalant
high dose initially recommended
often combined with bronchodilator
fluticasone-inhalant
tx of feline bronchial disease: other tx
leukotriene inhibitors
abx
cyprohepatadene-serotonin inhibitor
omega-3 fatty acids
cyclosporine
laser therapy
hyposensitization
How should you treat a mildly affect asthmatic
environmental changes
oral pred, slowly tapered
bronchodilator-oral BID, inhalation PRN
how should you treat a moderate to severely affected asthmatic?
environmental changes
oral pred for 2 weeks
fluticasone BID
bronchodilator
How should you treat a emergency case/dyspnic cat?
minimize handling
oxygen cage
SQ terbutaline
IV dexamethasone
Lasix if concurrent heart disease
Px for feline bronchial disease
early dx and proper therapy can be effective
environmental changes make a difference
some become refractory to therapy
chronic cases very challenging to manage
euthanasia for severe refractory cases
5 yo MC Siamese, indoor only
Presenting complaint: chronic coughing, intermittent, no episodes of dyspnea but owner sometimes hears wheezing, getting worse over past 6 months
PE: normal RR,Wheezes ausculted bilaterally, no cardiac abn, rest-normal
What diagnostic test do you recommend?
CBC
Chem
Response to terbutaline
chest rads
5 yo MC Siamese, indoor only
Presenting complaint: chronic coughing, intermittent, no episodes of dyspnea but owner sometimes hears wheezing, getting worse over past 6 months
PE: normal RR,Wheezes ausculted bilaterally, no cardiac abn, rest-normal
Lab: CBC-eosinophilia, Chem-normal, Wheezing improves after terbutaline
Chest rads: moderate bronchial pattern, early right middle lung lobe collapse
What is your next diagnostic step?
no additional testing is needed
5 yo MC Siamese, indoor only
Presenting complaint: chronic coughing, intermittent, no episodes of dyspnea but owner sometimes hears wheezing, getting worse over past 6 months
PE: normal RR,Wheezes ausculted bilaterally, no cardiac abn, rest-normal
Lab: CBC-eosinophilia, Chem-normal, Wheezing improves after terbutaline
Chest rads: moderate bronchial pattern, early right middle lung lobe collapse
What tx protocol do you recommend?
tapering oral steroids, oral bronchodilator BID
