Lecture 27 11/21/24

Question 1

How does the airway epithelium respond to stimuli?

Answer 1

-hypertrophy
-metaplastic change
-erosion/ulceration

Question 2

How do airway goblet cells and submucosal glands respond to stimulI?

Answer 2

-hypertrophy
-production of excessive amounts of viscous mucous

Question 3

What can cause injury to the airways?

Answer 3

-hypoxia-induced effects
-fibrotic destruction of vascular beds
-mechanical stress

Question 4

How do the bronchial mucosa and submucosa respond to stimuli?

Answer 4

-become infiltrated with variable number and type of inflammatory cells
-become edematous

Question 5

What are the possible responses of bronchial smooth muscle to stimuli?

Answer 5

-unaffected
-hypertrophy
-spasm

Question 6

What are the characteristics of feline bronchitis?

Answer 6

-inflammation of the bronchi
-underlying causes include insult to epithelium or parasites
-airway hyper-reactivity is NOT part of this disease
-no extreme resp. distress

Question 7

What are the characteristics of feline asthma?

Answer 7

-airway obstruction caused by heightened reactivity of tracheobronchial tree
-aeroallergens drive disease
-life long

Question 8

How does feline bronchitis compare to feline asthma?

Answer 8

-both are inflammatory diseases
-asthma may have more eosinophils in an ETW
-asthma has acute, severe bronchoconstriction
-asthma presents with resp. distress and airway hyperreactivity

Question 9

Which functions of the airway/lung anatomy contribute to asthma?

Answer 9

-bronchial smooth muscle hypertrophy
-inflammation and edema of the airway
-epithelial cell/mucociliary dysfunction
-intraluminal exudate and mucous plugs

Question 10

What are the steps of an asthmatic response?

Answer 10

-allergen is inhaled
-dendritic cells present allergens via MHCII to naive CD4 T cells
-polarized Th2-mediated immunity results in cytokine production and IgE activation
-IgE binds to FcEpsilonRI receptors on mast cells and basophils
-re-exposure to allergen results in IgE crosslinking, mast cell degranulation, and inflammatory cascade

Question 11

What is the role of the sympathetic nervous system in feline asthma?

Answer 11

-beta-2 activation increases cAMP
-causes bronchodilation and decreased mucous production

Question 12

What is the role of the parasympathetic nervous system in feline asthma?

Answer 12

-muscarinic activation increases cGMP
-stimulates glandular secretion, smooth muscle contraction, and vasodilation

Question 13

What is the role of vasointestinal peptide?

Answer 13

causes bronchodilation

Question 14

What is the role of substance P?

Answer 14

causes bronchoconstriction

Question 15

What is the pathophysiology of histamine?

Answer 15

-released during mast cell degranulation
-triggers bronchoconstriction, mucus secretion, increased capillary permeability, and granulocyte chemotaxis
-variable response to antihistamine treatment

Question 16

What is the pathophysiology of serotonin?

Answer 16

-released from mast cells
-mediator of smooth muscle contractility
-possible mediator in feline asthma

Question 17

What are the potential triggers of feline asthma?

Answer 17

-viruses
-mycoplasma
-litter
-dust
-smoke
-perfume
-exercise
-emotion

Question 18

What are the characteristics of airway resistance?

Answer 18

-affected by radius of airway
-small changes in radius make significant changes is resistance (4 fold)

Question 19

What affects the radius of the airway?

Answer 19

-bronchoconstriction and bronchodilation
-material in the lumen of the airway

Question 20

What are important questions to ask when trying to determine if a cat has asthma?

Answer 20

signalment; typically younger at first presentation
-determine severity of clinical signs
-determine if clinical signs are daily or intermittent

Question 21

What are the clinical signs of asthma in cats?

Answer 21

-coughing
-wheezing
-sneezing
-wretching/vomiting
-resp. distress
-cyanosis

Question 22

What are the clinical signs and signalment of feline bronchitis?

Answer 22

-occurs in middle aged to older cats
-cough persisting 2 months or longer
-not usually associated with severe resp. distress

Question 23

What are the characteristics of the physical exam in cats presenting for asthma or bronchitis?

Answer 23

-may appear normal at rest
-tracheal palpation may induce cough
-possible to auscult crackles and wheezes
-expiratory “push”/increased effort on expiration
-dyspnea, open-mouthed breathing, and cyanosis in asthmatic cats only

Question 24

what must be ruled out when assessing a cat for respiratory signs?

Answer 24

heart failure

Question 25

How is heart failure diagnosed?

Answer 25

-history -physical exam -radiographs -NT-proBNP

Question 26

What are the characteristics of radiographs in cats with lower airway disease?

Answer 26

-may be normal -bronchial disease prominent -interstitial to patchy alveolar infiltrate -lung lobe collapse -hyperlucent lung fields that may look hyperinflated

Question 27

What are the diagnostic steps for feline lower airway disease after taking radiographs?

Answer 27

-CBC -heartworm AG/AB -fecal exam -serum chem. -ETW/BAL for cytology and culture

Question 28

What are the long term treatment goals for feline lower airway disease?

Answer 28

-educate the owner that there may not be a cure -exclude underlying disease that could be treated specifically -achieve good quality of life for the cat -avoid exposure to trigger situations -reverse and prevent bronchoconstriction -suppress ongoing airway inflammation -treat secondary or concurrent infections

Question 29

What are the emergency treatment steps for cats with lower airway disease?

Answer 29

-oxygen -cage rest to calm animal -terbutaline SQ or inhaled albuterol -corticosteroids -sedation if severe -anesthesia/intubation if really severe

Question 30

What are the characteristics of bronchodilators?

Answer 30

-reduce bronchoconstriction in acute asthma attacks -should not be used for monotherapy; exacerbate airway hyper-responsiveness and fail to control airway inflammation -include methylxanthines and beta-2 agonists

Question 31

What are the characteristics of methylxanthines?

Answer 31

-include theophylline and aminophylline -inhibit PDE related breakdown of cAMP to increase relaxation -intracellular Ca conc. increase and increase diaphragmatic muscle contraction -end result of use in bronchodilation, CNS and cardiac stimulation

Question 32

What are the characteristics of terbutaline?

Answer 32

-selective beta2 agonist -administered SQ, IM, IV, PO. elixir -indicated in acute exacerbations -reduces resp. rate by 50% in short time frame -can be repeated -duration of action of 6-8 hrs

Question 33

What are the characteristics of albuterol sulfate?

Answer 33

-selective beta2 agonist -used in dogs, cats, and horses -administered parenteral, oral, and inhalation -duration of action of 4 hrs -not for long term use

Question 34

What are the characteristics of systemic corticosteroids?

Answer 34

-decrease inflammation in the airway -permissive effect on beta2 receptors -many side effects

Question 35

What are the characteristics of inhaled nebulization/aerosol corticosteroids?

Answer 35

-fluticasone or flunisolide -local action leads to less side effects -less systemic immunologic effects -not for emergency use; needs 7-10 days to work

Question 36

What are the characteristics of cough suppressant use in cats?

Answer 36

-not commonly done -want to allow productive coughs to continue -cats do not often cough continuously

Question 37

What are the characteristics of antibiotic use in feline lower airway disease?

Answer 37

-lungs are not sterile have a normal pop. of bacteria -treatment is based on # and type of bacteria on culture -Mycoplasma spp. may have a pathogenic role; can treat with doxy

Question 38

What are the potential treatments for feline lower airway disease?

Answer 38

-diet change -probiotics -omega 3s/antioxidants