Lower respiratory disease in individuals (Yr 4)

Question 1

what are the two names for the different severities of equine asthma?

Answer 1

mild… inflammatory airway disease
severe… recurrent airway obstruction (heaves)

Question 2

what can cause asthma?

Answer 2

inhalation of allergens (mild, bacteria, dust, gas…)
how horse responds to allergens

Question 3

what is happens once allergens are inhaled to cause asthma?

Answer 3

triggers inflammatory mediator release…
mucus production
increased blood flow and vascular permeability
cell accumulation/activation
neural reflex mechanism (parasympathetic)
increased airway smooth muscle tone (bronchoconstriction)

Question 4

what causes the respiratory noise heard with asthma?

Answer 4

bronchoconstriction (creates a wheeze)

Question 5

what contributes to the narrowing airways associated with equine asthma?

Answer 5

mucosal hyperplasia, inflammation, oedema
increased inflammatory cells
decreased mucociliary escalator and mucous production
(fibrosis in chronic cases)

Question 6

when do horses typically present with mild asthma?

Answer 6

young horses
signs of poor performance, coughing at exercise
often improve/resolve with treatment

Question 7

what are the factors of chronic asthma that lead to airway remodelling?

Answer 7

smooth muscle hypertrophy
peribronchiolar fibrosis
epithelial cell hyperplasia
mucus plugging

Question 8

what are the clinical signs of asthma?

Answer 8

exercise intolerance
cough, nostril flare, nasal discharge, tachypnoea
heave lines (forced expiration)
very severe - respiratory distress and weight loss

Question 9

does asthma cause an inspiratory or expiratory noise?

Answer 9

expiratory wheeze (respiratory tract collapses when breathing out)

Question 10

how can suspected equine asthma be diagnosed?

Answer 10

endoscopy of upper airway (increased mucous)
BAL - airway cytology (mild increase in neutrophils/eosinophils)

Question 11

how can the mucous be graded on endoscopy of equine asthma?

Answer 11

0-5
0 - no mucous
5 - river of mucous

Question 12

is tracheal aspirate or bronchoalveolar lavage better for asthma diagnosis?

Answer 12

BAL

Question 13

what result on tracheal aspirate would be associated with the horse having asthma?

Answer 13

neutrophils >40%

Question 14

what is done on bronchoalveolar lavage to diagnose equine asthma?

Answer 14

count cells, if >25% are neutrophils it indicates asthma (the severity of the increase correlates with grade of asthma)

Question 15

what are the three main treatment options for equine asthma?

Answer 15

environmental control
corticosteroids
bronchodilators

Question 16

what is the best treatment for asthma flares (short term treatment)?

Answer 16

bronchodilator

Question 17

what is the environmental control used for asthma?

Answer 17

reduce respirable particles (dust, mould, fungi, grass…)
ventilation and time outside
feed - soak hay, turn out to pasture, pelleted feeds
low dust bedding - paper, rubber mats, cardboard
turn out during/around mucking out

Question 18

what is the main treatment used for inflammation associated with equine asthma?

Answer 18

corticosteroids

Question 19

how do corticosteroids help to control asthma?

Answer 19

reduce cell accumulation/activation
reduce vascular changes
reduce bronchoconstriction (inhibit cytokines, histamine, prostaglandin release)

Question 20

how can corticosteroids be given for asthma?

Answer 20

systemic
inhaled

Question 21

what systemic corticosteroids are available for asthma?

Answer 21

prednisolone
dexamethasone (stronger)

Question 22

what inhaled corticosteroids are available for asthma treatment?

Answer 22

ciclesonide
beclomethasone dipropionate
nebulised dexamethasone

Question 23

what is the benefit of inhaled corticosteroid for asthma treatment?

Answer 23

targets specific area so there are less side affects associated with their use

Question 24

what are the two types of bronchodilators available for asthma treatment?

Answer 24

beta2 adrenergic agonists (sympathetic)
muscarinic antagonists (parasympathetic)

Question 25

what are the indications for using bronchodilators in equine asthma cases?

Answer 25

emergency therapy in flare ups before other inhaled medications before exercise (don't use a sole therapy)

Question 26

what is the most common bronchodilator used?

Answer 26

clenbuterol (salbutamol)

Question 27

what is the mode of action of clenbuterol?

Answer 27

beta2 adrenergic agonist

Question 28

why can't beta2 agonists be used long term as bronchodilators?

Answer 28

the receptors become down-regulated and tolerance is built up against them

Question 29

what are muscarinic antagonists used for bronchodilation in asthma cases?

Answer 29

atropine buscopan ipratropium bromide (inhaled)

Question 30

what are some extra therapies that might be useful in equine asthma cases?

Answer 30

mucolytics rest disodium cromoglycate antioxidants

Question 31

what causes bronchopneumonia/pleuropneumonia?

Answer 31

secondary infections from opportunistic pathogens

Question 32

what factors predispose horses to bronchopneumonia/pleuropneumonia?

Answer 32

transport inhalation (anaesthesia, reflux, choke, dysphagia...) viral URT disease exercise induced pulmonary haemorrhage

Question 33

what is the main site for bronchopneumonia/pleuropneumonia in the lungs?

Answer 33

right ventral lung lobes

Question 34

how are bronchopneumonias diagnosed?

Answer 34

clinical signs - dyspnoea, tachypnoea, pyrexia, dull, increase HR adventitious lung sounds tracheal aspirate - degenerative neutrophils and culture

Question 35

how are pleuropneumonias diagnosed?

Answer 35

clinical signs reduced lung sounds ventrally very painful (abducted elbows, short shallow breaths) thoracocentesis

Question 36

what are the three stages of pleuropneumonia?

Answer 36

acute exudative - inflammation of lung/pleura fibrinopurulent - bacteria invade, fibrin deposits organisational

Question 37

what is done to treat bronchopneumonia/pleuropneumonia?

Answer 37

broad spectrum antibiotics (penicillin, gentamicin) anti-inflammatory (meloxicam) drain/support drainage supportive therapy

Question 38

what is a specific part of the history in equine lungworm?

Answer 38

they have to graze with donkeys

Question 39

how is equine lungworm treated?

Answer 39

ivermectin

Question 40

what causes equine multinodular pulmonary fibrosis?

Answer 40

equine herpes virus 5 (EHV-5)

Question 41

what is the prognosis for equine multinodular pulmonary fibrosis?

Answer 41

guarded/poor