12.2 respiratory

Question 1

what is the pathophysiology of asthma and what is it driven by?

Answer 1

• mucosal oedema
• bronchoconstriction
• mucus plugging

it is Th2-driven/ eosinophilic inflammation

Question 2

what are the components of asthma control?

Answer 2

• minimal symptoms
• no exacerbations
• no limit of physical activity
• normal lung function (FEV1)

Question 3

name two short acting b2 agonists

Answer 3

salbutamol and terbutaline

Question 4

what is the importance of salbutamol?

Answer 4

it is used for symptom relief through reversal of bronchoconstriction

predominant action is on airway smooth muscle

Question 5

why should salbutamol only be used on an as required basis?

Answer 5

short acting b2 agonist should only be used on a as required basis as if used regularly, reduces asthma control

Question 6

what is the relation between salbutamol use and mast cell degranulation?

Answer 6

potentially inhibit mast cell degranulation if used intermittently, but if used regularly mast cell degranulation in response to an allergen increases

Question 7

name 2 long acting b2 agonists

Answer 7

formoterol

salmeterol

Question 8

what is the mechanism of action of inhaled corticosteroids?

Answer 8

they prevent inflammation by eosinophils so you don’t get mucosal oedema, bronchoconstriction and mucus plugging.

they do this through

• transactivation of B2 receptors
• trans repression of inflammatory mediators

Question 9

give examples of 3 inhaled corticosterioids

Answer 9

beclomethasone dipropionate
budesonide
fluticasone

Question 10

what should you prescribe long acting b2 agonists with?

Answer 10

inhaled corticosteroids as long acting b2 agonists are not anti inflammatory on their own

Question 11

what are leukotriene receptor antagonists mode of action?

Answer 11

LTC4 released by mast cells and eosinophils can induce bronchoconstriction, mucus secretion and mucosal oedema, and promote inflammatory cell recruitment.

LRA’s block the effect of cysteinyl leukotrienes in the airways at the CysLT1 receptor

Question 12

what are the ADRs of leukotriene receptor antagonists?

Answer 12

angioedema 
dry mouth
anaphylaxis
arthralgia 
fever
gastric disturbances
nightmares

Question 13

give 2 examples of leukotriene receptor antagonists

Answer 13

montelukast

zafirlukast

Question 14

what are the mechanisms of action of methylxanthines?

Answer 14

antagonise adenosine receptors

= inhibit phosphodiesterase = increase cAMP

Question 15

what are the weak points of use of methylxanthines?

Answer 15

• poorly efficacious
• narrow therapeutic window
• frequent ADRs e.g nausea, headache, reflux
• levels increased by cytochrome p450 inhibitors

Question 16

name 2 examples of methylxanthines

Answer 16

aminophylline

theophylline

Question 17

name 2 anticholinergic/ anti muscarinics

Answer 17

ipratropium bromide

tiotropium bromide

Question 18

what are the actions of long acting anti cholinergics?

Answer 18

M3 receptor antagonists so cause vasodilation

Question 19

what are the ADRS for long acting anti cholinergics?

Answer 19

Dry mouth
urinary retention
glaucoma

Question 20

what is the importance of stepping down in asthma?

Answer 20

once asthma is controlled stepping down is recommended as if it does not take place patients may receive a higher dose than is necessary

every asthmatics has a management plan for when to step up and step down dosage

Question 21

what are the features of severe asthma in adults?

Answer 21

• unable to complete sentences
• pulse = over 110 bpm
• resp rate >25
• peak flow 33-50% of best or predicted

life threatening if

• silent chest
• cyanosis
• hypotension, bradycardia, arrhythmia
• exhaustion, confusion, coma
• feeble respiratory effort

Question 22

how do you treat acute severe asthma?

Answer 22

• high flow oxygen
• nebuliser salbutamol
• oral prednisone
• if not responding, nebuliser ipratropium bromide
• IV aminophylline if no improvement