Pharmacological management

Question 1

How do beta agonists act?

Answer 1

Stimulate bronchial SM beta receptors - relax muscle, dilate airways, inhibit mediator release from mast cells and infiltrating leucocytes
Increase ciliary action of airway epithelial cells - aids mucus clearance

Question 2

ICS mechanism of action

Answer 2

Inhibits formation of cytokines (including interleukins)
Inhibits activation and recruitment to airways of inflammatory cells
Inhibits generation of inflammatory prostaglandins and leukotrienes, thus reducing mucosal oedema

Question 3

LRA mechanism

Answer 3

LTRAs block effects of bronchoconstricting cysteinyl leukotrienes in the airways, resulting in bronchodilation

SEs - abdo pain, headache, hyperkinesia (muscle spasm children)

Question 4

Theophylline (methylxanthines)

Answer 4

Phosphodiesterase inhibitors - increased IC cAMP in bronchial SM - relaxation
Bronchodilator and anti-inflamm properties

SE - GI upset, arrhythmias, CNS stimulation, hypotension (coffee)

Question 5

mAbs

Answer 5

Omalizumab - antibody to IgE, inhibits mediator release from basophils and mast cells
Preventer
Injectable, slow to work (peaks at 3-4 months), reduces exacerbations and is steroid sparing, expensive
Can cause anaphylaxis and increase stroke/heart disease risk

Question 6

Monitoring plans

Answer 6

PEFR
If less than 50% predicted - severe asthma
Nocturnal dip often present

Question 7

Childhood asthma

Answer 7

If less than 3 yrs - spacer plus mask

If less than 5 - PEFR not reliable guide

Question 8

What is mod acute asthma?

Answer 8

Increasing symps, PEF 50-75 predicted, no features of acute severe

Question 9

What is acute severe?

Answer 9

Any one of PEF 33-50, RR over 25, HR over 110, inability to complete sentences in one breath

Question 10

Life-threatening asthma?

Answer 10

Any one of following in an acute severe patient:

Altered consciosuness, exhaustion, arrhythmia, HTN, cyanosis, silent chest, poor resp effort, PEF<33, spo2<92, pao2<8

Question 11

Near fatal asthma?

Answer 11

Raised PaCO2 and/or requires ventilation

Question 12

Management of acute severe asthma?

Answer 12

Immediate tx - oxygen to maintain spO2, salbutamol/terbutaline plus ipratropium via neb, IV steroid and possible antibiotics

If not improving consider IV Mg, switch from IV salbutamol neb to aminophylline IV neb

Monitor blood gases and patient exhaustion/alertness

SOSIAM

Question 13

MRAs?

Answer 13

Case bronchodilation, decrease mucous secretion, may inc mucociliary clearance
Improves COPD outcomes
Slower onset of action (30-60mins) than beta agonists
SAMA - ipratropium
LAMA - tiotropim/aclidinium

Question 14

Why are CCS of limited benefit in COPD?

Answer 14

Inflamm cells responsible for COPD (macrophages and neutrophils) less responsive than lymphocytes and eosinophils to actions of CCS
Use if FEV1<50% predicted and have 2+ exacerbations in a year which require oral steroids/antibiotics
High doses may increase risk of pneumonia and osteoporosis

Question 15

Acute severe COPD exacerbations

Answer 15

Nebulise SABA/SAMA
Oral pred
Antibiotic if needed
Physio
24-28% oxygen with care
Extreme - NIV, intubation