Asthma

Question 1

What is asthma characterised by?

Answer 1

Recurrent episodes of dyspnoea, cough and wheeze caused by reversible airway obstruction

Question 2

What are the 3 factors contributing to airway narrowing?

Answer 2

Bronchial muscle contraction, mucus production, mucosal swelling/inflammation

Question 3

What often triggers asthma other than exertion?

Answer 3

IgE mediated reactions to specific antigens carried by dust mites and pollen etc

Question 4

What is atopy

Answer 4

A genetic susceptibility to developing allergic disease such as asthma, excema or rhinitis. Confirmed by IgE skin prick test

Question 5

What are the symptoms of asthma?

Answer 5

Intermittent dyspnoea, cough (esp nocturnal), wheeze, sputum production

Question 6

What can precipitate an attack?

Answer 6

Cold air, exercise, emotion, allergens, infection, cigarette smoke, pollution, NSAIDs (inhibit protective PGE2), beta blockers

Question 7

When might leak flow be especially low?

Answer 7

In the morning there is a dip in peak flow even if it is normal at other times

Question 8

What information is useful to get from the patient?

Answer 8

Exercise tolerance, disturbed sleep, other atopic illness, acid reflex (40-60% of asthmatics have it), home, pets, smoking, job

Question 9

Clinical signs of asthma are?

Answer 9

Tachypnoea, audible wheeze, hyper inflation of the chest, hyper resonance, decreased air entry

Question 10

Clinical signs of a severe asthma attack

Answer 10

Can’t complete sentences, HR >110, resp rate >25, PEF 35-50% of expected

Question 11

Clinical signs of a life threatening attack

Answer 11

Silent chest, confusion, exhaustion, bradycardia, PEF >33% of expected and PO2 of less than 92%

Question 12

What partial pressure change indicates the attack is near death?

Answer 12

Raised PCO2 as it indicates the respiratory system is beginning to fail

Question 13

How is the diagnosis of asthma made?

Answer 13

Asthma is a clinical diagnosis which is made on the presence of characteristic symptoms and spirometry with an unexplained FEV1 and CXR showing hyperinflation

Question 14

Diagnosis of an acute asthma attack?

Answer 14

PEF, sputum, FBC, U+E, CRP, ABG showing slightly lowered PCO2 and PO2 due to hyperventilation

Question 15

After assessing the severity of attack what would you give as immediate treatment?

Answer 15

Salbutamol 5mg nebulised with O2
Hydrocortisone 100mg or prednisalone 50mg or both if severe
If O2 sats below 93% aim to get sats of 94-98%

Question 16

The attack is life threatening what steps must you take?

Answer 16

Inform ICU
Give salbutamol every 15 minutes nebulised
Conduct ECG looking for arrythmias
Add ipatropium 0.5mg to nebuliser
Give a dose of magnesium sulfate IV 2g over 20 minutes

Question 17

What does magnesium sulfate do?

Answer 17

Shown to inhibit bronchconstriction, acetylcholine release and decrease histamine release from mast cells

Question 18

If the patient doesn’t improve….

Answer 18

Transfer to ICU and IV salbutamol may be required

Question 19

How many steps are there available in chronic asthma treatment?

Answer 19

5

Question 20

What is step 1

Answer 20

Short acting Beta agonist such as salbutamol for as and when needed, if used more than once daily or night time syptoms, move to step 2

Question 21

What is step 2?

Answer 21

Add an inhaled steroid such as beclometasone 200-800micrograms a day

Question 22

If control still not adequate then move to step 3 which is?

Answer 22

Add a long acting beta agonist such as salmetrol and if necessary up the dose of beclometasone

Question 23

What is step 4

Answer 23

Beclometasone upped to 2000micrograms per day and add modified release oral theophylline and modified release oral beta agonist

Question 24

Step 5

Answer 24

Refer to asthma specialist and give prednisalone 1/day

Question 25

How does theophylline work?

Answer 25

Inhibits phosphodiesterase raising cAMP levels which reduces bronchrestriction

Question 26

What percentage of the UK population is affected by asthma?

Answer 26

5-8%