Asthma Flashcards
Pathophysiology of Asthma? (3)
- Airway narrowing due to broncoconstriction
- Inflammation caused by mast cell degranulation
- Increased mucus production
List 4 symptoms of Asthma?
- Dry cough with wheeze
- Chest tightness
- Dyspnoea
- diurnal variation
What Family history is linked to asthma?
Family history of Asthma or Hx of other atopic conditions
List 4 signs of Asthma on examination
- Chest deformities
- Hyperinflation
- Hyper-resonance due to hyperinflation
- Prolonged expiratory phase with expiratory wheeze on auscultation
Describe the pattern of symptoms in Asthma?
Episodic and diurnal variability of symptoms (tend to be worst at night)
Is airway obstruction in asthma reversible or irreversible?
reversible
List 4 typical triggers of Asthma
- Dust (house dust mites)
- Animals
- Cold air
- Exercise
- Smoke
- Food allergens
Describe the wheeze heard in Asthma
Bilateral widespread “polyphonic” wheeze
First line investigation for Asthma
Spirometry FEV1/FVC <70%
List the investigations for Asthma
(In order)
- Spirometry with reversibility testing (>5yrs)
- Fractional exhaled nitric oxide (FeNO)
- Direct bronchial challenge test
- Peak flow variability
Stepwise management of Asthma?
- SABA
- SABA + ICS
- SABA + ICS + LRA
- SABA + ICS + LRA + LABA
- MART
- Theophylline
Example of a SABA?
Salbutamol
Example of a LABA?
Salmeterol
Example of a LRA?
Montelukast
Example of a LAMA
Tiotropium
What is Maintenance and Reliever Therapy (MART)
Combination inhaler containing low dose ICS and fast acting LABA
Replaces all other inhalers as both a “preventer” and “reliever”
How does an Acute Asthma exacerbation present?
- Progressively worsening SOB
- Signs of respiratory distress
- Tachypnoea
- Expiratory wheeze on auscultation
- Reduced air entry, chest sounds “tight” on auscultation
What is a silent chest?
Why is it worrying?
Airways are so tight, it is not possible to move enough air through the airways to create a wheeze
+
Reduce respiratory effort due to fatigue
PEFR in moderate vs severe vs life threatening Asthma
Moderate: 50 – 75% predicted
Severe: 33-50% predicted
Life threatening: <33%
List 4 features of severe asthma
- PEFR 33-50% predicted
- Resp rate >25
- Heart rate >110
- Unable to complete sentences
List 4 features of life-threatening Asthma
- PEFR < 33%
- Sats < 92%
- Becoming tired
- No wheeze - “silent chest”
- Haemodynamic instability (i.e. shock)
What would happen to the pO2 and pCO2 in an acute asthma attack
Incl initial changes AND prolonged changes
Initally: pO2 is low and pCO2 is low due to V/Q mismatch. pCO2 is low due to hyperventilation
Prolonged: pO2 is low and pCO2 is increases as ventilation is reduced by obstruction
What will ABGs in Asthma show?
Incl initial changes AND prolonged changes
Initially: respiratory alkalosis
Prolonged: may progress to respiratory acidosis - very bad sign due to high CO2
Treatment of Moderate Asthma
(OSHI)
- Oxygen
- Nebulised Salbutamol
- Oral prednisolone or IV Hydrocortisone
- Nebulised Ipratropium bromide
- Antibiotics if evidence of bacterial infection
Treatment of Severe Asthma
(OSHIT)
- Oxygen
- Nebulised Salbutamol
- Oral prednisolone or IV Hydrocortisone
- Nebulised Ipratropium bromide
- Tiotropium Bromide
- Antibiotics if evidence of bacterial infection
Treatment of life threatening Asthma?
(OH SHIT ME)
- Oxygen
- Nebulised Salbutamol
- Oral prednisolone or IV Hydrocortisone
- Nebulised Ipratropium bromide
- Tiotropium Bromide
- Magnesium Sulfate
- Escalate
What is the significance of a normal pCO2 or hypoxia on ABG during a life threatening asthma?
Very worrying as it means the patient is tiring
List 4 ways we can monitor response to treatment?
- Respiratory rate
- Respiratory effort
- Peak flow
- Oxygen saturations
- Chest auscultation
What must be monitored whilst on salbutamol?
Why?
Serum K+
Salbutamol causes potassium to be absorbed from the blood into the cells.
Can also causes tachycardia
When does NICE suggest referral to a respiratory specialist for Asthma?
After 2 attacks in 12 months
Explain a typical step down regime of inhaled salbutamol once control is established
- 10 puffs 2 hourly then
- 10 puffs 4 hourly then
- 6 puffs 4 hourly then
- 4 puffs 6 hourly
They prescribe a reducing regime of salbutamol to continue at home
Explain the direct challenge test
???
How is Peak flow variability measured?
Patient advised to keep a diary of peak flow measurements several times a day for 2 to 4 weeks
Gold standard investigation for diagnosis of Asthma