Asthma Flashcards
Define asthma?
Chronic inflammatory airway disease characterised by variable reversible airway obstruction, airway hyper-responsiveness and bronchial inflammation
What are the genetic risk factors for asthma?
Family History
Atopy (tendency for T lymphocytes to drive production of IgE on exposure to allergens)
What are the environmental factors?
House dust mites Pollen Pets Cigarette Smoke Viral Respiratory Tract Infections Aspergillus Fumigatus Spores Occupational Allergens
What is the epidemiology of asthma?
Affects 10% of children
Affects 5% of adults
Prevalance appears to be increasing
What are the presenting symptoms of asthma?
Episodic History
Wheeze
Breathlessness
Cough (worse in the morning and at night)
What’s important to ask when talking about asthma?
Ask about previous hospitalisation due to acute attacks - this gives an indication of the severity of the asthma
What are the precipitating factors of Asthma?
Cold Viral Infection Drugs (e.g. beta-blockers, NSAIDs) Exercise Emotions Check for history of atopic disease (e.g. allergic rhinitis, uritcaria, eczema)
What are the signs of asthma on physical examination?
Tachypnoea Use of accessory muscles Prolonged expiratory phase Polyphonic Wheeze Hyperinflated chest
What are the signs of a Severe Attack of Asthma?
PEFR < 50% predicted
Pulse > 110/min
RR > 25/min
Inability to complete sentences
What are the signs of a Life-Threatening Attack of asthma?
PEFR < 33% predicted Silent Chest Cyanosis Bradycardia Hypotension Confusion Coma
What are the acute appropriate investigations for asthma?
Peak Flow Pulse oximetry ABG CXR FBC CRP U&Es Blood and sputum cultures
Why do we do a Chest X-Ray (CXR)?
To exclude other diagnoses e.g. pneumonia, pneumothorax
What might we see on a FBC?
Raised WCC if infective exacerbation
What are some of the investigations we might do in chronic asthma?
Peak flow monitoring
Pulmonary Function Test
Bloods to check Eosinophilia, IgE level, Aspergillus antibody titres
Skin Prick Tests
What would we expect to see if we monitored peak flow?
Often shows diurnal variation with a dip in the morning
Why do we do skin prick tests for asthma?
Helps identify allergens
What is a management plan for acute asthma?
ABCDE Resuscitate Monitor O2 sats, ABG and PEFR High-flow oxygen Salbutamol nebulizer Ipratropium Bromide Steroid Therapy
What do we do if there’s no improvement after the acute management plan?
IV magnesium sulphate
How much salbutamol nebulizer do we give in acute asthma?
5 mg, initially continously, then 2-4 hourly
How much Ipratropium Bromide do we give?
0.5 mg 4 times a day
What is the steroid therapy we give to patients to treat acute asthma?
100-200mg IV hydrocortisone
Followed by, 40mg oral prednisolone for 5-7 days
What can you consider when thinking of the acute management plan for asthma?
Consider IV aminophylline infusion
Consider IV salbutamol
What may be needed if the patient is getting exhausted?
Anaesthetic Help
What is a bad sign in a patient having an asthma attack?
A normal PCO2
Why is a normal PCO2 a bad sign in a patient having an asthma attack?
This is because during an asthma attack they should be hyperventilting and blowing off their CO2, so PCO2 should be low
A normal PCO2 suggests that the patient is fatiguing
When would you give Antibiotics in an asthma attack?
You want to treat the underlying cause and if it is an infective exacerbation then you give antibiotics
Why do we monitor electrolytes closely in an asthma attack?
Bronchodilators and aminophylline causes a drop in K+
What may be needed in severe attacks of asthma?
Invasive Ventilation
When do you discharge a patient after an acute asthma attack?
PEF > 75% predicted
Diurnal variation < 25%
Inhaler technique checked
Stable on discharge medication for 24 hours
Patient owns a PEF meter
Patient has steroid and bronchodilator therapy
Arrange follow-up
How does chronic therapy of asthma work?
There are 5 steps and you start on the step that matches the severity of the patient’s asthma
What is Step 1 in the chronic therapy of asthma?
Inhaled short-acting beta-2 agonist used as needed
If needed > 1/day then move onto step 2
What is Step 2 in the chronic therapy of asthma?
Step 1 + regular inhaled low-dose steroids (400 mcg/day)
What is Step 3 in the chronic therapy of asthma?
Step 2 + inhaled long-acting beta-2 agonist (LABA)
If inadequate control with LABA, increase steroid dose (800 mcg/day)
If no response to LABA, stop LABA and increase steroid dose (800 mcg/day)
What is Step 4 in the chronic therapy of asthma?
Increase inhaled steroid dose (2000 mcg/day)
Add 4th drug (e.g. leukotriene antagonist, slow-release theophylline or beta-2 agonist tablet
What is Step 5 in the chronic therapy of asthma?
Add regular oral steroids
Maintain high-dose oral steroids
Refer to specialist care
What advice do you need to give to patients with chronic asthma?
Teach proper inhaler technique
Explain importance of PEFR monitoring
Avoid provoking factors
What are some of the possible complications of asthma?
Growth retardation Chest wall deformity (e.g. pigeon chest) Recurrent infections Pneumothorax Respiratory Failure Death
What is the prognosis for patients with asthma?
Many Children improve as they grow older
Adult-onset asthma is usually chronic
