Asthma Flashcards
Define Asthma
Asthma is characterized as recurrent episodes of dyspneoa, wheeze, and cough caused by reversible airway obstruction.
What three factors contribute to airway narrowing in asthma
- Brochial muscle constriction
- Mucosal swelling/inflammation
- Excess mucus production
What causes mucosal inflammation/swelling in asthma?
Mast cell and basophil degranulation resulting in the release of inflammatory mediators
List symptoms of asthma
- Wheeze
- intermittent dyspnoea
- cough (oft. nocturnal)
- sputum
List some precipitants of asthma attacks
- allergens (dust mite, pollen, pests, fur)
- Exercise
- Smoking (passive smoking too)
- Infection
- Pollutants
- NSAIDs & Beta Blockers
Describe what is meant by the term diurnal variation when used in the context of asthma
This is the marked decrease in peak flow rate in the dusk of the morning when compared with the peak flow rate during the day or at night.
What precipitants may be present in the home of a asthma patient?
- Pets
- Pests
- Carpets (with hidden dust mites)
- feather pillows
- any soft furnishing
What would indicate that the asthma precipitants may be work related?
If the symptoms remit on weekends or holidays
which occupations are more likely to have occupational asthma?
welders
paint sprayers
animall handlers
food processors
List some signs of an asthma attack
- tachypnoea
- audible wheeze
- hyperinflated chest
- hyper resonant percussion note
- decreased air entry
- polyphonic wheeze
List some signs of a severe asthma attack
- breath rate >25bpm
- Pulse rate >110bpm
- Inability to complete sentences
- PEF = 33-50%
List some signs of life threatening asthma attack
Silent Chest Confusion exhaustion Cyanosis Bradycardia PEF <33% low PaO2 <8kPa but normal PaCO2
List one important sign of near fatal asthma attack
Increased PaCO2
List some tests done to confirm Acute Asthma attack
- PEF : peak expiratory flow
- ABG: arterial blood gas
- CBC
- U and E
- Blood Culture
- C-reactive protein test
What will an arterial blood gas test show in a patient with acute asthma attack
- normal or slightly decreased PaO2
- decreased PaCO2 (because of hyperventilation)
What should be done if the patient’s PaCO2 is normal or raised
Transfer to Intensive therapy unit for ventilation, as this signifies failing respiratory effort
Why would you do a CXR on a patient with acute asthma attack
To rule out infection or pneumothorax
In chronic asthma PEF monitoring will show..
a diurnal variation of >20% on >/= 3days a week for 2 weeks
In chronic asthma a Spirometry test will show…
decreased forced expiratory volume 1sec (FEV1), normal forced vital capacity
ratio <75%
A chest x ray will show what presentation in a chronic asthmatic
Hyperinflation
What test is used to help identify allergens in Chronic asthma
Skin prick test
List some differentials for asthma
- Pulmonary Oedema (Cardiac asthma)
- Bronchiectasis
- Pulmonary embolism
- Large airway obstruction
- obliterative brochiolitis
- Superior vena cava obstruction
- pneumothorax
List 2 diseases and 1 syndrome that can be associated with asthma
- Acid reflux
- polyarteritis nodosa
- Churd-Strauss Syndrome
What is Polyarteritis nodosa
is a rare disease that results from blood vessel inflammation (“vasculitis”) causing injury to organ systems.
What are the three factors of Churd-Strauss Syndrome triad
- asthma
- hypereosinophilia
- pulmonary infiltrates
Which guideline is used in the management of asthma
British Guideline for the management of asthma
What is step 1 in the British Guideline for management of asthma
Step 1: Occasional use of inhaled short-acting
β -adrenoreceptor agonist bronchodilator
What is step 2 in the management of asthma according to the British Guidelines?
Introduction of a regular preventer ; preferably an inaled glucocorticoid
What is step 3 in the British Guideline for management of asthma
Add on therapy ; long acting B2 agonist (with the inhaled glucocorticoid)
What is step 4 in the British Guideline for management of asthma
Step 4: Poor control on moderate dose of inhaled glucocorticoid and add-on therapy: addition of a fourth drug
What is step 5 in the British Guideline for management of asthma
Add regular oral prednisolone (1 dose daily, at the lowest possible dose). Continue with high-dose inhaled steroids. Refer to asthma clinic.
Describe the steps in the management fo acute severe asthma
- Oxygen therapy
- High dose bronchodilators
- Systemic Glucocorticoids
Define the step-down therapy method in the treatment of chronic asthma
nce asthma control is established, the dose of inhaled (or oral) glucocorticoid should be titrated to the lowest dose at which effective control of asthma is maintained.
Give two examples of SABAs used in step1 of chronic asthma treatment
- salbutamol
- terbutaline
List 3 inhaled glucocorticoids used in step 2 treatment of chronic asthma
Beclometasone
Budesonide (BUD)
Fluticasone
What are the criteria for stepping up a chronic asthmatic with step 1 treatment to step 2 treatment
for any patient who:
• has experienced an exacerbation of asthma in the last 2 years
• uses inhaled β2-agonists three times a week or more
• reports symptoms three times a week or more
• is awakened by asthma one night per week
What is a resonable starting dose of beclometasone for adults stepping up to step 2 treatment?
400 micrograms per day (may be increased in smokers)
What should be done before stepping up to step 3 if a patient remains poorly controlled despite regular use of an inhaled glucocorticoid
Check:
- meds adherence
- inhaler technique
- ongoing exposure to modifiable aggrevating factor
Add on therpay (step 3) should be considered if the patient’s inhaled glucocorticoid dose is greater than or equal to what value
> 800 micrograms per day
Give 2 examples of a LABA (long acting b2 agonist) used in the add on therpay (step 3) of chronic asthma treatment
Salmeterol
Formoterol
Combination therapy of LABA and inhaled glucocorticoid is advised as LABA monotherapy has what side-effect
increased risk of life-threatening attacks
which two drugs are used in inhaled glucocorticoid-LABA therapy
Budesonide + Formoterol
In step 4 of chronic asthma management what are 4 drug class options that can be added to achieve control?
- slow releasing B2 agonist
- Aminophylline (Theophylline)
- Long acting anti-muscarinic agents
- leukotriene receptor anatagonist
Describe the MOA of B2-adrenoceptor agonist in asthma control
relax bronchial smooth muscle, acting within minutes.
What are some side effects of B2 agonists
tachyarrythmia
Describe the MOA of inhaled glucocorticoid (corticosteroid) in asthma control
The act over days to reduce brochomucosall inflammation
What precaustion should be taken after inhaling glucocorticoids?
Rinse mouth - to prevent oral candidiasis
What is the MOA of aminophylline/theophylline in asthma management?
acts by inhibiting phosphodiesterase (which reduces cAMP availabilty- so reduced muscle contraction) thus < bronchoconstriction
