2. Asthma and COPD Flashcards
Characteristics of Asthma
Smooth muscle contraction (bronchoconstriction) , irritation and swelling with mucosal oedema, mucous plugging of bronchioles (goblet cells)
What factors predispose to asthma
Airway hyperresponsiveness, sensitation to house dust mite, F sex smoking at age 21, atopy
What airway remodelling can occur in Asthma
Thickened basement membrane - can get fixed airway obstruction
How to diagnose asthma
Clinically - 1 or more of
Chest tightness, breathlessness, cough, wheeze esp if worse at night and early morning, in response to exercise, allergen and cold air, after taking aspirin or BB and M/FHx of asthma/atopy
Widepreade wheeze on chest ausc
Unexplained low FEV1/ PEF
Provoking factors for asthma
Viral infections, house dust mite, NSAIDS, aspirin and B blockers, other allergens, exercise, temp changes, anxiety, cigarette smoke, food and additives, obesity
What investigations should be done for Athma with intermediate probability
Need to check for airflow obstruction with revesibility testing/ treatment trials with bronchodilator or steroids. Need to have more than 400 mls improvement
Can monitor PEF- variability 20%
CXR, eos, IgE and skin prick tests can also be done.
Assessment of airway responsiveness- histamin to induce bronchoconstriction.
What should be done if asthma is suspected
initiate treatment with low dose ICS 6 weeks
Mx algorithm for asthma
2: Give SABA preventer if asthma diagnosed
3: Recheck compliance, technique, eliminate trigger factors. THEN Add on inhaled LABA to low dose ICS (beclamethasone + fometerol or fluticasone and vilanterol)
4a: If no response to LABA, stop it and consider increase ICS.
4b: IF LABA beneficial but control still inadequate, increase ICS to medium dose.
5: LABA beneficial but control still inadequate, continue both and add LTRA, SR theophyllines, or LAMA
SE of SABA
Tachycardia, vasodilation, arrhythmias, hypokalaemia, tremor, insomnia
When should nect step of therapy be considered for asthmatic patients
When >3 SABA doses a week
How does beclamethasone help with asthma
Reduces inflammatory cell infiltration, vascular permeability, and increases B2 responsiveness on airway smooth muscle
How do LTRAs work
prevent smooth muscle contraction, oedema, increased vasc permeability, mucus secretion and eos chemoattractatnt
How does theophylline work
Bronchodilation, rasies intracellular cAMP and is an adenosisne antaggonist
Possible drugs for severe asthma
High dose ICS
Tiotropium
IST
Macrolide Abx
Omalizumab or Mepolizumab
What is asthma exacerbation
PEF <0.8 pred, incr bronchodilator use, incr nocturnal Sx, incr sx scores for 2 or more days
What is a mild asthma ex and how to treat
PEF> 80 but incr salb freq , give 2-4 puffs BA 4hrly
What is a moderate asthma ex and how to treat
PEF 50-80, High dose bnronchodilator ( MDI via space or neb), and IV predni 40mg 5 days
What is moderate acute asthma
Normal speech, RR< 25, pulse <110
Severe acute asthme
Cannot complete sentences, RR>25, Pulse >110, spiro 33-50
Life threatening asthma
Silent chest, cyanosis, poor resp effort, brady, dysrhthmia, hypotension, exhuastion, confusion, coma
spiro <33
TIIRF
How to treat severe acute asthma
High flow O2 + similar as moderate ex, add ipa (SAMA) if no response
Magnesium recommended for severe attack
Aminophylline/ IV slab last line
Who to refer to ICU for acute asthma
If vent support required, or severe or life threatening asthma is not responsive, eg derioriating PEF, persiting or worsening hypoxia, hypercapnia, exhaution and feeble resp, drowsiness , confusion, coma or resp arrest
What is chronic bronchitis
Cough productive of sputum on most days for 3 months over 2 consecutive years
Characteristic of d chronic bronchitis
Hyperplasia of goblet cells in the airways, leads to mucus hypersecretion, usually associated with increased inflammatory cells in these areas of the lungs
What is emphysema
Permanent dialatation of airspaces distal to terminal nbonchiles, accompanied by destruction of their walls, w/o obv fibrosis
Loss of elastic recoil leads to airflow limitation
Types of emphysema, which lobe they are predominant in, and who they are common in
Centrilobular, UL, common in smokers
Panlobular ( whole lobule destroyed) , LL, common in a-1 AT deficiency ( predominantly pasal)
Risk factors for COPD
SMOKING
Occu dust and chemicals eg. coal mining
Second hand smoke
Air pollution
Recurrent childhood infxns
SES
—
a-1 antitrypsin deficiency
Hyper-responsiveness
How are airways affected in asthma and COPD respectively
Bronchoconstriction vs small airway narrowing and alveolar destruction
Characteristics of dyspnoea in COPD
Persistent
Progressive
Characteristically worse with exercise
Describe cough in COPD
Chronic, but may be intermittent and may be unproductive (Emphysema) , and may have chronic sputum production ( chronic bronchitis phenotype)
Possible Sx of COPD on inspection
Which ones are more common in emphysematous phenotype
Use of accessory muscles, overinflation of lungs eg. protruding abdomen, central cyanosis, peripheral oedema,
weight loss, barrell shaped chest, pursed lip breathing
What breath sound is common in COPD
Wheezing . Respiratory crackles may occur with coughing esp if pneumonia is present
Is COPD dx spirometry based or clinical
Both
Consider Sx of sputum pdtn, cough, or dyspnoea. or exposure to risk factors
+
Spirometry - FEV1/FVC <0.7
How to measure severity of COPD
post bronchodilator FEV1, not FEV1/FVC
Mild- FEV1>80
Moderate - 50 to 80
Severe 30 to 50
Very sever Less than 30
What is a sig. response to bronchodilators suggestive of asthma
Large increase in FEV1 (>400)
What scale to assess Sx of COPD/ asthma
mMRC
0- breathless with strenous ex
1- when hurrying on level or up slighthill
2- slower than most on level, or have to stop for breath on the level
3- stop for breath after 100m/ few mins on the level
4- Too breathless to leave the house/ breathless when dressing or undressing
CAT- self assessment tool
What is ABCD assessment for COPD
Based on risk ie. number of excaerbations ( or whether there was at least one that led to hospital), and symptoms ie. mMRC or CAT
What can CT scan be used for in COPD
To quantify emphysema (and bronchiectasis)
Residual volume and diffusing capacity in COPD
High RV, low DC due to gas trappinf
Vaccination for COPD
Influenza and penumococcal vacc (one off)
what chemical does BA increase and what is it
cAMP, results in bronchodilation
What must ICS be combined with in COPD Tx
LABA eg. beclomethasone and formoterol
OR LABA LAMA
First line for COPD
LAMA ( or LABA)
How to increase therapy for COPD
Add LABA or LAMA, or ICS if asthmatic qualities?
For severe, high risk, can give triple therapy if further exacerbations/ persistent Sx on LABA+ICS and then consider roflumilast if FEV1 <50 % predicted and chronic bronchitis in pt, or macrolides in former smokers
Most common bacterial and viral pathogens that cause COPD exacerbations
Rhinovirus and Influenza, esp during winter months
When should nebuilisers be given to COPD pts
if extremely bronchoconstricted (long term home therapy for severe COPD and Sx disease, or short term for exacerbations)
