Case 2: asthma Flashcards
Features of asthma
wheeze cough breathlessness chest tightness recurrent episodes symptom variability recorded observations of wheeze personal history of atopy historical record of variable PEF and FEV1
Normal FEV1/FVC
~80%
What happens to FEV1/FEV in asthma?
Decreases because FEV1 decreases in asthma
Define asthma
A heterogeneous disease
Chronic airway inflammation
History of respiratory symptoms e.g. wheeze, breathlessness, chest tightness and cough that vary over time and severity, together with variable expiratory airflow limitation
Pathophysiology of allergic asthma
B cells make IgE
Mast cells develop receptors for IgE on their surface
After priming, another allergen binds to IgE causing cross linking of IgE receptors on mast cells
Mast cell degranulation (release of bronchoconstrictors, chemoattractants, vasoactive compounds)
Describe the early and late phase of an asthma attack
Early phase: inhale allergen - immediate bronchoconstriction - FEV1 recovers in a couple of hours - cleared with bronchodilators
Late phase: inflammation - takes longer to clear - cleared with anti-inflammatories
Where do B2 agonists act
B2 adrenoceptors in bronchiole SM
Actions of B2 agonists
SM relaxation and inhibit mast cell degranulation
Features of salbutamol
SABA
Short acting
Max effects in 30 minutes
Effects for 4-6 hours
Features of salmeterol
LABA
Long acting
Effects for 12 hours
More for prophylaxis
Side effects of B2 agonists
tremor
Features of theophylline
PDE inhibitor
2nd line
Can be used via IV in acute asthma attack
SEs: CNS stimulant, CV, GIT
Ipratropium features
Muscarinic receptor antagonist Adjunct to B2 agonists Max effect: 30 minutes Lasts 3-5 hours Aerosol inhalation
Montelukast features
Is a Leukotriene receptor antagonist
Taken orally
adjunct therapy
Because leukotrienes usually cause bronchoconstriction on bronchiole SM cells
Glucocorticoids for asthma
e.g. beclomethasone, diproprionate
Anti-inflammatory
Inhalation usually
Take several days to have an effect
Reduce production of cytokines, spasmogens, leukocute chemotaxins
Reduce bronchospasms and recruitment of inflammatory cells
SE: suppress adrenal glands
3 Questions to ask in an annual asthma review
In the last month/week, have you had any DIFFICULTY SLEEPING DUE TO SYMPTOMS?
Have you had your USUAL ASTHMA SYMPTOMS DURING THE DAY?
Has your asthma INTERFERED WITH YOUR USUAL DAILY ACTIVITIES?
Describe normal breath sounds
Vesicular Low pitch Soft Inspiration longer and louder than expiration No gap between inspn and expn
Describe bronchial breathing
Loud and tubular quality High pitched Inspiration and Expiration equal length and loudness Gap between inspn and expn (Mimicked by listening over trachea)
What conditions cause bronchial breathing
Consolidation
Lobar collapse with patient bronchus
Lung cavity
Describe the crackles heard with different conditions
Bronchiolitis: early inspiratory
Pulmonary oedema: mid inspiratory
Pulmonary fibrosis/oedema/COPD/resolving pneumonia/lung abscess/tuberculous lung cavities: late inspiratory
Bronchiectasis: biphasic
Causes of fine and coarse crackles:
Fine: broncholitis, pulmonary oedema, pulmonary fibrosis
Coarse: COPD, resolving pneumonia, lung abscess, TB, bronchiectasis
Describe pleural rub
Commonly caused by inflammation of the visceral / parietal pleura
Low pitched, grating sound similar to walking on snow
Caused by consolidation, pulmonary infarction, uremia etc
Heard on inspiration when the pleura rub on eachother
Differentials if you hear a wheeze
Asthma COPD Foreign body aspiration Cardiac failure Eosinophilic lung disease Pulmonary disease
What is the link between asthma and flu
People with asthma are NOT more likely to get flu, but if they do it can be MORE SERIOUS because it can cause further inflammation of airways/lungs on top of already inflamed airways.
Flu can trigger asthma attacks or worsening of Sx. This can also lead to pneumonia.
Therefore a one off vaccination against Pneumococcal disease is recomended
