Asthma Flashcards
What are the 3 main characteristics of asthma?
Airway hyper-responsiveness:
Airflow limitation
Inflammation of bronchi
Airway remodelling may occur in the lungs of asthmatic what does this describe?
Inappropriate and excessive contraction of smooth muscle
Hypertrophy and proliferation of smooth muscle cells, further narrowing the airway lumen
What are the two main types of asthma?
Eosinophilic
Non eosinophilic
Asthma clinical presentation
Episodic wheeze Cough, Breathlessness Diurnal variation Brittle disease (type 1, chronic severe; type 2 sudden dips)
What provoking factors are there for asthma
allergens, infections, menstrual cycle, exercise, cold air, laugher/ emotion
What pathological immune differences are present in lungs of an asthmatic?
Mast cells, eosinophils and T cells are increased in bronchial walls, mucous membranes and secretions of asthmatics.
When stimulated by appropriate antigen Lymphocytes release inflammatory mediators which attract mast cells and eosinophils
Production of interleukin 3 and 4 helps maintain pro-allergic phenotype favouring IgE production from B cells over other antibodies.
IgE binds to mast cells with high affinity—> mast cells release histamine prostaglandins—> inflammatory response.
Assessing severity:
Royal College of Physicians 3 questions:
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Recent nocturnal waking?
Usual asthma symptoms in day?
Interference with ADLs?
What cell type is commonly increased in FBC of asthmatics?
Eosinophils
What tests are undertaken to diagnose atopy and allergy
Skin Prick Tests
RAST- blood test using radioimmunoassay test to detect specific IgE antibodies, to determine the substances a subject is allergic to.
Spirometry in an asthmatic will show airway obstruction during an exacerbation, what results indicate obstruction
FEV1 < 0.7 FVC
FEV1 < 0.8 of predicted
What variability is shown in asthmatics
Diurnal variation (worse in the morning)
What does exhaled NO test indicate?
Eosinophilic inflammation
What asthma test involves Histamine or methacholine
Patient inhales increasing dose and a decreasing FEV1 will indicate bronchial hypersensitivity. Avoid test if asthma is very bad.
What should asthmatics avoid?
Avoid triggering allergens. Make sure they are not on B blockers.
What are steps in asthma management
SABA
Low does inhaled corticosteroid
Add inhaled LABA to low-dose ICS (normally as a combination inhaler)
Increase to medium dose of inhaled corticosteroid. Consider adding one from: leukotriene receptor antagonist, theophyline or Long acting muscarinic antagonist.
Increase to high dose corticosteroid. Add another of leyukotrine receptor antagonist, theophyline or long acting muscarinic antagonist. Refer for specialist care.
Oral corticosteroid tablet (prednisolone)
