W20 - Asthma Flashcards
what is an inflammatory disease of the airways characterized by
recurrent reversible airway obstruction in response to irritant stimuli
hypersecretion of mucus by bronchial epithelial cells
Eosinophil infiltration
Bronchial smooth muscle cells hyperplasia causing airway hyper responsiveness and bronchospasm
what is hyperplasia
increase in number of cells in an organ or tissue
what is hypertrophy
increase in size of smooth muscle suspected contribute to the irreversible airflow obstruction and permanently impaired pulmonary function observed in patients with chronic asthma
what is bronchospasm
abnormal contraction of the smooth muscle of the bronchi resulting in an acute narrowing and obstruction of the respiratory airway
what happens to the airway in an asthmatic attack
increased smooth muscle contracts meaning hard to breathe
what factors are the chances to develop the condition
a family history bronchiolitis as a child exposure to tobacco smoke being born prematurely type of job occupational exposures
what are some triggers of asthma
indoor environment house dust mites moulds + fungi pollen food drugs stress or even a fit of laughter cold and viral infection
what is intrinsic asthma
asthma caused by substances within the body
do people with intrinsic asthma benefit from allergy shots or allergy medications
nop
what is extrinsic asthma
asthma caused by inhaling or ingesting foreign substane from without the body.
what are the symptoms of asthma
wheeze breathlessness cough daily or seasonal variation chest tightness
what are some tests we can use to diagnose asthma
airway inflammation measurement
lung function tests
airway hyperreactivity measurement
what does airway inflammation measure
fractional exhaled nitric oxide
what is a potive test on the airway inflammation
40 parts per billion +
what is a positive test of the obstructive airway test
<70%
what is forced vital capacity
maximal amount of air that can be exhaled after a maximal breath
what is the thought process behind obstructive airway
measure lung volumes and capacity to determine the presence of an obstructive or a restirctive disease
changes will differ depending on type of disease
what is a positive test on the bronchodilator reversibility test
FEV1 12 or more
+
Increase in volume of 200 ml or more
what is FEV1
forced expiraytory volume 1 second
what is a postive test on a peak flow variability test
20% +
what is a positive test on bronchial challenge test
provocative concentration of methacholine causing a 20% fall in FEV1 of 8mg / ml or less
describe the mechanism behind an asthma attack
a trigger occurs e.g. pollen
causes release of mast cell spasmogens e.g. histamine
+ chemotaxins
spasmogens causes bronchospasm
Chemotaxins cause influx and activation of inflammatory cells which release leuktriens, cytokines,eosinophil proteins
these can cause
- Bronchospasm
- wheezing
- cough
- increase of hyper reactivity and inflammation
leading to reduction in size of lumen of bronchiole
what are the two phases of an asthma attack
immediate
delayed
describe immediate phase of asthma attack
trigger
release mast cell spasmogen + chemotaxin
spasmogen cause bronchospasm
describe delayed phase of an asthma attack
influx of inflamatory cells which release leikotrienes cytokines eosinophil protein etc
these can cause
- Bronchospasm
- wheezing
- cough
- increase of hyper reactivity and inflammation
leading to reduction in size of lumen of bronchiole
what primary prevention (non pharmacological methods do we have to manage chronic asthma
multifcaceted approach to avoid indoor asthma
Aeroallergen and food avoidance
Weight loss interventions for overweiht and obese adults and children with asthma
Microbial exposure and hygiene hypothesis
avoid smoking and air pollution
what secondary prevention do we have to manage chronic asthma
house dust mite avoidance should not be routinely recommended
breathing exercise programmes can be offered to adult to improve quality of life and reduce symptoms
family therapy with pharmacotherapy
what can be used to relieve asthma
inhaled short acting fast onset beta adrenoceptor agonists
inhaled long acting fast onset beta adrenoceptor agonists as MART only
why are relievers used
they are used to relieve asthma symptoms and for asthmatic patients with infrequent short lived wheeze and normal lung function to control the symptoms quickly
what can be used to control + prevent
long acting bronchodilators and anti inflammatory drugs
- inhaled long acting beta 2 adrenoceptor agonists in combination with ICS
- inhaled and systemic corticosteroids
- leukotriene receptor antagonists
- long acting muscarinic receptor antagonists
- theophylline
why are controllers used
regular maintenance therapy to improve symptoms lung function and prevent asthma attack
what is salbutamol used for
occasional reliever and for acute asthma attacks it is suitable for this due to the fast onset, however it has short action
what is salmeterol onset compared to salbutamol
longer but longer duraiton
what are the advantage of long acting adrenceptor agonists
allow reduction of corticosteroid dose
reduction of symptoms and improvement of lung functions
what are the disadvantage of long acting adrenoceptor agonists
risk increase of asthma exarcerbation hospitilization and death
what does MART stand for
maintenance and reliever therapy and is a combined form of ICS and LABA treatment
what are the adverse affect of beta 2 adrenoceptor agonists
arrythmias
angina precipitation
palpitation
tachycardia
peripheral vasodilation
headache
tremor
what are contraindications and use with caution in regards to beta 2 adrenoceptor agonists
cardiovascular diseases
pregnancy
what might interact with other drugs beta 2 adrenoceptor agonists
hypokalaemia
what are the most effective anti inflammatory therapy for asthma
corticosteroids
what are the two mechanisms of action
trans repression
trans activation
What is trans repression
switch off multiple activated inflammatory genes and decrease transcription of
cytokines
chemokines
inflammatory enzymes
inflammatory receptors
others
what is trans activation
activate anti inflammatory gene expression and increase transcription of beta adrenergic receptor
what are the unwanted side effects of long term corticosteroid use
reduction of bone mineral density, osteoporosis
hypertension
cataracts and glaucoma
hyperglycaemia, diabetes
weight gain
increased vulnerability to infection
- lower respiratory tract infections
thinning of the skin and easy bruising hoarseness dysphonia, throat irritation, and candidiasis
what do blt1 and 2 mediate
chemotaxis and immunomodulation in several leukocyte populations and are in addition expressed on non myeloid cells such as vascular smooth muscle and endothelial cells.
what do cysLT1 and 2 exhibit
distinct expression patterns in human tissues, mediating for example smooth muscle cell contraction, regulation of vascular permeability and leukocyte activation
describe the mechanism of action for leuktriene receptor antagonists
block csyteinyl leukotrine receptors on bronchial tissue + others to reduce bronchoconstriction, mucus secretion, edema, eosinophil migration
Mechanism of action of anticholinergic agents
Antagonist of muscarinic acetylcholine receptors.
-Blockage of M3receptors reduces bronchoconstriction (promoting relaxation of pulmonary smooth muscle and bronchodilation) and reduces mucus secretion
Mechanism of action of theophylline
Non-selective phosphodiesterase inhibtor (=↑cAMP)
Non-selective antagonist at adenosine receptors
Activates histone deacetylases (HDACs)
Others unknown
mechanism of action of Anti lgE
Antibody binds to circulating IgE decreasing binding of IgE to the high-affinity IgE receptor (FceRI) in mast cells.
