asthma Flashcards
symptoms
- wheeze
- chest tightness
- cough
- shortness of breath (worse at night)
when does it occur
between 3-5 years old
what are the 3 characteristics
- airflow limitation
- airway hyper-responsiveness
- bronchial inflammation
is airflow limitation reversible
yes
may need treatment to do so
what is present in bronchial inflammation
- T lymphocytes
- mast cells
- eosinophils m
- oedema
- smooth muscle hypertrophy
- mucus plugging
- epithelial damage
what is the skin prick test result
positive to common inhalant allergens such as dust mite, animal danders, pollens and fungi
what is childhood asthma often accompanied by
eczema
what can be a cause of late onset asthma
sensitisation to chemicals or biological products in the workplace
what can cause non-atopic asthma in middle age
- sensitisation to occupation agents
- intolerance to NSAIDs (aspirin)
- prescription of beta-adrenoreceptor blockers
causes
- grass pollen
- domestic pets
- rhinovirus
- cold air
- emotion
- perfume
- cigarette smoke
- NSAIDs
- Beta blockers
- genetics
what does term atopy include
asthma and hayfever
atopic diseases are those that
- run in families
- skin reactions to common allergens
- circulating allergen-specific antibodies (IgE)
what is elevated serum IgE linked to in asthma
airway hyper-responsiveness
what genes control cytokine production
- IL-3
- IL-4
- IL-5
- IL-9
- IL-13
these affect mast cell development and eosinophils
what helper cells are involved in asthma
type 2 helper cells
how can airway hyper-responsiveness be demonstrated
ask patient to inhale gradually increasing concentrations of histamine or methacholine
aka bronchial provocation test
what would the bronchial provocation test be in asthmatic patient
they would respond to a very low dose of methacholine
what other conditions would react to methacholine
- wheezing with viral infection
- seasonal wheeze
- allergic rhinitis
what increases the risk of developing some forms of occupational asthma
smoking
when do asthmatics usually wheeze
after prolonged exercise or inhalation of cold, dry air (air conditioning included)
what is exercise induced wheeze driven by
release of histamine, prostaglandins and leukotrienes from mast cells
what can asthmatics experience worsening of symptoms
- exposure to tobacco smoke
- car exhaust fumes
- solvents
- strong perfumes
what drugs implicate asthma
NSAIDs
particularly aspirin
what do NSAIDs inhibit
arachidonic acid metabolism via the cyclo-oxygenase (COX) pathway
what is there a reduction of in aspirin intolerant asthma
reduce production of PGE2
leads to overproduction of cysteinyl leukotrienes by eosinophils, mast cells and macrophages
COX-2 inhibitors trigger asthma attacks
true or false
false
only COX-1 do
what drug contraindicates asthma and should never be given to patient
beta blocker
what is the inflammatory component of asthma driven by
Th2 T lymphocytes
what response occurs when there is a decrease in sensitivity to corticosteroids
Th1 response with release of mediators such as TNF-alpha
where is there an increase in mast cells in asthma
- epithelium
- smooth muscle
- mucous glands
what do mast cells release in asthma
- histamine
- tryptase
- PGD2
- cysteinyl leukotrienes
cause immediate asthmatic reaction
where are eosinophils found in asthma
in bronchial wall and secretions
how are eosinophils attracted to the airways
by cytokines:
- IL-3
- IL-5
- GM-CSF
what do eosinophils release when activated
LTC4
what drug can decrease activation of eosinophils
corticosteroids
epithelium changes
- loss of ciliated columnar cells
what is epithelium a major source of
- mediators
- cytokines
- growth factors
these enhance inflammation and promote tissue remodelling
what is a useful test for continuing inflammation
measurement of exhaled NO
what is smooth muscle like
hyperplasia
what happens to the smooth muscle
- contracts more easily
- remains contracted
what do smooth muscle secretes
- cytokines
- chemokines
- growth factors
what does acetycholine stimulate
M3
symptoms
- wheezing
- SOB (episodic)
- worse during night
- cough
what can be done for diagnosis
- PEFR
- spirometry
- exercise test
- CXR
- skin prick
how is PEFR done
- measure on walking before bronchodilator use
- measure in bed after bronchodilator m
what does PEFR show
the diurnal variability
how does spirometry show ashtma
greater than 15% improvement in FEV1 following bronchodilator use
what is used for diagnosis in children
exercise test
how is exercise test done
run for 6 minutes on treadmill
what can be seen on CXR
- overinflation
treatment for occasional symptoms not everyday
SABA
treatment for daily symptoms
corticosteroid
treatment for severe symptoms
corticosteroid + LABA
if not controlled add either leukotriene or theophylline
treatment for severe symptoms that are uncontrolled on high dose corticosteroid
increase corticosteroid + LABA
+ leukotriene/theophylline
treatment for severe symptoms with patient deteriorating
corticosteroid
+
prednisolone
treatment for severe symptoms and continued deterioration on prednisolone
hospital admission
example of SABA
salbutamol
example of LABA
salmeterol
example of corticosteroid
beclometasone
budesonide
fluticasone
example of leukotriene
monelukast
zafirlukast
when can drugs be reassessed
2-3 months after under control
what do beta adrenoreceptor agonist do
affect B2 only
- relax the bronchial smooth muscle
can LABAs be given on their own
no
what are LABAs given with
corticosteroids
what does sodium cromoglicate prevent
activation of many inflammatory cells, particularly mast cells, eosinophils and epithelial cells
SE of inhaled corticosteroids
- oral candidiasis
- hoarseness
- osteoporosis
drug against IgE
omalizumab
features of life threatening attack
- silent chest
- exhaustion
- bradycardia
drugs used for acute severe asthma
- SABA
- antimuscarinic
- magnesium sulphate
- hydrocortisone
- predisolone
- ventilation
order of treatment for acute severe asthma
- oxygen
- salbutamol
- ipatropium
- hydrocortisone
- prednisolone
- magensium sulphate IV
