Asthma Flashcards
Pathology of asthma
Inflammation of the bronchial tree with hyper sensivity of the lungs to one or more stimuli
Causing airways to narrow, secondary to bronchoconstriction and muscle oedema , with elevated mucus production.
What long term airway remodelling happens
Subepithelial fibrosis
Increased smooth muscle mass
Enlargement of submucosal glands
Epithelial alterations
Triggers of asthma
Allergens
Infection
Pollutants
Cold damp air - can make airways tighten
Occupational - eg paints, wood or grain dust
Drugs- NSAIDS(risk of bronchospasm) abd B blockers. ( block B blockers which cause bronchodilation)
Exercise
Classification of asthma (6)
Episodic / seasonal asthma - occurs at intervals throughout the year eg when fungal spores are realeased
Chronic asthma - persistent disease state, with acute exacerbations periodically
Exercise induced asthma - airway sensitive to colder , drier air from ‘mouth breathing ‘
Childhood asthma - asthma which is often due to allergic reactions. Resolution is common as the child ages
Status asthmaticus (severe acute Asthma) - a long lasting severe acute attack - aggressive early treatment needed ( can be fatal and unresponsive to later intervention)
Late onset asthma - asthma ores sit for for the first time in adult life. More likely to be female patients. Non allergic and respire higher does of corticosteroid to control ( can be relatively unresponsive to treatment).
Diagnosis of asthma
Peak expiratory flow (PEF)- a >= 20% variation In PEF on >= 3 days in one week over a 2 week period
Reversibility tests -measure function before and after administration of a B2 stimulant eg salbutamol
FeNO- Fraction of exhaled nitric oxide. Raised exhaled NO levels are related to eosinophilia but not conclusively . Other factors can confound and correlation is weak.
Skin tests - specific allergens can be identified eg mould , pollen
Chest radiograph - hyper inflation of lungs due to air trapping as a result of mucus plugging
Diagnosis of acute severe asthma
Respiratory rate >= 25 breaths/ min
Heart rate <= 110 beats/ min
PEF 33-50% best or predicted.
Inability to complete sentences in one breath.
Other Symptoms:
Increased co2 levels
Cyanosis - bluish colouration due to lack of o2
Absence of wheezing - no air psssing in or out
Non pharmacological treatment of asthma
Avoidance of triggers Desintistaion to sepecific allergens -immunotherapy House dust jute control measures Smoking cessation - including parents Weight loss
Relievers
B2 Adrenoreceptor agonists ( short and long acting )
Methylxanthines
Anti muscarinics
Preventers
Corticosteroids
Anti allergic agents
Leukotriene receptor antagonists
LAMA
Tiotropium
SAMA
Ipratropium
ICS
Beclomethasone
Example of anti allergic agent
Sodium cromoglicate
Example of leukotriene receptor antagonist
Montelukast
What are leukotrienes
Inflammatory chemicals the body release after coming into contact with an allergen or allergen trigger . They cause tightening of airway muscles and the production of excess mucus and fluid.
