Asthma Flashcards
Definition of Asthma
An obstructive lung disease that is reversible, accompanied by a degree of airway inflammation, increased mucus production and bronchial muscle contraction due to Bronchial Hyper-reactivity
What are the Factors leading to Airway obstruction in Asthma
(1) Bronchial muscle contraction (spasm)
(2) Mucosal Swelling/Inflammation
(3) Increased Mucus production
What are Mucus plugs made of?
(1) Mucus
(2) Dead epithelium
(3) Proteinaceous material
What does an Asthmatic airway look like on histology?
(1) Majority of epithelium is shed
(2) Thickening of basal membrane with Collagen deposition
(3) Massive infiltrate of inflammatory cells (Eosinophils, Lymphocytes, Mast cells)
What are the main reactive cells in the Early Asthmatic reaction?
Mast cells
What are the main reactive cells in the Late Asthmatic reaction?
Eosinophils & (Neutrophils- Occupational Asthma)
What do Eosinophils discharge that destroys Airway epithelium?
Eosinophils cationic protein
Major basic protein
What is the role of IL-3 secreted by TH2 cells in Asthma?
Increases Mast cell proliferation
What is the role of IL-4 secreted by TH2 cells in Asthma?
Changes the Isotype of B-cells to start producing IgE antibody which then attaches to Mast cells
Increases Mast cells proliferation
What is the role of IL-5 secreted by TH2 cells in Asthma?
It is a pro-eosinophilic cytokine = Increases the production of eosinophils (Increases likelihood that eosinophils reach areas of inflammation in the airway
Increases Mast cells proliferation
What are the most common allergens causing Asthma?
(1) House dust mites & their excrete
(2) Pollen
(3) Air Pollution (car exhaust)
How to assess Asthma symptom control over last month?
(1) Daytime Symptoms > 2x a week
(2) Any night walking due to Asthma
(3) SABA reliever >2x a week
(4) Any activity limitation due to Asthma?
What are the main symptoms of Asthma?
(1) Intermittent Dyspnoea & Wheeze
(2) Cough (Often nocturnal)
(3) White sputum production
(4) Symptoms vary during the day & get much more worse at night
What are the main signs of Asthma?
(1) Tachypnoea
(2) Audible Wheeze
(3) Hyper-inflated chest
(4) Hyper-resonant percussion note
(5) Decreased Air Entry
(6) Widespread polyphonic wheeze on Auscultation
What might precipitate an Acute Asthmatic attack?
(1) Cold Air
(2) Exercise
(3) Emotions
(4) Allergens
(5) Infection
(6) Smoking (Even passive)
(7) Pollution
(9) NSAID’s
(10) Beta-Blockers
How do you diagnose Asthma?
A History of wheeze, shortness of breath, chest tightness, cough that vary in intensity & over-time:
(1) Occur/worse at night/exercise
(2) Triggered by exercise/laughter/allergens/cold air
(3) Occur or worsen with viral infections
Objectively:
(1) FEV1/FVC ratio <80%
(2) FEV1 increases by >12% & >200mls after bronchodilator inhalation (SIGNIFICANT BRONCHODILATOR RESPONSIVENESS)
(3) >10% average daily diurnal PEF variability
(4) FEV1 increases >12% & >200mls after 4 weeks of anti-inflammatories
What are the normal PEFR rates?
Men = 48 litres/minute Women = 42litres/minute
What is the lifestyle management/Rx in Chronic Asthma?
(1) Quit smoking
(2) Avoid precipitants
(3) Weight loss
(4) Physical activity
(5) Educate about Inhaler technique & spacer use
(6) Educate about PEFR meter to monitor twice daily
(7) Educate about Asthma attacks & management
What is an Asthma control plan & what does it entail?
A plan formulated by the doctor & the patient about what and how to take medicines, what to do when the asthma symptoms are getting worse or an acute asthmatic attack has begun & how and when to access medical care.
(1) Increase frequency of inhaled reliever
(2) Increase controller therapy (Consider quadrupling dose of ICS)
If after 48 hours symptoms do not abide:
(3) Oral Corticosteroids (40-50mg Prednisolone for 5-7 das)
(4) Contact GP
How do you treat chronic Asthma?
(1-2) Low-dose ICS-formoterol PRN
(3) Low dose ICS-formoterol
(4) Medium dose ICS-formoterol
(5) High dose ICS-formoterol + LAMA (Umeclidinium)
OR
(1) ICS + SABA (Both PRN)
(2) Low-dose ICS + SABA PRN
(3) Low-dose ICS-LABA + SABA PRN
(4) Medium-high dose ICS-LABA + SABA PRN
(5) High dose ICS-LABA + LAMA + SABA PRN
What are the differential diagnosis of Asthma?
(1) COPD
(2) Pulmonary oedema
(3) Large Airway obstruction
(4) SVC obstruction
(5) Pneumothorax
(6) PE
(7) Bronchiectasis
(8) Obliterative bronchiolitis
What associated disease are there in Asthma?
(1) Acid Reflux
(2) Polyarteritis nodosa
(3) Churg-Strauss syndrome
(4) Allergic bronchopulmonary aspergillosis
What is Severe Asthma?
Asthma that is uncontrollad despite adherence with maximum optimised therapy & treatment of contributory factors OR that which worsens when a high dose treatment is decreased
Asthma with an allergic component
Commoner in young men (Boys)
Asthma without an allergic component
Commoner in Adult women
Easy Come/Easy Go Asthma:
Bronchospasm (Commoner in Males
Slow Come/Slow Go Asthma:
Chronic Inflammation with mucous hyper-secretion (Commoner in Women)
What is the main predictor of a life-threatening asthma?
A Previous Asthmatic life-threatening attack
How is Severe Acute Asthma Recognised?
(1) Inability to complete a sentence
(2) Tachycardia >120bpm
(3) Tachypnoea > 20
(4) Use of Accesory muscles of respiration
(5) Objectively = PEFR <50% of that predicted
Why is a nebulizer better than inhaler in Acute Asthmatic attack?
Patient will find it difficult or is unable to perform a correct inhaler technique during an Asthmatic attack. A nebuliser treatment is much easier
How is Life-threatening Asthma recognised?
(1) Exhaustion
(2) Inability to speak complete sentences
(3) Confusion/Drowsiness/Disoriented
(4) Cyanosis
(5) Sa02 = low
(6) Poor Respiratory effort
(7) Silent Chest
(8) PaCO2 = normal to high
Type 1 Brittle Asthma:
Asthma characterised by a wide PEF variability (>40% diurnal variation for >50% of the time over a period of at least 150 days despite considerable medical therapy including a dose of inhaled steroid of at least 1500mcg of beclomethasone or equivalent
Type 2 Brittle Asthma:
Asthma characterised by sudden acute attacks occurring in less than 3 hours without an obvious trigger on a background of apparent normal airway function or well controlled asthma
