Asthma Clincial features Flashcards
What is one symptom/sign must be seen in children for it to be asthma? (is not always present in adult asthma)
Wheeze
Describe what asthma is
It is when the smooth muscle around airways inappropriately contract and the airways are additionally reduced in size by inflammation and thickening of their walls.
What are the main proven risk factors for asthma?
- Familial atopic tendency ( maternal atopy is 3x that of father)- this is an inherited tendency of the IgE response to allergens. The variations are in the immune response genes IL-4, IL-5 and IgE and airway genes (e.g. ADAM33)
- Occupation (e.g. builder exposed to a lot of dust or baker exposed to wheat proteins and grain mites)
- Smoking (for children- Maternal smoking during pregnancy and maternal grandmother smoking, evidence suggests that these cause modifications of the epigenetics of oocytes.)
What substances cause occupation caused asthma?
Isocyanates (found in paint) Colophony (welding solder flux) Laboratory animals (rodent urinary proteins) Grains Enzymes (e.g. subtilisin, amylase) Drugs (antibiotics and salbutamol) Crustaceans (prawns, crabs etc)
What are possible risk factors for asthma?
Obesity (BMI is positively correlated with asthma)
Diet- low antioxidants, n-3 polyunsaturated fatty acids, high n-6 polyunsaturated fatty acids and low or high vitamin D are all associated with asthma. (and more)
Reduced exposure to microbes/microbial products in childhood
Indoor pollution by chemical household products
What conditions cause generalised airflow obstruction?
Asthma COPD Bronchiectasis Bronchiolitis Cystic Fibrosis
What is one of the differences between COPD and asthma?
Asthma airflow obstruction is reversible where as in COPD the airflow obstruction is largely irreversible (can have a reversible element).
What are the symptoms of asthma?
Wheeze
Shortness of breath (dyspnoea)
Chest tightness (pain)
Cough that is usually dry and has a sudden onset
Occasional sputum
Variation- could be daily (worse at night), weekly (occupation related) or annual (environmental allergens related)
What are signs that indicate it is not asthma?
Stridor ( a high pitched sound heard when inhaling)
Clubbing
Cervical lymphadenopathy
Asymmetrical expansion
Dull percussion note (lobar collapse or effusion)
Crepitations (bronchiectasis, CF, alveolitis, LVF)
What is the main cause of wheezing?
Obstruction of airflow, could be general or localised obstruction.
What are the keys things needed in asthma diagnosis?
Wheeze (for children) / generalised obstruction of flow
Variability- has periods of exacerbation
Responds to asthma treatment
What causes asthma?
It is the hosts response to the environment (NOT THE ALLERGENS THEMSELVES)
Infection can be an exacerbating factor (90% of asthma is in combination with infection, this is particularly important in paediatric asthma)
Physiology of the respiratory system (airways) is abnormal before symptoms occur (primary epithelial abnormality)
Why does the frequency and severity of asthma change with a child’s age?
Children with asthma tend to have more intermittent symptoms than an adult with asthma, but are more prone to asthma attacks as their bodies are developing. Asthma generally gets better or the symptoms stop during puberty but can reoccur later in life.
What are specific areas of interest in a history, is asthma is a possible diagnosis?
Familial atopy (family history of asthma)
Smoking (familial smoking for a child)
Childhood asthma, bronchitis (for an adult)
Eczema
Hay fever
Pets
Occupations (past and present) as occupations can have a lasting effect of asthma
Current inhalers they use (if any)
What investigations can be used to diagnose asthma (can only be used in adults, and can still not be that conclusive)?
Spirometry
Peak flow meter (can show variability of the obstruction, but my not be reliably filled out) (if Spirometry was normal)
Bronchial provocation- process of identifying hyper responsive airways by subjecting the to a known irritable agent.
Full pulmonary function testing (done if obstruction is shown in spirometry)
Spirometry before and after bronchodilator administered.
Response to oral corticosteroids
