Clinical Features of Asthma in Adults Flashcards
What is a definition of asthma?
(No universally accpted definition)
- A disease characterised by an increased responsiveness of the trachea and bronchi to various stimuli and manifested by a widespread narrowing of airways that changes in severity either spontaneously or as a result of therapy
What are the main symptoms of asthma?
wheezing, coughing, shortness of breath, chest tightness, together with difficulty in expiration, sputum (occasionally).
Why is asthma important?
It is common, dangerous and expensive.
What gender is thought to have the most cases of asthma in childhood?
Males
What gender is thought to have the most cases of asthma in adulthood?
Females.
What two disease processes result in asthma?
Widespread narrowing of airways and increased airway recativity
What can airway reactivity cause?
It can cause airway narrowing either sponatneously or to a stimuli.
What is atopy?
The body’s predisposition to to develop an antibody called immunoglobin E in response to exposure to environmental allergens and is an inheritable trait.
Such as asthma, eczema and hay fever.
What are proven risk factors for asthma?
Hereditary, Smoking, Ocupation, Obesity, Diet
Which parent is more important in passing on an atopical disease?
Mother by 3x
What is the hygiene hypothesis?
There is reduced exposure to microbes and so children born on farms are less likely to develop asthma
What are the types of variations of symtoms?
- Daily variation (Nocturnal/early morning)
- Weekly variation (occupation, better at weekends or holidays)
- Annual variation (environmental allergens)
What are other triggers to asthma?
Exercise, cold air, cigarette smoke, perfumes, Pets, Tree, Pollen, Food and drugs.
What are important questions to ask in the past medical history of an asthmatic patient?
Childhood asthma
Wheeze
Eczema
Hay Fever.
What are important questions to ask about during the history?
Current inhalers (also confirm the technique)
Beta-blockers, aspirin, and NSAIDs (Non-steroidal anti-inflammatory drugs)
Effect of previous drugs/inhalers.
What are important questions to ask in the family history?
Asthma and other atopic disease.
What are important questions to ask in the social history?
Tobacco, recreational drugs, vaping
Pets
Occupation
Psychological aspects
What might be helpful to do in an clinical examination for asthma?
Breathless on exertion
Hyperinflated chest
Wheeze
What signs might be present if it isn’t asthma?
Finger clubbing, Stridor, Asymmetrical expansion, dull percussion note, cervical lymphadenopathy (lymph nodes in the neck)
If it isnt asthma, what could it be?
- Generalised airflow obstruction (COPD (Irreversible AFO), Bronchiectasis, Cystic Fibrosis
- Localised airway obstruction: Tumour and foreign body
- Cardiac
What is a good test to differentiate between asthma and COPD?
Full pulmonary function testing
What is reversibility testing?
This is when the FEV1 is measured before and 15 minutes after a dose of salbutamol (inhaled or nebulized).
Response to oral corticosteroids is checked after 2 weeks.
What 3 chemicals are used to measure airway responsiveness?
Methacholine, Histamine, exhaled nitric oxide and Mannitol
What are other useful investigations for asthma?
Chest X-Ray (hyperlucent or hyperinflated)
Skin prick testing
Total and specific IgE
Full blood count
How do we assess how severe acute asthma is?
- Ability to speak
- Heart rate
- Respiratory rate
- PEF
- Oxygen saturation / Arterial blood gases
What symptoms are present in moderate asthma?
Able to speak and complete sentences, HR < 110, RR < 25, PEF (Peak expiratory flow) 50 - 75%
What symptoms are present in severe asthma?
Inability to complete sentences in one breath, HR > 110, RR > 25, PEF 33 - 50%
What symptoms are present in life-threatening asthma?
Grunting, impaired consciousness, confusion, exhaustion, bradycardia, arrhythmia, hypotension, PEF < 33%, silent chest
What are the main symptoms of near fatal asthma?
Raised PaCO2 and need for mechanical ventilation.
What causes the airways to be inflamed?
Immune system
What is the prevalence of asthma?
Children 10-15% M > F, Adults 5 - 10% F > M
What are the genetic risk factors for asthma?
Atopy
Inherited tendency to IgE response to allergens. Asthma, eczema, hayfever, food allergy Markers, skin prick tests, IgE. Strongest risk factor: personal, familial atopic tendency - Maternal atopy most influential
What allergens can occupation expose you to?
Isocyanates (paints), Colophony (welding solder flux), Laboratry Animals, Grains, Enzymes, Drugs, Crustaceans
What are essential investigation for asthma diagnosis?
Airflow obstruction Variability and reversibility of airflow obstruction
What is the effect of maternal smoking on FEV1?
FEV1 is reduced.
What is the effect of maternal smoking on Wheezy illness, airway responsiveness, asthma and severity?
All increase
What is the grandmother effect?
Grandchildren are far more likely to suffer from asthma if their grandmothers smoked while pregnant.
What is body mass index positively associated with?
Asthma, Wheezing, airway hyperactivity
Which diet substances affect risk of asthma?
Decrease in anti oxidants and N-3 polyunsaturated fatty acids = risk factor. Increase in N-6 polyunsaturated fatty aids = risk factor. Too much or too little vitamin D
Give an example of microbial products.
Endotoxin, glucans, extrascapular polysaccharide. Microbial diversity also important in redusing risk of asthma and allergy.
Which indoor cleaning products have an increased risk of causing cancer?
Volatile organic compounds, Formaldehyde, Fragrances.
What feature of the dust mite is allergenic?
Protease in droppings.
What influence does affluence have on allergens?
Increases the likelihood of sensitisation to local allergens
What is the most important consideration when making an asthma diagnosis?
HISTORY
What common health conditions are important to consider when diagnosing asthma?
Childhood asthma, bronchitis, eczema, hayfever and eczema are other atopic conditions
What are the two positive findings for asthma?
Airflow obstruction, variability and or reversibility of airflow obstruction.
How can you determine if someone has obstructed airways?
FEV1 is less than 80% predicted and FEV1/FVC ratio<70%
- What do FEV1 and FVC tell us respectively?
Airway diameter and lung capacity
After confirmation of obstructed airways, what is your next step in the diagnosis of asthma?
Full pulmonary function tests, confirmation of reversibility with B2 agonists and steroids
After confirmation of obstructed airways, what is your next step in the diagnosis of asthma?
Full pulmonary function tests, confirmation of reversibility with B2 agonists and steroids
If airways are not obstructed what is your next step in diagnosis?
Peak flow monitoring, Bronchial provocation with nitric oxide
What is a bronchial provocation test?
Evaluates how sensitive the airways in your lungs are.The spirometry results are compared before and after you inhale a spray to see what changes there are in your breathing. Spray is usually metyhacholine.
What are the tests involved in the full pulmonary function testing?
Lung volumes, Carbon monoxide gas transfer.
What is gas trapping?
Abnormal retention of air in thelungswhere it is difficult to exhale completely. Observed inobstructive lung diseasessuch asasthma, bronchiolitis obliterans syndrome andchronic obstructive pulmonary diseasessuch asemphysemaandchronic bronchitis.
How is lung residual volume measured of the lungs?
Helium dilution technique: The patient inhales breaths of helium and oxygen in a closed system. Concentration of helium will decrease as it diffuses into all areas of the lung. The amount of concentration reduction it indicative of the residual capacity
What is the residual volume and total lung capacity of a patient who is asthmatic?
Increased residual volume, increased total lung capacity.
What is the carbon monoxide gas transfer used to determine?
Ability of gas transport across the alveoli, alveoli are unaffected in asthma it is only the airway that are affected.
When spirometry is normal why is it important to measure peak flow?
Looking for variability in airflow obstruction. Lung function in clinic may(usually) be normal
What test is likely to increase use of according to NICE?
Exhaled nitric oxide tests
How would you read the methacholine responsiveness?
Reduction of FEV1 by over 20%
What is the effect of methacholine?
Acts like acetylcholine to constrict airways. Nebulising the substance you think they are susceptible to can be useful too.
What is the exhaled nitric oxide in an asthmatic patient compared to normal?
Increase in nitric oxide
