Asthma Flashcards
What is the definition of asthma?
A disease characterised by an increased responsiveness of the trachea and bronchi in response various stimuli and manifested by a widespread narrowing of airways which changes in severity either spontaneously or as a result of therapy
What mediates the airway inflammation?
The immune system
What are the proven risk factors for asthma?
Genetic atopy, occupation and smoking (maternal during pregnancy)
What are the possible risk factors for asthma?
Obesity, diet, reduced exposure to microbes and indoor pollution (household chemicals)
When taking a history what symptoms suggest asthma?
recurrent episodes, wheeze, history of atopy, shortness of breath, chest tightness, chest pain, cough (usually dry) and possibly sputum
What might differentiate asthma from other conditions?
Triggers: exercise, cold air etc.
Daily variation - usually worse at night
Weekly and annual variation
What would you be looking out for in their past medical history?
Childhood asthma, bronchitis, eczema and hayfever
What would you check in relation to medication?
Inhalers (dose and technique)
Other drugs such as beta blockers or aspirin
What would be looking out for in their social history?
Smoking, pets, occupation (past/present) and psychosocial aspects
On examination, which signs would suggest that it is not asthma?
Clubbing, cervical lymphadenopathy, stridor, asymmetrical expansion, dull percussion note or crepitations
If spirometry was normal in someone who you suspected of asthma, what would be your next step?
Give them a peak flow and monitor the variability
How could you exclude COPD from the list of possible diagnoses?
By using lung volume and carbon monoxide gas transfer investigations. Also the response to oral corticosteroids and bronchodilators
What is classed as significant reversibility?
An increase of FEV1 of 15%/200ml or more in response to a bronchodilator
Apart from bronchodilators, what else can be used to test the reversibility of and help diagnose a patients symptoms?
The response to oral corticosteroids such as prednisolone
What optional investigations can a specialist carry out to aid the diagnosis?
Airway responsiveness to methacholine, histamine, mannitol and exercise
Exhaled Nitric Oxide
How is occupational asthma diagnose?
Serial peak flow readings, antibodies and bronchial challenge
What investigations may be useful in ruling out something else or working out the trigger?
Chest X-ray, skin prick testing, total and specific IgE and full blood count (eosinophilia)
What signs are used in the assessment of acute severe asthma?
Ability to speak, heart rate, respiratory rate, PEF, oxygen saturation and arterial blood gases
What are the similarities between children and adults with asthma?
Similar symptoms and prevalence. Same triggers, same treatment and same pathology
What is the relevance of the reticular basement membrane in children with asthma?
It is thicker in children with asthma than in those without
In relation to children, which gender is asthma more common in?
In children asthma is more common in boys
What are the “multiple hits” that cause asthma?
Genes, abnormal lungs, atopy and exposure to triggers
What is mainly used to diagnose asthma in children?
History taking
When is it unlikely that a child has asthma?
When they only have a cough - likely to be one of many other things
Name the features of a moderate asthma attack
- Able to speak complete sentences
- HR < 110
- RR < 25
- PEF 50-75% of predicted or best
- SaO2 > 92%
- PaO2 >8 kPa
Name the features of a severe asthma attack
Any one of:
- Unable to speak or complete sentences
- HR > 110
- RR > 25
- PEF 33-50% predicted or best
- SaO2 > 92%
- PaO2 > 8 kPa
Name the features of a life threatening asthma attack
An one of:
- Grunting
- Impaired consciousness, confusion and exhaustion
- HR > 130 or bradycardic
- Hypoventilating
- PEF < 33% predicted or best
- Cyanosis
- SaO2 < 92%
- PaO2 < 8 kPa
- PaCO2 normal
Name the feature that suggests a near fatal asthma attack
Raised PaCo2
Which features would make it more likely that child has asthma?
- Wheeze (+/- URTI)
- SOB at rest
- Parental asthma
- Responds to treatment
List the differential diagnosis for asthma
- Foreign body
- Cystic fibrosis
- Immune deficiency
- Ciliary dyskinesia
- Aspiration
- Gastro-oesophageal reflux
- Tracheo-bronchomalacia
