Respiratory: Asthma Flashcards
(42 cards)
Define asthma
A disease that includes the symptoms of wheeze, cough and breathing difficulty together with reversible airway obstruction, airway inflammation and bronchial hyper responsiveness.
However, asthma is a heterogeneous and variable condition, frequently not all of the above are present in each individual.
Not everyone that wheezes has asthma. What other causes of wheeze are there?
Respiratory infections, especially viral - bronchiolitis, bronchiolitis obliterans
Airway abnormalities
- bronchiomalacia
- chronic lung disease of prematurity
Foreign body inhalation
What is viral induced wheeze?
A virus that triggers reversible narrowing in airways
Responds to asthma medication
Why can the diagnosis of asthma be difficult?
It is a variable condition - part of its characteristic
From what age can spirometry be typically done in children?
From 5 years old
What tests should be done (if old enough)?
Spirometry and bronchodilator reversibility test
Peak flow variability
To test for eosinophil inflammation or atopy: FeNO test, blood eosinophils, skin prick test for IgE
What symptoms are associated with asthma?
Wheeze Cough SOB Chest tightness Exercise induced cough/wheeze Nocturnal cough/wheeze
The symptoms tend to be…
Variable
Intermittent
Worse at night and early in morning
Provoked by triggers - pollen, dust, smoke, emotion, animal dander
Positive response to asthma therapy
Interval symptoms ie symptoms between acute exacerbation
What factors increase the risk of asthma?
Personal/family history of atopy Previous episode of bronchiolitis Low birth weight, prematurity Poor maternal control of asthma in pregnant women Bottle fed Exposure to passive smoking
What can be seen on examination?
Chest usually normal between attacks
Long standing asthma: hyperinflation, generalised wheeze, Harrison’s sulci
Evidence of eczema
In severe cases: growth restriction - plot growth each time
What are Harrison’s sulci?
Permanent indentation of the chest wall along the costal margins where the diaphragm inserts
What are features of a mild to moderate acute asthma presentation?
O2 more than 92% RR < 30 in over 5 RR < 40 under 5 No or minimal accessory muscle usage Feeding well, talking full sentences Wheeze (May need stethoscope to hear)
What are features of severe asthma?
O2 < 92% RR> 30 over 5 RR>40 under 5 Too breathless to feed or talk HR > 125 over 5 HR> 140 under 5 Use of accessory muscles Audible wheeze PEF 33-50% of best/predicted
What are features of life threatening asthma?
O2 <92% Silent chest Poor respiratory effort Altered consciousness - confused or drowsy Agitation Cyanosis PEF < 33% best or predicted
There should be a low threshold for admittance if…
Previous CICU/severe episode/rapid deterioration
Repeated ED attendance over last year
On high dose ICS
What is the airflow obstruction a result of?
Smooth muscle constriction
Mucous production
Bronchial inflammation
What does bronchial inflammation result from?
IgE dependent release of mediators from mast cells e.g histamine, tryptase, prostaglandins
These mediators cause further bronchoconstriction and inflammation
What can mucus plugs do?
Block small airways and further limit airflow
What is airway hyper responsiveness?
Exaggerated constriction in response to variety of stimuli
- sudden onset of symptoms
Although asthma is characteristically described as having reversible airflow limitation, what can happen over time?
Airway remodelling can occur - the airway limitation only partially reversible.
Ongoing inflammation can cause permanent structural changes e.g thickening of membrane, fibrosis, smooth muscle cell hypertrophy and hypersecretion
Describe the cough
Dry and non productive
Nocturnal
Describe the wheeze
Typically expiratory, but if severe can be biphasic
Usually polyphonic (variable pitch)
Can usually be heard w/o stethoscope
In severe asthma wheeze may disappear and no airway sounds = silent chest
What signs suggest increased work of breathing?
Tachypnoea Use of accessory muscles Intercostal, subcostal recessions Head bobbing Grunting Nasal flaring Sitting forward posture
Do children under 5 need investigations?
NICE recommends treating symptoms based on a clinical diagnosis without investigation and then carry out testing if symptoms still present at 5
