What is asthma?
Asthma is a chronic disease characterised by a hyper responsiveness of the trachea and bronchi to various stimuli and manifested by a widespread narrowing of the airways that changes in severity either spontaneously or as a result of treatment.
Discuss the pathological features of asthma.
Airway inflammation: inflammatory cell infiltration of airways, smooth muscle hypertrophy and thickening, and disruption of the airway membrane.
Describe an asthmatic airway.
An asthmatic airway has inflamed and thickened walls. During an exacerbation, the bronchial smooth muscles constrict causing air to be trapped in the alveoli.
What are some causes of acute exacerbations of chronic asthma?
-respiratory viruses.
-bacterial infections.
-allergens.
-pollutants.
-occupational exposure.
What are non-modifiable risk factors associated with asthma?
-Personal (hayfever, eczema, asthma) or family history of atopy.
-Male sex (asthma development) or female sex (persistence to adulthood).
-Prematurity and low birth weight.
What are modifiable risk factors associated with asthma?
-Exposure to tobacco smoke, inhaled particulates and occupational dusts.
-Obesity.
-Social deprivation.
-Infections in infancy.
Differentiate the main cause of wheezing illness.
Inflammation and narrowing of the airway in any location, from your throat out into your lungs, can result in wheezing. The most common causes of recurrent wheezing are asthma and chronic obstructive pulmonary disease (COPD), which both cause narrowing and spasms (bronchospasms) in the small airways of your lungs.
What are the respiratory symptoms of asthma?
-Coughing.
-Wheezing.
-Shortness of breath.
-Chest tightness.
-Together with difficulty in expiration.
Describe the specific features to be included in the clinical history of asthma.
- Recurrent episodes of symptoms.
- Recorded observation of wheeze.
- Symptom variability (e.g. nocturnal, occupation, environmental allergens (annual)).
- Personal history of atopy (e.g. hayfever, eczema etc.).
- Absence of symptoms of alternative diagnosis.
- Historical record of variable PEF or FEV1.
Define the investigations used to diagnose asthma.
-Initial detailed respiratory history and examination.
-If high probability of asthma > treatment initiated and monitored with spirometry and symptom scores.
-Intermediate probability > spirometry with bronchodilator reversibility, peak flow charts and skin prick testing, FeNO levels.
-low probability > other causes investigated.
Explain how to assess the severity of acute, severe asthma.
- Ability to speak > inability to complete sentences in one breath.
- Heart rate > or equal to 110.
- Respiratory rate > or equal to 25.
- PEFR > 33-50% or best.
Describe the clinical management of severe asthma.
- SABA + med dose ICS + LABA.
- SABA + high dose ICS + LABA.
- SABA + high dose ICS + LABA + oral corticosteroids.
Specialist:
-Omalizumab: anti-IgE antibody.
Describe the clinical management of acute asthma.
- Non-rebreather supplemental O2 >92%.
- SABA + SAMA ipratropium bromide (nebulizer or inhaler).
- IV or oral corticosteroids.
- IV magnesium sulfate.
- positive pressure ventilation.
- intubation.
Describe omalizumab.
Omalizumab is a specialist treatment, and is termed a “biologic” because it is an antibody. It specifically targets IgE (an antibody involved in the allergy response), compared to e.g. prednisolone which has a much more generalised anti-inflammatory action.
Carbon monoxide gas transfer is ______ or ______ in asthma and _______ in COPD.
Carbon monoxide gas transfer is normal or increased in asthma and decreased in COPD.
What likely causes the development of childhood asthma?
It is likely that an underlying abnormality in the epithelium leads to the development of both asthma and allergies.
