GP-respiratory Flashcards
Asthma definition
presentation of asthma, examination signs and differentials
typical asthma triggers
The NICE guidelines (2020) recommend initial investigations in patients with suspected asthma:
Diagnostic differences between patients over 17years old and those aged 5-16 years
How does spirometry work and which value indicates asthma?
test used to establish objective measures of lung function. It involves different breathing exercises into a machine that measures volumes of air and flow rates and produces a report. A FEV1:FVC ratio of less than 70% suggests obstructive pathology (e.g., asthma or COPD).
How does reversibility testing work and which results indicate asthma?
involves giving a bronchodilator (e.g., salbutamol) before repeating the spirometry to see if this impacts the results. NICE says a greater than 12% increase in FEV1 on reversibility testing supports a diagnosis of asthma.
How does FeNO testing work and which value indicates asthma?
Fractional exhaled nitric oxide (FeNO) measures the concentration of nitric oxide exhaled by the patient. Nitric oxide is a marker of airway inflammation. The test involves a steady exhale for around 10 seconds into a device that measures FeNO. NICE say a level above 40 ppb is a positive test result, supporting a diagnosis. Smoking can lower the FeNO, making the results unreliable.
How is peak flow variability measures and which result indicates asthma?
is measured by keeping a peak flow diary with readings at least twice daily over 2 to 4 weeks. NICE says a peak flow variability of more than 20% is a positive test result, supporting a diagnosis.
Direct bronchial challenge testing: how does it work and which value indicates asthma?
opposite of reversibility testing. Inhaled histamine or methacholine is used to stimulate bronchoconstriction, reducing the FEV1 in patients with asthma. NICE say a PC20 (provocation concentration of methacholine causing a 20% reduction in FEV1) of 8 mg/ml or less is a positive test result.
long term drug treatment for asthma
Maintenance and reliever therapy (MART)
* a form of combined ICS and LABA treatment in which a single inhaler, containing both ICS and a fast-acting LABA, is used for both daily maintenance therapy and the relief of symptoms as required
* MART is only available for ICS and LABA combinations in which the LABA has a fast-acting component (for example, formoterol)
additional management for ashtma
- Individual written asthma self-management plan
- Yearly flu jab
- Yearly asthma review when stable
- Regular exercise
- Avoid smoking (including passive smoke)
- Avoiding triggers where appropriate
Beta-2 adrenergic receptor agonists MOA and examples
are bronchodilators (they open the airways). Adrenalin acts on the smooth muscle of the airways to cause relaxation. Stimulating the adrenalin receptors dilates the bronchioles and reverses the bronchoconstriction present in asthma. Short-acting beta-2 agonists (SABA), such as salbutamol work quickly, but the effects last only a few hours. They are used as reliever or rescue medication during acute worsening of asthma symptoms. Long-acting beta-2 agonists (LABA), such as salmeterol, are slower to act but last longer.
Inhaled corticosteroids (ICS) MOA and example
such as beclometasone, reduce the inflammation and reactivity of the airways. These are used as maintenance or preventer medications to control symptoms long-term and are taken regularly, even when well.
Long-acting muscarinic antagonists (LAMA) MOA and examples
such as tiotropium, work by blocking acetylcholine receptors. Acetylcholine receptors are stimulated by the parasympathetic nervous system and cause contraction of the bronchial smooth muscles. Blocking these receptors dilates the bronchioles and reverses the bronchoconstriction present in asthma.
Leukotriene receptor antagonists MOA and example
such as montelukast, work by blocking the effects of leukotrienes. Leukotrienes are produced by the immune system and cause inflammation, bronchoconstriction and mucus secretion in the airways.
Theophylline MOA
works by relaxing the bronchial smooth muscle and reducing inflammation. Unfortunately, it has a narrow therapeutic window and can be toxic in excess, so monitoring plasma theophylline levels is required.
Maintenance and reliever therapy (MART) MOA
Involves a combination inhaler containing an inhaled corticosteroid and a fast and long-acting beta-agonist (e.g., formoterol). This replaces all other inhalers, and the patient uses this single inhaler both regularly as a preventer and also as a reliever when they have symptoms.
definition of low, moderate and high dose inhaled corticosteroids
- <= 400 micrograms budesonide or equivalent = low dose
- 400 micrograms - 800 micrograms budesonide or equivalent = moderate dose
- > 800 micrograms budesonide or equivalent= high dose.
Bronchiectasis definition
Bronchiectasis involves permanent dilation of the bronchi, the large airways that transport air to the lungs. Sputum collects and organisms grow in the wide tubes, resulting in a chronic cough, continuous sputum production and recurrent infections.
Bronchiectasis causes
- post-infective: tuberculosis, measles, pertussis, pneumonia
- cystic fibrosis
- bronchial obstruction e.g. lung cancer/foreign body
- immune deficiency: selective IgA, hypogammaglobulinaemia
- allergic bronchopulmonary aspergillosis (ABPA)
- ciliary dyskinetic syndromes: Kartagener’s syndrome, Young’s syndrome
- yellow nail syndrome
- Alpha-1-antitrypsin deficiency
- Connective tissue disorders (e.g., rheumatoid arthritis)
TOM TIP: Yellow nail syndrome is characterised by yellow fingernails, bronchiectasis and lymphoedema. Patients are stable and have good clinical signs, making it a good choice for OSCEs. As it is rare, examiners will score high marks if you can combine these features and name the diagnosis.
Bronchiectasis features
Key presenting symptoms are:
Shortness of breath
Chronic productive cough: large amount of sputum
Recurrent chest infections
Weight loss
Haemoptysis
Signs of bronchiectasis on examination include:
Signs of bronchiectasis on examination include:
- Sputum pot by the bedside
- Oxygen therapy (if needed)
- Weight loss (cachexia)
- Finger clubbing
- Signs of cor pulmonale (e.g., raised JVP and peripheral oedema)
- Scattered crackles throughout the chest that change or clear with coughing
- Scattered wheezes and squeaks
bronchiectasis CXR
Chest x-ray showing tramlines, most prominent in the left lower zone
Bronchiectasis CT
CT chest showing widespread tram-track and signet ring signs
Bronchiectasis investigations
Most common organisms isolated from patients with bronchiectasis:
Haemophilus influenzae (most common)
Pseudomonas aeruginosa
Klebsiella spp.
Streptococcus pneumoniae
Bronchiectasis management