Asthma Flashcards
Pathophysiology [4]
Environmental/genetic triggers cause CD4+ T cell inflammation
Eosinophil, mast cell, macrophage infiltration
Airway obstruction caused by:
- Chronic hyper responsiveness of airway - type I
- Smooth muscle contraction
- Inflammatory infiltrate + mucous = narrowing
What are the types of onset of asthma [5]
Early infant / VIW Childhood Adult Exertional Occupational - normal peak flow when not at work (refer to specialist)
Aetiology [2]
- Susceptibility loci in the genes ADAM33, GPRA and ORMDL3, and polymorphisms of tumour necrosis factor.
- Infection (rhinovirus, influenza, mycoplasma), allergens (pollen), occupational exposures and stress.
What is atopy and what happens in atopy [2]
- 1st exposure sensitises T cells, B cells produce IgE which binds to mast cells
- 2nd exposure mast cells release contents
What triggers asthma [5]
What drugs should be avoided [3]
- Exercise
- Cold air
- Pollen
- Smoke
- URTI
BB
NSAID
Aspirin
What are the symptoms of asthma [4]
- VARIABLE + REVERSIBLE
- Often worse at night - diurnal variation - Expiratory wheeze - narrow airways = turbulent
SOB - more effort to inflate hyper inflated lungs - Cough - dry, exertion, nocturnal
- Chest tightness - voluntary contract muscles
- What are the signs of asthma in a severe presentation [6]
Severe presentations:
* Tachycardia
* Tachypoea
* Hypercapnia + hypoxaemia
* Cyanosis
* Reduced PEFR
* Using acccessory muscles
What are complications of asthma
Pneumothorax - parenchyma ruptures due to increased alveolar pressure
What is a delayed eosinophil response [4]
Conjunctivitis
Rhinitis
Dermatitis
Bronchiole constriction
What are RF for asthma [4]
Atopy, family history of asthma
Nasal polyposis, obesity
Reflux esophagitis
Maternal factors: vit D deficiency, LBW, pre-term labour
Investigations in asthma
- Blood tests: FBC, eosinophilia (e.g. ABPA or Churg Strauss), IgE and aspergillus precipitins.
- Imaging: CXR may show hyperinflation.
- Spirometry, PEFR: show obstructive picture & diurnal variability.
- Allergy testing: on clinical suspicion specific IgE test (formerly known as a Radioallergosorbant test) or skin prick test can be performed.
- Bronchial challenge test: used in diagnostic uncertainty, this test uses inhaled histamine or metacholine to measure bronchial hyperresponsiveness (BHR).
What would spirometry results look like in a patient with asthma?
Amount of air and speed during exhalation
FEV1 <70% = obstructive
FVC = normal
Ratio reduced
◆ May be normal between episodes due to variability. A confident diagnosis of asthma can be made if there is:
◆ 15% diurnal PEFR variation on >3 days a week.
◆ FEV1 >15% decrease after 6 minutes of exercise.
◆ Reversibility with bronchodilator – FEV increase >2% or 200 mL increase.
Chronic asthma management [11]
BTS guidelines 2019 Steps 1-3
NICE guidelines 2017 Steps 4-7
SABA as adjunct
- SABA + ICS
- Add LTRA
- Add LABA
- SABA +/- LTRA + MART
- SABA +/- LTRA + MART (medium dose)
- SABA +/- LTRA: (choose one)
6a) MART (high dose)
6b) Add theophylline
6c) Refer to specialist - Oral steroids daily + high dose ICS
What are lifestyle measures [7]
Smoking cessation Weight loss Inhaler technique PEF 2x daily Asthma action plan Flu vaccine Yearly review
What should be covered in an annual review of a chronic asthma patient? [5]
Assess symptoms Measure lung function Check inhaler technique Adjust dose Consider step down
Salbutamol SE [4]
Tremor
Cramp, Headache
Flushing, Palpitations, Tachycardia
Hypokalaemia so monitor U+E