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.

Asthma Flashcards by Jia Ying Tan

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

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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)

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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.

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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

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What triggers asthma [5]

What drugs should be avoided [3]

Exercise
Cold air
Pollen
Smoke
URTI

BB
NSAID
Aspirin

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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

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What are the signs of asthma in a severe presentation [6]

Severe presentations:
* Tachycardia
* Tachypoea
* Hypercapnia + hypoxaemia
* Cyanosis
* Reduced PEFR
* Using acccessory muscles

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What are complications of asthma

Pneumothorax - parenchyma ruptures due to increased alveolar pressure

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What is a delayed eosinophil response [4]

Conjunctivitis
Rhinitis
Dermatitis
Bronchiole constriction

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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

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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).

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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.

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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

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What are lifestyle measures [7]

Smoking cessation
Weight loss
Inhaler technique
PEF 2x daily
Asthma action plan
Flu vaccine
Yearly review

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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

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Salbutamol SE [4]

Tremor
Cramp, Headache
Flushing, Palpitations, Tachycardia
Hypokalaemia so monitor U+E

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When do you start ICS (preventer) [3]

SABA 3x
Waking one night
Oral steroids for exacerbation in past 2 years

Beclometasone SE [4]

Adrenal crisis
Dysphona
Oral candidiasis
Stunted growth in children

What are SE of LAMA [4]

GI
Dry mouth
Headache
Glaucoma

How do you measure control [4]

S- SABA used 1+ a week
A- Absence from school or work
N- Nocturnal Sx
E- Exertional Sx

What should chronic asthma have [5]

Asthma action plan
Vaccines for flu and pneumonia
Smoking cessation
Bronchial thermoplasty
Annual review

What is Ddx of asthma [8]

Pulmonary oedema
COPD
Obstruction - foreign body / tumour
SVC obstruction - wheeze and SOB (not episodic)
Pneumothorax
PE
Bronchiectasis
Bronchiolitis

DDX for wheeze [3]

Tumour
FB
Localized obstruction

What are the low medium and high doses for ICS?

<400mcg
(different dosage for children)
400-800mcg medium dose
>800mcg is high dose

Presentation: moderate attack [3]

Increasing symptoms PEF>50-75% predicted No features of acute severe asthma Current guidelines suggest patient may be discharged from hospital if PEFR >75% 1 hour post-bronchodilator treatment.

Presentation: severe attack [4]

Any one of: - PEF 33-50% predicted - RR>25 - HR>110 - Inability to complete sentences.

What is life threatening? [8]

Any one of: - PEF <33% of predicted - SPO2 <92%, O2 <8kpa, normal PaCO2 - Silent chest - Cyanosis - Exhaustion - Impaired consciousness - Arrhythmia

What are signs of a (near) fatal attack? [2]

Raised PaCO2 | Requiring mechanical ventilation with raised inflation pressures

What do you do for mild attack [3]

Oral prednisone 7 days SABA Antibiotic therapy if infection

Management of severe acute exacerbations [6]

1. Oxygen (SpO2 target 94-98%) 2. High dose nebulised SABA (if deterioration continuous with 4-6h SAMA) 3. Nebulised IPATROPIUM BROMIDE 4. Oral PREDNISOLONE 40-50mg daily for at least 5d (or IV HYDROCORTISONE) 5. MAGNESIUM SULPHATE INFUSION after consultation with senior medical staff 6. IV AMINOPHYLLINE or SALBUTAMOL

Management of life-threatening asthma attack [8]

ITU - always if raised PaCO2 IV theophylline, IV salbutamol IV magnesium sulphate IV steroid = final step NIV Intubation ECMO in extreme cases

DDX asthma attack [5]

``` Exacerbation COPD PE anaphylaxis Pulmonary oedema Obstruction ```

When do you discharge [4] | Describe follow up

``` PEF >75% within 1h of Rx Stable 24 hours Steroid and bronchodilator therapy Written management plan Organise follow up with GP in 2 days and asthma clinic in 4 weeks ```

Occupational asthma | Causes - name 10

- baking, pastry making - spray painting - lab work, dental work - animal work - food processing - welding, soldering, metalwork, woodwork, chemical processing - textile, plastics and rubber manufacture - farming

Occupational asthma Classification [2] Presentation [3]

* Hypersensitivity induced occupational asthma: * Irritant induced asthma (reactive airways dysfunction syndrome (RADS)) Consider in all workers with recurrence of childhood asthma or a diagnosis of new asthma in adulthood Improve when away from work

Occupational asthma | Ix [4]

1. Serial PEFR measurements at home and at work every 2h from waking to sleeping for 4w, keeping mx constant and documenting times at work - >3 days in each consecutive work period, >3 series of consecutive days at work and 3d away from work >4 readings/d 2. Skin prick testing 3. Specific bronchial provocation testing

Describe specific bronchial provocation testing [3]

- gradual increase in specific inhalational agent with spirometry - positive result would be if FEV1 falls by ≥15% from baseline - generally safe and this is the gold standard but only done at tertiary centers

Management of occupational asthma

Relocation away from exposure | Within 12m of first symptoms

How does Mag sulf work in severe asthma?

Magnesium sulfate has bronchodilator activity, possibly due to inhibition of calcium influx into airway smooth muscle cells.

Further treatment for chronic asthma

* Daily oral steroid may be commenced at the lowest dose that gains control. * Steroid sparing agents if poor control persists. Methotrexate and ciclosporin are recommended, but there is limited evidence to support their use. * Continuous terbutaline (β2 agonist) infusions via a portable syringe driver. * Omalizumab (an IgE recombinant monoclonal antibody) has been approved by NICE as an add-on therapy to step 5 treatment in patients with severe atopic asthma. It has been shown to reduce exacerbation rates and asthma symptoms with a reduction in steroid usage (2). * Mepolizumab (an anti-IL-5 monoclonal antibody) may also be considered in severe eosinophilic asthma.