Asthma Flashcards by Elizabeth McCabe

What is the basic cellular underpinning of asthma?

Hyper-responsive airways disease
(type 1 hypersensitivity - IgE mediated)
Exposure - Th2 response, mast cells become sensitised to antigen, IgE binds to Fc epsilon receptors on mast surface
Second + exposure - mast cell degranulation, release mediators such as histamine (broncho constrict, vasodilate), PGD2 (vascperm inc), LTA4 (inc mucus), and pro-inflammatory cytokines TNF-A, IL4, IL12 etc
Later inflammatory response: eosinophils, basophils, Th2 cells. Proteases damage lung tissue. Leads to destruction of epithelium chronic inflammatory changes and risk of airway remodelling.

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What are the key gross changes in the pathophysiology of asthma?

Reduced airway diameter due to airway inflammation and production of excess mucous.
Bronchoconstriction
Airway oedema.
Difficult to exhale

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Define asthma

Chronic inflammatory airway disease characterised by: chronic bronchial inflammation, airway hyperresponsiveness and obstructive air-flow limitation

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What are the key distinctive features of asthma?

Diurnal variability - PEFR variation >20% - worse at night or early morning.
Usually presents in childhood, however can develop in adults.

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What are the different forms of asthma?

Eosinophilic
Non-eosinophilic
Occupational
Irritant induced
Exercise-induced bronchospasm.

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What are the typical symptoms of asthma?

Cough (nocturnal /dry)
Wheeze (widespread polyphonic wheeze)
Chest tightness
SOB - intermittent, worse at night/monring/trigger
Variable expiratory airflow limitation - vary in time and intensity
Triggerd by exercise, allergen, irritant, changes in weather, viral respiratory infection
May resolve spontaneously or in response to medication - may be absent for weeks or months at a time

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What is meant by acute asthma exacerbation?

Onset of severe asthma symptoms, can be life-threatening.

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What can cause a wheeze sound in the lungs?

Airway obstruction - narrowed airway - results in a wheeze
Asthma - reversible
COPD - fixed
Upper airway obstruction (stridor)
Foreign body
Pulmonary edema (cardiac wheeze)
Eosinophilic vasculitis /EGPA / MPO-ANCA
Respiratory bronchiolotitis

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What is important to do when taking a history from a potential asthmatic patient?

Characterise resp pathology - pattern of symptoms (variation, timing)
Explore trigger (pets, carpets, temp, occupational exposure, smoking)
Personal or family history of atopy
Assess severity of asthma - best expected and recent PEFR, treatment adherence, attendance to hospital with exacerbation/previous ICU
Normal SABA requirements

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What may be found during respiratory examination of an asthmatic patient?

Around bedside - oxygen, inhaler, space, PEFR meter
Inspection - inc work of breathing, cyanosis, cough, audible wheeze
Peripheries - fine tremor (salbutamol), tachycardia, oral candidiasis (steroid inhaler use)
Chest - polyphonic expiratory wheeze.

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What are some risk factors and triggers for asthma?

Irritant induced - chemical and perfumes - cause tissue damage and generate an immune response
Allergic/sensitized - classic, repeated trigger recongised as foreign (pets, pollen), should establish relationship between trigger and when asthma worse.
Family history - first degree relatives with atopic history
Prematurity and LWB
Medications - beta blockers and NSAIDs - exacerbate asthma.

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What is meant by occupation asthma?
Types?

Symptoms improve when patient away from work
Onset >1yrs after starting work - time for sensitivity to develop
Sensitised induced (allergen response) or irritant induced (chemical cause local inflammation, immune response to inflamed tissue)

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What is the diagnostic process behind asthma?

More than one variable wheeze, cough, breathlessness and chest tightness
pMH or FH of atopic conditions
FeNO - eosinophilic inflammation is 17yrs+, 40ppb+
Spirometry - obstructive (FEV1/FEV <70%)
Bronchodilator reversibility - 12% improvement
Variable PEFR - 20% variability after BD for 2-4w.

May also give a BHR test, IgE blood test, RAST test.

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Describe the difference between obstructive and restrictive lung disease on spirometry.

Obstructive - FVC remains normal or slightly reduced, FEV1 reduced, FEV1/FVC <70

Restritive - FVC reduced, FEV1 reduces proportionately . FEV1/FVC ration remains around normal.

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How do we assess the functional impact of asthma on a patient?

Number of SABA used per week/day
Number of days missed from school/work
Nocturnal symptoms
Any recent exacerbation?
Ever required hospital attendance?
Ever been to intensive care?

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What safety netting should be provided to patients receiving community chronic asthma treatment?

Use of SABA >3x weekly - go to GP
<4hr gas between requirements for salbutamol - go to A&E
10 puffs of salbutamol without relief of symptoms - call 999

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What conservative management is often recommended for asthmatics?

Smoking cessation/avoidance of triggers
PEFR diary
Regular annual asthma reviews (typically in GP annually) - presonalised asthma plan and inhlaer technique education
Vaccination - flu, covid-19,

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What are some side effects of inhaled salbutamol ? (asthmatics)

Tachycardia
Tremor (fine)

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When is the use of inhlaed corticosteroids indicated in asthmatics?

Nocturnal symptoms
Recent severe exacerbation
SABA use >3 times/week

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What are the side effects of inhaled corticosteroid use? (asthmatic inhlaers)

Oral candida

What is the pharmacological treatment pathway for adult asthmatics?

Newly diagnosed - SABA
SABA only if infrequent, short lived wheeze, normal lung function
ICS first line maintenance if symp 3>w, night waking, SABA use >3w
Then offer LTRA
Then offer combined LABA and ICS, review LTRA or consider inc ICS dose
MART (budesonide and formoterol) regime and refer for specialist care.

Name the typical drug used for each class of inhaler/medication given in asthmatics?

SABA = salbutamol
ICS = inhaled budesonide, oral prednisolone
LABA = salmeterol
LTRA = montelukast

What are some common complications of asthma?

Exacerbations
Secondary Pneumothorax

What is an asthma exacerbation?

Infective of non-infective
Bronchospasm, mucosal thickening and mucous production
Narrows terminal airway = acute deterioation in breathlessness
Leads to hyperventilation until exacerbation resolves

At what severity is asthma considered moderate acute?

Increasing symptoms PEF >50-75% best or predicted No features of acute severe

At what point is asthma considered acute severe?

PEF 35-50% best or predicted RR >25/min HR >110bpm Inability to complete sentences in one breath

At what point is asthma considered life-threatening?

Acute severe asthma with any one of the following: PED <33% BEST or predicted SpO2 <92% PaO2 <8 kPa Normal PaCo2 Altered conscious level /exhausation Arrhythmia Hypotension Cyanosis Silent chest Poor respiratory effort

At what stage is asthma considered near fatal?

Raised PaCO2 and/or mechanical ventilation with raised inflation pressures.

What investigations should be done on an asthmatic?

Peak flow - severity Observations - severity Sputum culture - infective exacerbation ECG - tachy/arryhtmia FBC - eosinophils CRP - inflammatory markers ABG - respiratory alkalosis in moderate exacerbation, nor in life threating asthma, high in near fatal. CXR - focal changes, pneumothorax Spirometry - obstructive and reversibility pattern

What acute management should be used for asthmatics?

1. oxygen - 15L non-rebreath 2. Help 3. Salbutamol - 2.5-5mg nebs 4. Hydrocortisone - 100mg IV or prednisolone 40mg PO 5. Ipatropium 500mg neb 6. Theophylline (PDE5 inhibitor)- aminophylline infusion 7. Magneisum sulphate 2g IV over 20mins Escalate care 8. +/- antibiotics if infective exacerbation.

Before discharging an acute asthma admission what should be ensured?

Stable for 4hrs after exacerbation Ensure PEFR returned to >75%

If infective exacerbation of asthma how long should steroid/abx be continued?

Pred for 5 days +/- antibitoics

In life threatening asthma/tiring asthmatic what additional support may be required in ICU?

BPAP Intubation ECMO Due to loss of respiratory drive.

When is it not safe to send ana cute asthmatic home from ED?

Exacerbation whilst on course of steroids History of poor compliance with treatment History of depression/anxiety History of severe/refractory asthma (previous ICU) Pregnancy Poor social circumstances.

What should be done at the annual review of an asthmatic?

Asthma control - spirometery or peak flow variability testing Inhlaer technique Risk factors Discuss treatment options Check/update asthma action plan Assess asthma severity May discuss smoking, exercise, healthy weight maintenance

What are the four key disease processes that occur in asthma?

Chronic bronchial inflammation Airway hyper-responsiveness Obstructive airflow limitation Reversible

What type of hypersensitivity reaction is asthma?

Type 1

What are the several forms of bronchial asthma?

Occupational Exercise induced NSAID induced Allergic Thunderstorm

What is meant by brittle asthma?

Term to describe a severe type of asthma Type 1 - uncontrolled - regularly use high doses of inhaled steroids but still have large changes in PEF and active symptoms Type 2 - suddenly develop severe asthma attacks for no apparent reason despite having otherwise well-controlled asthma.

How do we assess the severity of asthma?

Best expected and recent PEFR Adherence with treatment Attendance to hospital with exacerbation/previous ICU admission Normal requirement for SABA/whether this has changed.

What on examination can be a sign that an asthmatic is reliant on their medication?

Fine tremor due to salbutamol Oral candidiasis due to oral steroids.

When using clinical judgment to determine the probability of an asthma diagnosis, what features should it be based on?

1. Variable symptoms of wheeze, cough, breathlessness and chest tightness 2. Personal/FH of atopic conditions 3. Results of FeNO testing 4. Results of objective tests including - spirometry, BDR, PEFV 5. Results of a direct bronchial challenge test with histamine or methacholine (requires specialist)

What is asthma COPD overlap syndrome?

Clinical conditions characterised by peristent airflow limitation with several features usually associated with both asthma and COPD. Increased reversibility, eosinophilic bronchial and systemic inflammation, and increased response to corticosteroids.

Who is asthma COPD overlap syndrome more common in?

1. Smokers or ex-smokers with a history of childhood asthma 2. Suspected to have a genetic polymorphism relationship. 3. Long term exposure to pollutants such as occupational dust 4. Allergen exposure 5. Poorly controlled asthma 6. Recurrent resp infections particularly in childhood 7. Age - more in adulthood 8. Female

How does Asthma COPD overlap syndrome present clinically?

Frequent exacerbations - often more severe than in COPD or asthma in isolation. Severe dysponea Cough Wheezing and chest tightness Poor health related quality of life

How does Asthma COPD overlap syndrome present on examination?

Prolonged expiration Wheezing on auscultation Hyperinflation of the chest Use of accessory muscles for respiration including resp distress Advanced - signs of cor pulmonae such as peripheral oedema and raised JVP

What is the typical pharmacological treatment for asthma COPD overlap syndrome?

Inhaled corticosteroids combined with LABA are the first line. May then add on LAMA if remain symptomatic or frequent exacerbations

What co-morbidities are common in asthma COPD overlap syndrome?

Cardiovascular disease Osteoporosis Depression Anxiety GERD

What are the different theories around Asthma COPD Overlap Syndrome as a disease?

For reference not learning