Asthma a Clinical Perspective Flashcards by Elizabeth McCabe

What is the epidemiological burden of asthma?

1,000 deaths a year from asthma - most of which are preventable
9-10% of adults have asthma in the UK
35% of adults with asthma have had an attack within the last year
Costs the NHS £1bn per year.

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What is the clinical definition of asthma?

Chronic inflammatory conditions of the airways, characterised by bronchial hypersensitivity to variety of stimuli leading to variable airway obstruction from mainly bronchoconstriction.

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What level of variation in symptoms is characterisic of asthma?

A PEFR variation of more than 20%.

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What is the basic pathological description of asthma?
(allergic)

Chronic eosinophilic bronchitis
Airwayf inflammation with cellular infiltrate by Th2, mast cells and eosinophils
Large and small airway involvement
Cytokine production - PAF, IL5 and leukotrines contribute to inflammation and airway remodelling.

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What are some different phenotypes of asthma?

Cough variant - cough is only symptoms
Eosinophilic - type 2 response, with eosinophil infiltrate
Non-eosinophilic - severe, absent eosinophils, harder to treat
Occupational - exposure to inhaled irritants at work
Chronic asthma with fixed airflow obstruction - may be a result of COPD overlap
Exercise-induced bronchospasm - narrow when exercise.

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What causes the airway obstruction in asthma?

Inflammatory cell infiltration
Mucus hypersecretion and plugging
Smoot muscle contraction.

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What are the long term changes seen in smooth muscle in asthmatics?

Hypertrophy
Hyperplasia
Leads to thickened smooth muscle layers in the bronchi.

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Apply Pouiselles law to asthma.

Asthma leads to a reduction in the diameter of the airway lumen
R = 1/r4
Small reduction in airway radius leads a large reduction in resistance to airflow (x factor of 4 )

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How common is misdiagnosis of asthmatics?

1/3 are misdiagnosed

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How does gender influence asthma?

More common in boys than girls
As adults higher prevalence and higher mortality in women compared to men.

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What are some potential triggers to asthma?

Weather
LRTi - influenze, RSV, parainfluenza
Food
Pollution
Cigarette smoke
Emotion.stress
Mould/damo
Pets
Exercise
Dust
Pollen
Drugs including NSAIDs

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How does acute asthma present?

SOB
Cough +/- green phlegm
Chest pain/tightness
Difficulty completing sentences
Wheeze.

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How does chronic asthma present?

Coughing and wheezing - most common in childhood
Breathlessness, chest tightness or pressure, may also have chest pain
Poor school performance and fatigue may indicate from sleep deprivation from nocturnal symptoms.

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What investigations should be orders when a patient presents with an acute exacerbation of asthma?

ABC
PEFR
Chest X-ray
Bloods - eosinophil, wbc, CRP,
ABG

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What are the diagnostic criteria for moderate acute asthma?

Increasing symptoms
PEF 50-70% best or predicated
no features of acute severe asthma

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What is the diagnostic criteria for acute severe asthma?

PEF 33-50% best or predicted
Respiratory rate of 25 bpm or more
Heart rate of 110 bpm
Inability to complete sentences in one breath.

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What is the diagnostic criteria for life threatening asthma?

May present with any one of
PEF 33% or below of best or predicted
SpO2 less than 92%
PaO2 - less than 8kPa
Normal PaCO2
Silent chest
Cyanosis
Poor respiratory effort
Arrythmia
Exhasation
Altered consciousness level
Hypotension.

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What is the diagnostic criteria of near fatal asthma?

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

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What is important to gain in the history of an asthmatic?

How many times a week they use SABA
What are triggers/pets
How many courses of steroids have you had in the last year
How often do you forget to use your inhlaers
Smoking status
Job
Exercise
Anxiety element
Vocal hygiene

What can indicate a poorer asthma prognosis?

Poor adherence
Previous acute admission and or intubation
3+ different classes of asthma medication
Psychosocial dysfunction
Inadequately treated disease

What is an asthmatic wheeze?

High pitched expiratory sound produced when air is forced through narrow airways
Polyphonic normally
Often accompanied with low oxygen levels, high RR, signs of respiratory distress and decrease in PEFR.

What differential diagnosis must be considered alongside asthma?

COPD
Upper airway obstruction (stridor) - may be an inducible laryngeal obstruction
Foreign body
Hyperventilation syndrome
Anxiety
GERD
Pulmonary odema
Eosinophilic vasculitis
respiratory bronchitis
Interstitial lung disease
Pulmonary hypertension

What is an inducible laryngeal obstruction?

Hypersensitivity of vocal cord - incoordination of breathing cycle at vocal cords, can together during inspiration, unable to get air into lungs.
Requires treatment from speech and language therapise
Result in voice changes
Has a sudden onset, can be triggered by noxious smells or stimuli,

What is the diagnostic algorithm for highly suspected asthma?

Clinical assessment of symptoms and history
If suspected starts treatment
Assess response objectively - lung function/validated symptoms score, good response indicates asth,at.
Is poor response or more testing is required consider: spiromtery, bronchodilator reversibility, PEF charting, challenge tests, FeNO, blood eosinophils, sin prick test iGE

How is PEFR variability used to investigate for asthma?

SHould be done twice daily for 2-4 weeks Positive if more than 20% variability

How is spirometry used to investigate for asthma?

FEV1/FVC ratio of less than 70% 400ml/20% increase in FEV1 after SABA (or 200ml/12% as in NICE)

How is FeNO used to investigate asthma?

Marker of eosinophilic inflammation Positive is above 40.

How is bronchial provocation used to investigate for asthma?

Inhalation of noxious stimulants results in a drop in FEV1 of 20%.

What types of asthma can be non-eosinophilic?

Late onset asthma NSAID related asthma

What are some example of asthma plus syndromes?

ABPA - allergic bronchopulmonary asperigillosis - severe allergic reaction of hypersensitivit airways to aspergillus fungus - can exacerbate asthma, resistance to inhalers EGPA - Eosinophilic granulomatosis with polyangiitis - rare vasculitis - restricts blood flow to the lungs.

What treatment (not inhalers) tends to be offered to asthmatic patients?

Smoking cessation - NRT Trigger avoidance - previously recommend strict decontamination of dust

What is MART in asthma treatment?

Maintenance and Reliever Therapy Enables patient directed treatment. Uses a combination inhaler - combines a steroid (prevention) and a LABA normally (reliever) Some patients may also need to keep their blue SABA (relieved inhlare) for if they have a severe asthma attack. THought to make compliance easier by reducing the number and times that the inhalers must be used.

How might a patient with good asthma control present?

No daytime symptoms No night time awakening due to asthma No need for rescue medication No exacerbations No limitation on activity including exercise Normal lung function (FEV1 and/or PEF greater than 80%) Minimal side effects from medication.

What are some potential complications of a SABA?

Systemic absoprtion - can cause tachycardia, hypertension, lactic acidosis and hypokalemia Excreted in urine after liver metablism

What is the difference between an inhaler and a nebuliser?

Neubuliser - hospital only, electric machine, sprays fine mist, takes longer to take up medication, oftne given for people who can not use a MDI such as young children or those with severe asthma. Can deliver higher doses, require less finger dexterity and less incidence of incorrect technique. inhaler - Hand held, patient controlled

What are some potential complications of a leukotrienes antagonsit?

Careful in psychiatric history Can cause aggression, agitation, concentration and behavioural problems - if so should stop and consult doctor as soon as possible.

What are the different inhaled corticosteroids that may be used in asthma? how are they often used practically?

Beceletasone Budesonide Flucticasone Mometasone Often used with a LAVAL, once, twice a day or as needed.

What are the different oral steroids that may be used in asthma?

Prednisolone Dexamethasome

What are the different injected steroids used in asthma?

IV hydrocortisone IM triamcinalone

What are some potential side effects/complications of an inhaler use in asthma? How can we decrease this?

Can have poor technique or forget to use certain inhalers - offer a MART regime to reduce inhlaer number Patients can have a sore throat or oral thursh is medicine is deposited into oral cavity/thorat not lungs - use a spacer to help adminster Use mouthwash after use to remove medicine residue.

What are some potential side effects of muscarinic antagonists?

Dry mouth Constipation Blurred vision (particularly is gets in eyes)

What is the conditions for the use of mepolizumab, benralizumab or reislizumab in an asthmatic patient?

Need raised blood eosinophil levels.

What acute treatment should be used for a patient with an asthma flare up?

Assess and treat ABC Oxygen to maintain O2 stats above 94% Corticosteroids - oral preferable, norm 40mg prednisolone for 5-10days Nebulised bronchodilators - salbutamol and ipratropium bromide IV MgSO4 is acute severe and not responding. Antibiotics (amoxicillin) is suspect superimposed bacterial infection.

What ongoing care is offered to asthma patients?

Self management plans - monitor own pO2 and PEF - when to contact GP/hospital Patient education - inhaler technique Use of apps/telemedicine to monitor inhlaer technique doses, order repeat inhlaers Annual GP review - at practise or with an asthma nurse Secondary care review for more advanced cases - specialist consultant, specialist nurse, psychologist, physiotherapist or dietician.

What is included in a self management plant for an asthmatic?

Info on symptoms when well - norm PEF, medications, allergies and triggers. Info on symptoms when worse - what symptoms to look for, plan for what to do (inc med dose, take steroid course) Info on what an asthma attack may look like and what to do. Advice on when to contact GP and hospital.