Asthma Flashcards

1
Q

Define asthma

A
  • chronic airway inflammation
  • cough, wheeze, breathlessness
  • variable outflow obstruction
  • airways hyper-responsiveness
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2
Q

Symptoms

A

Wheeze
breathlessness
Chest tightness
Cough

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3
Q

Different phenotypes of asthma

A
  • allergic
  • non allergic
  • adult onset (late)
  • asthma with persistent airflow limitation
  • with obesity
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4
Q

Sympathetic action of respiratory system

A

Beta 2 receptors
Bronchodilation
Mucociliary clearance

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5
Q

Parasympathetic action of respiratory system

A

Muscarinic receptors

Bronchoconstriction

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6
Q

What surrounds bronchioles

A

Terminal and respiratory bronchioles surrounded by SM

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7
Q

What holds large airways open

A

Cartilage

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8
Q

What does flow =

A

pressure change/resistance

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9
Q

What is flow increased by?

A
  • increased pressure change

- decreased resistance

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10
Q

Pouseille’s Law

A

Flow = 1/resistance^4

Decreased resistance = increased flow

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11
Q

What do mast cells cause in the acute phase?

A

Bronchospasm
Oedema
Mucous

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12
Q

What happens in the late phase?

A

Th2 helper cells activate B cells to produce IgE and eosinophils
- these cause bronchoconstriction and muco-secretion

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13
Q

Extrinsic causes

A
  • air pollution
  • allergen exposure
  • maternal smoking
  • hygiene hypothesis
  • genetics
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14
Q

Intrinsic causes

A
  • non-allergic
  • less responsive
  • colds/infections
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15
Q

Occupational causes

A
  • allergens at work
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16
Q

Diagnosis

A
  • clinical
  • Evidence of airflow obstruction or airway inflammation
  • respiratory symptoms, signs and test results
  • absence of alternative explanation for presentation
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17
Q

Symptoms and presentation

A
Wheeze
Breathlessness
Chest tightness
Cough
Worse at night and morning
Triggers
Atopic features
FH
Low PEFR or FEV
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18
Q

What triggers it?

A
Allergens
Exercise
Cold air
Aspirin
Beta blocker
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19
Q

Less likely symptoms/presentation

A
  • dizziness/light – headedness/peripheral tingling
  • productive cough in absence of wheeze of breathlessness
  • normal exam when breathless
  • voice disturbance
  • symptoms with colds
  • smoking history >20 pack years
  • cardiac disease
  • normal PEF or FEV1 when symptomatic
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20
Q

Wheeze differentials

A
Asthma
COPD
Obstruction = foreign body
Anaphylaxis
Pulmonary oedema
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21
Q

Bronchodilator reversibility

A

> 12% or 200ml improvement in FEV1

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22
Q

Spirometry results

A

FEV1/FVC<70%

- may be normal when not symptomatic

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23
Q

Fraction exhaled nitric oxide

A

> 40 ppb

breath test marker of eosinophilic inflammation

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24
Q

Direct Challenge Testing

A
  • drop in FEV! when exposed to provoking substance

- concentration required for 20% fall in FEV1 of 8mg/ml or less

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25
Peak Flow
- twice daily readings over 2 weeks - diurnal variation - 20% variability
26
Diagnostic test
``` Peak Flow Spirometry Bronchodilator reversibility Fraction exhaled nitric oxide Direct challenge testing IgE Allergy/skin prick testing FBC/eosinophil count ```
27
Treatment
- patient education and self management plan - avoidance of triggers and allergens = smoking - weight reduction - breath exercises - stepwise approach
28
What is not recommended
- house dust mite avoidance | - air ionisers
29
When should patients be reviewed post discharge
<30 days if admitted | usually by specialist nurse
30
Drug treatment
- short and long acting B2 agonists - corticosteroids - leukotriene antagonists - Anti-IgE monoclonal antibodies
31
MOA of B2 agonists
Sympathetic action of B2 receptors = bronchodilation and mucociliary clearance - relax SM - relieve bronchospasm
32
Example of short acting B2 agonist
Salbutamol | Terbutaline
33
Example of long acting B2 agonist
Salmeterol | Formoterol
34
Side effects of beta 2 agonists
Tremor Tachycardia Sweats Agitation
35
Mechanism of action of corticosteroid
decrease inflammation
36
Examples of corticosteroids
Budesonide Beclometasone Fluticasone
37
Side effects of corticosteroids
Oral candidiasis | Systemic rare with inhaled corticosteroids
38
MOA of leukotriene antagonists
- block leukotriene receptors in SM | - reduce bronchoconstriction
39
Examples of leukotriene antagonists
Montelukast
40
Side effects of leukotriene antagonists
Nausea | headache
41
Example of Anti-IgE
omalizumab | subcutaneous
42
Side effects of Anti-IgE
- itching - joint pain - headache - nausea - anaphylaxis
43
Indications for anti-IgE
- confirmed allergic IgE mediated asthma - add on to optimised standard therapy - continuous/frequent treatment with oral corticosteroids (4 or more)
44
Stepwise treatment
- short acting B2 agonist - inhaled corticosteroid low dose - regular preventer - add LABA to low dose ICS and offer LTRA - increase ICS dose or add LTRA, consider stopping LABA if no response - MART, increase ICS OR fixed dose ICS/LABA + SABA then LAMA or theophylline
45
How much to reduce ICS?
25-50% reduction in dose every 3 months consider if not getting worse
46
Define uncontrolled asthma
- 3 ore more days a week with symptoms OR - 3 or more days a week with required use of SABA for symptomatic relief OR - 1 ore more nights a week with awakening due to asthma
47
Risk of future attacks in children
- comorbid atopic conditions - younger age - obesity - exposure to environmental tobacco smoke
48
Risk of future attacks in adults
- older age - female - reduced lung function - obesity - smoking - depression
49
Asthma control assessment
- scored 5-25 - 25 = complete control - ACT score >19 indicates well controlled asthma
50
Precipitating factors to acute asthma
- pets - exercise - pollen - bugs in home - chemical fumes - cold air - fungus spores - dust - smoke - strong odors - pollution - anger - stress
51
Brittle asthma
- 2 types - difficult to control - unstable/unpredictable
52
Type 1 brittle asthma
- wide PEF variability - >40% diurnal variation for >50% of time period >150 days - despite intense therapy
53
Type 2 brittle asthma
- sudden severe attacks on background of apparently well controlled asthma
54
Moderate acute asthma
- increasing symptoms - no features of acute severe - PEF >50-75% best or predicted
55
Acute severe asthma
Any 1 of - PEF 33-50% - RR 25>/min - HR 110/min> - inability to complete sentences in 1 breath
56
Life threatening asthma
Any 1 of - PEF <33% - Sats <92% - PaO2 <8 - Silent chest - Cyanosis - hypotension - exhaustion - feeble respiratory effort - tachy or bradycardia - dysrhythmia - confusion - coma
57
What to do if life threatening asthma
Call anaesthetist
58
When to admit in acute asthma
- if acute severe persisting after treatment or > life threatening
59
Near fatal asthma
- raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures
60
When to discharge in acute asthma
- PEF>75% after 1 hour - unless = symptoms significant, compliance concerns, live alone, psychological problems, previous near fatal/brittle asthma, pre-existing steroids, night time, pregnant
61
Management of acute asthma
- high flow oxygen - aim sats >92% - O2 driven nebs - IV fluids - reassess every 15 mins with PEFR
62
Drugs on management of acute asthma
OSHIT - oxygen - salbutamol - hydrocortisone/prednisolone - ipratropium bromide - theophylline - magnesium sulphate
63
Dose for salbutamol in acute
- 2.5-5mg every 10 mins | - nebulised with oxygen
64
Side effects of salbutamol
- tremor - arrhythmias - hypokalemia (monitor ECG)
65
Hydrocortisone dose in acute
- IV 100-200mg QDS | - or prednisolone PO 40mg OD
66
Ipratropium bromide dose in acute
500mg every 4-6 hours
67
Side effects of ipratropium bromide
- arrhythmias - cough - dizziness - dry mouth - headache - nausea
68
Magnesium sulphate dose in acute
1.2-2g over 20 mins IV | For acute severe
69
Side effects of theophylline
- palpitations - arrhythmias - nausea - seizures - alkali burns if extravasation occurs - drug interactions
70
When to involve ITU?
- If require ventilatory support - near fatal asthma - life threatning/acute severe not improving - early
71
Monitor In acute asthma
- peak flow reg. - ox sats - chest auscultation - ABG repeat 1hr? - potassium and glucose bloods - ECG = potassium, Mg, beta 2 agonists
72
When to repeat ABG every hour?
- hypoxic - normo-hypercapnoeic - patient deteriorates
73
Acute asthma follow up
- within 48 hours - <30 days post discharge by GP/nurse specialist - under specialist supervision for near fatal asthma - at least 1 year for severe asthma attack