Resp - Chronic Asthma Flashcards

1
Q

Definition of asthma

A

-Episodic, reversible airway obstruction due to bronchial hyper-reactivity to a variety of stimuli

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2
Q

Epidemiology

A
  • Incidence: 5-8%, higher in children

- peaks at 5 years, most outgrow it by adolescence

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3
Q

Pathophysiology: acute and chronic

A
  • Acute (30mins): mast cell-Ag interaction leads to histamine release = bronchoconstriction, mucus plugs and mucosal swelling
  • Chronic (>12h): TH2 cells release IL 3-5 —> mast cell, eosinophil and B cell recruitment = always remodelling
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4
Q

Causes: 3 main categories with 2 examples each

A
  • Atopy: T1 hypersensitivity to variety of antigens, dust mites, pollen, food, animals, fungus
  • Stress: cold air, viral URTI, exercise, emotion
  • Toxins: smoking, pollution, factory, NSAIDs, beta blockers
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5
Q

Hx

A
  • Ask about precipitants
  • diurnal variation (worse at night)
  • Exercise tolerance
  • Other atopy: hay fever/eczema
  • Home and job environment
  • smoking Hx
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6
Q

Symptoms

A
  • cough +/- sputum (often at night)
  • wheeze
  • dyspnea
  • diurnal variation
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7
Q

Signs

A
  • tachypnea, tachycardia
  • widespread polyphonic wheeze
  • hyper-inflated chest
  • decreased air entry
  • signs of steroid use
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8
Q

Differential

A
  • Younger pts: must consider severe dysfunctional breathing (ie hyperventilation)
  • Pts >45ya: COPD or LV failure
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9
Q

Distinguishing btw asthma, LVF and COPD (based on symptoms)

  • Breathless on exertion
  • Breathless at rest
  • Wheeze
  • Night time symptoms
  • Identifiable triggers
  • Progressive deterioration
  • Smoker or previous smoker
  • Previous cardiac event
A
  • Breathless on exertion: A (+/-), LVF (+), COPD (+)
  • Breathless at rest: A (+), LVF (-), COPD (-)
  • Wheeze: A (+), LVF (+), COPD (-)
  • Night time symptoms: A (+), LVF (+), COPD (-)
  • Identifiable triggers: A (+), LVF (-), COPD (-)
  • Progressive deterioration: A (-), LVF (+/-), COPD (++)
  • Smoker or previous smoker: A (+/-), LVF (+), COPD (++)
  • Previous cardiac event: (-), LVF (++), COPD (+/-)
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10
Q

Ix:

A
  • Bloods: FBC (eosinophilia), raised IgE, aspergillus serology
  • CXR: hyperinflation
  • Spirometry: obstructive pattern with FEV1: FVC <0.75 and with >15% improvement in FEV1 with B-agonist
  • PEFR: monitoring/diary with diurnal variation of >20%
  • Atopy: skin prick test
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11
Q

Mx- general measures

A

TAME

  • T: technique for inhaler use
  • A: avoidance of allergens/smoke
  • M: monitor: peak flow diary
  • Educate: lease with specialise nurse, Rx compliance, emergency action plan
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12
Q

Mx- drug ladder: Steps 1-2

A
  1. SABA PRN: if use >1/d or nocturnal symptoms then step 2

2. Low dose inhaled steroid: beclometasone 100-400ug BD

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13
Q

Mx- drug ladder: step 3

A
  1. LABA: salmeterol 50ug bd
    - Good response: continue
    - Benefit but still poor control: increased inhaled steroid (beclometasone) to 400ug bd)
    - No benefit: discontinue LABA + increase steroid to 400ug
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14
Q

Mx- drug ladder:steps 4-5

A
  1. Trials of
    - Increased inhaled steroid to 1000ug BD
    - Leukotrienne receptor antagonist (Montelukast)
    - SR theophylline
  2. Oral steroids
    - Eg oral prednisolone 5-10mg OD
    - Use lowest dose necessary for symptom control
    - maintain high-dose inhaled steroid too b/c they can reach areas very effectively
    - refer to asthma clinic
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15
Q

How do NSAIDs exacerbate asthma?

A
  • Block conversion of arichidonic acid to COX1 and this diverts production towards increased levels of Leukotriennes. (Via FLAP and 5-LO)
  • Monteleukast is a Leukotrienne receptor antagonist
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16
Q

Why should you ask patients about their mental health when assessing their asthma status?

A
  • There is a very big association between poorly controlled asthma and depression.
  • Antidepressants suppress cytokines production
  • Hormone levels associated with stress can worsen asthma in patients.