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Flashcards in 14 - Asthma Deck (23)
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1
Q

What is asthma?

A

Chronic inflammatory airway disease that is characterised by intermittent airway obstruction and hyperreactivity to stimuli

Obstruction is reversible with treatment or spontaneously

2
Q

What are the five defining characteristics of asthma?

A

FEV1 being measure with spirometry

3
Q

What is the pathophysiology of asthma?

A
  • Chronic inflammatory process mediated by TH2. Macrophages present antigents to T cells, activating TH2
  • TH2 release cytokines, which attract and activate inflammatory cells like mast cells and eosinophils
  • TH2 also activate B cells that produce IgE
4
Q

What is the 2 phase response when an asthmatic is exposed to an antigen?

A

Immediate (20 minutes): type 1 hypersensitivity. Interaction of allergen and IgE leads to mast cell degranulation and release of mediates (typtase, leukotriene, prostaglandin) so smooth muscle contraction and bronchoconstriction

Late (3-12 hours): type 4 hypersensitivity. Inflammatory cells like eosinophils and mast cells, release mediators that cause airway inflammation. Eosinophils release LTC4 which causes shedding of epithelial cells (sensitive to steroids

5
Q

How does airway inflammation in asthma lead to a reduced flow of airway in the bronchi?

A
  • Mucosal oedema due to vascular leak
  • Thickening of bronchial walls
  • Overproduction of mucus (dry cough)
  • Smooth muscle contraction
  • Epithelia shed and put into mucus
6
Q

How does asthma present on history and what are some precipitating factors of this condition?

A
7
Q

What can happen in long term poorly controlled asthma?

A
  • Hypertrophy and hyperplasia of smooth muscle
  • Hypertrophy of mucus glands
  • Thickening of basement membrane
8
Q

Whyy can cold air trigger asthma?

A
  • Airways are hyperesponsive so non allergic stimuli can trigger attacks
9
Q

How can asthma present on examination?

A
  • Wheezing
  • Increased residual volume due to air trapping
10
Q

What are some investigations we can do to diagnose asthma?

A
  • PEF
  • Obstructive spirometry with FEV/FVC <70% with reversibility after bronchodilators
11
Q

What are the similarities and differences of asthma and COPD?

A
12
Q

What type of respiratory failure is asthma and why?

A

- Mild to moderate: type 1 as V/Q mismatch but hyperventilation can compensate for the high pCO2

- Severe: type 2 as extensive involvement of airways, not just one area, and exhaustion. Rising pCO2 may need to ventilate as sign of life threatening asthma

13
Q

How do we decide whether to start treatment for suspected asthma in a newly presenting patient?

A
  • Management depends on probaility of asthma
  • Don’t want to wait with high risk as it is an airways disease
14
Q

How can we manage asthma in general ?

A
  • Primary prevention not possible as would have to avoid triggers as kid etc
  • Secondary prevention by educating patient on triggers and telling them to avoid, e.g stop smoking, get rid of cat
  • Pharmacological with BTS stepwise approach
15
Q

What are the different classes of drugs that can be used to treat asthma and how do they work?

A
16
Q

What is the stepwise management for adults with asthma?

A
  • Can raise and lower dose
  • Still not responding up the stairs then consider another diagnosis
  • In children under 5 drugs are different
17
Q

How can inhaled medication for asthma be administered to younger children who may not be able to master the correct technique of inhalation?

A

Spacer

18
Q

What do the different colours of inhalers represent?

A

- Blue: reliever when needed. Salbutamol, SABA

- Brown: preventer, inhaled corticosteroid

- Purple: mix of LABA (e.g salmeterol) and steroid

  • Red and pink are different combinations of LABA and steroid
19
Q

How does salbutamol work?

A

B2 agonist

20
Q

How would we treat acute severe asthma

A
  • Nebulised B2 short acting agonists and ipratropium
  • Give oxygen in nebuliser
  • IV steroids
  • Short course of high dose oral prednisolone
  • Magnesium sulphate and Aminophylline (a blocker) may also be needed
21
Q

How do we recognise the difference between acute sever asthma and life threatening asthma?

A

Acute severe can go to life threatening so monitor in case need ITU and assisted ventilation

22
Q

If you perform and ABG on an asthmatic patient and compared to their last one they have a rising pCO2, what should you consider?

A
  • Turning to life threatening asthma, may be exhausted
  • Consider sending to ITU and ventilation
23
Q

Which hypersensitivity is asthma associated with?

A

Type 1 hypersensitivity is mediated by IgE binding to Mast cells. This leads to an inflammatory response.