Med in Small Doses - Asthma


This is part of the Med in Small Doses series, which aims to give you a snapshot of a disease or disorder.  


Inflamed small airways due to hypersensitivity. Multifactorial – genetics + environmental influences

PATHO: Inflammation (T2H, IL-5, etc) → bronchoconstriction → oedema → ↑ mucus secretion → smooth muscle hypertrophy → damage to epithelium and shedding.


CFs: Classic Triad - Wheeze, Cough (dry, or productive of mucoid or pale yellow sputum), Dyspnoea. Nasal mucosal swelling, ↑nasal secretions

RFs: mnemonic - FEAR UP
F amily history
E czema
A cid reflux
R hinitis (allergic)
U rticaria
P olyps (nasal) 

Ix: Chest x-ray, Allergy testing, Eosinophil count 
Spirometry: ↓ FEV1/FVC, ↓ PEF, ↓ FVC 

The different PFTs:
SPIROMEtry
S pirometry
P EFR
I nhalation tests:
R eversibilty of
O bstruction with beta-agonist
M etacholine challenge
E xhaled NO 

Tx & Mgmt: Monitoring & scheduled visits, education and avoid triggers.
Relief vs prevention, B2-Agonists: airway dilation. Glucocorticoids: anti-inflammatory. 

Treatment of Status Asthmaticus: (severe acute asthma) 
  1. Oxygen
  2. Nebulised salbutamol
  3. IV hydrocortisone
  4. Oral prednisolone 
Mnemonic
A drenergics
S teroids
T heophyllines (althouigh not used as much now though)
H ydration
M ask
A ntibiotics if necessary.

Rule of 2's
Treatment needs to be changed if there are more than:
  • 2 uses of relief inhalers per week
  • 2 nocturnal awakenings per month
  • 2 canisters of relief inhaler used per year
For a review of respiratory pathology checkout an Introduction to Respiratory Pathology & Pulmonary Tumours.

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