Airways disease

Question 1

A patient comes in with an acute exacerbation of COPD. Explain your general approach to bronchodilator management

Answer 1

Salbutamol
* start with burst therapy – 2 – 10 puffs, 2 – 3 doses every 20 minutes
* 2 – 10 puffs every 1 – 4 hours until symptoms subside
* 2 – 4 puffs every 4 – 6 hours for 24 – 48 hours

Ipratropium
* 2 puffs QID

Steroids
* Prednisolone 3 – 5 days

If nil improvement, attempt use of magnesium

Question 2

What is the MOA of salbutamol?

Answer 2

• Salbutamol is a beta 2 adrenergic receptor  induces bronchial smooth muscle relaxation and inhibition of immediate hypersensitivity release, particularly from mast cells
• Mild beta 1 adrenergic effect, little impact on HR

Question 3

What is the MOA of ipatropium

Answer 3

• acetylcholine antagonist via the blockade of muscarinic cholinergic receptors
• Blocking cholinergic receptors decreases the production of cyclic guanosine monophosphate (cGMP). This decrease in the lung airways leads to decreased contraction of the smooth muscles

Question 4

What is the pathway and components from the spinal cord to a muscle fibre?

Answer 4

Think anterior horn cell—nerve root—plexus—peripheral nerve—NMJ—muscle*