Corticosteroids in adults with acute respiratory distress syndrome and severe pneumonia

Question 1

Pathogenesis of ARDS

Answer 1

• Stimulus (pneumonia/ aspiration/ trauma etc) causes the release of inflammatory cytokines (IL 1,6,8 TNFa)
• Cytokines activate and recruit neutrophils to the lungs increasing endothelial permeability and injuring the tight alveolar epithelial barrier
• Increased endothelial permeability allows translocation of fluid into the alveolar space
• Alveolar fluid causes reduced lung compliance, VQ mismatching and impaired gas exchange
• In some cases, fibroproliferation occurs in an attempt to reintroduce a barrier to fluid translocation causing pulmonary fibrosis

Question 2

Mechanism of corticosteroids in the treatment of ARDS

Answer 2

• Limitation of hypothalamic-pituitary-adrenal axis dysfunction
• Reduced production of pro-inflammatory cytokines
• Promote clearance of alveolar oedema by increasing density of Na-K ATPase pumps in alveolar epithelial cells

Question 3

Acute adverse effects of steroids in critical care

Answer 3

• Hyperglycaemia
• Delirium
• GI bleeding
• Neuromuscular weakness

Question 4

What ARDS sub-groups are likely to benefit from steroid therapy

Answer 4

• Early ARDS
• COVID-19 ARDS
• Comm acquired pneumonia ARDS
• PCP pneumonia ARDS

Question 5

What dose of steroids should be used in ARDS

Answer 5

• Hydrocortisone 200mg/day
• Dexamethasone 6-12mg/day