Overview
This lecture reviewed the impact of exogenous steroid use on adrenal insufficiency, the limitations of current evidence, and strategies for perioperative management based on available guidelines.
Physiology of the HPA Axis & Adrenal Insufficiency
- The hypothalamic-pituitary-adrenal (HPA) axis regulates cortisol release via central triggers and negative feedback.
- Cortisol is essential for metabolism, blood pressure, and stress response.
- Primary adrenal insufficiency: adrenal gland defect; secondary: pituitary defect; tertiary: iatrogenic from exogenous steroids.
Causes & Prevalence of Adrenal Insufficiency
- Exogenous glucocorticoid use is prevalent, especially in the elderly.
- All forms (oral, inhaled, topical, intraarticular) can cause adrenal suppression.
- About 2-4% of the population is prescribed glucocorticoids, higher in those over 80.
Clinical Consequences & Testing
- Both cortisol excess and deficiency are associated with increased mortality.
- The Short Synacthen Test (SST) assesses adrenal function but is not perfect.
- Higher daily steroid doses correlate with higher mortality.
- Even “safe” doses and non-oral routes can cause suppression.
Diagnostic Strategies
- Morning cortisol >300-350 nmol/L suggests intact HPA axis; <100 nmol/L suggests insufficiency.
- Universal SST testing for all steroid users is impractical; focus on high-risk patients.
Perioperative Management & Guidelines
- Adrenal crises can occur without steroid supplementation during major stress or surgery.
- UK and European guidelines recommend perioperative steroid coverage for patients on 5mg prednisolone equivalent for >4 weeks.
- Recommended regimen: 100mg IV at induction, then 200mg over 24 hours (via infusion or divided doses).
- Identify at-risk patients by dose, duration, multiple routes, symptoms, and drug interactions (e.g., CYP3A4 inhibitors).
Implementation Challenges & Evidence Gaps
- Major gap exists in outcome data for different supplementation regimens.
- Compliance with guidelines is low; only 9-50% adherence noted in surveys.
- Guideline awareness and practical barriers hinder correct implementation.
- More research is needed to determine whether supplementation improves outcomes.
Key Terms & Definitions
- HPA Axis — Hypothalamic-pituitary-adrenal axis; regulates stress hormone production.
- Cortisol — Main glucocorticoid hormone; regulates metabolism and stress response.
- Adrenal Insufficiency — Inadequate cortisol production due to gland, pituitary, or external steroid causes.
- Short Synacthen Test (SST) — Test for adrenal function by measuring cortisol response to synthetic ACTH.
- Exogenous Steroids — Steroids taken from outside the body, often as medication.
- Perioperative — Relating to the period around surgery.
Action Items / Next Steps
- Increase awareness of guidelines among relevant clinical staff.
- Identify high-risk patients for perioperative steroid supplementation.
- Monitor ongoing research for new evidence on steroid regimen outcomes.
- Review and discuss guideline implementation barriers in your practice.