💊 Chapter 97: Critical Illness–Related Corticosteroid Insufficiency (CIRCI)

Definition · Relative adrenal insufficiency · Septic shock · ACTH stimulation test (delta cortisol <9 μg/dL) · Hydrocortisone therapy · Etomidate risk · Fludrocortisone · Weaning · Complications (critical illness myopathy, hyperglycaemia, infection)

🔍 Core Concepts: Critical Illness–Related Corticosteroid Insufficiency

📌 Definition
CIRCI = inadequate cortisol response to critical illness (sepsis, trauma, surgery). Formerly "relative adrenal insufficiency". Diagnosis: delta cortisol <9 μg/dL after ACTH (cosyntropin) stimulation, or random total cortisol <10 μg/dL.
⚠️ Risk Factors
Septic shock (fluid-refractory, catecholamine-resistant), prior steroid use, etomidate administration (adrenal suppression), adrenal haemorrhage, pituitary disorders.
💊 Hydrocortisone Therapy
SCCM/Surviving Sepsis: consider hydrocortisone in children with fluid-refractory, catecholamine-resistant septic shock and suspected CIRCI. Dose: 50 mg/m²/day (or 1-2 mg/kg bolus then 0.1-0.2 mg/kg/h infusion).
🧪 ACTH Stimulation Test
Not required to start steroids emergently. If done: cosyntropin 250 μg IV, measure cortisol at 0 and 60 min. Delta <9 μg/dL suggests CIRCI. Random cortisol <10 μg/dL also supportive.
📉 Weaning & Duration
Treat for ≥7 days before tapering. Taper slowly to avoid recurrence of shock. Fludrocortisone (50 μg/day) optional if mineralocorticoid effect needed.
⚠️ Complications
Hyperglycaemia, immunosuppression (secondary infections), critical illness myopathy (especially with neuromuscular blockers), GI bleeding.

🩺 Stepwise Approach: Suspected CIRCI in Septic Shock

1
Identify at-risk patients
Fluid-refractory, catecholamine-resistant septic shock. Purpura fulminans (meningococcaemia). Prior steroid use. Recent etomidate administration. History of adrenal insufficiency.
2
Draw baseline cortisol (do not delay steroids)
Random total cortisol <10 μg/dL supports CIRCI. ACTH stimulation test not needed emergently; can be done after starting hydrocortisone.
3
Initiate hydrocortisone
IV hydrocortisone 50 mg/m²/day (or 1-2 mg/kg bolus, then 0.1-0.2 mg/kg/h continuous infusion). Alternative: 2-4 mg/kg/day divided Q6H. Continue for ≥7 days.
4
Monitor response
Improvement in BP, reduction in vasopressor requirement. If no response after 24-48h, reconsider diagnosis (ongoing infection, other causes of shock).
5
Tapering (after ≥7 days)
Taper slowly (e.g., reduce dose by 25-50% every 2-3 days) to avoid rebound hypotension and adrenal crisis. Consider fludrocortisone 50 μg/day if mineralocorticoid needed.
6
Monitor for complications
Hyperglycaemia (insulin as needed), secondary infections, critical illness myopathy (especially with neuromuscular blockers). Stress ulcer prophylaxis.