What is the appropriate perioperative endocrine assessment and management for an adult undergoing surgery, including diabetes, hypothyroidism, hyperthyroidism, adrenal insufficiency, pheochromocytoma, Cushing’s syndrome, and calcium/phosphate metabolism disorders?

Perioperative Endocrine Assessment and Management

All adults undergoing surgery require systematic preoperative screening for adrenal insufficiency, thyroid dysfunction, and diabetes, with specific hormone replacement protocols tailored to surgical stress level to prevent life-threatening perioperative crises.

Adrenal Insufficiency: The Highest Priority

Preoperative Assessment

• Screen all patients for glucocorticoid dependence from any cause: chronic steroid use (most common), primary adrenal insufficiency (Addison's disease), secondary/tertiary insufficiency from pituitary/hypothalamic disease, or recent prolonged steroid therapy 1
• Inquire specifically about steroid self-management history, previous adrenal crises, and medication adjustment practices for illness or injury 1
• Collaborate with the patient's endocrinologist when planning elective surgery 1

Intraoperative Management

For all adult patients with confirmed or suspected adrenal insufficiency:

• Administer hydrocortisone 100 mg IV at induction of anesthesia 1
• Follow immediately with continuous IV infusion of hydrocortisone 200 mg/24 hours until the patient can take double their usual oral dose 1
• This continuous infusion method is superior to bolus dosing for maintaining physiologic cortisol levels during surgical stress 1
• IM administration (50 mg every 6 hours) is acceptable only when IV infusion is impractical 1

Postoperative Management

• Continue hydrocortisone infusion until oral intake resumes, then give double the usual oral maintenance dose 1
• Taper to maintenance dose within 48 hours for uncomplicated surgery, but extend up to one week for major/complicated procedures 1
• Maintain high suspicion for impending adrenal crisis by monitoring for early signs: non-specific malaise, somnolence, cognitive dysfunction, orthostatic hypotension (before supine hypotension develops), hyponatremia, and persistent pyrexia 1
• Volume-resistant hypotension is a late and potentially agonal sign—do not wait for this to develop 1

Critical Pitfalls

• Never use dexamethasone as sole therapy in primary adrenal insufficiency—it lacks mineralocorticoid activity 1
• Avoid etomidate for induction when possible, as it suppresses cortisol production via 11-beta-hydroxylase inhibition 1, 2
• Consider higher hydrocortisone doses in obese patients and those on CYP3A4-inducing drugs, preferably via continuous infusion 1
• When in doubt, give glucocorticoids—short-term administration has no long-term adverse consequences, but withholding can be fatal 1

Thyroid Dysfunction

Hypothyroidism

• Patients with mild hypothyroidism can safely proceed with elective surgery 3
• Postpone elective surgery for moderate-to-severe hypothyroidism until euthyroid status is achieved 3
• Anticipate intraoperative hypotension; have vasopressors readily available and consider invasive blood pressure monitoring for major procedures 2
• Monitor cardiovascular function closely, particularly during cardiac surgery where heart failure risk is elevated 2
• Maintain high suspicion for postoperative infection despite absent fever, as hypothyroid patients have blunted febrile responses 2
• Distinguish true hypothyroidism from euthyroid sick syndrome in acutely ill patients: in euthyroid sick syndrome, free T4 remains in lower normal range, whereas true hypothyroidism with elevated TSH shows clearly low free T4 2

Hyperthyroidism

• Patients with mild hyperthyroidism can undergo elective surgery with preoperative beta-blockade 3
• Postpone elective surgery for moderate-to-severe hyperthyroidism until euthyroid 3
• Prepare for potential thyroid storm in the postoperative period with appropriate monitoring and treatment protocols 4, 5

Diabetes Mellitus

Preoperative Planning

• Base perioperative management on diabetes type, current medications, glycemic control status, and planned surgical procedure 3
• Implement bedside glucose monitoring protocols for all diabetic patients perioperatively 3
• Increasing evidence supports maintaining near-normal blood glucose throughout the perioperative period to reduce morbidity and mortality 6

Pituitary Adenomas (When Relevant)

Preoperative Endocrine Workup

• Test all anterior pituitary axes routinely in patients with suspected nonfunctioning pituitary adenomas, as hypopituitarism prevalence ranges from 37-85% 1
• Most commonly affected: GH axis (61-100%), followed by hypogonadism (36-96%), adrenal insufficiency (17-62%), and hypothyroidism (8-81%) 1
• Measure prolactin in all patients to rule out unsuspected prolactinoma 1
• Measure IGF-1 to exclude clinically silent GH-secreting tumors 1
• Replace adrenal insufficiency and significant hypothyroidism preoperatively before proceeding with surgery 1

Pheochromocytoma

Essential Preoperative Management

• Identify and properly treat before surgery to prevent catastrophic perioperative cardiovascular complications 3
• Ensure adequate alpha-blockade followed by beta-blockade preoperatively 4, 5
• Prepare for significant hemodynamic instability during tumor manipulation 7, 5

Special Populations

Pediatric Patients

• Children with adrenal insufficiency are more vulnerable to hypoglycemia than adults 1
• Require frequent blood glucose monitoring perioperatively 1
• Minimize fasting periods and prioritize on surgical lists 1
• Dosing: hydrocortisone bolus at induction followed by either continuous infusion or four-hourly IV boluses based on age and weight 1

Obstetric Patients

• Women with adrenal insufficiency may require higher maintenance doses after 20 weeks gestation 1
• At onset of labor: hydrocortisone 100 mg IV, then either continuous infusion 200 mg/24h or 50 mg IM every 6 hours until after delivery 1