Diabetes and other endocrine disease

What it is

Endocrine disease matters to the anaesthetist because surgery is a stress that releases cortisol, catecholamines and glucagon, while fasting removes food. In diabetes this combination swings glucose both ways: stress and infection push it up, fasting and insulin push it down, and hypoglycaemia is hidden under anaesthesia. Long-standing diabetes also brings coronary disease that may be silent, kidney disease, autonomic neuropathy with unstable blood pressure and slow gastric emptying, and stiff joints that can make laryngoscopy difficult. Newer medicines add their own problems: SGLT2 inhibitors can cause ketoacidosis with near-normal glucose, and GLP-1 receptor agonists slow gastric emptying. Perioperative hypertension is common; it is controlled before elective surgery and medicines are continued or paused according to class. Pheochromocytoma, a catecholamine-secreting tumour of the adrenal medulla, is the classic endocrine emergency of the operating room: induction, intubation and handling the tumour can release huge surges of catecholamines, and once the veins are tied the pressure and glucose may fall. Thyroid and adrenal disease also need preparation: an uncontrolled hyperthyroid patient risks thyroid storm, a hypothyroid patient is sensitive to depressant drugs, and a patient on long-term steroids may need steroid cover to avoid adrenal crisis.

What changes in this patient

• Diabetes: glucose swings, silent ischaemia, autonomic neuropathy with labile pressure, gastroparesis and aspiration risk, kidney disease and infection.
• Airway: stiff-joint syndrome in long-standing diabetes (the «prayer sign») can limit neck and jaw movement.
• Medicines: insulin, sulfonylureas, SGLT2 inhibitors, metformin and GLP-1 agonists each need a specific perioperative plan.
• Hypertension: uncontrolled pressure means exaggerated swings at induction and intubation, and a higher risk of stroke, ischaemia and bleeding.
• Pheochromocytoma: catecholamine excess with hypertension, tachycardia, headache, sweating, contracted plasma volume and sometimes cardiomyopathy.
• Thyroid and adrenal: hyperthyroidism risks thyroid storm; hypothyroidism slows recovery; long-term steroids suppress the adrenal response to stress.

Anaesthetic plan (and why)

1. Check HbA1c, glucose, kidney function and ECG, and look for neuropathy and stiff joints — they predict control, cardiac risk and airway difficulty.
2. Put patients with diabetes first on the list — this shortens fasting and lowers the risk of hypoglycaemia.
3. Write a medicine plan: basal insulin continued at a reduced amount, sulfonylureas and metformin omitted on the day, SGLT2 inhibitors stopped days before.
4. Use a variable-rate insulin infusion with glucose for long fasting, type 1 diabetes or poor control — keeps glucose steady and prevents ketosis.
5. Treat a recent GLP-1 agonist or gastroparesis as a possible full stomach and consider rapid-sequence induction — gastric emptying may be slow.
6. Control blood pressure before elective surgery and continue most antihypertensives, pausing ACE inhibitors or ARBs as local policy says — avoids vasoplegia.
7. For pheochromocytoma, give alpha-blockade first, then beta-blockade, with salt and fluid — prevents unopposed alpha crises and refills the circulation.
8. During pheochromocytoma surgery use an arterial line, deep anaesthesia at intubation and short-acting vasodilators and beta-blockers ready — surges come fast.
9. When the adrenal veins are tied, give fluid and vasopressors and check glucose often — catecholamines fall abruptly and insulin rebounds.
10. Give steroid cover to patients on long-term steroids and make hyperthyroid patients euthyroid before elective surgery — prevents adrenal crisis and storm.

Usual handling of diabetes medicines around surgery (principles; follow local protocol, no doses)

Risks and complications

• Hypoglycaemia hidden by anaesthesia and sedation, or hyperglycaemia leading to infection, poor wound healing and diabetic ketoacidosis.
• Euglycaemic ketoacidosis in patients on SGLT2 inhibitors, missed because glucose looks reassuring.
• Aspiration from gastroparesis or GLP-1 agonists; difficult laryngoscopy from stiff joints.
• Hypotension at induction from autonomic neuropathy or continued ACE inhibitors; silent myocardial ischaemia.
• Pheochromocytoma: hypertensive crisis, arrhythmia, myocardial ischaemia and pulmonary oedema, then profound hypotension and hypoglycaemia after removal.
• Thyroid storm in an unprepared hyperthyroid patient; adrenal crisis with refractory hypotension when steroid cover is missed.

Next step

• Check capillary glucose regularly in recovery and on the ward until the patient eats, and restart usual medicines once eating normally.
• Check ketones and a blood gas in any unwell patient on an SGLT2 inhibitor, even with a near-normal glucose.
• After pheochromocytoma removal, monitor blood pressure and glucose closely in a high-dependency setting for at least a day.
• Call a senior for refractory hypotension, a glucose that will not settle, ketoacidosis, or signs of thyroid storm or adrenal crisis.
• Taper steroid cover back to the usual regimen as recovery allows, and give the patient a written plan.
• Refer back to the diabetes or endocrine team when control was poor, and arrange genetic counselling after a pheochromocytoma.

Test yourself

Think of the answer, then tap the question to see it.

Add to my cards (4)

Elsewhere in DurgiPedia

• The adrenal medulla and catecholamines
• Islets and insulin: secretion and actions
• Capillary blood glucose testing
• Diabetes: acute complications (DKA, HHS)

Connections

← All of anaesthesia

Educational content; it does not replace supervised training, your institution's protocols or the anaesthetist's or intensivist's decision. It contains no doses and no ventilator or infusion settings.

Sources: Perioperative Management of Pheochromocytoma (StatPearls (NCBI Bookshelf), 2023); Evaluation and Management of Perioperative Hypertension (StatPearls (NCBI Bookshelf), 2026).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Send

Representative model, for educational purposes only.