15.3 Endocrine Disease and Emergencies: Diabetes, DKA and HHS, Thyroid, Adrenal, Phaeochromocytoma and Carcinoid
Key Takeaways
Diabetic ketoacidosis is defined by blood glucose above 11 mmol/L (or known diabetes), ketones of at least 3.0 mmol/L and either a pH below 7.3 or bicarbonate below 15 mmol/L; treatment is fluid, a fixed-rate insulin infusion of 0.1 units/kg/h and potassium replacement.
The hyperosmolar hyperglycaemic state features marked hyperglycaemia (often above 30 mmol/L), osmolality above 320 mOsm/kg and severe dehydration without significant ketosis, and carries a high thrombosis risk.
Thyroid storm presents with hyperthermia, tachycardia, agitation and heart failure; treat with beta-blockade, propylthiouracil or carbimazole, iodine given at least 1 hour after the thionamide, hydrocortisone, cooling and supportive care.
Adrenal crisis is treated with hydrocortisone 100 mg intravenously followed by 200 mg over 24 hours (infusion or 50 mg every 6 hours) with intravenous fluids.
Phaeochromocytoma requires alpha-blockade (phenoxybenzamine or doxazosin) for about 10-14 days before beta-blockade, and hypotension and hypoglycaemia often follow tumour removal.
15.3 Endocrine Disease and Emergencies: Diabetes, DKA and HHS, Thyroid, Adrenal, Phaeochromocytoma and Carcinoid
Diabetes Mellitus
Preoperative Assessment
- Type of diabetes and treatment, glycaemic control (HbA1c), hypoglycaemia awareness, and end-organ damage: ischaemic heart disease (often silent), nephropathy, autonomic neuropathy (gastroparesis, postural hypotension, cardiac instability) and stiff joint syndrome (difficult laryngoscopy).
- UK guidance suggests optimising control before elective surgery when HbA1c is above about 69 mmol/mol (8.5%).
Perioperative Management
- Aim for capillary glucose of about 6-10 mmol/L (up to 12 mmol/L acceptable), checked at least hourly during surgery.
- Short starvation (one missed meal): adjust oral agents and insulin, schedule first on the list.
- Longer starvation or poor control: variable-rate intravenous insulin infusion with a glucose-containing fluid (for example 5% glucose in 0.45% saline with potassium), and continue basal long-acting insulin at about 80% of the usual dose.
- Autonomic neuropathy increases aspiration risk and haemodynamic instability.
Diabetic Emergencies
| Feature | Diabetic ketoacidosis (DKA) | Hyperosmolar hyperglycaemic state (HHS) |
|---|---|---|
| Typical patient | Type 1 (any age) | Older, type 2 |
| Onset | Hours to a day | Days |
| Glucose | Above 11 mmol/L (may be normal in euglycaemic DKA) | Often above 30 mmol/L |
| Ketones | At least 3.0 mmol/L (or urine 2+) | Below 3.0 mmol/L |
| pH / bicarbonate | pH below 7.3 or bicarbonate below 15 mmol/L | pH above 7.3, bicarbonate above 15 mmol/L |
| Osmolality | Variable | Above 320 mOsm/kg |
| Main risks | Cerebral oedema (children), hypokalaemia, hypoglycaemia during treatment | Thrombosis, osmotic demyelination with rapid sodium shifts, high mortality |
DKA Treatment (Adult)
- Fluids: 0.9% saline, for example 1 L over the first hour, then guided by response; add 10% glucose when glucose falls below 14 mmol/L while continuing insulin.
- Fixed-rate insulin infusion: 0.1 units/kg/h; continue long-acting basal insulin.
- Potassium: total body potassium is depleted even when plasma levels are normal; add 40 mmol/L to fluids when potassium is 3.5-5.5 mmol/L.
- Treat the precipitant (infection, missed insulin, myocardial infarction).
- Resolution: ketones below 0.6 mmol/L and venous pH above 7.3.
Bicarbonate is not routinely given.
Euglycaemic DKA
SGLT2 inhibitors (dapagliflozin, empagliflozin) can cause ketoacidosis with near-normal glucose, especially with fasting, surgery and dehydration. Check ketones in any unwell patient on these drugs; treat with insulin plus glucose. This is why SGLT2 inhibitors are withheld before surgery.
HHS Treatment
Slow correction: 0.9% saline to restore volume, aiming for a gradual fall in osmolality (about 3-8 mOsm/kg/h) and sodium (no more than 10 mmol/L in 24 hours). Insulin at a lower fixed rate (about 0.05 units/kg/h) is started only once glucose stops falling with fluids alone, unless ketones are significantly raised. Give prophylactic low molecular weight heparin.
Thyroid Disease
Hyperthyroidism
- Make the patient euthyroid before elective surgery with carbimazole or propylthiouracil and beta-blockers.
- Large goitres may compress or deviate the trachea; assess with imaging and consider awake techniques if there is airway compromise.
- After thyroidectomy: haemorrhage with airway compression (remove sutures/clips at the bedside), recurrent laryngeal nerve injury (bilateral injury causes stridor), and hypocalcaemia from parathyroid damage.
Thyroid Storm
A life-threatening exacerbation precipitated by surgery, infection or stopping treatment in a poorly controlled patient. Features: hyperthermia above 40 °C, tachycardia and atrial fibrillation, heart failure, agitation, vomiting and diarrhoea. It can mimic malignant hyperthermia, but rigidity and the rapid rise in end-tidal carbon dioxide are less prominent.
Treatment:
- Beta-blockade: propranolol or esmolol (also reduces T4-to-T3 conversion).
- Thionamide: propylthiouracil (preferred, also blocks peripheral conversion) or carbimazole.
- Iodine (Lugol's solution or potassium iodide) at least 1 hour after the thionamide, so it is not used as substrate for new hormone.
- Hydrocortisone (reduces conversion and treats relative adrenal insufficiency).
- Cooling, fluids, treat the precipitant; avoid aspirin (displaces T4 from binding proteins).
Hypothyroidism
Patients are sensitive to sedatives and anaesthetic agents, may have hypothermia, hyponatraemia, bradycardia, reduced cardiac output and delayed gastric emptying. Elective surgery should wait for replacement. Myxoedema coma is treated with intravenous levothyroxine or liothyronine, hydrocortisone first (adrenal insufficiency may coexist), and supportive care.
Adrenal Disease
Adrenal Insufficiency
- Primary (Addison's disease): destruction of the adrenal cortex; both cortisol and aldosterone are lost (hyponatraemia, hyperkalaemia, pigmentation).
- Secondary: pituitary failure or, most commonly, suppression by exogenous glucocorticoids; aldosterone is preserved.
Perioperative steroid cover (Association of Anaesthetists 2020 guidance) for patients on at least 5 mg prednisolone daily (or equivalent) for at least 4 weeks: hydrocortisone 100 mg at induction, then 200 mg per 24 hours by infusion (or 50 mg every 6 hours) until eating and drinking, then double the usual oral dose for about 48 hours (minor surgery) or up to a week (major surgery).
Adrenal crisis: hypotension refractory to vasopressors, hyponatraemia, hyperkalaemia, hypoglycaemia, abdominal pain. Treat with hydrocortisone 100 mg intravenously immediately, then 200 mg per 24 hours, with intravenous fluids and glucose.
Cushing's Syndrome
Hypertension, diabetes, obesity, fragile skin and veins, osteoporosis (care with positioning), hypokalaemia and obstructive sleep apnoea.
Conn's Syndrome
Primary hyperaldosteronism causes hypertension and hypokalaemia with metabolic alkalosis; correct potassium with spironolactone before surgery.
Phaeochromocytoma
A catecholamine-secreting tumour of adrenal medullary chromaffin cells (extra-adrenal tumours are paragangliomas). Diagnosis: plasma or urinary metanephrines, then imaging.
Preoperative Preparation
- Alpha-blockade first: phenoxybenzamine (non-competitive, irreversible) or doxazosin (competitive alpha-1) for about 10-14 days, with liberal salt and fluid intake to restore plasma volume.
- Beta-blockade only after alpha-blockade, to control tachycardia; beta-blockade alone leaves unopposed alpha-stimulation and can cause a hypertensive crisis and heart failure.
- Targets (Roizen criteria, for example): blood pressure below about 160/90 mmHg, orthostatic hypotension, and few ventricular ectopics.
Intraoperative Management
- Invasive arterial monitoring before induction; avoid drugs that release histamine or catecholamines (morphine, atracurium in large doses, ketamine, ephedrine, metoclopramide, droperidol).
- Hypertensive surges during tumour handling: phentolamine, sodium nitroprusside, glyceryl trinitrate, magnesium sulphate, esmolol or clevidipine.
- After venous ligation: profound hypotension from loss of catecholamines and residual alpha-blockade (treat with fluids, noradrenaline, vasopressin) and rebound hypoglycaemia as insulin suppression ends; monitor glucose for 24-48 hours.
Carcinoid Syndrome
Neuroendocrine tumours, usually of the small bowel, secrete serotonin, histamine, kallikrein and bradykinin. The syndrome (flushing, diarrhoea, bronchospasm) usually indicates hepatic metastases, because the liver otherwise inactivates the mediators. Carcinoid heart disease affects right-sided valves (tricuspid regurgitation, pulmonary stenosis).
- Octreotide (somatostatin analogue) prevents and treats carcinoid crises: give preoperatively and intravenously during surgery (for example 50-100 boluses).
- Avoid histamine-releasing drugs and catecholamines where possible, because catecholamines can trigger mediator release; if a vasopressor is needed, vasopressin or phenylephrine may be preferred, with octreotide.
A 24-year-old with type 1 diabetes has glucose 22 mmol/L, ketones 5.2 mmol/L, pH 7.12 and potassium 4.2 mmol/L. Which initial plan is correct?
Intravenous sodium bicarbonate 8.4% to correct the pH before giving insulin
0.9% saline, insulin 0.1 units/kg/h, and potassium 40 mmol/L in the fluids
Insulin infusion at 0.05 units/kg/h, started only after glucose stops falling with fluids alone
Insulin without potassium, because plasma potassium is normal
A patient with phaeochromocytoma is being prepared for adrenalectomy. Which sequence is correct?
Beta-blockade first to control tachycardia and arrhythmias, then alpha-blockade on the day of surgery
No preoperative blockade, with control of hypertension intraoperatively using esmolol only
Alpha-blockade for about 10-14 days with fluid and salt loading, then beta-blockade if needed
Beta-blockade and alpha-blockade started together 24 hours before surgery
A patient who has taken prednisolone 20 mg daily for a year becomes profoundly hypotensive after major surgery despite noradrenaline. Sodium is 128 mmol/L and glucose 3.1 mmol/L. What is the immediate management?
Hydrocortisone 100 mg IV now, then about 200 mg over 24 hours, with fluids and glucose
Fludrocortisone 100 micrograms orally, because the problem is mineralocorticoid deficiency
Dexamethasone 0.75 mg intravenously as a physiological replacement dose, with fluid restriction
Restart oral prednisolone 20 mg the next morning
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