Residency · Residency · Critical Care

Endocrine Emergencies in Critical Care

Diabetic Ketoacidosis (DKA)

Diagnostic Criteria

Diabetic ketoacidosis is a life-threatening metabolic emergency requiring prompt recognition and systematic, protocol-driven management. The diagnosis rests upon four cardinal features: hyperglycemia with blood glucose exceeding 250 mg/dL, metabolic acidosis with arterial pH below 7.30 and/or serum bicarbonate below 18 mEq/L, an elevated anion gap exceeding 12 (calculated as sodium minus chloride minus bicarbonate), and ketonemia with beta-hydroxybutyrate levels exceeding 3 mmol/L (preferred over urine ketone testing, which measures acetoacetate and may underestimate the severity of ketosis).

A critical modern consideration is euglycemic DKA, in which patients present with anion gap metabolic acidosis and ketosis but with blood glucose levels that may be near-normal or only modestly elevated. This presentation is increasingly encountered with the widespread use of SGLT2 inhibitors, which promote urinary glucose excretion, and can also occur in pregnancy and starvation states. Clinicians must check ketones in any acidotic patient, even when glucose levels are not dramatically elevated.

Severity is stratified by pH and mental status: mild DKA (pH 7.25-7.30, patient alert), moderate DKA (pH 7.0-7.24, patient drowsy), and severe DKA (pH below 7.0, patient obtunded or comatose).

Management Protocol

The management of DKA requires simultaneous attention to fluid resuscitation, insulin therapy, potassium repletion, and monitoring. Fluid resuscitation begins with normal saline at 1 to 1.5 liters per hour for the first 1 to 2 hours, then 250 to 500 mL per hour. When the corrected serum sodium is normal or elevated, the infusion should be transitioned to 0.45 percent normal saline. When glucose falls below 200 mg/dL, dextrose 5 percent must be added to the intravenous fluids. This last point is one of the most important management principles: insulin should not be stopped when glucose reaches 200 mg/dL because the goal of insulin therapy in DKA is to close the anion gap (i.e., to clear ketoacids), not merely to lower blood glucose. Corrected sodium, calculated as measured sodium plus 1.6 multiplied by the quantity [(glucose minus 100) divided by 100], should rise during treatment, and a failure to rise suggests excessive free water administration.

Insulin therapy begins with regular insulin at 0.1 units/kg IV bolus (optional) followed by a continuous infusion at 0.1 units/kg/hr. The target rate of glucose decline is 50 to 75 mg/dL per hour. If glucose fails to decline at an adequate rate, the infusion should be doubled after verifying insulin delivery (checking the line and pump). When glucose reaches 200 mg/dL, the insulin infusion should be reduced to 0.02 to 0.05 units/kg/hr and dextrose added, maintaining glucose at 150 to 200 mg/dL until the anion gap closes.

Potassium management is critical because total body potassium is invariably depleted in DKA (total body deficit of 3 to 5 mEq/kg) even when the initial serum potassium is normal or elevated due to extracellular shifts driven by acidosis and insulin deficiency. If potassium exceeds 5.2 mEq/L, it should be held and rechecked in 2 hours. If potassium is between 3.3 and 5.2 mEq/L, 20 to 40 mEq of potassium chloride should be added per liter of intravenous fluid. If potassium is below 3.3 mEq/L, this represents a medical emergency: insulin must be held and potassium aggressively replaced before insulin therapy is initiated, as insulin drives potassium intracellularly and can precipitate life-threatening hypokalemia and cardiac arrest.

Bicarbonate administration is not routinely recommended and should be considered only when pH is below 6.9 (100 mEq sodium bicarbonate in 400 mL D5W over 2 hours). Phosphate replacement is indicated when levels fall below 1.0 mg/dL or when symptoms of phosphate depletion (muscle weakness, respiratory failure) are present.

Resolution Criteria

DKA resolution is defined by closure of the anion gap to below 12, which is the most important marker of ketone clearance, along with pH above 7.30, bicarbonate above 18 mEq/L, and glucose below 200 mg/dL. When the patient is able to eat, transition to subcutaneous insulin should proceed with a 1 to 2 hour overlap period during which both the intravenous and subcutaneous insulin are administered simultaneously to prevent recurrence of ketosis.

Complications of DKA

Cerebral edema, while primarily a concern in pediatric DKA, can occur with overly rapid correction of glucose or osmolality and should prompt avoidance of aggressive fluid boluses and rapid glucose lowering. Iatrogenic hypokalemia is the most dangerous complication of DKA treatment and mandates potassium monitoring every 2 hours during insulin therapy. Non-anion gap hyperchloremic metabolic acidosis commonly develops during treatment as a consequence of large-volume saline resuscitation and the renal excretion of ketone bodies as sodium salts; this is expected and self-limiting. VTE risk is elevated due to dehydration and a hypercoagulable state, and prophylaxis should be considered.

Hyperosmolar Hyperglycemic State (HHS)

Diagnostic Criteria

Hyperosmolar hyperglycemic state represents the other extreme of diabetic emergencies, characterized by massive hyperglycemia with blood glucose exceeding 600 mg/dL (often above 1000 mg/dL), effective serum osmolality exceeding 320 mOsm/L (calculated as 2 times sodium plus glucose divided by 18), pH above 7.30 with bicarbonate above 18 mEq/L (reflecting minimal ketosis, which distinguishes HHS from DKA), and altered mental status that correlates directly with the degree of hyperosmolality. Mental status changes typically appear when osmolality exceeds 320 mOsm/L and progress to coma above 340 mOsm/L. The mortality of HHS is substantially higher than DKA at 10 to 20 percent compared to 1 to 5 percent, reflecting the typically older and more comorbid patient population.

Management

The management of HHS differs from DKA in several important respects. Fluid resuscitation is even more aggressive than in DKA because the total body water deficit is typically 8 to 10 liters. Normal saline should be administered at 1 to 2 liters per hour for the first 2 hours, followed by 250 to 500 mL per hour with transition to 0.45 percent normal saline. The rate of osmolality correction should not exceed 3 mOsm/L/hr to minimize the risk of cerebral edema.

Insulin plays a less central role in HHS than in DKA because the primary pathology is dehydration and hyperosmolality rather than ketosis. Insulin is typically started at a lower dose (0.05 units/kg/hr) and may be deferred until initial fluid resuscitation is underway, as glucose may decline substantially with hydration alone. Potassium management follows the same principles as in DKA. Monitoring of serum osmolality, corrected sodium, and potassium every 2 hours, along with urine output, guides therapy.

<image>Side-by-side comparison table and flowchart for DKA vs. HHS management. Left column (DKA): diagnostic criteria (glucose >250, pH <7.30, AG >12, ketones positive), pathophysiology diagram showing insulin deficiency leading to lipolysis and ketogenesis, and treatment protocol flowchart (fluids → potassium check → insulin drip → monitor AG closure → transition to SQ insulin). Right column (HHS): diagnostic criteria (glucose >600, osmolality >320, pH >7.30, minimal ketones), pathophysiology showing relative insulin deficiency with preserved lipolysis suppression leading to massive hyperglycemia and osmotic diuresis, and treatment flowchart emphasizing fluid as primary therapy. Central overlap zone showing shared management principles (fluid resuscitation, electrolyte monitoring, insulin). Include monitoring parameters and frequency (glucose hourly, K+ q2h, AG q4h, osmolality q4h) and transition criteria at bottom.</image>

Adrenal Crisis

Critical Illness-Related Corticosteroid Insufficiency (CIRCI)

Critical illness-related corticosteroid insufficiency is a state of inadequate cortisol response relative to the severity of illness, recognized as a significant contributor to vasopressor-refractory shock. The mechanisms are diverse and include hypothalamic-pituitary-adrenal axis suppression from critical illness itself, adrenal hemorrhage (as in Waterhouse-Friderichsen syndrome), relative adrenal insufficiency in which cortisol production is present but insufficient for the degree of physiological stress, and prior exogenous steroid use causing adrenal suppression.

The clinical presentation is characterized by refractory hypotension despite adequate fluid resuscitation and escalating vasopressor doses, often accompanied by hyponatremia, hyperkalemia, hypoglycemia, and eosinophilia. A random cortisol level below 10 mcg/dL in a critically ill patient strongly suggests adrenal insufficiency. The cosyntropin (ACTH) stimulation test, using 250 mcg IV ACTH with cortisol measurement at 0 and 60 minutes, has traditionally been used for diagnosis, with an increment of less than 9 mcg/dL or a peak cortisol below 18 mcg/dL suggesting adrenal insufficiency. However, the Surviving Sepsis Campaign 2021 guidelines recommend against using the cosyntropin test to guide corticosteroid therapy in septic shock, instead advocating empiric treatment when clinical suspicion exists.

Treatment

Acute adrenal crisis requires immediate treatment with hydrocortisone 100 mg IV bolus, followed by 50 mg IV every 8 hours or 200 mg/day as a continuous infusion. Volume resuscitation with normal saline combined with dextrose 5 percent addresses both the hyponatremia and hypoglycemia. Fludrocortisone supplementation for mineralocorticoid effect is not needed acutely when the hydrocortisone dose exceeds 50 mg/day, as hydrocortisone at these doses provides sufficient mineralocorticoid activity. Notably, the APROCCHSS trial demonstrated that the combination of hydrocortisone 50 mg every 6 hours plus fludrocortisone 50 mcg daily reduced 90-day mortality in septic shock, supporting a combined approach in that specific population. Corticosteroids should be tapered gradually once the patient is hemodynamically stable and off vasopressors; abrupt discontinuation risks precipitating recurrent adrenal crisis.

Adrenal Hemorrhage

Bilateral adrenal hemorrhage, classically associated with meningococcal sepsis (Waterhouse-Friderichsen syndrome) but occurring with any overwhelming infection, represents a catastrophic and often rapidly fatal form of adrenal crisis. Risk factors include anticoagulation therapy (especially heparin and warfarin), antiphospholipid syndrome, and the postoperative state. CT abdomen reveals bilateral adrenal enlargement with hemorrhagic changes. The condition is frequently fatal if not promptly recognized, and empiric stress-dose steroids should be administered in any patient with unexplained vasopressor-refractory shock.

Thyroid Emergencies

Myxedema Coma

Myxedema coma represents the most severe manifestation of hypothyroidism, carrying a mortality of 30 to 60 percent even with treatment. The clinical features constitute a constellation of organ dysfunction driven by absent thyroid hormone: hypothermia, bradycardia, hypoventilation with carbon dioxide narcosis, hyponatremia from impaired free water excretion, hypoglycemia from impaired gluconeogenesis, and ileus. Precipitating factors include infection, cold exposure, surgery, medications (sedatives, opioids, amiodarone), and non-compliance with levothyroxine replacement.

Diagnosis rests on markedly elevated TSH with very low free T4, unless central hypothyroidism is present, in which case TSH may be inappropriately normal or low. Treatment requires a multimodal approach. Intravenous levothyroxine (T4) is administered as a loading dose of 200 to 400 mcg followed by 50 to 100 mcg IV daily, as oral absorption is unreliable in the myxedematous state. Intravenous liothyronine (T3) at 5 to 20 mcg IV every 8 to 12 hours provides faster onset of action and is used when poor T4-to-T3 conversion is suspected in severe illness. A critical sequencing point is that hydrocortisone 100 mg IV every 8 hours must be given before initiating thyroid hormone replacement, as thyroid hormone increases cortisol metabolism and may unmask concurrent adrenal insufficiency, precipitating adrenal crisis.

Supportive care includes passive rewarming, as active external warming may produce peripheral vasodilation and cardiovascular collapse in the myxedematous patient. Mechanical ventilation is frequently required for hypoventilation. Vasopressors may be needed for hemodynamic support.

Thyroid Storm

Thyroid storm is a life-threatening state of decompensated thyrotoxicosis carrying a mortality of 10 to 30 percent. The Burch-Wartofsky Point Scale (BWPS) provides a standardized diagnostic framework, with a score above 45 indicating thyroid storm and 25 to 44 suggesting impending storm. The score incorporates temperature, heart rate, central nervous system effects, gastrointestinal and hepatic dysfunction, precipitating event, and the presence of heart failure. Common precipitants include infection, surgery, radioactive iodine therapy, iodinated contrast exposure, and non-compliance with antithyroid medications.

Treatment of thyroid storm follows a specific multi-modal, sequentially ordered approach in which each step has a distinct mechanism and the order of administration matters. Step 1 is beta-adrenergic blockade: propranolol 60 to 80 mg orally every 4 to 6 hours (which also blocks peripheral T4-to-T3 conversion) or esmolol drip at 1 mg/min, targeting a heart rate below 100. Step 2 is thionamide administration: propylthiouracil (PTU) at a loading dose of 500 to 1000 mg followed by 250 mg every 4 hours is preferred over methimazole (20 to 25 mg every 6 hours) in storm because PTU blocks both thyroid hormone synthesis and peripheral T4-to-T3 conversion, whereas methimazole blocks synthesis only. Step 3 is iodine, which must be administered at least 1 hour after the thionamide: Lugol solution 4 to 8 drops every 6 to 8 hours or saturated potassium iodide (SSKI) 5 drops every 6 hours. Iodine blocks thyroid hormone release through the Wolff-Chaikoff effect, but if given before the thionamide has had time to block new hormone synthesis, iodine provides substrate for additional hormone production (Jod-Basedow phenomenon). Step 4 is glucocorticoids: dexamethasone 2 mg IV every 6 hours or hydrocortisone 100 mg every 8 hours, which block T4-to-T3 conversion and address possible relative adrenal insufficiency. Step 5 includes adjunctive therapies: cholestyramine 4 g orally every 6 hours (binds thyroid hormone in the GI tract and enhances elimination), cooling with acetaminophen (aspirin must be avoided as it displaces thyroid hormone from binding proteins, increasing free hormone levels), intravenous fluids, and identification and treatment of the precipitant.

Pheochromocytoma Crisis

Presentation

Pheochromocytoma crisis presents as severe hypertensive emergency with systolic blood pressure often exceeding 200 mmHg, frequently in a paroxysmal pattern. The classic triad consists of headache, diaphoresis, and palpitations. Crisis may be triggered by anesthetic induction, tumor manipulation during surgery, or administration of certain medications including beta-blockers without prior alpha-blockade, metoclopramide, and tricyclic antidepressants. Life-threatening complications include hypertensive encephalopathy, hemorrhagic stroke, myocardial infarction, aortic dissection, and acute pulmonary edema.

Management

The cardinal rule of pheochromocytoma management is that alpha-adrenergic blockade must be established before any beta-blockade is initiated. This is because beta-2 receptor blockade eliminates the vasodilatory component of catecholamine action, leaving unopposed alpha-1 mediated vasoconstriction, which paradoxically worsens hypertension. Acute alpha-blockade is achieved with phentolamine 2 to 5 mg IV every 5 minutes, while phenoxybenzamine 10 to 20 mg orally twice daily (an irreversible alpha-blocker) is used for preoperative preparation. Nicardipine infusion at 5 to 15 mg/hr provides an effective calcium channel blocker alternative for acute crisis management. Nitroprusside at 0.5 to 5 mcg/kg/min is reserved for severe refractory hypertension. Only after adequate alpha-blockade has been achieved should beta-blockade be introduced, with esmolol preferred for rate control. Magnesium sulfate at 2 to 4 g IV bolus provides additional benefit by reducing catecholamine release and offering antiarrhythmic effects. Definitive treatment is surgical resection after 10 to 14 days of adequate preoperative alpha-blockade.

<image>Thyroid storm treatment algorithm showing five sequential therapeutic steps as cascading arrows. Step 1 (immediate): Beta-blocker — propranolol 60-80 mg PO q4-6h or esmolol drip, target HR <100, with mechanism annotation (blocks T4→T3 conversion, symptom control). Step 2 (within 1 hour): Thionamide — PTU 500-1000 mg load then 250 mg q4h, with mechanism annotation (blocks new hormone synthesis + blocks T4→T3 conversion). Step 3 (1 hour after thionamide): Iodine — Lugol solution or SSKI, with mechanism annotation (blocks thyroid hormone release via Wolff-Chaikoff effect) and WARNING box: "must give AFTER thionamide to prevent substrate for new hormone synthesis." Step 4: Glucocorticoid — dexamethasone 2 mg IV q6h (blocks T4→T3 conversion + addresses relative adrenal insufficiency). Step 5: Adjuncts — cholestyramine, cooling (avoid aspirin), treat precipitant. Include Burch-Wartofsky scoring system in sidebar.</image>

Calcium Emergencies

Hypercalcemic Crisis

Hypercalcemic crisis is defined by a total calcium exceeding 14 mg/dL or ionized calcium exceeding 3.0 mmol/L accompanied by symptoms including altered mental status, cardiac arrhythmias, renal failure, or coma. The most common cause in the ICU setting is malignancy, either through PTHrP-mediated humoral hypercalcemia or direct bone destruction from metastases.

Treatment follows a stepwise approach. Aggressive intravenous normal saline at 200 to 300 mL/hr initially expands intravascular volume and enhances renal calcium excretion. Calcitonin at 4 units/kg subcutaneously or intramuscularly every 12 hours provides rapid onset of calcium lowering within 4 to 6 hours but is limited by tachyphylaxis within 48 hours. Zoledronic acid at 4 mg IV over 15 minutes is the cornerstone of definitive treatment, with onset over 2 to 4 days and a duration of 2 to 4 weeks. Denosumab at 120 mg subcutaneously is used for bisphosphonate-refractory cases. Hemodialysis with a low-calcium dialysate is reserved for severe, life-threatening hypercalcemia or when renal failure precludes other therapies. Glucocorticoids are specifically effective for hypercalcemia caused by granulomatous disease (sarcoidosis), lymphoma, or vitamin D toxicity. Thiazide diuretics must be avoided as they increase renal calcium reabsorption.

Severe Hypocalcemia

Severe hypocalcemia, defined by an ionized calcium below 0.8 mmol/L or the presence of symptoms including tetany, seizures, QTc prolongation, laryngospasm, or cardiac arrest, requires emergent treatment. Calcium gluconate 1 to 2 g IV over 10 to 20 minutes is the preferred initial therapy for peripheral intravenous administration because it causes less tissue necrosis with extravasation compared to calcium chloride. Calcium chloride, which contains three times more elemental calcium per gram, is reserved for central venous administration at 1 g IV over 10 minutes.

A critical point is that hypomagnesemia causes functional hypoparathyroidism and produces hypocalcemia that is refractory to calcium replacement alone. Magnesium must be corrected concurrently for calcium therapy to be effective. Ionized calcium should be monitored every 4 to 6 hours during IV calcium infusion with a target above 1.0 mmol/L. Once the patient is able to take oral medications, transition to calcium carbonate combined with calcitriol provides ongoing supplementation.

Key Clinical Pearls

• In DKA, do NOT stop insulin when glucose reaches 200 mg/dL — add dextrose and continue insulin until the anion gap closes
• Potassium <3.3 mEq/L in DKA is a medical emergency — hold insulin and replace potassium aggressively before starting insulin
• Always give hydrocortisone BEFORE thyroid hormone replacement in myxedema coma — concurrent adrenal insufficiency is common and can be precipitated by thyroid hormone
• In thyroid storm, iodine must be given at least 1 hour AFTER thionamide — otherwise iodine provides substrate for new hormone synthesis (Jod-Basedow phenomenon)
• Never give beta-blockers alone in pheochromocytoma crisis — unopposed alpha stimulation causes paradoxical hypertension
• Random cortisol <10 mcg/dL in a critically ill patient strongly suggests adrenal insufficiency — give empiric hydrocortisone
• SGLT2 inhibitor-associated euglycemic DKA is increasingly common — check ketones in acidotic patients even with normal glucose
• Corrected sodium should rise during DKA treatment — failure to rise suggests excessive free water administration

References

1. Kitabchi AE, Umpierrez GE, Miles JM, Fisher JN. Hyperglycemic crises in adult patients with diabetes. Diabetes Care. 2009;32(7):1335-1343.
2. Annane D, Pastores SM, Rochwerg B, et al. Guidelines for the diagnosis and management of critical illness-related corticosteroid insufficiency (CIRCI). Crit Care Med. 2017;45(12):2078-2088.
3. Chiha M, Samarasinghe S, Kabaker AS. Thyroid storm: an updated review. J Intensive Care Med. 2015;30(3):131-140.
4. Annane D, Renault A, Brun-Buisson C, et al. Hydrocortisone plus fludrocortisone for adults with septic shock. N Engl J Med. 2018;378(9):809-818.
5. Jonklaas J, Bianco AC, Bauer AJ, et al. Guidelines for the treatment of hypothyroidism. Thyroid. 2014;24(12):1670-1751.

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