What is the treatment for hyperosmolar non-ketotic coma (HONK)?

Treatment of Hyperosmolar Non-Ketotic Coma (HONK)

The treatment of hyperosmolar non-ketotic coma (HONK) requires aggressive fluid resuscitation with isotonic saline, followed by hypotonic solutions, careful insulin administration, and meticulous electrolyte management, with the primary goal of gradually correcting hyperglycemia and hyperosmolality while preventing cerebral edema. 1

Initial Assessment and Management

• HONK is characterized by severe hyperglycemia, effective serum osmolality ≥320 mOsm/kg H₂O, arterial pH >7.3, bicarbonate >15 mEq/L, minimal ketonuria/ketonemia, and altered mental status or severe dehydration 1
• Laboratory evaluation should include plasma glucose, blood urea nitrogen, creatinine, serum ketones, electrolytes with calculated anion gap, osmolality, urinalysis, arterial blood gases, complete blood count with differential, and electrocardiogram 1
• Serum sodium should be corrected for hyperglycemia by adding 1.6 mEq to sodium value for each 100 mg/dL glucose >100 mg/dL 1
• Identify and treat precipitating causes such as infection, stroke, myocardial infarction, or medication effects (diuretics, corticosteroids, beta-blockers) 1, 2

Fluid Therapy

• Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/h during the first hour to restore circulatory volume and tissue perfusion 1, 2
• Total body water deficit in HONK is typically 9 liters (approximately 100-200 mL/kg) 1
• After hemodynamic stabilization, transition to hypotonic saline (0.45% NaCl) to correct the free water deficit 2
• Fluid replacement should correct estimated deficits within the first 24 hours 1
• The induced change in serum osmolality should not exceed 3 mOsm/kg/h to prevent cerebral edema 1, 3

Insulin Therapy

• After excluding hypokalemia, administer an intravenous bolus of regular insulin at 0.15 U/kg body weight, followed by a continuous infusion at 0.1 U/kg/h 1
• If plasma glucose does not fall by 50 mg/dL from the initial value in the first hour, double the insulin infusion every hour until a steady glucose decline between 50-75 mg/h is achieved 1
• Once blood glucose reaches 250-300 mg/dL, add dextrose to the hydrating solution while continuing insulin infusion at a reduced rate 4, 1
• Continue insulin infusion until mental status improves and hyperosmolarity resolves 1

Electrolyte Management

• Total body deficits in HONK typically include sodium (5-15 mEq/kg), potassium (4-6 mEq/kg), chloride (5-13 mEq/kg), and phosphate (3-7 mmol/kg) 1
• Once renal function is assured and serum potassium is known, add 20-40 mEq/L potassium to the infusion 1
• Monitor potassium levels closely as total body potassium deficits are common despite potentially normal or elevated initial serum levels 1
• Phosphate replacement (20-30 mEq/L potassium phosphate) may be considered in patients with cardiac dysfunction, anemia, respiratory depression, or serum phosphate <1.0 mg/dL 4

Monitoring and Ongoing Management

• Draw blood every 2-4 hours to determine serum electrolytes, glucose, blood urea nitrogen, creatinine, and osmolality 1
• Monitor fluid input/output, hemodynamic parameters, and clinical examination to assess progress with fluid replacement 1
• Target blood glucose levels of 250-300 mg/dL until hyperosmolarity and mental status improve 4
• Watch for signs of cerebral edema (lethargy, behavioral changes, seizures, incontinence, pupillary changes, bradycardia, respiratory arrest) 4

Complications and Prevention

• Cerebral edema is a potentially fatal complication, especially with rapid correction of hyperosmolality 4, 3
• Hypoglycemia can occur due to overzealous insulin treatment 4
• Hypokalemia may develop during treatment due to insulin administration and fluid shifts 4
• Hyperchloremic metabolic acidosis can result from excessive saline administration 4

Transition of Care and Follow-up

• Successful transition from intravenous to subcutaneous insulin requires administration of basal insulin 2-4 hours before the intravenous insulin is stopped to prevent rebound hyperglycemia 4
• A structured discharge plan should be tailored to the individual patient to reduce length of hospital stay and readmission rates 1
• Many patients with HONK may not require long-term insulin therapy and can be managed with diet or oral agents after recovery 2

Remember that HONK has a high mortality rate, and careful attention to gradual correction of fluid deficits and hyperosmolality is essential to prevent cerebral edema and other complications 4, 2.