What is the immediate management for hyperosmolar hyperglycaemic syndrome?

Immediate Management of Hyperosmolar Hyperglycaemic Syndrome (HHS)

The immediate management of hyperosmolar hyperglycaemic syndrome requires aggressive fluid resuscitation as the primary intervention, followed by careful insulin administration, electrolyte replacement, and identification and treatment of underlying causes.

Initial Assessment and Diagnosis

• HHS is diagnosed by blood glucose >600 mg/dl, arterial pH >7.3, bicarbonate >15 mEq/l, mild ketonuria or ketonemia, and effective serum osmolality >320 mOsm/kg H₂O 1
• Calculate effective serum osmolality using the formula: 2[measured Na (mEq/l)] + glucose (mg/dl)/18 1
• Correct serum sodium for hyperglycemia by adding 1.6 mEq to sodium value for each 100 mg/dl glucose >100 mg/dl 2
• Obtain arterial blood gases, complete blood count, urinalysis, blood glucose, BUN, electrolytes, chemistry profile, and creatinine levels immediately 1
• Assess for precipitating factors including infection, myocardial infarction, stroke, medications (diuretics, corticosteroids, beta-blockers), and other acute illnesses 1

Fluid Resuscitation (First Priority)

• Begin with isotonic saline (0.9% NaCl) at 15-20 ml/kg/h (1-1.5 L in average adult) during the first hour to expand intravascular volume and restore renal perfusion 1
• After initial resuscitation, adjust fluid choice based on corrected serum sodium and hemodynamic status 1:
  • If corrected sodium is normal or elevated: use 0.45% NaCl at 4-14 ml/kg/h
  • If corrected sodium is low: continue 0.9% NaCl at similar rate
• Target fluid replacement should correct estimated deficits within the first 24 hours 1
• Monitor the rate of change in serum osmolality, which should not exceed 3 mOsm/kg/h to prevent neurological complications 3

Insulin Therapy (Second Priority)

• Withhold insulin initially until fluid resuscitation has been initiated and blood glucose is no longer falling with IV fluids alone 3
• Once insulin is started, administer as continuous intravenous infusion at 0.1 U/kg/h (typically 5-10 units/hour) 1
• When plasma glucose reaches 300 mg/dl, decrease insulin infusion to 0.05-0.1 U/kg/h (3-6 U/h) 2
• Add 5-10% dextrose to IV fluids when glucose falls below 300 mg/dl to prevent hypoglycemia while continuing to treat hyperosmolarity 2
• Target glucose level between 250-300 mg/dl until hyperosmolarity resolves 2

Electrolyte Replacement

• Once renal function is assured and serum potassium is known, add 20-30 mEq/L potassium (2/3 KCl and 1/3 KPO₄) to the infusion 1
• Monitor electrolytes (sodium, potassium, chloride, bicarbonate, phosphate, magnesium) every 2-4 hours during initial treatment 1
• Correct electrolyte imbalances based on laboratory results 1

Monitoring and Ongoing Assessment

• Monitor vital signs, mental status, fluid input/output, and hemodynamic parameters hourly 1
• Check blood glucose every 1-2 hours until stable 1
• Calculate effective serum osmolality regularly to guide fluid management 2
• Monitor for complications including cerebral edema, myocardial infarction, stroke, and vascular thrombosis 1
• In patients with cardiac or renal compromise, more careful fluid administration with frequent assessment of cardiac, renal, and mental status is necessary 1

Transition to Subcutaneous Insulin

• Successful transition from intravenous to subcutaneous insulin requires administration of basal insulin 2-4 hours before the intravenous insulin is stopped 1
• Consider low-dose basal insulin analog in addition to intravenous insulin infusion to prevent rebound hyperglycemia 1

Special Considerations

• Elderly patients and those with cardiac/renal compromise require more cautious fluid rates with closer monitoring 2
• Patients with HHS should be managed in an intensive care unit or high-dependency setting 3
• Involve the diabetes specialist team as soon as possible 3

Common Pitfalls to Avoid

• Do not administer insulin before adequate fluid resuscitation has begun 3
• Avoid rapid correction of osmolality (>3 mOsm/kg/h) to prevent neurological complications 3
• Do not use bicarbonate therapy routinely, as it has not been shown to improve outcomes 1
• Avoid excessive fluid administration in patients with cardiac or renal compromise 1