What is the recommended emergency management for hyperglycemic hyperosmolar syndrome in an older adult with type 2 diabetes, potentially precipitated by infection, dehydration, diuretics, or glucocorticoids?

Emergency Management of Hyperglycemic Hyperosmolar Syndrome in Older Adults

For critically ill older adults with hyperglycemic hyperosmolar syndrome, immediately initiate aggressive fluid resuscitation with 0.9% sodium chloride at 15-20 mL/kg/hour in the first hour, followed by continuous intravenous insulin only after fluid resuscitation has begun and hypokalemia is excluded, while simultaneously identifying and treating precipitating causes such as infection, with the primary goal being restoration of circulatory volume to prevent the high mortality associated with this condition. 1, 2, 3

Immediate Recognition and Initial Assessment (0-60 minutes)

HHS is a life-threatening emergency that develops over days to a week, presenting with:

• Severe hyperglycemia ≥30 mmol/L (540 mg/dL) 3
• Marked hyperosmolality ≥320 mOsm/kg (calculated as [2×Na+] + glucose + urea) 3
• Altered mental status or cognitive impairment (common in older adults) 2, 4
• Severe dehydration with fluid losses of 100-220 mL/kg body weight 3
• Absence of significant ketosis (ketones ≤3.0 mmol/L) and acidosis (pH >7.3, bicarbonate ≥15 mmol/L) 3

Critical point: One-third of hyperglycemic emergencies present as a hybrid DKA-HHS state, so check for ketones 2. HHS has higher mortality than DKA, particularly in elderly patients where age is the best prognostic indicator 5, 4.

Phase 1: Aggressive Fluid Resuscitation (First Priority)

Fluid replacement takes absolute priority over insulin in HHS 2, 4, 3:

• Start with 0.9% sodium chloride at 15-20 mL/kg/hour for the first hour to restore intravascular volume and tissue perfusion 1, 2, 6
• Continue fluid replacement to correct estimated deficits within 24 hours 2, 3
• After initial stabilization of vital signs, consider switching to 0.45% sodium chloride for ongoing replacement 6
• Aim for osmolality reduction of 3-8 mOsm/kg/hour to prevent cerebral edema and central pontine myelinolysis 2, 4, 3
• Target urine output ≥0.5 mL/kg/hour as a marker of adequate rehydration 3

Common pitfall: In elderly patients with heart failure or cerebral stroke, aggressive fluid replacement must be balanced against risk of fluid overload—these precipitating factors are frequent causes of death 5. Monitor for signs of fluid overload continuously.

Phase 2: Insulin Therapy (Delayed Until Appropriate)

Withhold insulin until blood glucose stops falling with IV fluids alone, unless significant ketonaemia is present 4, 3:

• Fluid replacement alone will cause blood glucose to fall 4, 3
• Early insulin use before adequate fluid resuscitation may be detrimental 4
• Once indicated, administer 0.1 units/kg bolus of regular insulin followed by continuous IV infusion at 0.1 units/kg/hour 2, 6
• When glucose reaches 14-15 mmol/L (250-270 mg/dL), add 5% or 10% dextrose to IV fluids while continuing reduced-rate insulin infusion to prevent hypoglycemia 6, 3
• Target blood glucose of 10-15 mmol/L (180-270 mg/dL) in the first 24 hours 3

For critically ill and mentally obtunded patients, continuous intravenous insulin is the standard of care 1.

Phase 3: Electrolyte Management

Monitor serum potassium every 2-4 hours as insulin drives potassium intracellularly, causing life-threatening hypokalemia 2, 3:

• Begin potassium replacement when serum levels fall below 5.2-5.5 mEq/L, provided adequate urine output is present 2, 3
• Typical potassium losses in HHS are significant and require aggressive replacement 6, 5
• Do not start insulin if potassium is low until replacement has begun 2

Expected sodium changes: An initial rise in sodium level during treatment is expected and normal—this is NOT an indication for hypotonic fluids 4, 3.

Phase 4: Continuous Monitoring Parameters

Monitor the following at specified intervals 2, 3:

• Blood glucose: Every 1-2 hours initially 2
• Serum osmolality: Every 2-4 hours to ensure reduction of 3-8 mOsm/kg/hour 2, 4, 3
• Electrolytes, BUN, creatinine: Every 2-4 hours 2
• Vital signs and mental status: Continuously 2
• Urine output: Hourly to ensure ≥0.5 mL/kg/hour 3

Phase 5: Identify and Treat Precipitating Causes

Infection is the most common precipitating factor 2, 5:

• Evaluate for pneumonia, urinary tract infection, sepsis 1, 5
• Other common precipitants in older adults: myocardial infarction, stroke, gastrointestinal hemorrhage, pancreatitis 5, 4
• Medication-related causes: diuretics, glucocorticoids, phenytoin, beta-blockers 6, 5
• Medication non-compliance or new-onset diabetes 2

Treat underlying precipitating illness simultaneously with metabolic correction—failure to do so contributes to the high mortality 6, 5.

Resolution Criteria and Transition

HHS is resolved when 3:

• Osmolality <300 mOsm/kg
• Hypovolaemia corrected (urine output ≥0.5 mL/kg/hour)
• Cognitive status returned to baseline
• Blood glucose <15 mmol/L (270 mg/dL)

Transition to subcutaneous insulin: Administer basal insulin 2-4 hours prior to stopping IV insulin to prevent rebound hyperglycemia 1. Many older adults with HHS will not require long-term insulin therapy and can be managed with oral agents or diet after recovery 6.

Special Considerations for Older Adults

• Reduced glomerular filtration rate and elevated renal threshold for glucose in elderly patients impair osmotic diuresis correction of hyperglycemia 5
• Lack of appropriate thirst response to dehydration is common in older adults 5
• Compromised hemodynamic state and renal function substantially contribute to increased mortality 5
• Patients should be managed by a physician with diabetes expertise and nursed in areas with experienced staff 1, 4, 3

Prevention Strategies

• Ensure adequate fluid intake in elderly diabetic patients, especially those in nursing homes 5
• Use caution with thiazides, steroids, and phenytoin in older adults with diabetes 5
• Never discontinue insulin during intercurrent illness 2
• Educate patients on when to contact healthcare providers during illness 2
• Ensure adequate supervision for elderly patients unable to self-manage 5