What are the criteria for Hyperosmolar Hyperglycemic Syndrome (HHS)?

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Last updated: April 13, 2025View editorial policy

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From the Guidelines

The criteria for diagnosing Hyperosmolar Hyperglycemic State (HHS) include blood glucose ≥600 mg/dl, arterial pH ≥7.3, bicarbonate ≤15 mEq/l, effective serum osmolality ≥320 mOsm/kg H2O, and mild ketonuria or ketonemia. When evaluating patients for HHS, it is essential to consider the severity of symptoms, including mental status change or severe dehydration, which may require admission to an intensive care unit 1. The diagnostic criteria for HHS can be calculated using the effective serum osmolality formula: 2[measured Na (mEq/l)] + glucose (mg/dl)/18 1. Key considerations in the management of HHS include:

  • Aggressive fluid resuscitation to correct dehydration and reduce osmolality
  • Insulin administration to reduce glucose levels, with careful monitoring to avoid hypoglycemia
  • Potassium replacement to prevent hypokalemia
  • Identification and treatment of the underlying cause of HHS, such as infection or medication non-compliance 1. In terms of specific treatment protocols, the study recommends an initial insulin infusion rate of 0.1 U kg-1 h-1, which may be doubled every hour until a steady glucose decline between 50 and 75 mg/h is achieved 1. It is also crucial to monitor patients closely for signs of improvement or deterioration, including regular measurements of serum electrolytes, glucose, blood urea nitrogen, creatinine, osmolality, and venous pH 1.

From the Research

Criteria for Hyperosmolar Hyperglycaemic State (HHS)

The criteria for HHS include:

  • Marked hypovolaemia
  • Osmolality ≥320 mOsm/kg
  • Marked hyperglycaemia ≥30 mmol/L
  • Without significant ketonaemia (≤3.0 mmol/L)
  • Without significant acidosis (pH >7.3)
  • Bicarbonate ≥15 mmol/L 2
  • Plasma glucose level >600 mg/dL and increased effective plasma osmolality >320 mOsm/kg in the absence of ketoacidosis 3
  • Serum osmolality greater than 320 mOsm/kg, lack of metabolic acidosis, and minimal to no presence of ketones 4

HHS Resolution Criteria

The resolution criteria for HHS are:

  • Osmolality <300 mOsm/kg
  • Hypovolaemia corrected (urine output ≥0.5 ml/kg/h)
  • Cognitive status returned to pre-morbid state
  • Blood glucose <15 mmol/L 2

Diagnostic Considerations

HHS is often triggered by an underlying illness, most commonly infection, but may also be triggered by stroke, acute coronary syndrome, and other acute illnesses 4 The incidence of HHS is estimated to be <1% of hospital admissions of patients with diabetes, with a reported mortality between 10 and 20% 3 HHS is an underrecognized diabetic emergency with high morbidity and mortality 4

References

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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