Symptoms of Hyperosmolar Hyperglycemic State (HHS)
The classical clinical picture of HHS includes polyuria, polydipsia, polyphagia, weight loss, dehydration, weakness, clouding of sensoria, and ultimately coma, with mental status changes being more frequent and severe than in DKA. 1
Clinical Presentation
HHS typically develops over a longer timeframe compared to DKA, usually evolving over several days to weeks. The symptoms progress in a predictable pattern:
Early Symptoms
- Polyuria (excessive urination)
- Polydipsia (excessive thirst)
- Polyphagia (excessive hunger)
- Weight loss
Progressive Symptoms
- Profound dehydration with poor skin turgor
- Weakness and fatigue
- Tachycardia
- Hypotension
Neurological Symptoms (More Prominent in HHS than DKA)
- Altered mental status ranging from mild confusion to profound lethargy
- Progressive clouding of consciousness
- Stupor
- Coma (occurs more frequently in HHS than in DKA) 1
Physical Examination Findings
- Severe dehydration (may lose 100-220 ml/kg of fluid) 2
- Hypotension
- Tachycardia
- Decreased skin turgor
- Dry mucous membranes
- Neurological impairment (ranging from lethargy to coma)
Laboratory Findings
HHS is characterized by specific laboratory abnormalities that distinguish it from DKA:
- Marked hyperglycemia (≥600 mg/dL or ≥30 mmol/L) 1, 2
- Hyperosmolality (≥320 mOsm/kg) 1, 2
- Minimal or absent ketosis (small urine and serum ketones)
- Absence of significant acidosis (pH >7.30)
- Serum bicarbonate ≥15 mEq/L
- Variable anion gap
Important Clinical Distinctions
HHS vs. DKA
- HHS typically has more severe hyperglycemia than DKA
- HHS has little to no ketosis compared to significant ketosis in DKA
- Mental status changes are more common and severe in HHS
- Abdominal pain is typically absent in HHS (whereas it's common in DKA) 1
Special Considerations
- Although infection is a common precipitating factor, patients may be normothermic or even hypothermic due to peripheral vasodilation
- Hypothermia, if present, is a poor prognostic sign 1
- Up to 25% of patients may have coffee-ground emesis due to hemorrhagic gastritis 1
High-Risk Populations
- Elderly individuals with type 2 diabetes
- Residents of chronic care facilities
- Individuals with undiagnosed diabetes
- Patients taking medications that affect carbohydrate metabolism (corticosteroids, thiazides, sympathomimetic agents) 1
- Increasingly being recognized in children and adolescents with type 2 diabetes and occasionally with type 1 diabetes 2, 3
Warning Signs Requiring Immediate Medical Attention
- Altered mental status
- Severe dehydration
- Hypotension
- Extreme hyperglycemia
HHS carries a significantly higher mortality rate (approximately 15%) compared to DKA (approximately 5%), with worse prognosis at extremes of age and in the presence of coma and hypotension 1. Early recognition of symptoms and prompt treatment are essential to reduce mortality and prevent complications.