Hyperosmolar hyperglycemic state

Hyperosmolar hyperglycemic state
SynonymsHyperosmolar hyperglycemic nonketotic coma (HHNC), hyperosmolar non-ketotic coma (HONK), nonketotic hyperosmolar coma, hyperosmolar hyperglycemic nonketotic syndrome (HHNS)[1]
SpecialtyEndocrinology
SymptomsSigns of dehydration, altered level of consciousness[2]
ComplicationsDisseminated intravascular coagulopathy, mesenteric artery occlusion, rhabdomyolysis[2]
Usual onsetDays to weeks[3]
DurationFew days[3]
Risk factorsInfections, stroke, trauma, certain medications, heart attacks[4]
Diagnostic methodBlood tests[2]
Differential diagnosisDiabetic ketoacidosis[2]
TreatmentIntravenous fluids, insulin, low molecular weight heparin, antibiotics[3]
Prognosis~15% risk of death[4]
FrequencyRelatively common[2]

Hyperosmolar hyperglycemic state (HHS) is a complication of diabetes mellitus in which high blood sugar results in high osmolarity without significant ketoacidosis.[4] Symptoms include signs of dehydration, weakness, legs cramps, vision problems, and an altered level of consciousness.[2] Onset is typically over days to weeks.[3] Complications may include seizures, disseminated intravascular coagulopathy, mesenteric artery occlusion, or rhabdomyolysis.[2]

The main risk factor is a history of diabetes mellitus type 2.[4] Occasionally it may occur in those without a prior history of diabetes or those with diabetes mellitus type 1.[3][4] Triggers include infections, stroke, trauma, certain medications, and heart attacks.[4] Diagnosis is based on blood tests finding a blood sugar greater than 30 mmol/L (600 mg/dL), osmolarity greater than 320 mOsm/kg, and a pH above 7.3.[2][3]

Initial treatment generally consists of intravenous fluids to manage dehydration, intravenous insulin in those with significant ketones, low molecular weight heparin to decrease the risk of blood clotting, and antibiotics among those in whom there is concerns of infection.[3] The goal is a slow decline in blood sugar levels.[3] Potassium replacement is often required as the metabolic problems are corrected.[3] Efforts to prevent diabetic foot ulcers are also important.[3] It typically takes a few days for the person to return to baseline.[3]

While the exact frequency of the condition is unknown, it is relatively common.[2][4] Older people are most commonly affected.[4] The risk of death among those affected is about 15%.[4] It was first described in the 1880s.[4]

Signs and symptoms

Symptoms of high blood sugar including increased thirst (polydipsia), increased volume of urination (polyuria), and increased hunger (polyphagia).[5]

Symptoms of HHS include:

  • Altered level of consciousness
  • Neurologic signs including: blurred vision, headaches, focal seizures, myoclonic jerking, reversible paralysis[5]
  • Motor abnormalities including flaccidity, depressed reflexes, tremors or fasiciculations
  • Hyperviscosity and increased risk of blood clot formation
  • Dehydration[5]
  • Weight loss[5]
  • Nausea, vomiting, and abdominal pain[5]
  • Weakness[5]
  • Low blood pressure with standing[5]