14th September 2024

Hyperosmolar hyperglycaemic state

In contrast to DKA, hyperosmolar hyperglycaemic state (HHS) develops over several days. It is characterised by profound fluid deficit, excessively high osmolality (2x Na + urea + glucose), and high glucose levels (>30 mmol/l) in the absence of ketosis or acidosis. Despite normal serum potassium concentrations, patients are often potassium-depleted. The treatment aims to rehydrate the patient using crystalloids and to reduce osmolality. Insulin therapy should not be routinely used as it can cause dangerously rapid reductions in osmolality, potentially leading to cerebral complications. However, in cases of mixed DKA/HHS syndromes, where acidosis and ketosis are present, insulin may be used. HHS has an extremely high mortality rate, up to ten times higher than that of DKA.