Hyperosmolar Hyperglycaemic State

Key points

• HHS: medical emergency, typically elderly T2DM, onset over days; higher mortality than DKA; may be first presentation of T2DM.
• Hyperglycaemia → osmotic diuresis → severe dehydration and electrolyte deficiency; dehydration and metabolic disturbance more extreme than DKA.
• MUST differentiate from DKA — treating HHS with insulin per a DKA protocol can cause adverse outcomes.
• Best managed in a medical high-dependency unit for the first 24 hours.
• Complications: MI · stroke · peripheral arterial thrombosis · seizures · cerebral oedema · central pontine myelinolysis.

Decision points in this pathway

• DKA features present (pH < 7.3, ketones > 3)?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.