Hyperosmolar hyperglycemic state

Hyperosmolar hyperglycaemic state (HHS) (previously known as hyperosmolar non-ketotic coma (HONK))is a serious metabolic derangement that can occur in patients with diabetes mellitus, predominantly those with type 2. While there are no distinct imaging features, it is useful for a radiologist to be familiar with this condition.

Epidemiology

It usually occurs in type 2 diabetics who have some concomitant illness that leads to reduced fluid intake. The typical patient is 50-70 years old and there may be a precipitating event such as a stroke, MI, chest/urinary/urinary infection or systemic inflammatory response ².

Clinical presentation

Complications

Due to a combination of hypovolaemia, patients are at increased risk of thromboembolic disease, which may be a presenting complaint or complicate hospital management ³.

Pathology

High blood glucose levels lead to severe dehydration, increases in osmolarity (relative concentration of solute) and, in turn, carries a high risk of complications, coma, and death.

Treatment and prognosis

Hyperosmolar hyperglycaemic state is common in more elderly diabetic patients and is associated with volume depletion without compensating fluid intake. Principles of management are as follows ²:

• correction of volume depletion with intravenous fluids
• insulin infusion to correct high blood sugar levels (BSLs)
  • rehydration often produces significant reductions in BSLs and HHS patients often require less insulin than DKA patients
• BSL and electrolyte monitoring
• search for precipitating cause

History and etymology

Hyperosmolar hyperglycaemic state is thought to have been first described by von Frerichs and Dreschfeld in the 1880s ¹.

Related pathology

• non-ketotic hyperglycaemic hemichorea
• non-ketotic hyperglycaemic seizures