Severe hyperglycaemia without significant ketosis; the characteristic metabolic emergency of T2DM
Aetiology
People present in middle or later life, often with previously undiagnosed diabetes
Common precipitating factors include consumption of glucose-rich fluids, concurrent medication such as thiazide diuretics or steroids, and intercurrent illness
Pathophysiology
Pathophysiology is similar to DKA, but HHS, there are still small amounts of insulin being secreted by the pancreas
This is sufficient to prevent DKA by suppressing lipolysis and, in turn, ketogenesis, but level is not high enough to lower blood glucose to a safe level
HHS is characterized by symptoms of marked dehydration (and loss of electrolytes) due to the predominating hyperglycaemia and osmotic diuresis (hyperosmolar urine)
Clinical features
Dehydration due to polyuria
Polydipsia
Nausea and vomiting
Stupor/coma
Impaired consciousness is directly related to degree of osmolarity
Investigations
HHS is characterised by:
Profound hyperglycaemia (glucose >33.3mmol/L)
Hyperosmolality (serum osmolarity >320mmol/kg)
Can be measured directly or calculated as (2 x Na+) + glucose + urea
Volume depletion in the absence of ketoacidosis (pH >7.3 and bicarbonate >15mmol/L)