What are the key clinical features to identify Hyperglycaemic Hyperosmolar State (HHS) in a patient with Type 2 Diabetes?

Key clinical features to identify Hyperglycaemic Hyperosmolar State (HHS) in a patient with Type 2 Diabetes include:

• Severe hyperglycaemia, typically with plasma glucose levels significantly elevated, often >30 mmol/L.
• Marked hyperosmolarity due to extreme dehydration, leading to increased serum osmolality.
• Profound dehydration signs such as dry mucous membranes, reduced skin turgor, tachycardia, and hypotension.
• Neurological impairment ranging from confusion, drowsiness, to reduced level of consciousness or coma, reflecting the severity of hyperosmolarity.
• Absence or minimal ketosis and acidosis, distinguishing HHS from diabetic ketoacidosis.
• Polyuria and polydipsia preceding presentation, often with a history of inadequate fluid intake or intercurrent illness.

These features reflect the pathophysiology of HHS, where insulin deficiency is relative rather than absolute, leading to severe hyperglycaemia without significant ketone production. The clinical picture is dominated by dehydration and neurological symptoms due to hyperosmolarity (Mustafa et al., 2023). Early recognition relies on identifying these signs in a patient with known or suspected Type 2 Diabetes, especially in the context of precipitating factors such as infection or other acute illness ¹.