Dr Health-shared Official
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Hyperosmolar Hyperglycaemic State (HHS)

Hyperosmolar Hyperglycaemic State (HHS)

What is Hyperosmolar Hyperglycaemic State (HHS)?

Hyperosmolar Hyperglycaemic State (HHS) is a life-threatening condition characterised by high blood sugar levels, increased concentration of blood (also known as hyperosmolarity), and loss of body water that occurs when there is insufficient insulin in the body. Hyperosmolar Hyperglycaemic State is a very treatable condition if recognised. It is most commonly seen in type 2 diabetics.

What causes Hyperosmolar Hyperglycaemic State (HHS)?

HHS is caused by insufficient levels of insulin circulating in the body. Insulin is a hormone produced by the pancreas (an organ in the abdomen) after ingestion of food. It signals to the body that there is energy taken in and acts to normalise blood sugar levels. In HHS, the levels of insulin drop over a long period of time, leading to the blood sugar levels rising since insulin normally keeps blood sugar in control by regulating the amount of glucose available through the creation of new glucose (gluconeogenesis) and breaking down bigger energy stores to release some of the glucose (glycogenesis) as well as increasing the uptake of glucose by muscles. Reduced levels of insulin lead to less inhibition on gluconeogenesis and glycogenesis as well as reduced uptake by muscles leading to an increasing blood glucose. The body loses water due to the high blood sugar levels and in the presence of dehydration, the blood becomes very concentrated with an imbalance of ions. This can affect the function of the organs and ultimately cause death.

Key risk factors include states in which there is insufficient insulin produced by the body:

Not taking insulin as prescribed (due to insufficient supplies or patient choice)


Undiagnosed and untreated type 2 diabetes 

Furthermore, risk factors for diabetic ketoacidosis includes anything that increases the insulin demands or overall stress placed on the body (or the total volume of insulin required).

This includes:

Infections (such as chest infections and urine infections)

Viral illnesses such as gastroenteritis (winter vomiting bug)

Traumatic injuries

Recreational drug use (such as cocaine)


Undergoing a recent operation 

How is HHS diagnosed?

HHS is diagnosed in hospital, and it is generally associated with another illness such as an infection. The key investigations are blood tests and then further assessment to assess for precipitating causes.

For example, diagnosing HHS  generally requires three key parameters:

Loss of water in the body, known as hypovolaemia

Extremely high blood glucose (over 30 mmol) ⁄ l or known diabetes mellitus;

Concentration of ions in blood, also known as hyperosmolarity 

Further investigations for other precipitating causes can include:

Chest x-ray to assess for a chest infection

Urine test to assess for urine infection

Blood cultures to assess for a blood infection

Blood testing to assess for signs of infection or inflammation

ECG to check that ion balance has not affected the rhythm of the heart

How common is HHS?

Overall, the rate at which people develop HHS has remained largely unchanged with around 18 per 100,000 people developing it each year. It is seen most commonly in the older type 2 diabetes patients however in recent times it seems to be affecting younger patients and is often what young type 2 diabetics patients present with. 

Abdominal pain

Pain anywhere between chest and groin


Due to water loss and dehydration

Frequently passing water urination

Due to the effects of high blood sugar pulling water out of the body creating increasing volumes of urine

General fatigue

Feeling tired

Dry mucous membranes

Having dry lips and nasal passages

Increased heart rate

Your heart beating faster

Reduced blood pressure

Can lead to you feeling dizzy

Nausea and Vomiting

Feeling sick and throwing up

Cerebral oedema

Swelling of the brain causing increased pressure on the vital brain structures Another serious complication is giving too much insulin at once, this can cause the blood sugar levels to drop too low, known as hypoglycaemia .Furthermore, salt imbalances can develop which, if not replenished, can cause the arrhythmias in the heart rhythm.


Complication from giving too much insulin at once, this can cause the blood sugar levels to drop too lo


Salt imbalances can develop which, if not replenished, can cause the arrhythmias in the heart rhythm (irregular heartbeats)