Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) are two serious complications of diabetes that are potentially life threatening. Although both conditions cause a dangerous rise in sugar levels, there are important differences between the two.

DKA is usually associated with type 1 diabetes, whereas people with type 2 diabetes are at risk of HHS.

Both conditions occur as a result of an insulin deficiency that causes hyperglycemia.

This article reviews the differences and similarities between DKA and HHS.

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DKA and HHS have some similar features. They both result from an issue with insulin that causes an unsafe rise in blood sugar levels.

DKA is typically an issue for people living with type 1 diabetes, although people living with type 2 diabetes can also develop the condition. It occurs when the body lacks enough insulin to convert sugar into energy.

As a result of this deficiency, the liver starts to break down fats for energy instead of sugar. As part of this process, it creates chemicals called ketones. The number of ketones can rapidly become too high, creating a potentially dangerous situation for the person.

HHS typically occurs in people living with type 2 diabetes. Unlike in DKA, the pancreas continues to create insulin. However, the peripheral tissue is highly resistant to this hormone, causing an unsafe buildup in blood sugar levels.

Both conditions can be life threatening if a person does not receive immediate care.

Learn more

Learn more about diabetic emergencies.

The table below shows the causes, symptoms, and treatment of DKA and HHS. It also compares the mortality rates.

ConditionPrimarily affectsPossible causesTreatment optionsMortality rateSymptoms
DKApeople with type 1 diabetes• illness
• missing an insulin dose
• cardiac event
• heavy alcohol use
• injury
IV delivery of:
• fluids
• insulin
• electrolytes
• medications for illness
up to 2%• fruity-smelling breath
• high ketone levels in urine
• symptoms present within a few hours
HHSpeople with type 2 diabetes• illness
• cardiac event
IV delivery of:
• fluids
• insulin
• electrolytes
• medications for illness
up to 20%• fast heart rate
• neurological symptoms such as confusion
• symptoms present over days or weeks

DKA and HHS can present with similar symptoms.

The early stages of both conditions cause:

DKA

The symptoms of DKA can worsen quickly if a person does not get treatment. They can include:

HHS

HHS can present very similarly to DKA, meaning that doctors must take care to distinguish between the two syndromes.

The symptoms of HHS can include:

One distinguishing characteristic is that HHS can cause neurological signs and symptoms, which may include:

Finally, HHS can also present with symptoms related to its cause. Sometimes, a person may develop HHS following an infection or a cardiac event, such as a heart attack or stroke.

If an infection causes HHS, a person might also experience:

  • tachycardia, or a fast heart rate
  • general weakness
  • abnormally rapid breathing
  • fever

If a cardiac event causes HHS, a person might also experience:

DKA and HHS can present similarly, as many of their symptoms overlap.

However, one key difference is the presence of neurological symptoms. HHS can cause a person to experience hallucinations, confusion, drowsiness, loss of vision, or a coma.

Both conditions cause an unsafe level of blood sugar. However, DKA is associated with high levels of ketones in the blood, whereas HHS is not.

Both conditions may result from similar factors, such as:

  • medication use
  • illness
  • cardiac events

However, DKA can occur due to a missed insulin dose, heavy alcohol use, or a physical injury.

Although both conditions can lead to diabetic coma and death, the mortality rate of HHS is 10 times higher than that of DKA. However, a person can survive either condition with proper treatment.

The causes of both DKA and HHS are similar. Both may occur due to:

  • illness
  • a cardiac event, such as a heart attack or stroke
  • issues with diabetes medications, such as missing a dose or taking too much or too little
  • the use of certain other medications, such as diuretics

However, the most common causes are different.

For HHS, the most common cause is an infection, which accounts for at least 50% of all cases.

The two most common causes of DKA are missing a dose of insulin and an acute illness. Other possible causes include an injury, such as a car accident, and alcohol or drug use.

The treatments for DKA and HHS are similar. Doctors will typically recommend the use of an IV line to deliver:

  • electrolytes
  • fluids
  • insulin
  • medications to treat any underlying conditions, such as antibiotics for bacterial infections

A doctor may discuss ongoing diabetes management with the person, including any necessary changes to their diet and exercise regimen. They may also adjust the person’s medications.

A person can take steps at home to help prevent the development of either DKA or HHS. These include:

  • monitoring blood glucose levels frequently, particularly when sick
  • taking medications on time and according to the prescription
  • keeping blood glucose levels within a target range
  • discussing adjustments to medication or insulin based on dietary or exercise-related changes

DKA and HHS are emergencies that require immediate medical attention. A person living with diabetes should seek emergency care if they develop symptoms of either condition.

It is also advisable for a person to test their blood sugar levels if they start to have early warning signs of hyperglycemia, such as extreme thirst or frequent urination.

Below are the answers to common questions about DKA and HHS.

Which is worse out of DKA and HHS?

Both DKA and HHS can be life threatening and require prompt treatment. However, HHS has a fatality rate that is about 10 times that of DKA.

What is the difference between HONK and HHS?

HONK stands for hyperglycemic hyperosmolar non-ketotic coma, which is how the medical community previously referred to HHS.

Non-ketotic hyperglycemic coma and hyperosmolar hyperglycemic non-ketotic syndrome are two other former names for the condition.

DKA and HHS are two complications of diabetes that have similar symptoms, causes, and treatments. Both conditions result from high blood glucose levels and require insulin to help treat them.

DKA typically affects people living with type 1 diabetes, whereas HHS usually occurs in people living with type 2 diabetes. HHS tends to be more dangerous than DKA, but both conditions can be deadly if a person does not receive treatment.

Prompt medical attention is necessary in both cases. A person should seek emergency medical care if they develop symptoms that could indicate HHS or DKA.