Diabetic Hyperglycemic Hyperosmolar Syndrome: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Diabetic Hyperglycemic Hyperosmolar Syndrome?
This condition is usually treated first in a hospital emergency department by emergency medicine doctors. After the crisis passes, an internal medicine doctor or an endocrinologist often manages follow-up care. An endocrinologist is a doctor who treats hormone problems like diabetes. A primary care doctor helps with long-term diabetes control.
What it is
Diabetic hyperglycemic hyperosmolar syndrome (HHS) is a serious problem that can happen in people with type 2 diabetes. Blood sugar rises to extremely high levels, often above 600 milligrams per deciliter. The body gets rid of the extra sugar through the urine, pulling out water and causing severe dehydration. Unlike diabetic ketoacidosis, HHS usually does not produce ketones.
Symptoms
Symptoms often come on slowly. Early signs include extreme thirst, frequent urination, and weakness. As fluid loss worsens, confusion, trouble speaking, and drowsiness can appear, and severe cases can lead to loss of consciousness. Because early signs look like ordinary high blood sugar, HHS is sometimes missed.
Causes and who gets it
HHS is most often triggered by an infection. Other triggers include a heart attack, stroke, certain medicines such as steroids, or not taking diabetes medicines as directed. It is most common in adults over 60 and can be the first sign of undiagnosed diabetes.
How doctors diagnose it
Doctors diagnose HHS with blood and urine tests. Blood sugar will be extremely high, and the blood becomes thicker and saltier than normal. Doctors also check kidney function.
Treatment
HHS is treated in the hospital. Treatment starts with intravenous fluids to replace lost water, followed by insulin given through the same IV line. Blood sugar is brought down slowly, and doctors also treat the underlying cause.
When to see a doctor
Anyone with diabetes who has very high blood sugar along with confusion, extreme drowsiness, or trouble staying awake needs emergency care right away. Call 911 if a person with these signs cannot be woken.
What kind of doctor treats it
The first treatment happens in a hospital, where emergency doctors manage the crisis. Afterward, care usually moves to a primary care doctor. Some patients also see an endocrinologist, a specialist in hormone and blood sugar disorders. A direct primary care doctor charges a flat monthly fee, while a concierge doctor offers similar access at a higher cost.
Common questions
Is HHS the same as diabetic ketoacidosis?
No. Both are diabetes emergencies with very high blood sugar. HHS involves extreme dehydration and usually no ketones, while diabetic ketoacidosis involves ketones and acid buildup. HHS develops more slowly and is more common in older adults with type 2 diabetes.
Can HHS be prevented?
Often, yes. Taking diabetes medicines as directed, checking blood sugar during illness, drinking enough water, and getting prompt care for infections all lower the risk. Many doctors give patients a sick-day plan that explains when to call for help.
How long does recovery take?
The hospital stay often lasts several days to a week or more. Full recovery depends on age and other health problems, and it differs from person to person. Some people have lasting weakness or confusion for a while.
Can HHS happen to someone who does not know they have diabetes?
Yes. HHS is sometimes the first sign of type 2 diabetes. This is one reason sudden confusion and severe dehydration in an older adult should always be checked by a doctor.
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Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
