Hyperglycemic hyperosmolar syndrome (HHS) is a potentially life-threatening condition involving extremely high blood sugar, or glucose, levels. Any illness that causes dehydration or reduced insulin activity can lead to HHS. It’s most commonly a result of uncontrolled or undiagnosed diabetes. An illness or infection can trigger HHS. Failure to monitor and control blood glucose levels can also lead to HHS.

When your blood sugar gets too high, the kidneys try to compensate by removing some of the excess glucose through urination. If you don’t drink enough fluids to replace the fluid you’re losing, your blood sugar levels spike. Your blood also becomes more concentrated. This can also occur if you drink too many sugary beverages. This condition is called hyperosmolarity. Blood that’s too concentrated begins to draw water out of other organs, including the brain.

Some possible symptoms are excessive thirst, increased urination, and fever. Symptoms may develop slowly and increase over a period of days or weeks.

Treatment involves reversing or preventing dehydration and getting blood glucose levels under control. Prompt treatment can relieve symptoms within a few hours. Untreated HHS can lead to life-threatening complications, including dehydration, shock, or coma.

Go to an emergency room or call 911 if you have symptoms of HHS.This is a medical emergency.

HHS can happen to anyone. It’s more common in older people who have type 2 diabetes.

Symptoms may begin gradually and worsen over a few days or weeks. A high blood sugar level is a warning sign of HHS. The symptoms include:

  • excessive thirst
  • high urine output
  • dry mouth
  • weakness
  • sleepiness
  • a fever
  • warm skin that doesn’t perspire
  • nausea
  • vomiting
  • weight loss
  • leg cramps
  • a loss of vision
  • speech impairment
  • a loss of muscle function
  • confusion
  • hallucinations

Go to the emergency room or call 911 immediately if you have the symptoms of HHS.

Untreated HHS can lead to life-threatening complications such as:

  • dehydration
  • blood clots
  • seizures
  • shock
  • a heart attack
  • a stroke
  • swelling of the brain
  • high levels of acid in the blood
  • a coma

Older people with type 2 diabetes are more likely to develop HHS. Some factors that can contribute to HHS are:

  • extremely high blood sugar levels due to uncontrolled or undiagnosed diabetes
  • an infection
  • medications that lower glucose tolerance or contribute to fluid loss
  • recent surgery
  • a stroke
  • a heart attack
  • impaired kidney function

A physical exam will show if you have:

  • dehydration
  • fever
  • low blood pressure
  • rapid heart rate

Doctors commonly use a blood test to diagnose this conditions. The blood test determines your current blood sugar level. Your doctor will diagnose HHS if your blood sugar is 600 milligrams per deciliter or higher.

Your doctor may perform other tests to confirm a diagnosis or gauge potential complications. Tests may include blood tests to check for levels of:

  • blood sugar
  • ketones
  • creatinine
  • potassium
  • phosphate

Your doctor can also order a glycated hemoglobin test, which indicates your average blood sugar level for the previous two to three months.

If you haven’t already received a diabetes diagnosis, but you have HHS, your doctor may perform a urinalysis. This is to see if you have diabetes. According to the Mayo Clinic, HHS may occur in people who haven’t already received a diabetes diagnosis.

HHS is as a medical emergency due to the risk of complications. Emergency treatment will include:

  • fluids given through your veins to prevent or reverse dehydration
  • insulin to lower and stabilize your blood sugar levels
  • if necessary, potassium, phosphate, or sodium replacement to help return your cells to their normal function

Treatment will also address any complications from HHS.

Old age, severity of dehydration at the time of treatment, and the presence of other illnesses all increase the risk for serious complications and death. Delayed treatment also greatly increases risk. However, prompt treatment can improve symptoms within a few hours.

The most important things you can do to prevent HHS are to monitor your diabetes carefully and control it. You can take the following steps to prevent HHS:

  • Familiarize yourself with the early warning signs of HHS, and don’t ignore them.
  • Check your blood sugar levels regularly, especially when you feel ill.
  • Take your prescribed medications.
  • Maintain a healthy diet as advised by your doctor.
  • Exercise regularly.
  • If you live alone, have a relative or neighbor on alert for emergency situations.
  • Teach family, friends, and coworkers the early warning signs of HHS and instruct them to seek medical care for you if you can’t do it yourself.
  • Get a medical ID bracelet or card for diabetes and always keep it with you.
  • Get regular medical checkups and stay current with vaccinations.
  • Go to your doctor immediately if you have the symptoms of HHS.