High Blood Sugar Emergencies

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By : dLife Editors

Blood sugar levels that are too high (hyperglycemia) can quickly turn into a diabetic emergency without quick and appropriate treatment. The best way to avoid dangerously high blood sugar levels is to self-test to stay in tune with your body, and to stay attuned to the symptoms and risk factors for hyperglycemia.

Extremely high blood sugar levels can lead to one of two conditions—diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar nonketotic syndrome (HHNS; also called hyperglycemic hyperosmolar nonketotic coma). Although both syndromes can occur in either type 1 or type 2 diabetes, DKA is more common in type 1, and HHNS is more common in type 2.

Diabetic Ketoacidosis (DKA)

Ketoacidosis (or DKA) occurs when blood sugars become elevated (over 249 mg/dl, or 13.9 mmol/l) over a period of time and the body begins to burn fat for energy, resulting in ketone bodies in the blood or urine (a phenomenon called ketosis). A variety of factors can cause hyperglycemia (high blood glucose), including failure to take medication or insulin, stress, dietary changes without medication adjustments, eating disorders, and illness or injury. This last cause is important, because if illness brings on DKA, it may slip by unnoticed, since its symptoms can mimic the flu (aches, vomiting, etc.). In fact, people with type 1 diabetes are often seeking help for the flu-like symptoms of DKA when they first receive their diagnosis.

Symptoms of diabetic ketoacidosis may include:

  • fruity (acetone) breath
  • nausea and/or vomiting
  • abdominal pain
  • dry, warm skin
  • confusion
  • fatigue
  • breathing problems
  • excessive thirst
  • frequent urination
  • in extreme cases, loss of consciousness

DKA is a medical emergency, and requires prompt and immediate treatment. A simple over-the-counter urine dipstick test (e.g., Ketostix) can check for ketones; anyone who has blood glucose levels above 240 mg/dl (13.3 mmol/l) should test their urine for ketones. There is also at least one glucose meter on the market that tests blood ketone levels. It’s normal to occasionally have trace amounts of ketones in the urine, but you should call your healthcare provider immediately if you experience moderate to heavy ketones. Treatment for DKA involves administering insulin to lower blood glucose levels, and restoring fluid balance to the bloodstream with an intravenous (IV) saline drip. Electrolytes may also be given via IV.

Hyperglycemic Hyperosmolar Syndrome (HHS)

Hyperglycemic hyperosmolar syndrome (HHS) is a complication of type 2 diabetes that can occur when blood glucose levels exceed 600 mg/dl (33.3 mmol/l), but ketosis (ketone bodies in the blood) is low or not present. With such high blood sugar, the body becomes severely dehydrated. HHS occurs most often in the elderly (who are either newly diagnosed with diabetes or unaware of having high blood glucose levels) and those who are not able to tell they are thirsty (impaired thirst mechanism). If you or a loved one are elderly or have a decreased thirst mechanism, it is important to always have water within reach, and to drink plenty of fluids. Impaired kidney function and infections are also risk factors.

HHS is a life-threatening condition. If you experience any of the following symptoms of the syndrome, seek emergency medical care immediately:

  • excessive thirst
  • dehydration
  • disorientation and confusion
  • sudden hypotension or low blood pressure (as evidenced by faintness or dizziness when changing positions, especially lying or sitting to standing up)
  • visual problems
  • extreme, unexplained fatigue
  • fever
  • in advanced cases, coma, seizure, and/or hemiplegia (paralysis on one side of the body)

Treatment for HHS involves administering intravenous fluids (i.e., saline and sometimes electrolyte solutions) to restore fluid balance. Insulin therapy may also be required.

It’s ideal to avoid these blood sugar emergencies altogether by self-testing regularly and managing your blood sugar with diet, exercise, and any medications prescribed to you. But what if your blood sugar levels do become elevated? Here are some simple tips for handling a high:

  • You can often lower your blood sugar by exercising. If your levels are elevated, try doing some light exercise, such as going for a walk. If you have ketones in your urine, do not exercise, as this can cause blood sugar levels to rise even more.
  • Be sure to drink plenty of water. Elevated blood sugar levels are often associated with being dehydrated.
  • If you’re on insulin, your doctor may be able to give you a “correction dose” of insulin. This will temporarily correct a blood sugar high, and is not a permanent adjustment to your daily insulin injection.
  • Make sure you are taking the correct amount of medication at the right time. If you’re not, medications may be less effective at controlling blood sugar levels. Discuss your medications with your doctor to see if you need to adjust the dose or timing of your meds.


American Diabetes Association. “Standards of Medical Care in Diabetes—2016.” Diabetes Care. January 2016. http://care.diabetesjournals.org/content/suppl/2015/12/21/39.Supplement_1.DC2/2016-Standards-of-Care.pdf.

Gosmanov, A. R., Gosmanova, E. O., and Kitabchi, A. E. “Hyperglycemic Crises: Diabetic Ketoacidosis (DKA), and Hyperglycemic Hyperosmolar State (HHS).” May 19, 2015.  https://www.ncbi.nlm.nih.gov/books/NBK279052/

U.S. National Library of Medicine and National Institutes of Health. “Hyperglycemia.” MedlinePlus. https://medlineplus.gov/hyperglycemia.html.

Updated by Julia Telfer, MPH, 11/16