Updated on November 7, 2023.
If you have diabetes, you may have heard of diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic nonketotic syndrome (HHNS), also known as hyperosmolar hyperglycemic state (HHS). These are two of the most common life-threatening emergencies that may stem from diabetes. The complications can develop when diabetes is poorly controlled, causing your blood sugar to rise to dangerous levels.
What’s the best defense against these complications? A good preventive strategy. This means checking your blood sugar levels as often as your health care team recommends and taking your diabetes medicine as prescribed.
But even with your best intentions, diabetes can be difficult to manage. Sudden illness, unexpected surgery, pregnancy, straying from your everyday routine due to travel—all of these things may lead to an unexpected spike in blood glucose. And that can increase your risk for diabetic ketoacidosis and HHNS. In the worst-case scenarios, left untreated, these conditions can lead to brain swelling, diabetic coma, and even death.
While they sound daunting, diabetic ketoacidosis and HHNS can be treated. In order to head them off, it’s crucial to learn how to spot the warning signs so you can notify your healthcare provider (HCP) and seek care. Although symptoms may take days or weeks to develop in some cases, they can often progress quickly, requiring immediate medical attention.
What is diabetic ketoacidosis?
In order to understand DKA, it helps to know how the body powers itself.
The body’s normal source of energy is glucose. With the help of insulin, glucose moves from the bloodstream into the body’s cells to deliver energy. If you don’t have enough insulin in your blood—for example, if you missed your daily insulin injection—your body is unable to use glucose so it instead begins to burn fat for energy.
The breakdown of fat produces acidic chemicals called ketones. When ketones are produced too fast and build up in the urine and blood, they can poison the body by making the blood acidic. While this buildup may occur slowly, DKA can develop within a few hours, especially if you are vomiting.
Early warning signs of diabetic ketoacidosis
When ketones first start to build up, you may notice you:
- Are dehydrated
- Are urinating often
- Have high blood glucose levels
- Have high levels of ketones in your blood and urine (see section below on how to detect ketones)
If you ignore these initial symptoms and ketones continue to accumulate, you may then experience vomiting, nausea, or abdominal pain. Your skin may also feel dry or flushed, and you may notice your breath smells fruity or foul. The condition may also manifest with cognitive symptoms, such as confusion or difficulty paying attention.
Checking for ketones at home
You can check your ketone levels with over-the-counter blood and/or urine testing kits. Ask your HCP about how to keep track of your levels, when and how often you should test, and when you should call for help.
Most experts recommend checking for ketones if you:
- Are ill, such as with a cold or flu
- Have a blood glucose level higher than 240 mg/dl
- Have any symptoms of diabetic ketoacidosis (as mentioned above)
Potential triggers of DKA may include:
- Missing a dose of insulin
- An injury or recent surgery
- A severe infection or illness such as pneumonia, urinary tract infection, or other infection
- A traumatic event (emotional or physical)
- Taking a new medicine that may affect your blood glucose (such as corticosteroids or diuretics)
If your ketone levels are high, you’re vomiting, or your blood sugar level is high and not responding to treatment, don’t hesitate—call 911 immediately.
Who’s at risk for diabetic ketoacidosis?
While anyone with diabetes can get diabetic ketoacidosis, it’s usually seen in those with type 1 diabetes, including those with type 1 who have not yet been diagnosed.
If you have type 2 diabetes, you aren’t completely out of harm’s way. A sudden infection, such as pneumonia, could make you so severely insulin deficient that you develop ketoacidosis.
The bottom line: When you’re ill—regardless of whether you have type 1 or type 2 diabetes—make sure you are extra vigilant when it comes to checking your blood sugar levels.
How is HHNS different than diabetic ketoacidosis?
People who get HHNS and not diabetic ketoacidosis are producing enough insulin to keep their body from needing to burn fat for energy (so ketone levels are normal or only slightly elevated), but they’re not producing enough insulin to prevent high blood sugar levels.
Initially, your body tries to unload the extra sugar through your urine. So if you find yourself running to the bathroom a lot, it’s a good idea to stop and check your blood sugar levels.
But if you’ve got high blood sugar levels and you’re not drinking enough water or you’re guzzling sugary sodas and eating high-carb foods, your kidneys may become overwhelmed and unable to get rid of the extra sugar.
Other warning signs of HHNS to watch out for include:
- A blood sugar level higher than 600 mg/dl
- A high fever
- Dry mouth or extreme thirst
- Warm skin that doesn’t sweat
- Vision loss
- Leg cramps
- Weight loss
- Difficulty moving
- Hallucinations, seizures, or having trouble speaking
- Coma
At this point you may or may not be thirsty, but it’s critical that you start drinking liquids or you could become dehydrated. If you don’t take in fluids, your blood can become too concentrated in sodium and glucose, a condition known as hyperosmolarity. When this occurs, your body will start drawing water out of your organs, including your brain.
HHNS may develop more slowly than DKA but HHNS is also a medical emergency. If you have any symptoms, go to the emergency room or call 911.
What causes HHNS?
Like diabetic ketoacidosis, infection—mainly pneumonia and urinary tract infection—is a major trigger of HHNS, responsible for 30 to 60 percent of all cases.
Other factors that can increase your risk for HHNS include:
- Stressful events, such as heart attack or stroke
- Conditions or medicines that increase fluid loss
- Poor kidney function
- Stopping or running out of insulin or other medicines that lower glucose level
- Reduced thirst
- Having uncontrolled type 2 diabetes
HHNS is commonly seen in people ages 55 and up, as older people have a higher risk of becoming dehydrated and having impaired kidney function. With dehydration comes a vicious cycle: Because it can cause confusion and weakness, you may find it harder to recognize that you’re thirsty.
What you can do to prevent HHNS
HHNS only occurs when your blood sugar isn’t under control. Here are some ways to help you avoid it:
- Check your blood sugar regularly. How often you should check depends on the type of diabetes you have and your current treatment plan. For example, a person with type 1 diabetes may be advised to check their blood sugar 10 times a day. Talk with your HCP about what your target blood sugar ranges should be.
- Take extra care of yourself when you’re sick—especially if you’re older. Drinking a glass of water every hour and checking your blood sugar more often than you normally do are both smart moves. It’s also a good idea to work with your HCP to create a sick-day plan specific to your needs.
