Hyperglycemia: Recognizing High Blood Sugar Symptoms and What to Do in an Emergency
When your blood sugar climbs above 180 mg/dL, your body starts sending warning signs-signs many people ignore until it’s too late. Hyperglycemia isn’t just a number on a glucose meter. It’s your body screaming that something’s wrong. Left unchecked, it can lead to diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic state (HHS), coma, or even death. The good news? You can stop it before it escalates-if you know what to look for and what to do.
What Hyperglycemia Really Means
Hyperglycemia means your blood glucose is too high. For most people with diabetes, that’s anything above 180 mg/dL. But it’s not just about the number. It’s about what’s happening inside your body. Insulin isn’t doing its job-either because your pancreas doesn’t make enough (type 1 diabetes) or your cells have stopped responding to it (type 2 diabetes). Glucose piles up in your bloodstream instead of fueling your muscles, brain, and organs. That’s when trouble starts.
Early symptoms are easy to miss. You feel tired, thirsty, or need to pee more often. People blame it on stress, a long day, or drinking too much coffee. But if your blood sugar stays above 250 mg/dL for hours, those symptoms get worse. You might notice blurred vision, a headache, or trouble focusing. By the time you feel confused or nauseous, you’re already in danger.
The Warning Signs: From Mild to Life-Threatening
Hyperglycemia doesn’t hit all at once. It creeps up in stages.
- Mild (180-250 mg/dL): You’re urinating more than usual-sometimes over 2.5 liters a day. You’re constantly thirsty, drinking more than 4 liters of fluids. Your vision gets blurry. Fatigue sets in. These are the red flags most people overlook.
- Moderate (251-300 mg/dL): Headaches become common. Concentration fades. You lose weight without trying-even if you’re eating normally. This is when insulin correction is still possible at home, but time is running out.
- Severe (300+ mg/dL): Your body starts breaking down fat for energy. Ketones build up. You smell fruity on your breath. Your breathing gets deep and fast. You feel dizzy, weak, or confused. If your blood sugar hits 500-600 mg/dL, you’re at risk of HHS or DKA.
Diabetic ketoacidosis (DKA) hits fast-usually in type 1 diabetes. You’ll have nausea, stomach pain, vomiting, and rapid breathing. Your blood becomes acidic. This is a hospital emergency. Hyperosmolar hyperglycemic state (HHS) creeps in slowly, mostly in type 2 diabetes. You become severely dehydrated. Your blood thickens. You may slip into a coma. HHS has a higher death rate than DKA, especially in older adults.
What Triggers a Blood Sugar Spike?
It’s not just forgetting insulin. The real triggers are often hidden.
- Illness: Infections like the flu or a urinary tract infection can spike blood sugar by 100-200 mg/dL. Your body releases stress hormones that block insulin.
- Insulin pump failure: A kinked tube or empty reservoir can stop insulin delivery. One missed dose can push you into DKA within hours.
- Carb miscounting: Eating a large pizza or a whole bag of chips without adjusting insulin is a common mistake. Even a 50% error in carb counting can cause a dangerous spike.
- Medications: Steroids, certain antidepressants, and antipsychotics can raise blood sugar by 50-100 mg/dL. If you’re prescribed one of these, your diabetes plan needs an update.
- Dawn phenomenon: Between 4 and 8 a.m., your liver dumps glucose into your blood. For many, this causes fasting highs. It’s not laziness-it’s biology.
- Emotional stress: Anxiety, grief, or even a big argument can trigger a spike. Cortisol and adrenaline fight insulin.
One study found that 42% of hyperglycemia emergencies happened during illness. Another showed 29% were due to eating too many carbs without adjusting insulin. These aren’t accidents-they’re predictable.
What to Do When Blood Sugar Is Too High
If your blood sugar is over 240 mg/dL, don’t wait. Act now.
- Check for ketones. Use a urine strip or blood ketone meter. If ketones are moderate or high, you’re at risk for DKA. Do not exercise. Moving can make it worse.
- Take your correction dose. Use your insulin-to-carb ratio or correction factor. Most people need 0.1 units of rapid-acting insulin per kg of body weight every hour until blood sugar drops below 200 mg/dL. Never skip this step.
- Drink water. Consume 8-16 ounces of sugar-free fluid every hour. Dehydration makes hyperglycemia worse. Avoid soda, juice, or sports drinks-they’ll make it worse.
- Recheck every 2-4 hours. Blood sugar can keep rising even after insulin. Monitor closely. If it doesn’t drop after two correction doses, or if you feel worse, call your doctor or go to the ER.
Many people make the mistake of taking too much insulin too fast. That’s called insulin stacking. It can cause your blood sugar to crash later, leading to hypoglycemia. One study found 33% of insulin pump users had this error. Patience matters.
When to Go to the Emergency Room
You don’t need to guess. Here’s when to call 911 or head to the ER:
- Your blood sugar is above 300 mg/dL and not coming down after two correction doses.
- You have ketones in your urine or blood (above 1.5 mmol/L).
- You’re vomiting, having stomach pain, or can’t keep fluids down.
- You’re confused, drowsy, or having trouble staying awake.
- Your breathing is fast and deep (more than 24 breaths per minute).
- You have dry skin, sunken eyes, or can’t stand up without dizziness-signs of severe dehydration.
Don’t wait for coma. Don’t hope it’ll get better. HHS and DKA don’t resolve on their own. Emergency treatment includes IV fluids, insulin, and electrolyte replacement. The sooner you get help, the better your chances.
How to Prevent Hyperglycemia Before It Starts
Prevention beats emergency care every time.
- Use a continuous glucose monitor (CGM). CGMs show trends, not just numbers. They warn you when your sugar is rising-30 minutes before it hits 250 mg/dL. People using CGMs cut hyperglycemia episodes by 57%.
- Know your insulin sensitivity. Everyone’s different. Work with your doctor to find your personal correction factor. Don’t guess.
- Check your insulin pump daily. Look for kinks, air bubbles, or disconnected tubing. Replace infusion sets every 2-3 days.
- Plan for illness. Have a sick-day plan ready. Increase monitoring. Adjust insulin. Keep sugar-free fluids and fast-acting insulin on hand.
- Manage stress. Meditation, deep breathing, or even a walk can lower cortisol and help insulin work better.
Structured education works. People who complete CDC-approved diabetes self-management programs reduce emergency visits by 42%. Knowledge saves lives.
The Bigger Picture: Why This Matters
Hyperglycemia isn’t just a personal problem. It’s a national crisis. In the U.S., it causes 1.2 million hospitalizations every year. Each DKA admission costs $14,200. HHS costs even more-$18,500. The total price tag for diabetes complications? $327 billion annually.
And it’s not evenly distributed. Black patients experience 2.3 times more hyperglycemia emergencies than White patients-not because of behavior, but because of access. Insulin is still too expensive. Some people skip doses to save money. That’s not negligence. It’s systemic failure.
Technology is helping. The FDA approved Dexcom’s Glucose Guardian in early 2024-a predictive algorithm that warns you 30 minutes before a spike. Medicare now covers CGMs for more people. But tools mean nothing without education, access, and support.
Final Thought: You’re Not Alone
High blood sugar feels scary. It feels like you’ve failed. But it’s not a moral issue. It’s a medical one. Your body isn’t working the way it should. That’s not your fault.
If you’ve ever ignored a high reading because you didn’t want to deal with it, you’re not alone. But now you know what to do. Check your blood sugar. Check for ketones. Take your insulin. Drink water. Call for help if you need to.
Hyperglycemia is preventable. It’s treatable. And with the right knowledge, it doesn’t have to end in the ER.
What is the normal blood sugar range for someone with diabetes?
For most adults with diabetes, the target range is 80-130 mg/dL before meals and under 180 mg/dL two hours after eating. But goals vary by age, health, and other factors. Older adults or those with other conditions may have higher targets, like under 180 mg/dL fasting. Always follow your doctor’s personalized plan.
Can you have high blood sugar without having diabetes?
Yes. Stress, illness, certain medications like steroids, or conditions like Cushing’s syndrome or pancreatitis can cause temporary hyperglycemia. Even severe infections or trauma can spike blood sugar in people without diabetes. But if it happens repeatedly, it’s a sign you may be developing prediabetes or type 2 diabetes.
How do I know if I’m in diabetic ketoacidosis (DKA)?
DKA shows up with high blood sugar (over 250 mg/dL), ketones in your urine or blood, nausea, vomiting, abdominal pain, fruity-smelling breath, and deep, rapid breathing. You may feel confused or extremely tired. If you have these symptoms, test for ketones immediately. If they’re moderate or high, seek emergency care-don’t wait.
Is it safe to exercise when my blood sugar is high?
Only if your blood sugar is under 250 mg/dL and you have no ketones. If your sugar is above 250 mg/dL and ketones are present, exercise can make DKA worse by releasing more glucose and ketones. Wait until your levels come down and ketones are gone before resuming activity.
Why does my blood sugar spike in the morning even if I didn’t eat?
This is called the dawn phenomenon. Between 4 and 8 a.m., your body releases hormones like cortisol and growth hormone that signal your liver to release glucose. For people with diabetes, insulin doesn’t rise to match this surge, so blood sugar climbs. Adjusting nighttime basal insulin or changing your insulin pump settings can help.
Can I treat high blood sugar with just water and no insulin?
Water helps with dehydration and can slightly lower blood sugar by diluting it, but it won’t fix the root problem. Without insulin, your body can’t move glucose into cells. If your blood sugar is over 240 mg/dL, especially with ketones, insulin is necessary. Relying only on water can lead to DKA or HHS.
How often should I check my blood sugar during a high?
Check every 2 to 4 hours until your blood sugar returns to target. If you’re using a CGM, watch the trend arrow. If it’s pointing sharply up, even if the number is still under 250, take action early. Don’t wait for it to hit 300 before doing something.
What should I do if I’m too sick to eat but my blood sugar is high?
Even if you can’t eat, you still need insulin. Your body is under stress and producing glucose. Skip your insulin and your blood sugar will keep rising. Take your usual basal insulin. If you’re vomiting or can’t keep fluids down, call your doctor. You may need IV fluids or emergency treatment.
