🩸 14 Symptoms That May Indicate Very High Blood Sugar Levels
Very high blood sugar (hyperglycemia) can develop gradually, particularly in people with diabetes. Mild elevations may cause few or no symptoms, while severe hyperglycemia can become a medical emergency.
1. Excessive Thirst
Feeling unusually thirsty and needing to drink much more than usual can occur when blood sugar is elevated.
2. Frequent Urination
High glucose levels can cause the kidneys to remove more glucose and water, resulting in frequent urination.
3. Increased Hunger
Some people experience unusual or persistent hunger because glucose isn’t being used normally by the body’s cells.
4. Blurred Vision
Temporary changes in the fluid balance of the eye can cause blurry vision when blood glucose is significantly elevated.
5. Unusual Fatigue
Very high blood sugar can leave you feeling tired or lacking energy.
6. Headache
Headaches can occur with high blood sugar, although they aren’t specific to hyperglycemia and can have many other causes.
7. Dry Mouth
Frequent urination can contribute to dehydration, which may leave your mouth unusually dry.
8. Dry or Itchy Skin
Dehydration associated with elevated blood glucose can contribute to dry or itchy skin.
9. Slow-Healing Cuts
Persistently elevated blood glucose can impair wound healing and increase susceptibility to infection.
10. Frequent Infections
People with poorly controlled diabetes may be more prone to certain infections, including urinary and skin infections.
11. Unexplained Weight Loss
Significant high blood sugar, particularly when diabetes is untreated, can cause the body to break down fat and muscle for energy.
12. Nausea or Vomiting
Nausea and vomiting can occur when hyperglycemia becomes severe and may be a warning sign of diabetic ketoacidosis (DKA).
13. Abdominal Pain
Abdominal pain, particularly together with nausea, vomiting, dehydration, or rapid breathing, can occur with DKA.
14. Fruity-Smelling Breath or Confusion
A fruity odor on the breath, confusion, unusual sleepiness, or difficulty staying awake can indicate dangerously high blood sugar and possible DKA.
🚨 When It’s an Emergency
Seek emergency medical care immediately if someone with diabetes has very high blood sugar together with:
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Vomiting or severe abdominal pain
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Rapid or deep breathing
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Fruity-smelling breath
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Severe dehydration
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Confusion or unusual drowsiness
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Difficulty staying awake
These can be signs of diabetic ketoacidosis, which requires urgent treatment.
Important
Symptoms alone cannot tell you how high your blood sugar is. If you have diabetes or are concerned about hyperglycemia, check your blood glucose with an appropriate meter or continuous glucose monitor and follow your clinician’s instructions. Don’t change insulin or other diabetes medication doses based solely on symptoms unless you’ve been given a specific plan.
If you’re experiencing symptoms right now and tell me your blood sugar reading, symptoms, and whether you have diabetes, I can explain what they may mean.

