Hyperglycemia (elevated blood sugar level) refers to a condition in which the blood sugar level is above the normal range. Values from 180 mg/dl (10 mmol/l) are clinically relevant and require treatment. If left untreated, hyperglycemia can lead to serious complications.
Causes
Hyperglycemia results from an imbalance between insulin and glucose requirements. Common triggers are:
- Insulin deficiency in type 1 diabetes
- Insulin resistance in type 2 diabetes
- Infections, stress or inflammation
- Too much carbohydrate intake
- Certain medications (e.g. cortisone)
- Diseases of the pancreas
Symptoms
Typical signs of hyperglycemia are:
- Severe thirst (polydipsia) and frequent urination (polyuria)
- Tiredness and exhaustion
- Blurred vision
- Dry skin and itching
- In severe cases: nausea and abdominal pain
Severity and complications
| Severity | blood sugar level | Possible complications |
|---|---|---|
| Mild hyperglycemia | 180-250 mg/dl | Usually with few symptoms |
| Severe hyperglycemia | > 250 mg/dl | Dehydration, ketoacidosis |
| Hyperglycemic coma | > 600 mg/dl | Life-threatening emergency |
Acute management
The following measures help with mild hyperglycemia:
- Adjust insulin dose (after consulting your doctor)
- Drink enough sugar-free fluids
- Light physical exercise (except in ketosis)
- Monitor blood sugar closely
Immediate medical attention is required if hyperglycemia is severe or ketoacidosis is suspected.
Further information:
→ Diabetes mellitus – knowledge and overview
→ Why hyporest
→ Hypoglycemia
Sources
- German Diabetes Society (DDG). S3 guideline “Diabetes mellitus type 1 and type 2”. As of 2025. Available at: www.deutsche-diabetes-gesellschaft.de/leitlinien.
- American Diabetes Association. Standards of Medical Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1). Available at: diabetesjournals.org.
- Robert Koch Institute (RKI). Federal health reporting – diabetes mellitus in Germany. Berlin 2024.
- International Diabetes Federation (IDF). IDF Diabetes Atlas. 11th edition. Brussels 2025. Available at: diabetesatlas.org.
Important note:
The information in this encyclopedia article is intended solely for general and non-binding information. They do not replace medical advice, diagnosis or therapy. If you have any health questions or complaints, please always consult a doctor or qualified healthcare professional. The content was created with the greatest possible care, but errors cannot be completely ruled out.
Last updated: February 26, 2026
