High blood sugar, or hyperglycemia, occurs when there is too much glucose in the bloodstream. While occasional elevations can often be managed through diet, exercise, or medication adjustments, extremely high blood sugar levels can quickly escalate into a medical emergency. These situations can lead to severe health complications if not addressed promptly. Understanding when to seek immediate medical attention is important for preventing serious outcomes.
Understanding High Blood Sugar Levels
Sustained elevations indicate hyperglycemia. Generally, a fasting blood sugar level above 125 mg/dL (6.9 mmol/L) or a reading above 180 mg/dL (10 mmol/L) two hours after eating suggests high blood sugar. While these levels may not always require emergency care, they indicate a need for closer monitoring and management. If blood sugar readings are consistently above 240 mg/dL (13.3 mmol/L), especially with accompanying symptoms, it is advisable to contact a healthcare provider.
If blood sugar levels are 300 mg/dL (16.7 mmol/L) or higher for more than one test, medical advice should be sought. Levels exceeding 400 mg/dL (22.2 mmol/L) are dangerous and indicate a medical emergency, even in the absence of other symptoms. These values can lead to severe complications like coma. Furthermore, a condition known as hyperglycemic hyperosmolar state (HHS) often presents with blood sugar readings greater than 600 mg/dL (33.3 mmol/L).
Recognizing Emergency Symptoms
Dangerously high blood sugar can trigger emergency symptoms requiring urgent medical care. Two serious complications are diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar state (HHS).
DKA often develops rapidly and is characterized by a buildup of acids called ketones in the blood. Symptoms include:
Excessive thirst
Frequent urination
Nausea, vomiting, and abdominal pain
A distinct fruity smell on the breath
Confusion
Rapid, deep breathing (Kussmaul breathing)
Weakness, fatigue, and blurred vision
Hyperglycemic hyperosmolar state (HHS) typically develops more gradually, often over days or weeks, and is more common in individuals with type 2 diabetes. Symptoms include:
Extreme thirst and profound dehydration
Altered consciousness (confusion, drowsiness, or coma)
Vision changes
Weakness
Leg cramps
Seizures or a high fever
The presence of these symptoms, especially with very high blood sugar, signals an emergency.
Immediate Actions to Take
If you suspect dangerously high blood sugar, take immediate steps. It is advisable to check for ketones if your blood glucose is consistently high, typically above 250 mg/dL (13.9 mmol/L) or 300 mg/dL (16.7 mmol/L), or if you are feeling unwell. Ketone levels can be measured using urine strips or a blood meter. A blood ketone level above 0.6 mmol/L is considered slightly elevated, while levels between 1.6 and 3.0 mmol/L indicate a risk of DKA. A reading above 3.0 mmol/L suggests DKA is likely and requires urgent medical attention.
Staying hydrated is also important if you are not experiencing nausea or vomiting. Drinking water can help dilute the excess sugar in your blood. However, do not delay seeking professional help if emergency symptoms are present. If you experience symptoms such as persistent vomiting, severe dehydration, confusion, fruity-smelling breath, or extreme weakness, call emergency services (like 911) or go to the nearest emergency room without delay.
What to Expect at the Hospital
At the hospital for severe hyperglycemia, medical professionals will stabilize your condition. Treatment goals are to lower blood sugar, correct dehydration, and restore electrolyte balance. You will likely receive intravenous fluids to rehydrate and dilute excess glucose.
Insulin will be administered, often intravenously, to help cells absorb glucose and reduce ketone production in DKA cases. Electrolyte replacement, particularly potassium, is common, as severe hyperglycemia can disrupt mineral balance. Your blood sugar and vital signs will be closely monitored for a safe recovery.