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EndocrineICD-10: E16.2Affects the majority of people with type 1 diabetes and many with insulin-treated type 2 diabetes

Hypoglycemia (Low Blood Sugar)

Also known as: Low Blood Sugar, Insulin Reaction, Low Blood Glucose, Sugar Crash

Hypoglycemia occurs when blood glucose levels drop below 70 mg/dL, causing a range of symptoms from mild shakiness and sweating to severe confusion, seizures, and loss of consciousness. It is most commonly associated with diabetes treatment, particularly insulin and certain oral medications, but can also occur in people without diabetes due to other medical conditions. Prompt recognition and treatment of hypoglycemia is critical, as prolonged severely low blood sugar can cause brain damage and can be life-threatening.

Symptoms

Shakiness and trembling
Sweating, chills, and clamminess
Rapid heartbeat (tachycardia)
Anxiety, irritability, and confusion
Dizziness or lightheadedness
Hunger and nausea
Blurred vision
Seizures and loss of consciousness in severe cases

Causes

  • Excessive insulin or diabetes medication dosing
  • Skipping meals or not eating enough carbohydrates
  • Increased physical activity without adjusting food or medication
  • Alcohol consumption, which impairs the liver's ability to release glucose
  • Insulinoma (insulin-producing pancreatic tumor) in non-diabetic hypoglycemia
  • Adrenal or pituitary gland insufficiency

Risk Factors

  • Type 1 or type 2 diabetes treated with insulin or sulfonylureas
  • Irregular meal timing or inadequate food intake
  • Heavy alcohol use
  • Kidney or liver disease affecting glucose metabolism
  • Elderly age with decreased appetite and renal function
  • Intensive blood sugar control targeting low HbA1c levels

Diagnosis

  • Blood glucose measurement showing levels below 70 mg/dL
  • Whipple's triad: low glucose, symptoms of hypoglycemia, and symptom resolution after glucose administration
  • Fasting blood tests to evaluate for non-diabetic causes
  • Insulin and C-peptide levels to distinguish between causes
  • CT or MRI of the pancreas if insulinoma is suspected

Treatment

  • Rule of 15: consume 15 grams of fast-acting carbohydrates and recheck blood sugar after 15 minutes
  • Glucose tablets or gel for rapid blood sugar elevation
  • Glucagon injection or nasal spray for severe hypoglycemia when the person cannot eat
  • Adjustment of diabetes medication dosing by the healthcare provider
  • IV dextrose in emergency settings for unconscious patients
  • Dietary counseling to prevent recurrent episodes

Prevention

  • Monitor blood glucose regularly, especially before and after exercise
  • Eat regular meals and snacks, particularly when taking diabetes medications
  • Adjust insulin and medication doses before planned physical activity
  • Carry fast-acting glucose sources (glucose tablets, juice) at all times
  • Limit alcohol consumption and never drink on an empty stomach
  • Wear a medical alert bracelet identifying diabetes and hypoglycemia risk

When to See a Doctor

  • You experience recurrent episodes of hypoglycemia despite medication adjustments
  • Hypoglycemia causes loss of consciousness, seizure, or confusion
  • You have symptoms of low blood sugar but do not have diabetes
  • Hypoglycemia unawareness develops (loss of warning symptoms)

Frequently Asked Questions

Related Conditions

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