Hypoglycemia

Summary

Hypoglycemia, otherwise known as low blood sugar, is often caused by insulin therapy or certain medications in individuals with diabetes. Typically, symptoms of hypoglycemia arise when blood glucose levels fall below 70 mg/dL, but the onset may vary depending on a person's unique physiological responses. The condition can lead to autonomic symptoms like hunger, sweating, and rapid heartbeat, as well as neuroglycopenic symptoms including confusion, changes in behavior, and drowsiness. If a patient's mental state seems altered, an immediate blood glucose test should be conducted, followed by necessary treatment, since prolonged hypoglycemia can potentially lead to serious brain injury. Glucose is the treatment of choice. Conscious patients should be given a quick-acting carbohydrate such as glucose tablets, candy, or fruit juice, while IV dextrose or intramuscular glucagon is used for those who are unresponsive.

Definition

Hypoglycemia refers to an abnormally low level of glucose in the blood, typically less than 70 mg/dL, leading to various symptoms and potential complications.

Whipple triad: helps to confirm the diagnosis of hypoglycemia

• Low blood glucose levels
• Signs or symptoms consistent with hypoglycemia
• Relief of symptoms when blood glucose increases after treatment

Classification

• Reactive Hypoglycemia: Occurs within hours after eating; postprandial hypoglycemia can happen within 5 hours after the last meal and may follow gastrectomy or gastric bypass.
• Fasting Hypoglycemia: Occurs after prolonged fasting or in between meals.
• Drug-Induced Hypoglycemia: Due to medications, including insulin or oral hypoglycemics.
• Hormonal Hypoglycemia: Resulting from deficiencies in hormones like glucagon.

Risk Factors

• Diabetes and its treatment
• Certain medications (including non-diabetes medications)
• Alcohol abuse
• Chronic liver, heart, and kidney disorders (CLD, CKD)
• Critical illness

Causes

• Surreptitious use of insulin or other hypoglycemic agents
• Insulinoma
• Chronic disorders like severe liver and kidney diseases
• Hypocortisolism
• Infant of a diabetic mother
• Anorexia nervosa

Clinical Features

• Shaking or tremors
• Sweating
• Irritability or behavioral changes
• Fatigue
• Hunger
• Blurred vision
• Confusion or altered consciousness
• Tachycardia
• Seizure

Diagnosis

• Whipple's Triad: Decreased consciousness, serum glucose < 55 mg/dL, improvement after glucose administration.
• Blood Glucose Test: Confirms with glucose <70 mg/dL.
• Oral Glucose Tolerance Test: For reactive hypoglycemia.
• Insulin Levels: Elevated in non-diabetic individuals may indicate insulinoma.

Treatment

• Immediate Care: 15-20 grams of simple carbohydrates for conscious patients.
• Intravenous Dextrose: For unconscious patients at 0.25 g/kg (2.5 ml/kg of 10% dextrose or 1 ml/kg of D25%).
  • Use a Central Line: For dextrose concentrations over 10% to minimize the risk of thrombophlebitis.
• Glucagon Injection: If needed.
• Underlying Cause: Correct as necessary.
• Postprandial Hypoglycemia: Small meals with fat, high-fibers, and complex carbohydrates.

Complications

• Cardiac arrhythmias
• Seizures
• Coma
• Death if untreated
• Long-term neurological damage