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Hypoglycemia: Symptoms, Diagnosis, Treatments and Preventions

Hypoglycemia refers to a condition in which blood sugar decreases below the normal level due to various causes, and thus the amount of glucose supplied to the body organs decreases, resulting in various symptoms. In a normal human body, blood sugar is kept constant at about 70~150mg/dL, becoming the main source of energy sent to each part of our body.


When hypoglycemia occurs, glucose supplied to the nervous system including the brain becomes insufficient and the autonomic nervous system is activated. As a result, dizziness and fatigue can occur, which can lead to epileptic seizures and loss of consciousness, and in the worst case death. In addition, adrenaline is secreted to overcome hypoglycemia, which can cause increased blood pressure, increased pulse rate, heart palpitations, tremors, and anxiety. Cold sweat, feelings of hunger, and abnormal sensations may occur due to the action of the parasympathetic nerve.


  • The most common cause of hypoglycemia is insulin or oral hypoglycemic drugs used to treat diabetes. In the treatment of diabetes, it is important to balance the appropriate dose of oral hypoglycemic drugs or insulin, the timing of administration, regular meals, and exercise. Hypoglycemia can occur when the dose of oral hypoglycemic drugs or insulin is too high or the timing of administration is inappropriate. In addition, even with regular oral hypoglycemic drugs or insulin treatment, hypoglycemia may occur if the amount of meal is irregularly reduced or the amount of exercise is inappropriately increased. It is known that drinking alcohol can also cause hypoglycemia.
  • Pentamidine (PCP pneumonia, parasite remedy), quinine (malaria remedy), sulfonamide (antibiotic), salicylate (aspirin), phenylbutazone (anti-inflammatory analgesic), etc. In rare cases, hypoglycemia can be caused.
  • Hypoglycemia can also occur in severe physical ailments such as liver, kidney, heart disease, severe infection, and malnutrition, or deficiency of the adrenal corticosteroid, growth hormone, glucagon, and epinephrine hormones.
  • Hypoglycemia can occur even when the amount of insulin produced by the body is abnormally high, such as an insulin-producing pancreatic tumor or an autoimmune disease against insulin.
  • Postprandial hypoglycemic disease can occur after gastrectomy, disorders of inherited carbohydrate metabolism enzymes, alcohol, etc.


The diagnosis is made by confirming that the blood sugar level of the patient suspected of hypoglycemia is lower than the normal level.

Test methods

In addition to measuring blood glucose, insulin and C-peptide tests are performed to determine the cause of hypoglycemia. Detailed examination should be conducted for other possible causes. In addition, various hormone tests and chemical tests can be performed depending on the cause of the suspicion. Fasting tests are performed to differentiate between fasting hypoglycemia and postprandial hypoglycemia.


If hypoglycemia is suspected, consciousness is important in the treatment decision. If the patient is conscious, eat sugary foods as soon as possible. If unconscious, the patient should be immediately transferred to the emergency room to receive glucose through intravenous fluids. After that, appropriate treatment is required depending on the cause.

Prognosis and complications

Hypoglycemia, if left untreated, can be severe enough to cause brain damage and life-threatening in a short period of time. Therefore, if hypoglycemia is suspected, prompt treatment and identification of the cause should be performed.

Daily life tips for patients

Patients who have a history of hypoglycemia or who have a high risk of hypoglycemia due to diabetes medications should always be aware of the symptoms of hypoglycemia. It is recommended to bring a sugary snack (candy, chocolate, fruit, etc.) or beverages that can be consumed in case of suspected hypoglycemia symptoms.

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