Hypoglycemia (lower level of blood glucose)

Hypoglycemia (lower level of blood glucose)


Hypoglycemia is a condition of lower than normal level of blood glucose. Criteria referred to as Whipple’s triadare used to determine a diagnosis of hypoglycemia: 

  1. Symptoms known to be caused by hypoglycemia 
  2. Low glucose at the time the symptoms occur 
  3. Reversal or improvement of symptoms or problems when the glucose is restored to normal

Symptoms of hypoglycemia usually do not occur until the blood sugar is in the level of 2.8 to 3.0 mmol/L (50 to 54 mg/dl). The precise level of glucose considered low enough to define hypoglycemia is dependent on (1) the measurement method, (2) the age of the person, (3) presence or absence of effects, and (4) the purpose of the definition.

Signs and symptoms

Hypoglycemic symptoms and manifestations can be divided into those produced by the counter regulatory hormones (epinephrine/adrenaline and glucagon) triggered by the falling glucose, and the neuroglycopenic effects produced by the reduced brain sugar.

 Adrenergic manifestations

  • Shakiness, anxiety, nervousness 
  • Palpitations, tachycardia 
  • Sweating, feeling of warmth (although sweat glands have muscarinic receptors, thus “adrenergic manifestations” is not entirely accurate) 
  • Pallor, coldness, clamminess 
  • Dilated pupils(mydriasis) 
  • Feeling of numbness “pins and needles” (paresthesia)

Glucagon manifestations

  • Hunger, borborygmus 
  • Nausea, vomiting, abdominal discomfort 
  • Headache

Neuroglycopenic manifestations

  • Abnormal mentation, impaired judgment 
  • Personality change, emotional liability 
  • Fatigue, weakness, apathy, lethargy, daydreaming, sleep 
  • Confusion, amnesia, dizziness, delirium 
  • Stupor, coma, abnormal breathing 
  • Generalized or focal seizures


The circumstances of hypoglycemia provide most of the clues to diagnosis. Circumstances include the age of the patient, time of day, time since last meal, previous episodes, nutritional status, physical and mental development, drugs or toxins (especially insulin or other diabetes drugs), diseases of other organ systems, family history, and response to treatment.

When hypoglycemia occurs repeatedly, a record or “diary” of the spells over several months, noting the circumstances of each spell (time of day, relation to last meal, nature of last meal, response to carbohydrate, and so forth) may be useful in recognizing the nature and cause of the hypoglycemia.
Glucose requirements above 10 mg/kg/minute in infants, or 6 mg/kg/minute in children and adults are strong evidence for hyper-insulinism.

In this context this is referred to as the glucose infusion rate (GIR). Finally, the blood glucose response to glucagon given when the glucose is low can also help distinguish among various types of hypoglycemia. A rise of blood glucose by more than 30 mg/dl (1.70mmol/l) suggests insulin excess as the probable cause of the hypoglycemia.    For patients who have recurrent hypoglycemia’s the following tests might be needed depending on the history and physical examination: insulin, cortisol, and electrolytes, with C-peptide and drug screen for adults and growth hormone in children. 


Management of hypoglycemia involves immediately raising the blood sugar to normal, determining the cause, and taking measures to hopefully prevent future episodes. The blood glucose can be raised to normal within minutes by taking 10-20 grams of carbohydrate. It can be taken as food or drink if the person is conscious and able to swallow. 

This amount of carbohydrate is contained in about 100-120 ml of orange juice or non-diet soda. Starch is quickly digested to glucose (unless the person is taking acarbose), but adding fat or protein retards digestion. Symptoms should begin to improve within 5 minutes, though full recovery may take 10–20 minutes. Overfeeding does not speed recovery and if the person has diabetes will simply produce hyperglycemia afterwards. 

If unconscious or for other reasons cannot feed orally secure an IV line and give intravenous dextrose, concentrations vary ing depending on age (infants are given 2 ml/kg dextrose 10%, children are given dextrose 25%, and adults are given dextrose 50%). Care must be taken in giving these solutions because they can be very necrotic if the IV is infiltrated. If an IV cannot be established, the patient can be given 1 to 2 milligrams of glucagon in an intramuscular injection


One situation where starch may be less effective than glucose or sucrose is when a person is taking acarbose. Since acarbose and other alpha-glucosidase inhibitors prevents starch and other sugars from being broken down into monosaccharide’sthat can be absorbed by the body, patients taking these medications should consume monosaccharide-containing foods such as glucose powder, honey, or juice to reverse hypoglycemia.



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