Definition of Hypoglycemia
Hypoglycemia is defined by this triad:
- Development of autonomic or neuroglycopenic symptoms
- Plasma glucose <70 mg/dL
- Response to carbohydrate load
So hypoglycemia is defined by this triad. First, the patients develop what is called the autonomic or neuroglycopenic symptoms. Second, the plasma glucose should be less than 70 mg per decilitre. And third, the symptoms should respond to treatment with a carbohydrate load.
Symptoms of Hypoglycemia
| Neurogenic Symptoms | Neuroglycopenic Symptoms |
|---|---|
| Trembling | Dizziness |
| Palpitations | Weakness |
| Sweating | Difficulty concentrating |
| Anxiety | Visual change |
| Hunger | Difficulty speaking |
| Nausea | Confusion |
| Drowsiness |
These are the symptoms of hypoglycemia. They are divided into:
- Neurogenic symptoms: Caused by excess catecholamines including trembling, palpitations, sweating, anxiety, hunger, and nausea.
- Neuroglycopenic symptoms: Caused by reduced glucose supply to the brain and these include feeling dizzy, feeling weak, having difficulty concentrating, visual blurring, difficulty with speech, then confusion followed by drowsiness.
Classification of Hypoglycemia
The ADA standards and other guidelines now agree on a unified classification for hypoglycemia:
- Level 1 hypoglycemia: <70 mg/dl but is >54 mg/dl.
- Level 2: <54 mg/dl.
- Level 3 hypoglycemia: Does not depend on a measured glucose level but is a severe event which is characterized by alteration in the mental and/or the physical status which requires help or assistance from someone else to treat the hypoglycemia.
Factors that Increase the Risk of Hypoglycemia
- Use of insulin or insulin secretagogues e.g. SUs.
- Impaired renal or hepatic function.
- Long duration of diabetes.
- Frailty and old age.
- Cognitive impairment.
- Impaired counter-regulatory response e.g. hypoglycemia unawareness.
- Polypharmacy.
There are certain factors that make patients more prone to developing hypoglycemia: Of course, the use of insulin or insulin-secretogogues such as sulfonylureas increase the risk. Patients with impaired renal function or hepatic function are more at risk. Those who have had diabetes for many years. Older and frail patients. Those with cognitive impairment. And those who have impaired counter-regulatory response i.e. they have hypoglycemia unawareness are more at risk. And lastly, those who take many drugs or what we call polypharmacy because of the interactions between drugs.
Treatment of Hypoglycemia
The ADA advises treating hypoglycemia with approximately 15 to 20 grams of glucose if the patient is conscious and their glucose level is below 70 mg/dl. Any form of carbohydrate that contains glucose of 15 to 20 grams can be used.
It recommends that 15 minutes after this, if the blood glucose monitoring shows the patient still has hypoglycemia, the treatment should be repeated.
Once the blood glucose monitoring shows the levels going up, the patient should be made to consume a meal or snack to prevent recurrence of the hypoglycemia.
Treatment of Severe Hypoglycemia in an Unconscious Patient
- Give glucagon (SC or IM): For those who are unconscious, the treatment of choice is glucagon which can be given subcutaneously, intramuscularly, and recently an intranasal preparation has been made available.
- Treat with 10-25 g of glucose (20-50 mL of Dextrose 50%) intravenously over 1-3 minutes: The other alternative for treating severe hypoglycemia is to give intravenous glucose in the form of dextrose 50% over one to three minutes.
- Re-test in 15 minutes to ensure the glucose >70 mg/dL and re-treat with a further dose of dextrose 50%: Glucose level should be re-tested in 15 minutes to ensure it has gone above 70 mg/dl and if not, another dose of dextrose 50% should be given.
- Once conscious, eat meal or a snack: Once the patient is conscious, they should be made to eat a meal or a snack.
Prevention of Hypoglycemia
Education is key to the prevention of hypoglycemia. Education not only for the patient but also for family members on prevention, recognition, and treatment of hypoglycemia.
Summary
- Have a low index of suspicion for DKA in any unwell patient with hyperglycemia, especially in type 1 diabetes.
- HHS is much less common than DKA but it is much more serious and is associated with a higher mortality.
- The cornerstones for management of both DKA and HHS are intravenous fluids, IV insulin, and replacement of potassium.
- Hypoglycemia is another important emergency and should be treated by any rapid-acting glucose available.
- The most important message is that education is the most important measure to prevent DKA, HHS, and also hypoglycemia.