US Pharm
. 2019;44(10):13-14.

Low Blood Sugar

Hypoglycemia is the term used to describe the physical state of having low blood sugar (glucose). The cells of the human body require steady supplies of energy in the form of glucose to function properly, and we get most of our glucose supply from the food we eat. Over the course of the day, blood sugar goes up and down depending on several factors, including what food we ingest, when we last ate, and our level of physical activity. Continuous glucose monitors implanted in the skin can send alerts when glucose rises or falls. When blood sugar drops below 70 mg/dL, it is a signal that the body is becoming hypoglycemic. Symptoms are typically present when blood-glucose levels are below 55 mg/dL, but they can also develop at higher levels. Sometimes symptoms do not occur at all. 

Symptoms Are Nonspecific

The symptoms of hypoglycemia can come on suddenly and can present differently for each person. The most common symptoms include dizziness, fatigue, weakness, headaches, inability to concentrate, confusion, inappropriate behavior that can be mistaken for drunkenness, slurred speech, blurred vision, seizures, and coma. Symptoms can begin slowly or suddenly, progressing from mild discomfort to severe confusion or panic within minutes.

Since the symptoms are common and not specific to hypoglycemia, blood-sugar levels must be measured to identify whether the blood-sugar level is the root cause. When hypoglycemia is to blame, a phenomenon known as the Whipple triad is characteristically present. First, testing confirms low blood-sugar levels. Second, there are physical symptoms; and third, symptoms improve when blood-glucose levels return to normal.

Treatment for Diabetes Is Often the Cause

The conditions that cause hypoglycemia are different for everyone. Frequently, it occurs as a complication from the medications used to manage type 1 or type 2 diabetes. A person with diabetes may take insulin shots because their body is resistant to insulin or because it does not produce enough of this hormone. In people with diabetes, taking too much insulin can cause blood-sugar levels to drop too low. However, people who do not have diabetes can also experience hypoglycemia. Nondiabetic conditions that cause hypoglycemia are renal insufficiency/failure, alcoholism, hepatic cirrhosis/failure, other endocrine diseases, or recent surgery.

Many people with diabetes may be hypoglycemic but unaware of it because there are no obvious physical symptoms. This situation is known as hypoglycemia unawareness. Not being aware of low blood-sugar levels is a particularly dangerous situation because the person is not alerted to take action and improve his or her blood-sugar level. Severe hypoglycemia can be life-threatening if a person does not receive treatment, and severe, prolonged hypoglycemia may permanently damage the brain.

Treatments for hypoglycemia are focused on returning the blood sugar to safe levels. The first step is to check blood-glucose levels and determine the amount of carbohydrate that is needed to raise blood sugar back to a safe level.

Applying the 15/15 Rule to Remedy Hypoglycemia

Have one of the following (which each contain about 15 grams of carbohydrates) right away to raise blood glucose:

• Three or four glucose tablets

• One-half cup (4 ounces) of fruit juice, such as orange juice

• One-half cup (4 ounces) of a regular (not diet) soft drink

• 8 ounces of milk

• Five to seven pieces of hard candy (not sugar-free)

• One tablespoon of sugar or honey

After 15 minutes, check your blood-glucose level again. If it is still below 70 mg/dL, you should eat another 15 grams of carbohydrates. Repeat these steps until the blood-glucose reading is at least 70 mg/dL. If a meal is not planned within 1 to 2 hours after treating the hypoglycemic reaction, eat a snack containing 15 to 30 grams of carbohydrate to prevent another episode.

If blood-glucose readings are often low, a change in the regular meal plan, physical activity, or diabetes medicines should be considered. It is important to keep track of low blood-glucose events, noting possible causes, such as unplanned physical activity. Reviewing the tracked results with the healthcare team will help to manage blood-glucose levels within a normal range.

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