Hypoglycemia (Low Blood Sugar)

Hypoglycemia occurs when there is not enough sugar (glucose) in the blood.

Hypoglycemia or low blood sugar is a syndrome that results from low blood sugar.

Hypoglycemia definition: Hypoglycemia is defined as a condition in which blood glucose (sugar) levels fall below 70 mg/dL (3.9 mmol/L), leading to symptoms such as shakiness, sweating, confusion, or, in severe cases, unconsciousness.

The severity and symptoms of hypoglycemia can vary from person to person. Blood tests can diagnose low blood sugar, and symptoms resolve when the levels of sugar in the blood return to the normal range. The medical term for blood sugar is blood glucose.

Despite advances in the treatment of diabetes, low blood sugar episodes occur as a side effect of many treatments for diabetes. In fact, these episodes are often the limiting factor in achieving optimal blood sugar control, because many medications that are effective in treating diabetes carry the risk of lowering the blood sugar level too much, causing symptoms.

In large-scale studies looking at tight control in both type 1 and type 2 diabetes, low blood sugars occurred more often in the patients who were managed most intensively. This is important for patients and physicians to recognize, especially as the goal for treating patients with diabetes becomes tighter control of blood sugar.

While people who do not have any metabolic problems can complain of symptoms that resemble low blood sugar, true hypoglycemia usually occurs in people with diabetes mellitus (type 1 and type 2). People with pre-diabetes or insulin resistance also can have low blood sugars on occasion if their high circulating insulin levels are further challenged by a prolonged period of fasting. There are other rare causes for the condition, such as insulin-producing tumors (insulinomas) and certain medications.

What causes low blood sugar without diabetes?

Low sugar levels can also be caused by reasons other than diabetes, which may include:

• Skipping meals
• Excessive alcohol intake
• Certain medications
• Hormonal imbalances
• Prolonged fasting
• Critical diseases, such as end-stage liver disease, sepsis, starvation, or renal failure
• Rare tumors such as insulinomas

These uncommon causes of hypoglycemia will not be discussed in this article, which will primarily focus on the condition occurring with type 1 or 2 diabetes and its treatment.

The normal range of glucose in the bloodstream is from 70 to 100 mg/dL when the individual is fasting (that is, not immediately after a meal). The body's biochemical response to hypoglycemia usually starts when sugars are in the high/mid-70s. At this point, the liver releases its stores, and the hormones mentioned above start to activate. In many people, this process occurs without any clinical symptoms. The amount of insulin produced also declines in an attempt to prevent a further drop in glucose.

While there is some degree of variability among people, most will usually develop symptoms suggestive of low blood sugar when blood glucose levels are lower than 50 mg/dL. The first set of symptoms is called adrenergic (or sympathetic) because they relate to the nervous system's response to hypoglycemia.

What does low blood sugar feel like?

Many people experience hypoglycemia symptoms that can come on suddenly, and this may feel different from person to person. Many describe it as a wave of discomfort or uneasiness that's hard to ignore. You might feel "off" or disconnected or have trouble thinking clearly. These early signs are known as adrenergic symptoms because they indicate activation of the sympathetic nervous system (body's "fight-or-flight" response to stress or danger).

People with hypoglycemia may experience any of these symptoms and signs:

• Nervousness
• Sweating
• Intense hunger
• Dizziness or lightheadedness
• Trembling
• Weakness
• Palpitations
• Trouble speaking
• Pallor
• Trouble concentrating
• Dimming of vision or tunnel vision
• Irritability
• Changes in behavior or personality
• Seizures
• Unconsciousness

In most people, these symptoms are easily recognizable. The vast majority of individuals with diabetes only experience this degree of hypoglycemia if they are on medications or insulin. People (with diabetes or who have insulin resistance) with high circulating levels of insulin who fast or change their diet to lower their carbohydrate intake drastically should also be cautioned. These individuals may also experience modest hypoglycemia.

People being treated for diabetes who experience the condition may not experience symptoms as easily as people without diabetes. This phenomenon has been referred to as hypoglycemic unawareness. This can be dangerous as blood sugars may approach extremely low levels before any symptoms are perceived.

Anyone who has experienced an episode of hypoglycemia describes a sense of urgency to eat and resolve the symptoms. And, that's exactly the point of these symptoms. They act as warning signs to tell the body to consume more fuel. At this level, the brain still can access circulating blood glucose for fuel. The symptoms provide a person the opportunity to raise blood glucose levels before the brain is affected.

If a person does not or cannot respond by eating something to raise blood glucose, the levels of glucose continue to drop. With further drops in blood glucose, patients progress to neuro-glyco-penic ranges (meaning that the brain is not getting enough glucose). At this point, symptoms progress to confusion, drowsiness, changes in behavior, coma, and seizure.

Special types of hypoglycemia

• Reactive hypoglycemia (also called postprandial hypoglycemia) symptoms occur shortly after eating, particularly after meals high in refined carbohydrates, with individuals often experiencing shakiness, brain fog, and fatigue.
• Nocturnal hypoglycemia occurs during sleep and may include symptoms such as nightmares, night sweats, or waking up feeling confused or shaky.
• Ketotic hypoglycemia primarily affects children, particularly during fasting or illness. It is associated with symptoms such as vomiting, fatigue, and the presence of ketones in the blood or urine.

The acute management of low blood sugar involves the rapid delivery of a source of easily absorbed sugar. If you're unsure about what to do when blood sugar is low, remember the "15-15 rule." The American Diabetes Association recommends the "15-15 rule" for treating mild to moderate hypoglycemia:

1. Consume 15 grams of fast-acting carbohydrates to raise your blood sugar.
2. After 15 minutes, check your blood sugar level.
3. If it is still below 70 mg/dL, consume another 15 grams of fast-acting carbohydrates.
4. Repeat this process until your blood sugar reaches at least 70 mg/dL.

Regular soft drinks, juice, lifesaver candies, table sugar, and the like are good options. In general, 15 grams of glucose is the dose that is given, followed by an assessment of symptoms and a blood glucose check if possible. If after 10 minutes there is no improvement, another 10-15 grams should be given. This can be repeated up to three times. At that point, the patient should be considered as not responding to the therapy, and an ambulance should be called.

DO NOT administer food or drinks to patients with hypoglycemia who are unconscious and unresponsive. Call emergency services immediately and use a glucagon injector if prescribed previously to the patient.

If you are wondering what to eat when blood sugar is low, equivalency of 10-15 grams of glucose (approximate servings) are:

• 4 lifesavers
• 4 teaspoons of sugar
• 1/2 can of regular soda or juice
• 1 small piece of fruit, such as half a banana
• 4 ounces (half-cup) of juice or regular soda (not diet)
• 1 tablespoon of honey or syrup
• 1 tube of instant glucose gel (check the instructions)
• 3-4 glucose tablets (check the instructions)

These are ideal first-line options for acute hypoglycemia treatment because they are rapidly absorbed, and they quickly restore glucose levels. Many people like the idea of treating low blood sugar with dietary treats such as cake, cookies, and brownies. However, sugar in the form of complex carbohydrates or sugar combined with fat and protein is much too slowly absorbed to be useful in acute treatment.

Once the acute episode has been treated, a healthy, long-acting carbohydrate to maintain blood sugars in the appropriate range should be consumed. Half a sandwich is a reasonable option.

If the hypoglycemic episode has progressed to the point at which the patient cannot or will not take anything by mouth, more drastic measures will be needed. In many cases, a family member or roommate can be trained in the use of glucagon:

• Glucagon is a hormone that causes a rapid release of glucose stores from the liver. It is an injection given intramuscularly to an individual who cannot take glucose by mouth. A response is usually seen in minutes and lasts for about 90 minutes. Again, a long-acting source of glucose should thereafter be consumed to maintain blood sugar levels in the safe range.
• If glucagon is not available and the patient is not able to take anything by mouth, emergency services (for example 911) should be called immediately. An intravenous route of glucose administration should be established as soon as possible.

A good example of diet management after initial treatment includes:

• Half a sandwich
• Whole-grain crackers with peanut butter
• A small bowl of cereal with milk

This helps replenish glycogen stores and maintain stable blood sugar levels over time.

With a history of recurrent hypoglycemic episodes, the first step in treatment is to assess whether it is related to medications or insulin treatment. Patients with a consistent pattern of the condition may benefit from a medication dose adjustment. People with diabetes who experience low blood sugar must check blood glucose values multiple times a day to help define whether there is a pattern related to meals or medications. Some people who experience recurrent episodes will benefit from changes in when and what they eat, for example, eating multiple small meals and frequent small snacks throughout the day rather than three larger meals.

When the circulating level of blood glucose falls, the brain senses the drop. The brain then sends out messages that trigger a series of events, including changes in hormone and nervous system responses that are aimed at increasing blood glucose levels. Insulin secretion decreases and hormones that promote higher blood glucose levels, such as glucagon, cortisol, growth hormone, and epinephrine all increase. As mentioned previously, there is a storage in the liver of glycogen that can be converted to glucose rapidly. In addition to the biochemical processes that occur, the body starts to consciously alert the affected person that it needs food by causing the signs and symptoms of hypoglycemia. If the glucose continues to fall, the person can become unresponsive and in some severe, unrecognized cases, die from hypoglycemia.

How low is too low for blood sugar?

To understand what number is too low for blood sugar and what level of low blood sugar is dangerous, you can check out the following:

• Mild hypoglycemia: The sugar level is below 70 mg/dL (3.9 mmol/L) but 54 mg/dL or higher.
• Moderate hypoglycemia: A blood sugar level below 54 mg/dL is considered clinically significant hypoglycemia.
• Severe hypoglycemia: If hypoglycemia leads to impaired brain function, causing seizures, brain damage, and even loss of consciousness regardless of values, then it is considered severe hypoglycemia. This type of hypoglycemia can lead to hypoglycemic shock.
• Low blood sugar death level: A value below 30 mg/dL is considered a dangerously low level of blood sugar, which can lead to death, especially if not treated promptly.

The onset of symptoms varies among individuals, but as blood glucose levels continue to drop, the risk of seizures, loss of consciousness, and even death increases.

The body needs fuel to work. One of its major fuel sources is sugars, which the body gets from what is consumed as either simple sugar or complex carbohydrates in the diet. For emergencies (like prolonged fasting), the body stores a stash of sugar in the liver as glycogen. If this store is needed, the body goes through a biochemical process to make new sugar (gluco-neo-genesis) and converts these stores of glycogen to sugar. This backup process emphasizes that the fuel source of sugar is important (important enough for human beings to have developed an evolutionary system of storage to avoid a sugar deficit).

Of all the organs in the body, the brain depends on sugar (glucose) almost exclusively. Rarely, if necessary, the brain will use ketones as a fuel source, but this is not preferred. The brain cannot make its glucose and is 100% dependent on the rest of the body for its supply. If for some reason, the glucose level in the blood falls (or if the brain's requirements increase and demands are not met), there can be effects on the function of the brain.

Risk factors are having type 1 or 2 diabetes or, in some cases, prediabetes.

Despite advances in the treatment of diabetes, low blood sugar episodes often are the limiting factor in achieving optimal blood sugar control, because many medications that are effective in treating diabetes carry the risk of lowering the blood sugar level too much, causing symptoms of the condition. In large-scale studies looking at tight control in both type 1 and type 2 diabetes, low blood sugars occurred more often in the patients who were managed most intensively. This is important for patients and physicians to recognize, especially as the goal for treating patients with diabetes becomes tighter control of blood sugar.

Can you die from low blood sugar in your sleep?

You can have low blood sugar levels while you sleep, a condition known as nocturnal hypoglycemia, and this can lead to death. This is a very rare, but serious and potentially life-threatening condition that occurs when blood sugar levels drop dangerously low during sleep, leading to a variety of distressing symptoms, such as:

• Night sweats
• Nightmares
• Waking up confused or shaky or not waking up at all

What is hypoglycemic shock?

Hypoglycemic shock occurs when the body's blood sugar levels drop below 40 mg/dL, depriving the brain and other organs of the energy they need to function. It's mostly seen in people with diabetes, especially those taking insulin or certain oral medications that lower blood sugar.

Symptoms of hypoglycemic shock may include:

• Early: Sweating, shaking, hunger, irritability, fast heartbeat
• Late/severe: Confusion, slurred speech, seizures, unconsciousness

Treatment:

• Quickly consume fast-acting sugar (such as glucose tablets or juice).
• If the person is unconscious, administer an emergency glucagon injection.
• Call emergency services if recovery does not occur rapidly.

People with diabetes should wear identification stating they have diabetes and whether they have recurrent low blood sugar. Those at risk for the health condition should be counseled on checking blood sugars before they drive a car, operate heavy machinery, or do anything physically taxing.

In addition, it is important to carry a quick-acting glucose source (such as those mentioned above) at all times, and keep a source in their car, office, and by their bedside. Efforts should be made to minimize the hypoglycemic effects of drug regimens and to avoid variable surges in exercise, activity, and drinking alcohol.

• Can non-diabetics get hypoglycemia? People without diabetes can get hypoglycemia, though it's less common. This is called nondiabetic hypoglycemia and can occur due to various factors such as:
  • Fasting or malnutrition
  • Excessive alcohol intake
  • Hormonal imbalances (such as adrenal insufficiency)
  • Certain medications (such as quinine or salicylates)
  • Critical illnesses (such as liver or kidney disease)
  • Insulinoma
• How do you manage hypoglycemia? To manage hypoglycemia, you need to treat with 15-20 grams of fast-acting carbohydrates, check blood in 15 minutes, and repeat if needed. If unconscious, use glucagon and call emergency services. Prevent hypoglycemia with regular meals and glucose monitoring.
• What can happen with low blood sugar? Low blood sugar can cause dizziness, sweating, confusion, blurred vision, seizures, and loss of consciousness. In severe cases, it can lead to coma or death.
• What to eat if blood sugar is low? If blood sugar is low, eat 15-20 grams of fast-acting carbs, such as:
  • 1/2 can of regular soda or juice
  • One small piece of fruit, such as half a banana
  • 4 ounces (half-cup) of juice or regular soda (not diet)
  • 1 tablespoon of honey or syrup
  • One tube of instant glucose gel (check the instructions)
  • Three to four glucose tablets (check the instructions)
• How do you treat hypoglycemia in adults? To treat hypoglycemia in adults, give them 15-20 grams of fast-acting carbs, recheck blood in 15 minutes, and repeat if needed. If unconscious, administer glucagon and call emergency services.
• What happens if you have very low sugar? Extremely low sugar can lead to impaired brain function, causing confusion, slurred speech, seizures, unconsciousness, and, in extreme cases, coma or death.