Hypoglycemia Symptoms, Causes, Diagnosis, Treatment And Prevention

Hypoglycemia Symptoms, Causes & Treatment 


What is Hypoglycemia


Glucose, a form of sugar, is the body's main fuel. Hypoglycemia, or low blood sugar, occurs when blood levels of glucose drop too low to fuel the body's activity.

Hypoglycemia Symptoms, Causes, Diagnosis, Treatment And Prevention


Carbohydrates (sugars and starches) are the body's main dietary sources of glucose. During digestion, the glucose is absorbed into the blood stream (hence the term "blood sugar"), which carries it to every cell in the body. Unused glucose is stored in the liver as glycogen.

Hypoglycemia can occur as a complication of diabetes, as a condition in itself, or in association with other disorders.

Blood Sugar Range


The normal range for blood sugar is about 60 mg/dL (milligrams of glucose per deciliter of blood) to 120 mg/dL, depending on when a person last ate. In the fasting state, blood sugar can occasionally fall below 60 mg/dL and even to below 50 mg/dL and not indicate a serious abnormality or disease. This can be seen in healthy women, particularly after prolonged fasting. Blood sugar levels below 45 mg/dL are almost always associated with a serious abnormality.

How Does the Body Control Glucose?


The amount of glucose in the blood is controlled mainly by the hormones insulin and glucagon. Too much or too little of these hormones can cause blood sugar levels to fall too low (hypoglycemia) or rise too high (hyperglycemia). Other hormones that influence blood sugar levels are cortisol, growth hormone, and catecholamines (epinephrine and norepinephrine).

The pancreas, a gland in the upper abdomen, produces insulin and glucagon. The pancreas is dotted with hormone-producing tissue called the islets of Langerhans, which contain alpha and beta cells. When blood sugar rises after a meal, the beta cells release insulin. The insulin helps glucose enter body cells, lowering blood levels of glucose to the normal range. When blood sugar drops too low, the alpha cells secrete glucagon. This signals the liver to release stored glycogen and change it back to glucose, raising blood sugar levels to the normal range. Muscles also store glycogen that can be converted to glucose.

Who is at risk for hypoglycemia?


While people who do not have any metabolic problems can complain of symptoms suggestive of low blood sugar, true hypoglycemia usually occurs in people being treated for diabetes (type 1 and type 2). Individuals with pre-diabetes who have insulin resistance can also 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 hypoglycemia, such as insulin producing tumors (insulinomas) and certain medications. These uncommon causes of hypoglycemia will not be discussed in this article, which will primarily focus on the hypoglycemia occurring with diabetes mellitus and its treatment.

Despite our advances in the treatment of diabetes, hypoglycemic 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 of hypoglycemia. 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 become tighter blood sugar control.

Can the body protect itself from hypoglycemia?


When the circulating level of blood glucose falls, the brain actually 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 above, there is a store 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.

What are symptoms of hypoglycemia


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 70's. 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 hypoglycemia when blood glucose levels are lowered to the mid 60's. The first set of symptoms are called adrenergic (or sympathetic) because they relate to the nervous system's response to hypoglycemia. Patients may experience any of the following;

Hypoglycemia Symptoms, Causes, Diagnosis, Treatment And Prevention
Hypoglycemia Symptoms

  • nervousness,
  • sweating,
  • intense hunger,
  • trembling,
  • weakness,
  • palpitations, and
  • often have trouble speaking.
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, diet, or lower their carbohydrate intake drastically should also be cautioned. These individuals may also experience modest hypoglycemia.

People being treated for diabetes who experience hypoglycemia 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. Somewhere in the 50 mg/dl range, most 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.

Diagnosis for Hypoglycemia



To diagnose hypoglycemia in people who do not have diabetes, the doctor looks for the following three conditions:

  • The patient complains of hypoglycemia symptoms
  • Blood glucose levels are measured while the person is experiencing those symptoms and found to be 45 mg/dL or less in a woman or 55 mg/dL or less in a man
  • The symptoms are promptly relieved upon ingestion of sugar.
For many years, the oral glucose tolerance test (OGTT) was used to diagnose hypoglycemia. Experts now realize that the OGTT can actually trigger hypoglycemia symptoms in people with no signs of the disorder. For a more accurate diagnosis, experts now recommend that blood sugar be tested at the same time a person is experiencing a hypoglycemic symptom.
The doctor will also check the patient for health conditions such as diabetes, obtain a medication history, and assess the degree and severity of the patient's symptoms. Laboratory tests to measure insulin production and levels of C-peptide (a substance that the pancreas releases into the bloodstream in equal amounts to insulin) may be performed.

Hypoglycemia in Diabetes


The most common cause of hypoglycemia is as a complication of diabetes. Diabetes occurs when the body cannot use glucose for fuel because either the pancreas is not able to make enough insulin or the insulin that is available is not effective. As a result, glucose builds up in the blood instead of getting into body cells.

The aim of treatment in diabetes is to lower high blood sugar levels. To do this, people with diabetes may use insulin or oral drugs, depending on the type of diabetes they have or the severity of their condition. Hypoglycemia occurs most often in people who use insulin to lower their blood sugar. All people with type 1 diabetes and some people with type 2 diabetes use insulin. People with type 2 diabetes who take oral drugs called sulfonylureas are also vulnerable to low blood sugar episodes.

Conditions that can lead to hypoglycemia in people with diabetes include taking too much medication, missing or delaying a meal, eating too little food for the amount of insulin taken, exercising too strenuously, drinking too much alcohol, or any combination of these factors. People who have diabetes often refer to hypoglycemia as an "insulin reaction."

Managing Hypoglycemia in Diabetes


People with diabetes should consult their health care providers for individual guidelines on target blood sugar ranges that are best for them. The lowest safe blood sugar level for an individual varies, depending on the person's age, medical condition, and ability to sense hypoglycemia symptom. A target range that is safe for a young adult with no diabetes complications, for example, may be too low for a young child or an older person who may have other medical problems.

Because they are attuned to the hypoglycemia symptoms, people with diabetes can usually recognize when their blood sugar levels are dropping too low. They can treat the condition quickly by eating or drinking something with sugar in it such as candy, juice, or nondiet soda. Taking glucose tablets or gels (available in drug stores) is another convenient and quick way to treat hypoglycemia.

People with type 1 diabetes are most vulnerable to severe insulin reactions, which can cause loss of consciousness. A few patients with long-standing insulin-dependent diabetes may develop a condition known as hypoglycemia unawareness, in which they have difficulty recognizing the symptoms of low blood sugar. For emergency use in patients with type 1 diabetes, physicians often prescribe an injectable form of the hormone glucagon. A glucagon injection (given by another person) quickly eases hypoglycemia symptoms of low blood sugar, releasing a burst of glucose into the blood.

Emergency medical help may be needed if the person does not recover in a few minutes after treatment for hypoglycemia. A person suffering a severe insulin reaction may be admitted to the hospital so that blood sugar can be stabilized.

People with diabetes can reduce or prevent episodes of hypoglycemia by monitoring their blood sugar levels frequently and learning to recognize a hypoglycemia symptom and the situations that may trigger it. They should consult their health care providers for advice about the best way to treat low blood sugar. Friends and relatives should know about the symptoms of hypoglycemia and how to treat it in case of emergency.

Episodes of hypoglycemia in people with type 1 diabetes may become more common now that research has shown that carefully controlled blood sugar helps prevent the complications of diabetes. Keeping blood sugar in a close-to-normal range requires multiple injections of insulin each day or use of an insulin pump, frequent testing of blood glucose, a hypoglycemia diet and exercise plan, and guidance from health care professionals.

How is hypoglycemia treated?


The acute management of hypoglycemia involves the rapid delivery of a source of easily absorbed sugar. 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.

The equivalency of 10-15 grams of glucose (approximate servings) are:

  • Four lifesavers
  • 4 teaspoons of sugar
  • 1/2 can of regular soda or juice
Many people like the idea of treating hypoglycemia with dietary treats such as cake, cookies, and brownies. However, sugar in the form of complex carbohydrates or sugar combined with fat and protein are much too slowly absorbed to be useful in the acute treatment of hypoglycemia.

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.

With a history of recurrent hypoglycemic episodes, the first step in treatment is to assess whether the hypoglycemia is related to medications or insulin treatment. Patients with a consistent pattern of hypoglycemia may benefit from a medication dose adjustment. It is important that people with diabetes who experience hypoglycemia check blood glucose values multiple times a day to help define whether there is a pattern related to meals or medications.

Hypoglycemia Prevention


Are You…

  • Having frequent low blood glucose?
  • Unaware of low blood glucose symptoms?
  • Too afraid or not afraid enough of low blood glucose?
  • Having frequent motor vehicle accidents or violations?
  • Experiencing family conflict due to low blood glucose?
  • Having trouble at work due to low blood glucose?
  • Attempting intensive insulin therapy?
  • Attempting pregnancy?
This one-day Hypoglycemia Prevention workshop helps people with either type 1 or type 2 diabetes who are taking insulin to anticipate, recognize and prevent hypoglycemia. The instructors are Joslin Clinic nurses, dietitians, exercise physiologists and behavioral specialists.


Other Causes of Hypoglycemia


Hypoglycemia in people who do not have diabetes is far less common than once believed. However, it can occur in some people under certain conditions such as early pregnancy, prolonged fasting, and long periods of strenuous exercise. People on beta blocker medications who exercise are at higher risk of hypoglycemia, and aspirin can induce hypoglycemia in some children. Drinking alcohol can cause blood sugar to drop in some sensitive individuals, and hypoglycemia has been well documented in chronic alcoholics and binge drinkers. Eating unripe ackee fruit from Jamaica is a rare cause of low blood sugar.

Rare Causes of Hypoglycemia



Fasting hypoglycemia occurs when the stomach is empty. It usually develops in the early morning when a person awakens. As with other forms of hypoglycemia, the symptoms include headache, lack of energy, and an inability to concentrate. Fasting hypoglycemia may be caused by a variety of conditions such as hereditary enzyme or hormone deficiencies, liver disease, and insulin-producing tumors.

In hereditary fructose intolerance, a disorder usually seen in children, the body is unable to metabolize the natural sugar fructose. Attacks of hypoglycemia, marked by seizures, vomiting, and unconsciousness, are treated by giving glucose and eliminating fructose from the diet.

Galactosemia, a rare genetic disorder, hampers the body's ability to process the sugar galactose. An infant with this disorder may appear normal at birth, but after a few days or weeks of drinking milk (which contains galactose), the child may begin to vomit, lose weight, and develop cataracts. The liver may fail to release stored glycogen into the blood, triggering hypoglycemia. A specific hypoglycemia diet which removes milk from the diet is the usual treatment.

A deficiency of growth hormone causes increased sensitivity to insulin. This sensitivity occurs because growth hormone opposes the action of insulin on muscle and fat cells. For this reason, children with growth hormone deficiency sometimes suffer from hypoglycemia, which goes away after treatment.

People with insulin-producing tumors, which arise in the islet cells of the pancreas, suffer from severe episodes of hypoglycemia.

To diagnose these tumors, called insulinomas, a doctor will put the patient on a 24- to 72-hour fast while measuring blood levels of glucose, insulin, and proinsulin. High levels of insulin and proinsulin in the presence of low levels of glucose strongly suggest an insulin-producing tumor. These tumors are usually benign and can be surgically removed.

In rare cases, some cancers such as breast cancer and adrenal cancer may cause hypoglycemia through secretion of a hormone called insulin-like growth factor II. The treatment is removal of the tumor, if possible.

Reactive Hypoglycemia


A diagnosis of reactive hypoglycemia is considered only after other possible causes of low blood sugar have been ruled out. Reactive hypoglycemia with no known cause is a condition in which the symptoms of low blood sugar appear 2 to 5 hours after eating foods high in glucose.

Ten to 20 years ago, hypoglycemia was a popular diagnosis. However, studies now show that this condition is actually quite rare. In these studies, most patients who experienced a hypoglycemia symptom after eating glucose-rich foods consistently had normal levels of blood sugar--above 60 mg/dL. Some researchers have suggested that some people may be extra sensitive to the body's normal release of the hormone epinephrine after a meal.

People with symptoms of reactive hypoglycemia unrelated to other medical conditions or problems are usually advised to follow a healthy eating plan. The doctor or dietitian may suggest a hypoglycemia diet that avoids foods high in carbohydrates; that the person eat small, frequent meals and snacks throughout the day; exercise regularly; and eat a variety of foods, including whole grains, vegetables, and fruits.