Fear of the low: What you need to know about hypoglycemia

Approximately 25.8 million children and adults in the United States have diabetes. Especially with the diabetes rate rising yearly, you’re likely to care for many patients with this disorder.

Of those diagnosed with diabetes, 80% take diabetes medication (oral drugs, insulin, or both). Hypoglycemia is one of the most feared complications of such diabetes treatments—feared by both patients and healthcare providers alike. Common in hospital patients, it’s linked to poor outcomes, including increased mortality. Hypoglycemia occurs in about 12% to 18% of patients with diabetes, with even higher rates when more aggressive antihyperglycemic therapy is used.



Did you know? 
Direct medical costs linked to hypoglycemia in the United States totaled $1.84 billion in 2009



Blood glucose regulation

To understand hypoglycemia, you need to understand normal blood glucose regulation. Glucose levels are regulated by glucagon and insulin—endocrine glands of the pancreas. When the glucose level rises, as from carbohydrate metabolism or the stress response, beta cells in the pancreas release insulin. In turn, insulin lowers glucose levels by driving cellular uptake of glucose to use for energy, and initiates conversion of glucose to glycogen for storage in the liver and muscle. When the glucose level decreases, as from lack of carbohydrate intake or increased activity, alpha cells in the pancreas release glucagon. Glucagon promotes conversion of liver and muscle glycogen to glucose, which is released in the bloodstream to raise the blood glucose level (glycogenesis).

Defining hypoglycemia

Hypoglycemia generally is defined as a blood glucose level of 70 mg/dL or lower. But due to variances in individual patients and limitations of current glucose testing, the American Diabetes Association divides hypoglycemia into several types, described below.

Severe hypoglycemia occurs when a patient isn’t able to treat a hypoglycemic reaction on his or her own (generally due to decreased neurologic function) and instead must rely on others to take action to raise the glucose level. In the hospital, for instance, the nurse may administer glucose to a patient who becomes unconscious.

In documented symptomatic hypoglycemia, the patient has typical hypoglycemia signs and symptoms, and hypoglycemia is confirmed by a blood glucose level below 70 mg/dL.

With symptomatic hypoglycemia, the patient doesn’t experience hypoglycemia signs and symptoms despite a blood glucose level below 70 mg/dL.

A patient with probable symptomatic hypoglycemia feels hypoglycemia symptoms and treats them without verifying the blood glucose level with a blood glucose test.

In pseudohypoglycemia, hypoglycemia signs and symptoms develop at a blood glucose level above 70 mg/dL. This can occur in someone with uncontrolled diabetes who isn’t accustomed to a normal glucose level.

Risk factors

Diabetes and glucose-lowering medications are the most common risk factors for hypoglycemia. Others include septic shock, renal failure, severe critical illness, heart failure, liver failure, and cancer. Hypoglycemia risk also rises with altered nutritional intake and changes in medication dosages or timing.

Causes

Hypoglycemia can result from any of the following:

  • Adrenal insufficiency: The adrenal glands secrete cortisol and epinephrine, which help regulate the glucose level. Low cortisol and epinephrine levels may impede glucose regulation.
  • Alcohol ingestion: Metabolism of alcohol can prevent the liver from releasing glycogen to maintain a normal blood glucose level.
  • Beta blockers: Some beta blockers antagonize the beta1-receptor blockade, which can impede adrenergic warning signs of hypoglycemia.
  • Depression: One study found a positive relationship between depression and increased hypoglycemic effects.
  • Liver failure: This condition may impair the liver’s ability to store glucose as glycogen and to release glucose (glycogenolysis).
  • Certain medications: Insulin and insulin secretagogues (sulfonylureas and meglitinides) increase circulating insulin levels.
  • Poor nutrition: Nausea, vomiting, and appetite loss can lead to reduced carbohydrate intake.
  • Pregnancy: Severe hypoglycemia is more common during early pregnancy. Incidence peaks at gestational weeks 8 to 16, and falls during the second half of pregnancy. Women with a history of severe hypoglycemic reactions and those with hypoglycemic unawareness have a threefold higher risk for severe hypoglycemia during pregnancy. In early pregnancy, a combination of nausea, vomiting, and hormone fluctuations contributes to hypoglycemia.
  • Renal insufficiency: This condition stems from a combination of decreased gluconeogenesis and delayed renal metabolism of insulin.

As a nurse, you need to be aware of comorbidites that may affect glucose control and, as appropriate, advocate for medication changes to reduce the threat of hypoglycemia in high-risk patients.

Hypoglycemia signs and symptoms

As the blood glucose level decreases, initial signs and symptoms result from activation of the autonomic nervous system. Also called neurogenic symptoms, these manifestations result from acetylcholine release (causing cholinergic symptoms) and epinephrine/norepinephrine release (causing adrenergic symptoms).

  • Cholinergic symptoms include sweating, hunger, and paresthesia.
  • Adrenergic symptoms include palpitations, anxiety, and tremors.

If blood glucose continues to fall, cerebral neurons become glucose-deprived, resulting in neuroglycopenic symptoms, including fatigue, weakness, confusion, and behavior changes. If blood glucose keeps falling, loss of consciousness and seizures may occur. Prolonged severe hypoglycemia can lead to brain damage and death.

During sleep, hypoglycemia symptoms may be masked. However, nocturnal hypoglycemia may cause increased perspiration, restlessness, and nightmares.

Keep in mind that hypoglycemic symptoms are idiosyncratic. Warning signs vary from one person to the next.

Hypoglycemic unawareness
Patients who experience severe hypoglycemia episodes may have a reduced counterregulatory response (especially by epinephrine) to subsequent hypoglycemic episodes. This can suppress adrenergic symptoms until the glucose level drops much lower. Those with type 1 diabetes may develop a blunted glucagon response to low glucose levels, making the body unable to aid in glucose elevation. Some patients lose all ability to sense hypoglycemia and must rely on others to notice signs and symptoms for them. Studies show that preventing hypoglycemia by raising the patient’s blood glucose target level can reestablish the counterregulatory response in about 3 months.



Did you know?
Hypoglycemia is linked to about 6% of deaths in persons with diabetes who are younger than age 40.



Hypoglycemia treatment
Glucose is used to treat hypoglycemia. It’s given either as an oral supplement or through a glucose-elevating agent. If the patient is alert and can take oral treatment safely, a quick-acting carbohydrate is preferred. To help you remember administration guidelines, think of the “rule of 15.” (See the box below.)



Rule of 15
If you encounter a patient you suspect has hypoglycemia, administer 15 g of a fast-acting carbohydrate. Wait 15 minutes, then recheck the blood glucose level. If it’s still low, repeat treatment with 15 g of a fast-acting carbohydrate and recheck again in 15 minutes. Examples of 15 g of a fast-acting carbohydrate are one tube of glucose gel, three or four glucose tablets, candy containing dextrose (such as three rolls of Smarties®), and 4 oz of juice. For severe hypoglycemia, give 30 g of dextrose.



If the patient isn’t fully conscious and can’t take oral carbohydrates safely, never force juice or glucose gel, because this may contribute to choking and aspiration. If the patient can’t take oral treatment and doesn’t have I.V. access, inject glucagon intramuscularly or subcutaneously to raise the glucose level. Glucagon for injection is a synthetic form of the glucagon hormone, which promotes glycogenesis and increases the glucose level. Be aware that administering glucagon can deplete liver glycogen stores for up to 24 hours, making repeat glucagon injections ineffective.

If the patient can’t tolerate oral administration but has I.V. access, dextrose is the preferred treatment; it’s given as dextrose 50% solution by I.V. push. One ampule of dextrose 50% in water contains 50 g of dextrose. In most cases, the entire amp should be administered.

Know that because hypoglycemia causes unpleasant symptoms, most patients with diabetes consume more carbohydrates than needed to raise their blood glucose levels. This overtreatment can cause wide fluctuations in glucose levels.



Did you know?
The average person with type 1 diabetes has two hypoglycemia episodes per week and one episode of severe hypoglycemia per year.



Preventing hypoglycemia
Multiple effective approaches can help prevent hypoglycemia in patients with diabetes. The most important step is patient education. Instruct patients about hypoglycemia signs and symptoms so they can recognize a hypoglycemic reaction and quickly administer an oral carbohydrate or glucagon. Advise them to always carry a fast-acting carbohydrate with them. Recommend they check their blood glucose level before driving or operating other dangerous equipment. Instruct all patients with diabetes to wear a medical alert bracelet or necklace that identifies them as diabetic or to carry a medical identification card attached to their driver’s license. Include family members, significant others, and friends in diabetes education, including how to recognize and treat hypoglycema signs and symptoms.

Teach patients about medications
Explain how diabetes medications work, including their onset, peak, and duration, so patients can better understand their treatment regimen. For instance, if the patient’s glucose level drops 2 hours after injecting rapid-acting insulin, explain that approximately 2 hours of insulin action time is left. This means the patient should increase the amount of carbohydrate treatment to avoid another hypoglycemic episode. Instruct patients to withhold rapid-acting insulin or decrease the amount administered if they’ve had nausea or vomiting or have reduced their food intake due to a poor appetite.

Review exercise effects
Teach patients how exercise affects blood glucose levels. Explain that physical activity increases the body’s glucose use, possibly leading to hypoglycemia. With exercise, the body uses two types of fuel to power the activity. Initially, it uses glucose for fuel. Glucose comes both from glucose circulating in the blood and from stored glucose in the form of glycogen in the liver and muscle. After about 30 minutes of activity, glucose and glycogen stores may become depleted, causing the body to break down free fatty acids for energy. The body may require up to 24 hours to replenish glycogen stores in the liver and muscle, raising the hypoglycemia risk after the activity—termed the “lag effect” of exercise.

To help prevent hypoglycemia during exercise, advise patients to check their blood glucose level before exercising and frequently afterward to assess for hypoglycemia. For patients who inject insulin, insulin doses may need to be altered to help avoid hypoglycemia. Patients on oral diabetes medications may need an additional snack of 15 to 30 g of carbohyderates after exercise to prevent hypoglycemia. Remind patients that everyday activities, such as shopping and cleaning, also can induce hypoglycemia.

Collaborate on blood glucose goals
Using a patient-centered approach, help develop blood glucose goals in collaboration with the patient. Consider individual factors, such as age, comorbidities, and life expectancy, to help direct the treatment plan and establish glycemic targets. For example, patients with hypoglycemic unawareness may benefit from higher blood glucose goals. Elderly patients, on the other hand, may need less stringent blood glucose goals to avoid hypoglycemia, which could lead to such problems as fractures from falls. Teach patients how to adjust diabetes medications to meet their blood glucose goals.

Eradicate fear of the low
Fear of hypoglycemia can significantly affect patients and families. As mentioned earlier, a causal relationship exists between frequent hypoglycemia and depression. What’s more, a severe hypoglycemia episode can cause extreme fatigue, disrupting daily activities. In one study, 80% of patients with type 2 diabetes who’d experienced severe hypoglycemic reactions answered “sometimes” or “always” when asked if they feared recurrent hypoglycemic episodes. This fear may lead to medication nonadherence.

In addition, hypoglycemia may strain relationships. Personality changes can occur during a hypoglycemic event. For instance, neuroglycopenic symptoms can lead to bizarre or violent behavior; those witnessing this behavior may not understand that the patient can’t control it and may not even realize what’s happening. Meanwhile, patients may become frustrated if family members assume all emotional changes are related to hypoglycemia and thus insist that the patient get frequent glucose testing.

As healthcare providers, our role is to educate, encourage discussion, and provide support to patients. Approximately 85% of patients who experience hypoglycemia episodes don’t tell their healthcare providers about these incidents. To help ease their fears of hypoglycemia, initiate the dialogue, including recommendations for treatment, and provide support. In the immortal words of Marie Curie, “Nothing in life is to be feared; it is only to be understood. Now is the time to understand more, so that we may fear less.”

Stacey A. Seggelke is a clinical nurse specialist in the adult diabetes program at the University of Colorado Denver School of Medicine.

Selected references
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