28.1 Introduction to Diabetes

Type 1 Diabetes

Type 1 diabetes is an autoimmune disorder that causes the body’s immune system to attack and destroy the β cells in the pancreas that make insulin. As a consequence, the pancreas stops making insulin. Without insulin, glucose homeostasis is disrupted, resulting in glucose not being able to get into the cells of the body, thus causing elevated glucose levels in the blood. Because the body is destroying the β cells in the pancreas, clients with type 1 diabetes will need to take insulin for the rest of their lives to survive (Holt et al., 2021).

According to the Centers for Disease Control and Prevention (n.d.-a), 1.6 million U.S. adults aged 20 years or older have type 1 diabetes. The onset of symptoms with type 1 diabetes is often sudden. It typically appears in adolescents and young adults but can occur in childhood as well. Symptoms of type 1 diabetes can be severe, and the disease process can be difficult to control. Risk factors include family history and age. White clients are more likely to develop type 1 diabetes than Black, Asian American, Hispanic, or Latino/Latina clients (CDC, 2022b).

Type 2 Diabetes

Type 2 diabetes occurs when the pancreas does not produce enough insulin or the body is not using insulin effectively. Figure 28.2 shows the mechanism of normal blood sugar absorption versus insulin resistance with type 2 diabetes. The β cells in the pancreas continue to have some degree of functionality with varying amounts of insulin secretion, resulting in elevated blood glucose levels and insulin resistance. Type 2 diabetes may be managed with healthy eating and being active, or the health care provider may prescribe insulin, other injectable medications, or oral diabetic medicines to help clients manage blood sugar and avoid complications (CDC, n.d.-b).

The Centers for Disease Control and Prevention (n.d.-b) reported that of the approximately 37 million U.S. adults who have diabetes, approximately 90%–95% of them have type 2 diabetes. Unlike type 1 diabetes, type 2 diabetes symptoms are gradual in onset. The disease typically appears in people over age 45; however, it is becoming more common in children, adolescents, and young adults. Risk factors include having prediabetes, obesity, age 45 or older, family history, sedentary lifestyle, fatty liver, and a history of gestational diabetes. Black, Alaska Native, American Indian, Hispanic, and Latino/Latina people are more likely to develop type 2 diabetes (CDC, 2022b).

Gestational Diabetes

Gestational diabetes is a type of diabetes that can develop during pregnancy in clients who do not already have diabetes. Testing for gestational diabetes usually occurs between 24 and 28 weeks of pregnancy (NIH, n.d.). Gestational diabetes causes high blood glucose levels that can affect the pregnancy and the fetus. Symptoms are usually unnoticeable; however, the client may exhibit signs of increased thirst and increased urination. Gestational diabetes is controlled with dietary management and exercise. Pharmacologic methods are incorporated only if the disease process is unmanageable with diet and exercise and only introduced if safe for both the pregnant person and the fetus. Blood sugar levels typically return to baseline soon after the delivery of the newborn. Clients with gestational diabetes are at a higher risk of developing type 2 diabetes as they age (American Diabetes Association, n.d.-a).

Complications of Diabetes

Complications from diabetes can affect all body systems. They include cerebrovascular disease, cardiovascular disease, diabetic neuropathy, diabetic retinopathy, cataracts, glaucoma, periodontal disease, peripheral vascular disease, foot damage, stroke, increased risk of infection, and poor wound healing.

Prevention

There is no known way to prevent type 1 diabetes. Type 2 diabetes can be prevented with lifestyle modifications such as diet, exercise, weight loss, and developing a diabetes prevention program with the health care provider (American Diabetes Association, n.d.-a).

Clinical Manifestations of Diabetes

Typical clinical manifestations of diabetes include polyuria (increased urination), polydipsia (increased thirst), weight loss without trying, blurry vision or vision changes, paresthesia (tingling in the feet and hands), dry skin, and fatigue (see Figure 28.3). Hypoglycemia and hyperglycemia play a role in diabetes management and are discussed in the following sections.

Figure 28.3 There are a number of clinical manifestations of diabetes affecting the respiratory, gastric, urinary, and central nervous system. (credit: modification of work “Main symptoms of diabetes” by Mikael Häggström, used with permission/Wikimedia Commons, Public Domain)

Hypoglycemia

Hypoglycemia occurs when the blood glucose level in the body falls below the normal range. The expected values for normal fasting blood glucose concentration are between 70 mg/dL and 100 mg/dL (World Health Organization [WHO], n.d.). When blood glucose levels are too low, the brain does not get enough glucose to function, which in its most severe form can cause coma and death. Signs and symptoms of hypoglycemia include feeling shaky, sweating/chills, clammy skin, dizziness/feeling faint, agitation, confusion, blurred or impaired vision, slurred speech, and tachycardia/bradycardia (American Diabetes Association, n.d.-c).

Treatment of hypoglycemia includes the “15–15 rule”: 15 grams of carbohydrates to raise the blood glucose level and a blood glucose monitoring check 15 minutes after administration of the carbohydrates. If the blood glucose level remains under 70 mg/dL, then glucose tablets or 15 grams of carbohydrates may be repeated until the blood glucose is at least 70 mg/dL. Glucagon may be used to treat clients with diabetes when their blood glucose is too low to treat using the 15–15 rule (American Diabetes Association, n.d.-c). Glucagon can be given intravenously, intramuscularly, or subcutaneously if the client is unable to eat or drink or if the client is unconscious.

Hyperglycemia

Hyperglycemia occurs when the blood glucose level in the body is above the normal range and the body has too little insulin or is too insulin resistant to lower the blood glucose level on its own. This causes a disruption in glucose homeostasis. If a blood glucose level is above 110 mg/dL, it is considered hyperglycemia. Symptoms vary per individual. Some clients may have mild symptoms with blood glucose levels between 110 mg/dL and 240 mg/dL. Severe symptoms can result in diabetic ketoacidosis, coma, and death. Signs and symptoms of hyperglycemia include frequent urination (polyuria), increased thirst (polydipsia), increased hunger (polyphagia), blurred vision, restlessness, unintentional weight loss, abdominal pain, vomiting, drowsiness, hot/dry skin, hypotension, and coma (American Diabetes Association, n.d.-b; Sapra & Bhandari, 2023).

Treatment of hyperglycemia can be as simple as dietary management and exercise if blood glucose levels are 110–240 mg/dL. However, if increasing fluid intake, diet, and exercise does not lower blood glucose levels, the individual will require an oral diabetes agent, insulin, and/or a non-insulin injectable drug to lower the blood glucose levels (American Diabetes Association, n.d.-b; Feingold, 2022).

Diagnostic Testing for Diabetes

There are several diagnostic tests to determine if a person has diabetes. Health care providers will typically use one or more of the following tests to determine if an individual has diabetes.