Learning Objectives
By the end of this section, you will be able to:
- Discuss the pathophysiology, risk factors, and clinical manifestations for diabetes mellitus
- Describe the diagnostics and laboratory values for diabetes mellitus
- Apply nursing concepts and plan associated nursing care for patients with diabetes mellitus
- Evaluate the efficacy of nursing care for diabetes mellitus
- Describe the medical therapies that apply to the care of patients with diabetes mellitus
Pathophysiology of Diabetes Mellitus
The endocrine function of the pancreas is to produce hormones that help to regulate blood sugar levels and appetite. The two main hormones produced by the pancreas are insulin and glucagon. Produced by beta cells in the pancreas, insulin helps cells absorb glucose for energy, lowering the body’s blood sugar levels, and stimulates protein synthesis and the storage of free fatty acid in adipose tissue. Released by alpha cells of the pancreas when the body’s blood glucose is too low, glucagon triggers the liver to release stored glucose to raise glucose levels.
Characterized by inappropriately levels of high blood glucose, diabetes mellitus (DM) is a disease caused by an imbalance of insulin and glucagon. The most common types of DM are Type 1 diabetes mellitus (T1DM), Type 2 diabetes mellitus (T2DM), and gestational diabetes (GDM) (ADA, 2024a). The pathologies of the different types of DM vary (Table 21.5) (Plows et al., 2018).
| Type of Diabetes Mellitus | Pathology |
|---|---|
| Type 1 diabetes mellitus (T1DM) |
|
| Type 2 diabetes mellitus (T2DM) |
|
| Gestational diabetes (GDM) |
|
Because of the imbalance of insulin and glucagon, patients with DM have a risk for hyperglycemia (high blood glucose levels), which can further impair beta cell function and insulin secretion (Dapra & Bhandari, 2023). Hyperglycemia can lead to an impaired metabolic state, causing increased urination, or osmotic diuresis, due to the excess glucose concentrations in the kidneys. Chronic hyperglycemia also causes excess fatty acids and pro-inflammatory cytokines, contributing to further insulin resistance and inappropriate glucagon production. The excess glucose also bonds to proteins and lipids, causing damage to blood vessels in the eyes, kidneys, and peripheral nerves. The damage can cause complications such as diabetic neuropathy, kidney disease, and peripheral neuropathy (Dapra & Bhandari, 2023).
Risk Factors
Known risk factors for T1DM are age or family history. A person is more likely to develop T1DM at a young age, or if they have a close family member with the disease. In some circumstances, research has shown it can also be caused by certain viral infections (Rajsfus et al., 2023). However, scientists do not fully understand the risk factors for T1DM since it is viewed as a complex autoimmune disease.
Risks for T2DM include being overweight, age 45 or older, or of American Indian, Black, Hispanic, Latinx, or Alaska Native descent (CDC, 2022b). Having a sedentary lifestyle, a personal history of GDM, or a family history of T2DM are also risk factors (CDC, 2022b).
GDM risk factors include being overweight, age 25 and older, or of American Indian, Black, Hispanic, Latinx, Native Hawaiian, Pacific Islander, or Alaska Native descent. Having a personal history of GDM or polycystic ovary syndrome or a family history of T2DM are also risk factors (CDC, 2024; Mayo Clinic, 2022).
Clinical Manifestations
Common symptoms associated with DM are polyuria, increased thirst, unplanned weight loss, increased hunger, blurry vision, tingling or numbness in hands or feet, decrease in energy, dry skin, increased infections, and slow wound healing (CDC, 2023). Patients may also experience symptoms of hypoglycemia, such as the following:
- Shakiness (tremors) or jitteriness
- Feeling nervous or anxious
- Sweating (diaphoresis), chills, and clamminess
- Irritability or mood swings
- Confusion
- Fast heartbeat (tachycardia)
- Dizziness or lightheadedness
- Hunger
- Nausea
- Color draining from the skin (pallor)
- Feeling sleepy
- Weakness, fatigue, or having no energy
- Blurred/impaired vision
- Tingling or numbness in the lips, tongue, or cheeks (paresthesia)
- Headaches
- Coordination problems (ataxia) or clumsiness
- Irregular heart rate (arrythmia)
Symptoms that indicate a medical emergency include seizures, inability to eat or drink, and loss of consciousness.
Link to Learning
Watch this video to learn more about the pathophysiology of hypoglycemia and its etiology and classification.
Patients with T1DM may experience nausea, vomiting, and abdominal pain. Symptoms may not be present in patients with T2DM, since symptoms can take years to develop. GDM usually doesn’t have any symptoms but is often diagnosed in the second or third trimester of pregnancy.
Complications
There are many complications associated with DM, regardless of what type a patient has. Most complications are microvascular (affect small blood vessels) or macrovascular (affect larger vasculature):
- Microvascular complications include diabetic retinopathy, blindness, and neuropathy.
- Macrovascular complications include nephropathy, cardiovascular disease, and myocardial infarction.
- Other complications include end-stage kidney disease, limb amputations, hypoglycemia, gastroparesis (delayed gastric emptying), and increased risk for certain types of cancer, such as pancreatic, liver, kidney, and gallbladder (Zhu & Qu, 2022).
Emergent complications of DM are diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS). DKA is an acute condition with a low mortality rate. HHS develops slowly, sometimes in weeks, but has a much higher mortality rate. Treatment occurs in the intensive care unit (ICU) and is the same in both cases. Table 21.6 provides additional information about DKA and HHS (Sapra & Bhandari, 2023).
| Diabetic Ketoacidosis (DKA) | Hyperosmolar Hyperglycemic State (HHS) | |
|---|---|---|
| Pathophysiology |
|
|
| Symptoms |
|
|
| Treatment |
|
|
Link to Learning
This video provides a comparison of DKA and HHS as an effective NCLEX review.
Diagnostics and Laboratory Values
DM symptoms can vary according to type and severity. Accurate assessment is important to provide an accurate diagnosis and prevent complications. Diagnostic testing can provide information about disease type and severity. DM is diagnosed primarily through evaluation of fasting serum glucose levels, hemoglobin A1c levels, or oral glucose tolerance testing (OGTT). A patient can be diagnosed with DM with any one of the following results (ADA, 2024a):
- A fasting blood glucose level test result of 126 mg/dL or higher
- A glycosylated hemoglobin (A1c) level greater than or equal to 6.5%
- A1C, used to assess long-term blood glucose levels over 3 months
- An OGTT value greater than or equal to 200 mg/dL during a 75-g OGTT
- Random blood glucose level of greater than or equal to 200 mg/dL in the presence of symptomatic hyperglycemia or a hyperglycemic crisis
- A urinalysis may be positive for glucose and ketones
An OGTT is performed in all pregnant patients between 24 to 28 weeks’ gestation as a screening tool for GDM. The patient has their blood glucose level drawn, then drinks glucose and has another blood glucose level drawn at 1 hour, 2 hours, and/or 3 hours. The patient is diagnosed based on the results of the blood glucose levels.
Nursing Care of the Patient with Diabetes Mellitus
While diabetes is a manageable condition, there is the potential for serious complications. Lifestyle changes, robust patient education, and timely intervention are key interventions to optimize outcomes.
Recognizing and Analyzing Cues
The nurse providing care to a patient with DM utilizes both objective and patient-reported data to optimize care. Subjective assessment findings may include a patient or family history of obesity, DM, unplanned weight loss, neuropathic pain, polyuria, or polydipsia. Possible physical findings may include decreased touch and temperature sensation, blurred vision, hypertension, Kussmaul respirations (rapid, deep breathing at a consistent pace), loss of deep tendon reflexes in ankles, weak dorsalis pedis and posterior tibialis pulses, dry skin, muscle atrophy, foot ulceration, obesity, candida infections, thick hyperpigmentation of the skin under creases or folds, and poor skin turgor.
Life-Stage Context
Vision Loss in Older Patients
Visual acuity changes are a common cause of vision loss in older patients with DM. It is important to assess the visual acuity of older patients with DM while in the hospital setting, and to provide sufficient lighting for the patient to carry out activities and prevent falls. Reinforce to these patients at time of discharge the importance of regular eye exams by an optometrist (CDC, 2022a).
Prioritizing Hypotheses, Generating Solutions, and Taking Action
Patients with DM should be continuously monitored for complications, such as signs of hypoglycemia and hyperglycemia. When a person is fighting illness, their body releases extra glucose into the bloodstream to combat disease. Extra insulin is then produced to balance the extra glucose. A patient with DM that is experiencing stress or an infection doesn’t have the ability to provide that balance, so the nurse should plan to assess the blood glucose levels more frequently. A nursing care plan for a patient with DM may include monitoring glucose levels, medication management, nutrition therapy, and thorough patient education. When educating your patient, consider covering the following topics:
- Fundamentals of DM: Explain the underlying mechanisms of DM, including what the condition is, the typical ranges for normal blood glucose levels, and the goals for target blood glucose levels.
- Treatment strategies: Provide guidance on prescribed treatments, such as how to correctly use insulin and oral antidiabetic medications. Also, discuss strategies for meal planning and techniques for monitoring blood glucose levels and urine ketones.
- Management of acute complications: Educate the patient on how to identify, address, and prevent acute complications, including both hypoglycemia and hyperglycemia.
The nurse should follow facility policy for safe insulin administration. Onset and peak times of insulin and sulfonylureas, in association with anticipated mealtimes, should always be considered to avoid hypoglycemia episodes. In the hospital setting, patients may be temporarily taken off oral agents and treated exclusively with insulin, since insulin can be easily adjusted to manage hyperglycemia. If a hypoglycemic episode occurs, the nurse should intervene quickly using the facility’s established hypoglycemia protocol, and the event should be reported to the provider and in handoff or shift report. Symptomatic hyperglycemia should be immediately reported to the provider.
Evaluation of Nursing Care of the Patient with Diabetes Mellitus
Evaluating nursing care for patients with DM focuses on glucose monitoring and control. Accurately understanding the patient’s understanding of the disease and willingness to participate in care can increase the nurse’s ability to evaluate outcomes.
Evaluating Outcomes
The nurse should evaluate the outcome of the care provided with the patient and family. Sometimes interventions and timelines need to be adjusted to meet care goals. In caring for the patient with DM, questions that the nurse can ask themselves to evaluate care are:
- Did the patient’s fluid volume status normalize to target ranges?
- Did the patient’s electrolytes normalize to target ranges?
- Did the patient maintain adequate blood glucose levels?
- Did the patient experience a hypoglycemic/hyperglycemic episode?
- Did the patient seem engaged during education, and did they retain the information given?
Medical Therapies and Related Care
Treatment of DM is patient-specific and involves education and patient engagement, medication, lifestyle changes, and glucose monitoring (ADA, 2024b). Treatment is lifelong in order to prevent complications.
Patients with T1DM require insulin for treatment, while patients with T2DM may use insulin if other treatments are insufficient. The primary therapeutic effect of diabetes medications is to maintain serum blood glucose levels within the normal range and achieve an individualized target level of A1C, often set around 7 percent. However, patients should be aware of potential adverse and side effects associated with these treatments. Common side effects include hypoglycemia, characterized by abnormally low blood glucose levels, and hypokalemia, a deficiency of potassium in the blood. Additionally, specific medications, such as Afrezza, an inhaled insulin, can cause acute bronchospasm, especially in individuals with pre-existing respiratory conditions.
There are several different types of insulins that vary in terms of onset, peak, and duration (Table 21.7). It is critical for the nurse to be knowledgeable of these differences to help prevent episodes of hypoglycemia due to mismatched administration of insulin with food intake.
| Class and Subclass | Prototypes and Generics | Onset/Peak/Duration | Administration Considerations |
|---|---|---|---|
| Rapid-acting insulin | Insulin lispro (Humalog) Insulin aspart (Novolog) Inhaled insulin (Afreeza) |
Onset: 15-30 minutes Peak effect: 1-3 hours Duration: 3-5 hours |
|
| Short-acting insulin | Humulin R Novolin R |
Onset: 30 minutes Peak effect: 3 hours Duration: 8 hours |
|
| Intermediate-acting insulin | Humulin N Novolin N |
Onset: 1-2 hours Peak effect: 6 hours (range 2.8-13 hours) Duration: up to 24 hours |
|
| Combination: Intermediate-acting/Rapid-acting | Humalog Mix 50/50* Humalog Mix 75/25* Novolog Mix 70/30* *First number is % intermediate-acting insulin, second number is % rapid-acting |
Onset: 15-30 minutes Peak effect: 1-5 hours Duration: 11-22 hours |
|
| Combination: Intermediate-acting/Short-acting | Humulin 70/30 Novolin 70/30 |
Onset: 30-90 minutes Peak effect: 1.5-6.5 hours Duration: 18-24 hours |
|
| Long-acting insulin | Insulin glargine (Lantus) Insulin detemir (Levemir) |
Onset: 3-4 hours Peak effect: none Duration: >24 hours |
|
There are several different classes of oral antihyperglycemic drugs used in conjunction with a healthy diet and exercise for the management of T2DM. According to the American Diabetes Association, metformin is the preferred initial pharmacologic agent for the treatment of T2DM (ADA, 2024b). Three of the most-used antihyperglycemic classes and prototypes are sulfonylureas (glipizide), biguanide (metformin), and DPP-IV (sitagliptin). Administration considerations for each of these prototypes are described in Table 21.8.
| Class | Prototype | Administration Considerations |
Adverse/Side Effects |
|---|---|---|---|
| Sulfonylureas | Glipizide | Time with meals; peak plasma concentrations occur 1 to 3 hours after administration | Hypoglycemia; may be potentiated by nonsteroidal anti-inflammatory agents and other drugs that are highly protein-bound |
| Biguanide | Metformin | Contraindicated in renal and hepatic diseases Should be temporarily discontinued in patients undergoing radiologic studies involving intravascular administration of iodinated contrast materials |
Stop immediately if signs of lactic acidosis or any condition associated with hypoxemia, dehydration, or sepsis occur Common adverse effects: diarrhea, nausea/vomiting, weakness, flatulence, indigestion, abdominal discomfort, and headache |
| DPP-IV inhibitor | Sitagliptin | Can be given with or without food | Hypoglycemia Report hypersensitivity reactions, blisters/erosions, headache, or symptoms of pancreatitis, heart failure, severe arthralgia, or upper-respiratory infection |
Lifestyle changes play a crucial role in managing DM effectively and improving overall health. For individuals with DM, adopting a balanced diet rich in whole grains, lean proteins, and vegetables while reducing the intake of refined sugars and saturated fats can help control blood glucose levels and prevent complications. Regular physical activity, such as walking, cycling, or swimming, enhances insulin sensitivity and helps maintain a healthy weight. Additionally, managing stress through techniques like mindfulness or yoga can positively impact blood sugar levels. Monitoring blood glucose regularly and making informed adjustments to diet and exercise based on these readings further supports effective DM management. By integrating these lifestyle changes, individuals with DM can achieve better glycemic control and enhance their quality of life.
Oral antihyperglycemic medications have historically not been recommended during pregnancy because they cross the placenta and may pose risks to the developing fetus, potentially leading to harmful effects. Instead, insulin has traditionally been the preferred treatment for managing DM during pregnancy, as it does not cross the placenta and is considered safe for both the mother and the fetus. While some oral medications, like metformin, may be used cautiously in specific cases, insulin remains the standard choice to effectively control blood glucose levels and minimize risks to fetal development.
Regular screenings are crucial for preventing complications in DM management. Diabetic retinal exams should be performed annually to monitor for signs of diabetic retinopathy. Neurologic exams, including assessments for neuropathy, are typically recommended at least once a year. Urinalysis should be conducted periodically, often annually, to check for signs of nephropathy or urinary tract infections. Blood pressure should be monitored at each visit, with treatment adjustments made as needed to maintain control. Lipid levels are generally assessed annually to manage cardiovascular risk. Additionally, patients should conduct frequent self-inspections of their feet and have them checked regularly by a health-care professional, as often as every visit or at least every three to six months, to detect and address any sores or breakdowns promptly.
In addition to regular screenings and monitoring, comprehensive DM care includes several other essential standards. Routine vaccinations, such as those for influenza, pneumococcal disease, and hepatitis B, are crucial for preventing infections that could complicate DM management. Support for smoking cessation is also vital due to the increased risk of cardiovascular disease associated with smoking. Regular nutrition counseling helps individuals manage their diet effectively, while mental health support addresses psychological challenges related to DM. Additionally, monitoring kidney function through tests like serum creatinine and urine albumin-to-creatinine ratio helps in the early detection of diabetic nephropathy.
In DM management, the frequency of blood glucose monitoring varies depending on the type of DM and the treatment regimen. For individuals with T1DM, frequent monitoring is essential due to the need for precise insulin dosing. Typically, blood glucose should be checked multiple times a day, including before and after meals, before exercise, and at bedtime, to effectively manage insulin levels and prevent hypo- or hyperglycemia. For those with T2DM, the frequency of monitoring can vary based on the treatment approach. Patients who are on insulin therapy or other glucose-lowering medications may need to monitor their blood glucose levels several times a day, similar to T1DM patients. However, those managing their DM with oral medications alone or through lifestyle changes may only need to check their blood glucose levels once a day or a few times a week. The specific frequency should be tailored to each individual’s treatment plan and glycemic control needs, as determined by their health-care provider.
It is crucial to reinforce to the patient the importance of keeping a detailed log of blood glucose results and to consistently check levels before meals and at bedtime. Regular monitoring and logging help provide valuable data for health-care providers, allowing for more accurate adjustments to treatment plans. This approach ensures better management of DM and contributes to improved overall health outcomes. Regular A1C testing, usually every three to six months, further helps assess long-term glucose control and informs any necessary changes in the monitoring routine.