Diabetes Mellitus Case Study
Introduction
Diabetes mellitus is a chronic, metabolic disease characterized by persistent hyperglycemia that damages multiple organ systems over time. According to the World Health Organization (WHO), the global burden of diabetes has increased dramatically; the number of people living with diabetes rose from 200 million in 1990 to 830 million in 2022[1]. Over half of individuals with diabetes do not receive treatment, especially in low and middle‑income countries[2]. Hyperglycemia is associated with complications such as blindness, kidney failure, heart attacks, stroke and lower‑limb amputations[3]. Lifestyle factors unhealthy diet, physical inactivity, obesity and tobacco use contribute significantly to the development of type 2 diabetes mellitus (T2DM), which accounts for more than 95 % of all diabetes cases[4]. The following case study presents an in‑depth analysis of a patient with T2DM, including pathophysiology, risk factors, complications, diagnosis, treatment and nursing management. The goal is to integrate evidence‑based practice with patient centered care and illustrate how nurses play a critical role in managing chronic diseases like diabetes.
Background and Pathophysiology of Diabetes Mellitus
Classification and Epidemiology
Diabetes mellitus comprises several types:
- Type 1 diabetes is characterized by autoimmune destruction of pancreatic β‑cells, leading to absolute insulin deficiency. It often presents in childhood or adolescence but can occur at any age. Individuals require lifelong insulin therapy to survive[5].
- Type 2 diabetes results from a progressive loss of adequate β‑cell insulin secretion in the context of chronic insulin resistance. It typically develops in adulthood but increasingly affects younger populations and children due to rising obesity and sedentary lifestyles[6]. More than 95 % of people with diabetes have T2DM[7].
- Gestational diabetes occurs during pregnancy and increases the risk of maternal and fetal complications and later development of T2DM[8].
- Prediabetes and impaired glucose tolerance represent intermediate stages between normal glycemia and diabetes, indicating elevated risk for progressing to T2DM[9].
The global prevalence of diabetes has been rising rapidly: adults aged ≥18 years living with diabetes increased from 7 % in 1990 to 14 % in 2022[10]. Diabetes causes millions of deaths annually and contributes significantly to cardiovascular mortality[11]. The economic burden includes direct medical costs and loss of productivity, making diabetes a public health priority.
Pathogenesis of Type 2 Diabetes Mellitus
The pathophysiology of T2DM is multifactorial and complex. Insulin resistance and β‑cell dysfunction are central features[12]. In insulin‑resistant states, skeletal muscle and adipose tissues fail to respond adequately to insulin, leading to decreased glucose uptake. The liver continues to produce glucose despite hyperglycemia, contributing to augmented endogenous glucose production[13]. Adipose tissue insulin resistance results in increased lipolysis and elevated free fatty acids, further impairing glucose utilization and β‑cell function[14].
Over time, β‑cell compensatory mechanisms fail. Chronic exposure to high glucose and lipids referred to as glucotoxicity and lipotoxicity damages β‑cells, resulting in reduced insulin secretion[15]. Inappropriate glucagon secretion from pancreatic α‑cells exacerbates hyperglycemia and is partly attributed to an incretin defect diminished secretion or action of hormones such as GLP‑1 and GIP[16]. The gut microbiome, hypothalamic insulin resistance, increased renal glucose reabsorption and genetic/epigenetic factors also contribute to T2DM pathophysiology[17].
Pathogenesis of Microvascular and Macrovascular Complications
Chronic hyperglycemia leads to vascular damage through several biochemical pathways. For microvascular complications, hyperglycemia induces activation of the polyol pathway, formation of advanced glycation end‑products (AGEs), increased flux through the hexosamine pathway, protein kinase C activation, oxidative stress and inflammation[18]. These changes damage capillaries and small vessels, causing diabetic retinopathy, nephropathy and neuropathy[19]. Emerging research highlights the roles of long non‑coding RNAs, extracellular matrix accumulation and abnormal neovascularization in diabetic nephropathy and retinopathy[20]. Macrovascular complications such as coronary artery disease, cerebrovascular disease and peripheral arterial disease result from endothelial dysfunction, oxidative stress, dyslipidemia and accelerated atherosclerosis[21].
Diabetic Nephropathy
Diabetic nephropathy, now often termed diabetic kidney disease (DKD), is the leading cause of end‑stage renal disease[22]. Pathologically, DKD is characterized by glomerular hypertrophy, thickening of the basement membrane, podocyte loss and mesangial expansion[23]. Hyperglycemia generates reactive oxygen species and activates pathways involving AGEs, nuclear factor κB, protein kinase C and transforming growth factor‑β, leading to renal fibrosis and progressive decline in glomerular filtration rate[24]. Early detection through albuminuria assessment and aggressive management of glycemic and blood pressure control can delay progression[25].
Diabetic Retinopathy
Diabetic retinopathy (DR) is the most common microvascular complication and leading cause of vision loss in working‑age adults. The retina experiences damage from long‑standing hyperglycemia, resulting in microaneurysms, hemorrhages, lipid exudates and neovascularization[26]. Risk factors for DR include poor glycemic control, hypertension, dyslipidemia, nephropathy, male sex and obesity[27]. Early detection and tight metabolic control are crucial to prevent progression[28]. New insights conceptualize DR as a neurovascular–inflammatory process involving microglial activation and oxidative stress[29].
Diabetic Peripheral Neuropathy
Diabetic peripheral neuropathy (DPN) is the most common neuropathic disorder in people with diabetes. It is characterized by sensory loss, numbness, tingling, burning pain and weakness[30]. Hyperglycemia leads to metabolic and neurovascular changes that damage distal nerve fibers, resulting in loss of protective sensation and risk of ulceration and amputation[31]. Early screening of sensation and monofilament testing is recommended; management includes glycemic control, foot care, pharmacologic treatment of neuropathic pain and education[32].
Macrovascular Complications
Macrovascular complications include coronary artery disease (CAD), cerebrovascular disease and peripheral arterial disease. Patients with T2DM have a 2–4‑fold increased risk of cardiovascular disease. The Yangtze Medicine review notes that about 20–30 % of diabetic patients experience macrovascular complications, which substantially increase morbidity and mortality[33]. Mechanisms involve endothelial dysfunction, oxidative stress, platelet activation, dyslipidemia and hypertension[34]. Atherosclerosis develops more rapidly in diabetic patients, and the interplay between microvascular and macrovascular disease further worsens outcomes[35].
Risk Factors and Screening
Modifiable and Non‑Modifiable Factors
Important risk factors for developing T2DM include:
- Age and ethnicity: Advancing age is a strong risk factor; certain ethnic groups (African, Hispanic, Native American, Asian) have higher susceptibility[36]. Family history of diabetes increases risk, reflecting genetic predisposition[36].
- Obesity and overweight: Approximately 90 % of patients with T2DM are overweight or obese[37]. Excess adiposity promotes insulin resistance through inflammatory cytokines and adipokines[37].
- Physical inactivity: Sedentary lifestyle reduces insulin sensitivity and contributes to weight gain[38].
- Dietary patterns: High consumption of processed foods, saturated fats and sugar‑sweetened beverages increases risk, whereas diets rich in whole grains, fruits and vegetables are protective[38].
- Gestational diabetes and polycystic ovary syndrome (PCOS): Women with a history of gestational diabetes or PCOS have elevated risk for developing T2DM[36].
- Hypertension and dyslipidemia: These metabolic conditions often coexist with diabetes and contribute to insulin resistance and vascular damage[36].
- Non‑modifiable factors: Genetic predisposition, ethnicity, family history and age cannot be changed but inform screening strategies[36].
Screening and Diagnostic Criteria
The American Diabetes Association (ADA) recommends screening asymptomatic adults every three years, starting at age 35 or earlier in high‑risk individuals[36]. Diagnostic criteria include[36]:
- Fasting plasma glucose (FPG) ≥126 mg/dL (7.0 mmol/L) after at least 8 hours of fasting.
- 2‑hour plasma glucose ≥200 mg/dL (11.1 mmol/L) during a 75‑g oral glucose tolerance test (OGTT).
- Glycated hemoglobin (HbA₁c) ≥6.5 % (48 mmol/mol) on two separate tests.
- Random plasma glucose ≥200 mg/dL in a patient with classic symptoms of hyperglycemia.
Individuals with prediabetes meet criteria such as FPG 100–125 mg/dL or HbA₁c 5.7–6.4 %[36].
Nursing Case Presentation
Patient History
Mr. John W., a 55‑year‑old male of African descent, presents to the outpatient clinic for routine evaluation. He was diagnosed with T2DM ten years ago and initially managed with metformin. Over the past five years, he gained 15 kg, with a body mass index (BMI) of 33 kg/m². He works as an accountant, spends most of his day seated, and rarely exercises. He admits to consuming processed foods, sugar‑sweetened beverages and minimal fruits or vegetables. He has a family history of diabetes (father) and hypertension (mother). He smokes one pack per day and occasionally drinks alcohol. Mr. W. reports increased fatigue, blurred vision, tingling in his feet and difficulty healing a minor foot wound.
Past medical history includes hypertension treated with a thiazide diuretic, dyslipidemia treated with a statin and stage II CKD. He had episodes of hyperglycemia requiring emergency care two years ago but denies diabetic ketoacidosis. Medications include metformin 1000 mg twice daily, lisinopril 20 mg daily, hydrochlorothiazide 25 mg daily, atorvastatin 40 mg daily and low‑dose aspirin. He does not regularly monitor his blood glucose at home and has not attended diabetes education classes.
Physical Examination
- Vital signs: Blood pressure 152/94 mmHg; heart rate 88 bpm; respiratory rate 16 breaths/min; temperature 36.6 °C; BMI 33 kg/m².
- General: Overweight male, alert and oriented; appears fatigued.
- Eyes: Mild retinopathy noted on fundoscopic exam microaneurysms and hard exudates. Visual acuity is decreased.
- Cardiovascular: Regular rate and rhythm; no murmurs; peripheral pulses palpable but decreased dorsalis pedis pulses.
- Respiratory: Clear lungs bilaterally.
- Abdomen: Soft, non‑tender; no hepatosplenomegaly.
- Extremities: Poor capillary refill; skin is dry; calluses present on soles; a 1‑cm ulcer on the right great toe with surrounding erythema. Sensation decreased in both feet; vibration sense absent.
- Neurological: Mild symmetrical distal sensory neuropathy; normal motor strength; absent ankle reflexes.
Laboratory and Diagnostic Tests
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