Type 2 Diabetes Mellitus: Pathophysiology and Case Analysis

Introduction to Type 2 Diabetes Mellitus

Diabetes is described as a condition that results from a chronic problem of hyperglycemia brought about by insulin inaction in the body. Type 2 diabetes is a condition characterized by a range of pathophysiological symptoms, including increased insulin resistance and impaired insulin secretion. The problems observed in cell function and the deteriorating pancreatic condition develop over time. The root and development of Type 2 diabetes is linked to the abnormal secretion of insulin, its action, and the endogenous output of glucose (EGO).

Type 2 diabetes affects over 6.4% of the world's population, representing more than 285 million people worldwide. It is expected that this number will increase to 7.7% — approximately 439 million people — by the year 2030. The epidemic of diabetes mellitus type II (T2DM), as perceived by medical experts, is closely linked to obesity. It has been established that over 85% of patients with diabetes are obese or overweight. Furthermore, many of the treatments used for lowering glucose cause weight management complications, leading to even more weight gain. The rise in the prevalence of diabetes and its accompanying comorbidities and complications exerts a significant burden on society and available primary care facilities.

Diabetes mellitus calls for controlling one's diet and restricting caloric intake. Patients are advised to reduce their consumption of fat and simple carbohydrates while increasing their intake of fiber and complex carbohydrates. Regular aerobic exercise is also recommended, as it is an effective way of treating T2DM by reducing insulin resistance and burning excess glucose. Regular exercise may also lower blood lipids and help manage the effects of stress. These two elements are important in forestalling complications and treating diabetes (Quillen & Kuritzky, 2015).

Studies show that Type 2 diabetes has a genetic link related to problems with insulin secretion and resistance. Some contributing factors are environmental, including obesity, lack of exercise, overeating, stress, and aging. It is a condition brought about by a combination of genetic and environmental factors to varying degrees. Insulin resistance and impaired secretion contribute equally to the development of physiological complications. Impaired insulin secretion is manifested in decreased glucose responsiveness and is observed just before the onset of diabetes proper.

The occurrence of impaired glucose tolerance (IGT) is triggered by reduced glucose responsiveness in insulin secretion during the early stages, accompanied by a decrease in insulin secretion after eating. A decrease in postprandial insulin secretion leads to postprandial hyperglycemia. Patients showing reduced insulin secretion in the early phase exhibit an excessive response. This phenomenon is an important feature in the development of diabetes and is an essential element in the pathophysiological changes that diabetes patients experience. The impaired insulin secretion problem is noted as a progressive response, characterized by glucose toxicity and lipotoxicity. If left untreated, these conditions are known to cause a reduction in pancreatic secretion (Kohei, 2010).

Type 2 diabetes manifests four main metabolic anomalies: insulin secretory dysfunction, impaired insulin action, obesity, and a high rate of endogenous glucose output (Weyer, Bogardus, Mott & Pratley, 1999).

Case Study Symptoms

The patient manifests increased dyspnea on minimal exertion — a condition described as abnormal breathlessness elicited in a person relative to their fitness status. It is caused by a wide range of factors and has multiple etiologies. Pulmonary and cardiac organ systems are the most common causes of dyspnea etiology.

Dyspnea can be managed by the family physician. The diagnosis constitutes four basic categories: pulmonary, cardiac, mixed cardiac and pulmonary, and non-pulmonary or non-cardiac. Dyspnea cases caused by pulmonary or cardiac diseases can usually be identified through a careful examination of the patient's history and a physical exam. A screening spirometry and electrocardiograph should be conducted to further evaluate the patient's condition, given his family history of diabetes.

The cardiac causes of dyspnea include left, right, or congestive heart failure from both ventricles, resulting in systolic dysfunction; coronary artery disease; myocardial infarction (recent or remote); valvular dysfunction; cardiomyopathy; diastolic dysfunction; asymmetric septal hypertrophy; ventricular hypertrophy causing diastolic dysfunction; arrhythmias; and pericarditis. Pulmonary triggers include restrictive and obstructive processes. Asthma and chronic obstructive pulmonary disease (COPD) are the most common obstructive triggers. Obesity, chest wall or spine deformities, interstitial fibrosis, pneumoconiosis, collagen and vascular disease, and granulomatous disease constitute common restrictive causes. Mixed pulmonary and cardiac disorders — including pulmonary emboli and trauma, cor pulmonale, pulmonary hypertension, and deconditioning — are also common triggers of dyspnea.

Dyspnea may also manifest as a somatic signal of psychiatric problems, including anxiety disorder and consequent hyperventilation. Reviewing the patient's history is a key way to identify important clinical clues. The differential diagnosis can be narrowed by factors such as the number of pillows a patient uses during sleep, complaints of chest pain, quality of sleep, daytime and nighttime exertion, exercise tolerance, history of tobacco use, environmental allergies, occupational lifestyle, and the presence of congestive heart failure, coronary artery disease, valvular complications, or asthma (Morgan & Hodge, 1998).

The patient's family shows a history of diabetes, including a death attributable to Type 2 diabetes. A comprehensive family history — checking for lung problems, pulmonary infections, diabetes, and bronchitis, among other conditions — should be obtained. Dyspnea can usually be diagnosed if a careful study of the patient's history and physical examination points to common pulmonary or cardiac etiologies. Specific diagnostic tests may be needed to confirm the condition or assist in therapeutic management.

Peripheral edema is a common cause of confusion for clinicians and is a common finding in the investigation of many diseases. A systematic and rational evaluation of the patient presenting with edema is necessary to ensure a cost-effective diagnosis and appropriate treatment. This section reviews the pathophysiological causes of edema formation as a basis for understanding its complexities in specific disease conditions, including the implications for treatment (Morgan & Hodge, 1998).

The patient's legs and feet are swollen — typical signs of peripheral edema, resulting from the accumulation of fluids in the tissues. Although peripheral edema is not ordinarily painful, swelling is clearly visible in the lower parts of the body owing to gravity. While swelling is a common occurrence among older individuals and may not necessarily signal a serious problem, a medical evaluation is always advisable to establish the underlying cause. In this patient's case, being overweight and using certain blood pressure medications are likely contributing factors. Leg tissue inflammation — which may result from injury, rheumatoid arthritis, or another inflammatory disorder — may also be a cause. The lower parts of the patient's legs are warm to the touch and mildly painful (Mandal, 2016).

Blood sugar tests show that the patient's blood sugar is abnormally high — 190 mg/dL in the morning and 290 mg/dL before dinner. The blood sugar test is a straightforward examination using blood samples obtained from a vein puncture or a finger stick. Diabetes results from excessive blood sugar and can lead to serious complications including blindness (retinopathy), kidney failure requiring dialysis (nephropathy), and the need for limb amputation.

Regular exercise and a healthy diet can help maintain lower blood sugar levels. Studies have shown that patients at risk of developing diabetes who walked for approximately 20 minutes four to five times per week experienced significant reductions in blood sugar levels. Some glucose tests require preparation — fasting tests, for instance, require the patient to abstain from food for 8 to 12 hours beforehand.

In a group of 66 patients with varying fasting glucose levels, acute insulin response was evident in those with fasting glucose levels below 115 mg/dL but was notably absent in those recording higher values. A glucose disappearance rate of over 1.06% per minute was observed when the acute insulin response was zero. All patients with fasting glucose levels above 115 mg/dL had disappearance rates exceeding 1.06% per minute. These findings suggest: (1) epidemiological data supports 115 mg/dL as the upper limit of normal fasting glucose and 1.0% per minute as the lower limit for normal glucose disappearance; and (2) acute insulin response plays an important role in determining the rate of glucose disappearance. Fasting plasma glucose (FPG) is easier to obtain in routine health checkups (Mandal, 2016).

The patient has gained 10 pounds since his last visit one month ago. Checking hormone levels, vitamin deficiencies, and current prescription medications can help identify the cause of weight gain. Contributing factors include:

Dietary choices: The quality and quantity of food consumed plays a central role in weight management.

Genetic predisposition: Some individuals are genetically predisposed to weight gain. However, regular exercise and a proper diet can still help maintain healthy weight levels.

Physical inactivity: Regular exercise has a significant impact on weight control and general health. Weight gain is associated with numerous other health complications.

Insufficient sleep: There is a well-documented relationship between sleep duration and weight. A general trend shows that the fewer hours of sleep a person gets, the more likely they are to gain weight (Mandal, 2016).

Conclusion

This case focuses on a patient exhibiting a significant rise in dyspnea on exertion, swollen legs, reddening of the lower legs, mild pain approximately 4 out of 10 on a pain scale, and warm skin to the touch. The patient's blood sugar levels on finger sticks have been high — 190 mg/dL fasting in the morning and 290 mg/dL before evening meals. The patient has gained 10 pounds since his last visit one month ago.

There is insufficient glycemic control in this patient, suggesting a need for more intensive treatment. If triple therapy is to be applied, complementary mechanisms of action should be considered. Oral agents generally lower blood sugar by approximately 1.0%, meaning that achieving a target of 7% may be difficult without significant lifestyle change. There is also an increased risk of drug interactions and adverse effects, and patient reluctance to adhere to therapy is commonly associated with multidrug regimens. For these reasons, close monitoring of this patient is essential (Quillen & Kuritzky, 2015).

Imran, M., Ardasenov, Z., Brown, K., Maz, M., & Magadan, J. (2015). Diabetic myonecrosis of bilateral thighs in newly diagnosed Type 2 diabetes mellitus.

Kohei, K. A. K. U. (2010). Pathophysiology of type 2 diabetes and its treatment policy. JMAJ, 53(1), 41–46.

Leontis, L., & Hess, A. (n.d.). Type 2 diabetes risk factors. Retrieved February 24, 2016, from http://www.endocrineweb.com/conditions/type-2-diabetes/type-2-diabetes-risk-factors

Mandal, A. (2016). Diabetes mellitus type 2 pathophysiology. Retrieved February 21, 2016, from http://www.news-medical.net/health/Diabetes-Mellitus-Type-2-Pathophysiology.aspx

Mayo. (2016). Type 2 diabetes. Retrieved February 20, 2016, from http://www.mayoclinic.org/diseases-conditions/type-2-diabetes/symptoms-causes/dxc-20169861

Morgan, W. C., & Hodge, H. L. (1998). Diagnostic evaluation of dyspnea. American Family Physician, 57, 711–718.

Quillen, D., & Kuritzky, L. (2015). Case studies of patients with Type 2 diabetes mellitus: Exercises in problem solving. Retrieved February 24, 2016, from http://www.consultant360.com/articles/case-studies-patients-type-2-diabetes-mellitus-exercises-problem-solving

Weyer, C., Bogardus, C., Mott, D. M., & Pratley, R. E. (1999). The natural history of insulin secretory dysfunction and insulin resistance in the pathogenesis of type 2 diabetes mellitus. The Journal of Clinical Investigation, 104(6), 787–794.