Diabetes Mellitus

 

Introduction

Diabetes Mellitus is a syndrome that occurs as a result of inappropriate hyperglycemia which occurs when the human body experiences a deficiency in insulin secretion or insulin resistance or as a result of the occurrence of both.^1,2 Diabetes is a disease that is responsible for causing major complications in the body, these complications have led to multiple pre-mature deaths. This syndrome falls under the classification of a heterogeneous group of disorders. According to the World Health Organization, there are two major types of diabetes mellitus Type 1 diabetes mellitus and Type 2 diabetes mellitus. This type of diabetes is also a result of increased plasma glucose concentration and the disturbance of glucose metabolism in the body.² The pathophysiology of these two types of diabetes mellitus are very different and are connected to insulin secretion, however, this paper discusses into details the epidemiology, etiology, types normal physiology and homeostasis, pathophysiology and molecular basis of the disease, signs, laboratory features, differential diagnosis complications and prognosis of both.

Epidemiology

According to the latest reports the rate of development of diabetes mellitus is approaching epidemic proportions and has increased in the last two decades.² On a general scale, diabetes is a major cause of death world-wide.  The prevalence of diabetes in the United States is increasing with age and the rate of increase is slightly higher in people that are 65 years ².  These age-related rates are slightly high among African Americans and other minority groups to include Hispanics when compared to their white counterparts. In the United States, it has been estimated that about three million individuals are living with diabetes.  

By the year 2002, the World Health Organization identified diabetes as the sixth leading cause of death. According to statistics presented by the International Diabetes Federation, there is an estimate of over 300 million individuals who are currently experiencing high glucose blood levels which puts them at a high risk of developing diabetes.³ By the year 2017, the IDF had also established that there were over 400 million people between the age of 20 to 80 who were suffering from diabetes mellitus, the IDF went gone further to predict that the number is expected to rise to over 600 million people by the year 2045.³ It has also been established that the proportion of undiagnosed cases of diabetes mellitus are slightly high.

Etiology

Diabetes mellitus prevents the body from fully and properly utilizing the energy obtained from glucose in the body, therefore, diabetes mellitus is a diabetic disorder that is caused by abnormal carbohydrate metabolism that results in hyperglycemia.² Insulins circulate sugar from the blood to the cells to be stored for energy, however, with any form of diabetes the human body is not able to make enough insulins and when it does is not capable to effectively use it. ²

Types/ Classification

There are two major classifications of this diabetes, Type 1 diabetes mellitus that is as a result of autoimmune beta-cell destruction in the pancreases, this type of diabetes mellitus results in the complete impairment of insulin production.⁴  Type 2 diabetes mellitus develops when the human body experiences abnormally increased resistance to insulin and the lack of the ability to produce enough insulin to overcome this resistance at the same time.⁴ Previously Type 1 diabetes mellitus was referred to as insulin-dependent diabetes or juvenile-onset diabetes and Type 2 diabetes mellitus was commonly referred to as non- insulin-dependent diabetes mellitus^.1  There are other minor subgroups of diabetes mellitus, these include infection-induced diabetes mellitus, drug and chemical-induced diabetes mellitus.⁵ The types of diabetes mellitus are more heterogenous that the two major types.

Normal Physiology and Homeostasis

Diabetes is related to the level of insulin in the body and the capacity of the body to utilize this insulin.  Normally the beta cells in the pancreas are responsible for releasing insulin when there is normal increased blood glucose concentration. ^1-6 Glucose is responsible for providing over 60% of the energy needed by the human body, glucose absorbed from the intestine metabolizes by being stored as glycogen, being converted to amino acids and proteins and lastly through energy conversion that is conducted by the carbon dioxide and water circulating in the body. Homeostasis imbalance occurs when positive and negative feedback loops are altered.  Diabetes disorder is a result of metabolism that is caused by high glucose levels.⁶ Diabetes mellitus is a result of failed homeostasis; the human body depends on tight control glucose levels. To ensure that the blood glucose levels are under control body parts to include the brain, pancreas, liver, and intestine play a major role. These organs form a network and the pancreas plays a vital role in this network, it is responsible for secreting blood sugar lowering, hormone insulin, and glucagon. If a disturbance occurs and disrupts the normal functions of this network a metabolic disorder, type 2 diabetes mellitus occurs.⁶

Pathophysiology and Molecular Basis of the Disease

Type 1 diabetes develops when the immune system initiates proinflammatory responses. Antigen-presenting cells are responsible for presenting beta-cell antigens to the immune system, subsequently, chronic immunological responses occur as a result of lack of regulation of immunological reactions, thus causing the destruction of beta-cells.⁵  The depletion of beta cells via physiological mechanism induces the release of antigens and subsequently, immune responses are initiated against the remaining Beta-cells.  The pathophysiology of type 2 diabetes mellitus revolves around the body’s incapability of secreting insulin.⁵  

Signs/ Symptom

Signs and symptoms of diabetes mellitus include unexplained weight loss, polydipsia, frequently feeling fatigued, polyphagia, reoccurring infections, especially in areas including the genital areas, urinary track and slow wound healing, Polyuria.⁷ Erectile dysfunction, impotence reactive hypoglycemia and loss of vision are also signs that accompany this type of diabetes. Lastly, irritability that is accompanied by dark patches on the neck and other areas, these dark patches are indicators of insulin resistance. ⁷

Laboratory Features

The main goal of laboratory testing diabetes mellitus is to check for high blood glucose levels as well as diagnose the type of diabetes mellitus. The laboratory techniques used to screen and diagnose diabetes mellitus included fasting plasma glucose test (FPG), an oral glucose tolerance test (OGTT) and a hemoglobin A1c test (A1c).⁸ The most important test is the A1c test, this test measures the average amount of glucose in the red blood cell hemoglobin.⁸  After being diagnosed with diabetes individuals are expected to attend regular laboratory tests with a focus on assisting in glycemic management and to ensure that diabetes-related complications are monitored to improve the overall health of the individual.  In the laboratory diabetes mellitus is confirmed using abnormal test results that indicate hyperglycemia.⁸ The various tests used may prove to be unreliable when used on different individuals, However, OGTT is a necessary lab test in the diagnosis of diabetes mellitus.⁸ This test takes approximately 2 hours and is used to assess the response of the human body to sugar, the test is conducted through a glucose load that contains an equivalent of 75g of anhydrous glucose when dissolved in water.⁸ In a laboratory setting when conducting secondary testing type 1 diabetes and type 2 diabetes mellitus are differentiated using patient factors to include age and weight. ⁸

Differential Diagnosis

            The first differential diagnosis of diabetes mellitus is made when the glycosylated hemoglobin is greater than 6.5% and when an individual shows signs of hyperglycemia.⁹ The second differential diagnosis of this diabetes is when the individual shows signs of metabolic syndrome which is diagnosed using conditions to include rising glucose value that is equivalent or slightly higher than 100mg/dL, high blood pressure and an elevated level of triglyceride as well as abdominal obesity.  The third differential diagnosis is made when an individual shows signs to include fatigue which is a result of indicative hyperthyroidism. ⁹

Complications and Prognosis

To treat the two major types of diabetes mellitus a treatment plan will need to be adjusted from time to time, as the human body continues to grow the more it continues to be resistant to insulins and as a result, there are higher chances that the pancreas may wear out as the beta cells continue to produce insulin to meet the body’s needs. The prognosis in individuals with type 2 diabetes mellitus varies from one individual to the other.  The prognosis varies depending on how the patient manages their risk complication.¹⁰ Complications of this disease include death from heart attacks, kidney-related diseases, and stroke.

Conclusion

Diabetes mellitus syndrome is as a result of inappropriate hyperglycemia that occurs when the human body lacks the ability to produce the insulin needed and when the body experiences a deficiency in insulin secretion. The prevalence of diabetes mellitus is extremely high in the world, this number is expected to rise as the years pass.   There are two major types of diabetes mellitus, type 1 diabetes mellitus and type 2 diabetes mellitus. The signs of this types of diabetes include erectile dysfunctions, fatigue and reactive hypoglycemia. There are similarities and differences surrounding the pathophysiology surrounding these two types of diabetes mellitus.

 

 

 

 

 

 

 

 

 

 

 

Reference

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²Zheng, Y., Ley, S. H., & Hu, F. B. Global aetiology and epidemiology of type 2 diabetes mellitus and its complications. Nature Reviews Endocrinology. 2018.  14(2), 88.

³Mekala, K. C., & Bertoni, A. G. Epidemiology of diabetes mellitus. In Transplantation, Bioengineering, and Regeneration of the Endocrine Pancreas. 2020. (pp. 49-58). Academic Press.

⁴ Das, H., Naik, B., & Behera, H. S. Classification of diabetes mellitus disease (DMD): a data mining (DM) approach. In Progress in computing, analytics and networking. 2018,  (pp. 539-549). Springer, Singapore.

⁵World Health Organization. Classification of diabetes mellitus. 2019

⁶Deem, J. D., Muta, K., Scarlett, J. M., Morton, G. J., & Schwartz, M. W. How should we think about the role of the brain in glucose homeostasis and diabetes? Diabetes. 2017, 66(7), 1758-1765.

⁷ Bustan, R. S., Wasim, D., Yderstræde, K. B., & Bygum, A. Specific skin signs as a cutaneous marker of diabetes mellitus and the prediabetic state-a systematic review. Dan Med J, 2017.  64(1), A5316.

⁸Dilek, E., Bezen, D., Ozguc, C. F., Ozkaya, B., & Tutunculer, F. Clinical and Laboratory Features at the Onset of Childhood Type 1 Diabetes Mellitus in the Nortwest Region (Trakya) of Turkey. 2018. In 57th Annual ESPE (Vol. 89). European Society for Paediatric Endocrinology.

⁹Robertson, G. L. Diabetes insipidus: differential diagnosis and management. Best Practice & Research Clinical Endocrinology & Metabolism, 2010. 30(2), 205-218.

¹⁰ Gandhi, J., Dagur, G., Warren, K., Smith, N. L., & Khan, S. A.Genitourinary complications of diabetes mellitus: An overview of pathogenesis, evaluation, and management. Current diabetes reviews, 2017 13(5), 498-518.