Diabetes mellitus is a metabolic disease that results from the accumulation of glucose in the blood. Diabetes is not a single disease but rather a pathologic metabolic state that is influenced by insulin. Insulin is a hormone that is produced by the pancreas, and it is involved in the regulation of glucose by promoting its uptake into cells. The defect in the insulin effect leads to the development of diabetes mellitus. Two types of diabetes mellitus are studied, and these are insulin dependent diabetes mellitus, also called type 1 diabetes mellitus and insulin type 2 diabetes mellitus, also called non-insulin dependent diabetes mellitus. The pathophysiology of diabetes mellitus is based on the metabolic disturbance caused and the long term complications that arise from the disease. The clinical manifestations of diabetes are based on the several aspects of pathophysiology, and the treatment is mainly symptomatic and preventive of the complications.
Anatomical Consideration
Diabetes Mellitus (DM) is a disease that arises from a defect in the metabolism of glucose. In diabetes Mellitus, there is the presence of high levels of glucose in the blood, a state that is referred to as hyperglycemia. 1 Diabetes can occur as a primary disease, or it may arise as a secondary condition that develops as a result of another disease such as pancreatitis. Primary diabetes mellitus is the commonplace among the two broad types. Diabetes mellitus has two distinct classifications which are based on the development of the disease. These types are Type 1 Diabetes Mellitus and type two Diabetes Mellitus. 1 Type 1 DM develops when there is a destruction of the pancreatic cells and therefore leading in defunct insulin secretion. In Type 2 DM, there is resistance to the produced insulin, and the cells of the body do not react to the influence of diabetes. 3 It leads to a situation where glucose cannot be appropriately metabolized by the body cells.
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Insulin is a hormone produced by the beta cells of the Islets of Langerhans in the pancreas. The hormone is responsible for the breakdown of glucose in human cells with actions such as promoting glucose uptake in muscle and liver, generation of glycogen in the body and generation of lipids in adipose tissue. Type 1 DM occurs when there is an autoimmune reaction that leads to the destruction of the islets of Langerhans. Therefore, type 1 DM is an autoimmune disease. On top of that, it is much less familial, and therefore genetics play a lesser role in the development of the disease. In type 2 DM, there is a higher inheritance ratio, with people developing it if family members have it. The development of Type 2 DM is caused by intra-abdominal obesity that causes insulin resistance.
Pathophysiology
Diabetes is endocrinology that develops from the inability to maintain the correct levels of glucose in the blood due to low levels of insulin or insensitivity to the action of glucose. The hyperglycemia that is observed in the Diabetes Mellitus is primarily a result of an increase in the production of glucose in the liver and secondarily due to decreased removal of glucose from the blood. Therefore, there is a rise above the renal threshold of glucose which is 10mmol/L which results in the presence of glucose in the urine; a condition referred to as glycosuria. 1 In a healthy person, insulin enables the entry of glucose into cells for metabolism thereby resulting in the decrease of insulin levels in the blood. In a diabetic patient, there is excess glucose in the blood and therefore in urine. 2 Glycosuria causes osmotic diuresis, increasing water excretion and in turn raising the plasma osmolality. This state causes the diabetic person to have polydipsia and polyuria. In the long term, the continued poor glycemic control causes severe effects in the microvasculature in both type 1 and type 2 diabetes. Continued exposure to high glucose concentrations is resultant in the narrowing of the lumen of the small blood vessels. 7 The narrowing is related to the formation of sorbitol by the action of aldose reductase and the formation of glycated compounds that accumulate in the blood vessels. The result of these processes are the diseases that present in a patient with unmanaged diabetes mellitus, which include neuropathy and retinopathy.
Clinical Manifestation and Diagnoses
The classical presentation of DM is polyuria, polydipsia, and polyphagia. Polyuria is the excessive secretion of urine, and it is a direct result of osmotic diuresis. Essentially, there is increased water excretion due to the presence of glucose in urine. 3 On the other hand, there is polydipsia, which is the feeling of excessive thirst that results from increased plasma osmolality. It is also, in turn, contributed to by the increased water excretion that results in the stimulation of the thirst center. 1 Polyphagia, the excessive intake of food is contributed to by the consistent lack of glucose in cells. Other symptoms that develop due to diabetes mellitus include weight loss in type 1 DM, fatigue due to the lack of glucose in the cells, nocturnal enuresis in children and fruity breath in case the complication of ketosis occurs.
Diagnosis of diabetes mellitus is the illustration of the presence of hyperglycemia. The presence of the classical signs of polyuria, polyphagia, and polydipsia is complemented by the establishment of glycosuria to establish hyperglycemia. 6 The first test done for the diagnosis of DM is the random blood sugar test. A random blood sugar 11.0 mmol/L or more is diagnostic of diabetes mellitus. In the absence of the classic symptoms, this level of the random blood sugar must be obtained in more than one occasion. The other test done is the fasting blood sugar that is done after an individual has fasted overnight for more than 8 hrs. Fasting blood sugar levels in the diabetic range is over 7.0 mmol/L.
Another test done for diabetes is the oral glucose tolerance test, otherwise referred to as the OGTT test. This test is done after the testing of the FBS followed by testing of glucose levels for 2 hours after oral glucose of 75g is ingested. 5 The samples of blood and urine levels are taken in intervals of 30 minutes, and then a graph of the results is plotted with the renal threshold indicated. The normal ranges for the fasting blood sugar are 3.9 to 6.1 mmol/L, and levels above these indicate hyperglycemia. 1 The diagnosis of diabetes is made if the fasting blood sugar levels are above 7.0 mmol/L; glucose levels go above the renal threshold and the 2 hr. Post glucose levels are above 11.0 mmol/L. 2
Other tests that are of importance in diabetes mellitus are the intravenous glucose tolerance test which is rarely done, the glycated hemoglobin test with normal levels of 6.5% and the testing of Islets of Langerhans antibodies in case of type 1 DM. 8 In the diagnosis of DM, the establishment of the level of glucose in random blood sugar test is enough. 2 The presence of the three classic symptoms and the level of RBS being more than 10 mmol/L is diagnostic of the disease, and therefore the other tests such as OGTT don’t need to be done.
The problems with the tests are minor; for instance, the RBS may be high without the presence of the classic symptoms of the disease. Also, the OGTT may be impaired due to poor FBS levels or behavioral factors that may affect the correct levels. 4 These behavioral factors include smoking and eating outside the allocated time for fasting.
Medical Management
The management of DM depends on the complications that have arisen due to the disease. Glucose levels must be monitored at all times, and this is done through the use of random blood sugar and the levels of glycated hemoglobin. 5 The complications that may arise include acute diabetic ketoacidosis, hyperosmolar hyperglycemic state and other long term complications. 3 The goal of the treatment is to get rid of the symptoms and then ensure that there are no acute or long term complications. 1 This is done through the proper maintenance of blood glucose with the use of insulin shots in type 1 DM. The aggressive glycemic control, especially in type 1 DM, is essential in ensuring that the complications are dealt with, and therefore the patient needs to be educated on the management of glucose. 2 After that, the patients can partake in dietary control with substitution of complex carbohydrates; they may use oral hypoglycemic agents such as sulphonylureas and metformin, and the use of insulin shots.
In type 2 DM, the glycemic control is not as strict, and the insulin use may or may not be recommended. The use of physical exercises to curb obesity may be used in the management of the condition. Either way, the monitoring of treatment is essential with tests done to ensure that treatment is going according to plan. 2 The monitoring of treatment is also done to ensure that side effects such as hypoglycemia in insulin therapy are spotted. 5 The management of diabetes does not result in complete treatment, and it is necessary that the patient understands his or her role in the management of the disease in their lifetime.
Conclusion
Diabetes mellitus is a metabolic state that is characterized by high levels of glucose in the blood. This state is brought about by the effect of insulin, which is produced in the beta cells of the islets of Langerhans in the pancreases. Type 1 diabetes mellitus develops because of the lack of insulin and type 2 DM develops because of the insensitivity of boy cells to insulin. The pathophysiology of DM is because of the disturbances caused in metabolism, whereby DM causes the constriction of the microvasculature leading to various complications. The clinical presentation is chiefly polydipsia, polyuria, and polyphagia. The medical tests for the diagnosis include the random blood sugar, fasting blood sugar, and the OGTT. These tests are dependent on the identification of the clinical symptoms first. The management of DM is done by the control of diet, use of drugs such as metformin, insulin injection and the use of physical exercise. The patient needs to be educated well to understand the significance of the tests.
References
1. American Diabetes Association. Diagnosis and Classification of Diabetes Mellitus. Diabetes Care . 2010;34(Supplement_1):S62-S69.
2. Asmat U, Abad K, Ismail K. Diabetes mellitus and oxidative stress—A concise review. Saudi Pharmaceutical Journal . 2016;24(5):547-553. doi:10.1016/j.jsps.2015.03.013
3. Bailey C. Insulin resistance: Impact on therapeutic developments in diabetes. Diabetes and Vascular Disease Research . 2019;16(2):128-132. doi:10.1177/1479164119827570
4. DeFronzo R, Ferrannini E, Groop L et al. Type 2 diabetes mellitus. Nature Reviews Disease Primers . 2015:15019. doi:10.1038/nrdp.2015.19
5. Kharroubi A. Diabetes mellitus: The epidemic of the century. World J Diabetes . 2015;6(6):850. doi:10.4239/wjd.v6.i6.850
6. Napoli N, Chandran M, Pierroz D, Abrahamsen B, Schwartz A, Ferrari S. Mechanisms of diabetes mellitus-induced bone fragility. Nature Reviews Endocrinology . 2017;13(4):208-219. doi:10.1038/nrendo.2016.153
7. Raygor V, Abbasi F, Lazzeroni L et al. Impact of race/ethnicity on insulin resistance and hypertriglyceridaemia. Diabetes and Vascular Disease Research . 2019;16(2):153-159. doi:10.1177/1479164118813890
8. Ta S. Diagnosis and Classification of Diabetes Mellitus. Diabetes Care . 2014;37(Supplement_1):S81-S90. doi:10.2337/dc14-s081
