Diabetes Mellitus: A Review and Update
Authors:   North Manchester General Hospital Department of Urology, Delaunays Road, Manchester, United Kingdom, Grey Venyo Anthony Kodzo 
Published: October 2023

Diabetes mellitus is a group of metabolic diseases which are typified by the development of hyperglycaemia which do emanate from defects in insulin secretion, insulin action, or both. The chronic hyperglycaemia of diabetes is associated with long-term damage, dysfunction, and failure of various organs, especially the eyes, kidneys, nerves, heart, and blood vessels. Various types of diabetes mellitus exist which have been discussed in the main part of this article. Many pathogenic processes are involved in the development of diabetes mellitus. These pathogenic processes range from autoimmune destruction of the beta-cells of the pancreas with consequent insulin deficiency to abnormalities which result in resistance to insulin action. The basis of the abnormalities in carbohydrate, fat, and protein metabolism in diabetes is deficient action of insulin on target tissues. Deficient insulin action ensues inadequate insulin secretion and / or diminished tissue responses to insulin at one or more points within the complex pathways of hormone action. Impairment of insulin secretion and defects in insulin action frequently coexist in the same patient, and it is often unclear which abnormality, if either alone, is the primary cause of the hyperglycaemia. The manifestations of marked hyperglycaemia do include: polyuria, polydipsia, weight loss, sometimes with polyphagia, and blurred vision. Impairment of growth and susceptibility to certain infections may also ensue chronic hyperglycaemia. Acute, life-threatening consequences of diabetes mellitus include: hyperglycaemia with ketoacidosis or the nonketotic hyperosmolar syndrome. Long-term complications of diabetes mellitus do include: diabetic retinopathy with potential loss of vision; diabetic nephropathy which leads to kidney (renal) failure; peripheral neuropathy with risk of foot ulcers, amputation, and Charcot joints; as well as autonomic neuropathy which cause gastrointestinal, genitourinary, as well as cardiovascular symptoms and sexual dysfunction. Glycation of tissue proteins and other macromolecules and excess production of polyol compounds from glucose are among the mechanisms that had been postulated to produce tissue damage from chronic hyperglycaemia. Patients who have diabetes mellitus do have an increased incidence of atherosclerotic cardiovascular, peripheral vascular, and cerebrovascular disease. Hypertension, abnormalities of lipoprotein metabolism, and periodontal disease are often found in people who have diabetes mellitus. The emotional and social impact of diabetes mellitus as well as the demands of treatment of diabetes and its complications could cause significant psychosocial dysfunction in patients who have diabetes mellitus as well as their families. Even though there are many types of diabetes mellitus, the vast majority of cases of diabetes mellitus do fall into two broad etiopathogenetic categories which have been extensively discussed in the ensuing article below that has been divided into (a) Overview and (b) miscellaneous narrations. In one category of diabetes mellitus type 1 diabetes mellitus, the cause is an absolute deficiency of insulin secretion. Individuals at increased risk of developing this type of diabetes could often be identified by serological evidence of an autoimmune pathological process that occur within the pancreatic islets and by genetic markers. In the other type of diabetes mellitus, which is the much more prevalent category that is referred to as type 2 diabetes mellitus, the cause of the disease is a combination of resistance to insulin action and an inadequate compensatory insulin secretory response. In the latter category, a degree of hyperglycaemia sufficient to cause pathological and functional changes in various target tissues, but without clinical symptoms, could be present for a long period of time before diabetes mellitus is diagnosed. During this asymptomatic period, it is possible to demonstrate an abnormality in carbohydrate metabolism by measurement of plasma glucose in the fasting state or after a challenge with an oral glucose load. Considering that diabetes mellitus is common as well as the symptoms of diabetes mellitus are non-specific symptoms that may simulate diabetes mellitus, a number of individuals who are afflicted by diabetes mellitus do not know they have diabetes mellitus, there is need for a global educational program on the manifestations and approach that is needed for early diagnosis of the disease so that all clinicians and the entire global population would have a high index of suspicion of the disease. There also a global life style education including regular exercise that would delay onset of or reduce the severity of type 2 diabetes and to improve the quality of life of patients who have diabetes mellitus. It is important to dedicate time to read the article carefully which contains documentations related to the World Health Organization’s global effort to reduce the incidence and severity of diabetes mellitus and all individuals globally should follow carefully recommendations of the World Health organization as well as recommendations of other organizations in the world that have devoted their time to health education on diabetes mellitus. and a number of people