A Concise Clinicopathological Handbook of Diabetes Mellitus

Diabetes Mellitus is a complex disorder. It affects various organ systems of the body. Insulin is the key regulator of glucose metabolism along with other hormones. This chapter will discuss the key concepts of the physiological aspects of pancreas as an endocrine organ and physiology of Insulin secretion and action in maintaining blood glucose levels. This chapter also will discuss the physiologic concepts of development of Diabetes along with the classification and diagnostic criteria of Diabetes Mellitus.

Diabetes refers to a group of conditions characterized by a high level of blood glucose. Too much sugar in the blood can cause serious, sometimes life threatening health problems. There are two types of chronic diabetic conditions: Type 1 and Type 2. In type 1 diabetes, the beta cells are destroyed by one’s own immune system leading to reduced insulin production and eventually hyperglycemia. Diabetic Ketoacidosis is an acute and potentially life-threatening complication of mainly type 1 diabetes, and is caused by critically low insulin levels, more often caused when further stress triggers the diabetic individuals like infections, cardiovascular events etc.

Amongst the diabetes, Type 2 Diabetes Mellitus is the most common type and comprises of over 90% of the cases. It is characterized by 2 metabolic defects, viz, 1) Deranged insulin secretion and  2) Insulin resistance. The insulin resistance syndrome i.e Metabolic syndrome is characterized by 5 factors amongst which one is impaired glucose tolerance and impaired fasting glucose. Obesity, sedentary lifestyle, high caloric diet are the main culprits to increase the incidence and prevalence of diabetes.

The complications of diabetes mellitus includes microaangiopathy, macroangiopathy, retinopathy, nephropathy and neuropathy. Many studies have concluded that complications are nothing but the consequences of metabolic dysfunction. The late systematic complications of diabetes are the major causes for its morbidity and mortality. Diabetic patients have a two to four folds higher frequency of coronary artery diseases, and a four times greater threat of dying from cardiovascular complexities than non-diabetic patients. Also, Kidneys are prime targets of diabetes causing diabetes nephropathy. In long standing diabetes, it usually affects the peripheral nerves, brain and spinal cord.

Insulin plays a crucial role in the body's metabolic processes, especially glucose homeostasis. Hyperglycaemia can be caused by a relative or total absence of insulin, as observed in diabetes mellitus. Retinopathy, nephropathy, neuropathy, and cardiovascular problems may develop if not addressed. Control of blood sugar levels with insulin or glucose decreasing agents can delay or prevent progression to overt diabetes.

Diabetes Mellitus, an endocrine disorder caused by the destruction of beta cells of pancreas. Diabetes mellitus could be of type 1 or type 2 depending on its etiology. Prompt management of Diabetes enables to reduce the microvascular and macrovascular complications associated with diabetes mellitus. We will discuss the role of injection insulin and its various forms in the management of diabetes.

The main route of administration of injection insulin is usually subcutaneous and in special situations like DKA, Hyperosmolar non ketotic diabetic coma it is given intravenously. Apart from these routes other routes and various devices are discussed.

Diabetes mellitus is associated with grave immediate complication. These complications if not managed effectively and vigorously can result in increased mortality. Diabetic Ketoacidosis, Hyperosmolar hyperglycemic state and hypoglycaemia are few such complication. Paramount attention is mandatory for life saving management of these complications.

Diabetic foot is considered as most avoidable complication amongst all diabetic complications which can be in form of blisters/ ulcers/ wound infections/ gangrene. It can be prevented by proper preventive medicine. Surgical treatment involve wound offloading, wound debridement, reconstructive surgery.

Pregnancy is a diabetogenic condition physioloigicaly.Incidence of diabetes in pregnancy is increasing globally. This chapters covers the effects of diabetes on pregnancy and effect of pregnancy on pre-existing diabetes. The disease has adverse fetomaternal outcomes. Early detection and good glycemic control achieves good outcomes. Multidisciplinary approach should be followed in management of this medical disorder in pregnancy.