Written by epgonline.org - Last updated 29 May 2018
Diabetes mellitus is one of the oldest recognised diseases affecting humans; there is archaeological evidence to suggest that in 1500 BCE, diabetes was known in both ancient Egypt and in India, with descriptions of urine that attracted insects. In recent times the disease burden of diabetes has exploded, and can be closely linked to the rise in obesity. The global population living with diabetes was estimated at 108 million in 1980, while World Health Organisation figures for 2014 have shown that has nearly quadrupled to 422 million. Diabetes is divided into type 1, type 2 and gestational diabetes (discussed as a separate disease).
Type 1 diabetes is typically diagnosed earlier in life, and although the precise mechanism is unknown, the result is a lack of pancreatic production of insulin. Common symptoms include fatigue, weight loss, polydipsia and polyuria; although it may also present as a medical emergency with diabetic ketoacidosis. The cornerstone of treatment for type 1 diabetes is insulin therapy, and prior to the discovery and refinement of insulin in the 1920s, children born with this condition experienced vastly shortened lives.
Type 2 diabetes is largely a disease of later life, although it is increasingly being seen in children and adolescents due to rising obesity levels. It has a more indolent course, and may not be discovered until several years have passed. It shares the characteristic of hyperglycaemia, although the mechanism of disease is increased peripheral tolerance to insulin – rather than a lack of the hormone. Initial treatment pathways can focus on lifestyle interventions, before progressing to medication, and ultimately adding exogenous insulin.
The chronic hyperglycaemia that is a hallmark of both types of diabetes can lead to significant comorbidities; these can be divided into micro- and macrovascular complications. Microvascular complications occur in areas where the capillary networks are vulnerable, manifesting as retinopathy, nephropathy and peripheral neuropathy. The macrovascular complications are a result of atherosclerosis, thought to arise due to chronic arterial wall inflammation. Depending on the site of atherosclerosis, patients are more likely to suffer from coronary artery disease, carotid stenosis or stroke and peripheral arterial disease. Equally, hypoglycaemia is a potentially significant side-effect of treatment, particularly for those dependant on insulin – and can lead to loss of consciousness and occasionally death.
There is a large amount of innovation in the field of diabetes, from prevention and lifestyle programmes, to new drugs targeting novel therapeutic mechanisms, to an artificial pancreas in development. Luckily, there are many future treatment possibilities for an ever-expanding problem.