Diabetes

There are many valuable resources for diabetes, but also some gaps. Please let us know if you would like to recommend something.

Overview

In Diabetes Mellitus blood glucose is high because the glucose-lowering hormone Insulin is either under-produced, or its effect is blunted by insulin resistance. Under-production is the main problem in Type 1 diabetes, and insulin resistance is a major problem in type 2 diabetes, but this can be an oversimplification, and some patients have combined or different problems.

Pathophysiology

Diabetes mellitus is the generic term for a group of disorders, all of which share the common feature of an uncontrolled elevation of blood glucose (hyperglycaemia).  Hyperglycaemia may result from a lack of the anabolic hormone, insulin, (as in Type 1 Diabetes) or a reduction of its action (as in Type 2 Diabetes) and may be associated with other disorders such as pancreatic or liver disease.

Hyperglycaemia is only one manifestation of the abnormal metabolism inherent in diabetes.   In humans, insulin plays a central role in cell metabolism and modulates carbohydrate, fat and protein metabolism, so its absence or dysfunction has a profound effect on most tissues and organs. Immunological concepts of autoimmune disease are considered in the pathogenesis of type 1 (insulin dependent) diabetes. The more chronic pathological changes of tissue glycation leading to vascular complications is cover in part here, but mainly in later sections.

Classification of Diabetes

Diabetes is crudely divided into type 1 diabetes (an autoimmune disease predominantly affecting young people), and type 2 diabetes, which is often associated with insulin resistance and obesity. Emerging monogenic forms of diabetes, and latent onset autoimmune disease however challenge these traditional categorizations. The WHO documentation (below) tackles the issues of diabetes diagnosis and classification in the modern era.

Diagnosis of diabetes and laboratory tests

Diabetes diagnosis currently rests on testing for raised fasting plasma glucose or raised plasma glucose following oral glucose tolerance testing, although there may be a move towards using HbA1C for diagnosis. The WHO publication (below) discusses the current methods for diagnosing diabetes. Making the individual diagnosis and initiating treatment in the clinic is covered in the case scenarios.

Patient Self Management and Lifestyle

Patient education is crucial to tackle lifestyle factors and allow patients to manage their diabetes effectively, and understand the impact of diet, alcohol and exercise. These resources demonstrate the impact of lifestyle through clinical scenarios/ interactive modules and point to resources to help with patient education.

Obesity and the Metabolic Syndrome

Obesity is associated with many metabolic consequences, including hypertension, dyslipidaemia, insulin resistance or frank diabetes. Lifestyle modification is key to the management of type 2 diabetes. Clinicians need to understand the pathophysiology of obesity, and consider therapeutic measures to induce weight loss where appropriate.

Diabetes  Complications

Severe insulin deficiency may provoke an acute metabolic crisis, such as life-threatening ketoacidosis. Other acute complications of diabetes include severe hypoglycaemia, HONK and lactic acidosis.
The biggest long-term problem associated with diabetes is the greatly increased risk of developing vascular disease.   This affects both small blood vessels in the form of microvascular disease, which targets and damages organs such as the eyes, kidneys and peripheral nerves.  It also promotes the premature development of atherosclerosis, the common disease of large blood vessels, which results in heart attacks, strokes and ischaemia of the lower limbs (sometimes necessitating amputation).   Diabetes is therefore a systemic disease with complications affecting most systems of the body and having widespread manifestations leading to major morbidity and reduced life expectancy. There are lots of resources in this area.

Diabetes and Pregnancy

Traditionally, most women with diabetes who become pregnant had Type 1 diabetes (insulin-dependent diabetes), however increasing numbers of pregnant women with Type 2 diabetes (non-insulin dependent diabetes), and gestational diabetes are now being treated. Diabetes in pregnancy poses a number of risks to mother and baby: babies born to mothers with poor blood sugar control are more likely to have birth defects or be stillborn and babies born to mothers with diabetes weigh more than average, especially if glucose control has been poor.

For the mother, diabetes and pregnancy can be associated with extra risks. Retinopathy may increase in severity, and diabetic kidney disease increases the chance of developing high blood pressure and a more serious condition called pre-eclampsia that can affect mother and baby.
Good glucose control well before conceiving and throughout pregnancy reduces the chance of all these problems occurring. Insulin treatment was the mainstay of diabetes management in pregnancy although there is growing evidence that metformin may be safe during pregnancy and preferable as a first line agent in patients with type 2 diabetes.  More and better teaching resources are required in this specialist area.

Pharmacotherapies

There are many medications already available for the treatment of diabetes and a huge number of new drugs currently going through clinical trials.
Insulin remains the mainstay of treatment for type 1 diabetes, although new insulin preparations and pump administration are widening the therapeutic options.
In type 2 diabetes most current drugs work by either increasing insulin secretion by the pancreas, improving tissue sensitivity to circulating insulin or altering carbohydrate digestion and absorption in the gut.  Insulin therapy may ultimately be required for type 2 patients if pancreatic reserve fails.