Persons with diabetes who take insulin must be careful about indulging in unplanned exercise. Strenuous physical activity can rapidly lower their blood sugar and precipitate a hypoglycemic reaction. For a person whose blood glucose level is over 250 mg/dl, the advice would be not to exercise at all. At this range, the levels of insulin are too low and the body would have difficulty transporting glucose into exercising muscles. The result of exercise would be a rise in blood glucose levels.
Most cases (95%) of type 1 diabetes mellitus are the result of environmental factors interacting with a genetically susceptible person. This interaction leads to the development of autoimmune disease directed at the insulin-producing cells of the pancreatic islets of Langerhans. These cells are progressively destroyed, with insulin deficiency usually developing after the destruction of 90% of islet cells.

People with Type 1 diabetes are usually totally dependent on insulin injections for survival. Such people require daily administration of insulin. The majority of people suffering from diabetes have the Type 2 form. Although they do not depend on insulin for survival, about one third of sufferers needs insulin for reducing their blood glucose levels.
Diabetes mellitus (DM) is best defined as a syndrome characterized by inappropriate fasting or postprandial hyperglycemia, caused by absolute or relative insulin deficiency and its metabolic consequences, which include disturbed metabolism of protein and fat. This syndrome results from a combination of deficiency of insulin secretion and its action. Diabetes mellitus occurs when the normal constant of the product of insulin secretion times insulin sensitivity, a parabolic function termed the “disposition index” (Figure 19-1), is inadequate to prevent hyperglycemia and its clinical consequences of polyuria, polydipsia, and weight loss. At high degrees of insulin sensitivity, small declines in the ability to secrete insulin cause only mild, clinically imperceptible defects in glucose metabolism. However, irrespective of insulin sensitivity, a minimum amount of insulin is necessary for normal metabolism. Thus, near absolute deficiency of insulin must result in severe metabolic disturbance as occurs in type 1 diabetes mellitus (T1DM). By contrast, with decreasing sensitivity to its action, higher amounts of insulin secretion are required for a normal disposition index. At a critical point in the disposition index curve (see Figure 19-1), a further small decrement in insulin sensitivity requires a large increase in insulin secretion; those who can mount these higher rates of insulin secretion retain normal glucose metabolism, whereas those who cannot increase their insulin secretion because of genetic or acquired defects now manifest clinical diabetes as occurs in type 2 diabetes (T2DM).
Blurred vision can result from elevated blood sugar. Similarly, fluid that is pulled from the cells into the bloodstream to dilute the sugar can also be pulled from the lenses of your eyes. When the lens of the eye becomes dry, the eye is unable to focus, resulting in blurry vision. It's important that all people diagnosed with type 2 diabetes have a dilated eye exam shortly after diagnosis. Damage to the eye can even occur before a diagnosis of diabetes exists.
There are some interesting developments in blood glucose monitoring including continuous glucose sensors. The new continuous glucose sensor systems involve an implantable cannula placed just under the skin in the abdomen or in the arm. This cannula allows for frequent sampling of blood glucose levels. Attached to this is a transmitter that sends the data to a pager-like device. This device has a visual screen that allows the wearer to see, not only the current glucose reading, but also the graphic trends. In some devices, the rate of change of blood sugar is also shown. There are alarms for low and high sugar levels. Certain models will alarm if the rate of change indicates the wearer is at risk for dropping or rising blood glucose too rapidly. One version is specifically designed to interface with their insulin pumps. In most cases the patient still must manually approve any insulin dose (the pump cannot blindly respond to the glucose information it receives, it can only give a calculated suggestion as to whether the wearer should give insulin, and if so, how much). However, in 2013 the US FDA approved the first artificial pancreas type device, meaning an implanted sensor and pump combination that stops insulin delivery when glucose levels reach a certain low point. All of these devices need to be correlated to fingersticks measurements for a few hours before they can function independently. The devices can then provide readings for 3 to 5 days.
The major eye complication of diabetes is called diabetic retinopathy. Diabetic retinopathy occurs in patients who have had diabetes for at least five years. Diseased small blood vessels in the back of the eye cause the leakage of protein and blood in the retina. Disease in these blood vessels also causes the formation of small aneurysms (microaneurysms), and new but brittle blood vessels (neovascularization). Spontaneous bleeding from the new and brittle blood vessels can lead to retinal scarring and retinal detachment, thus impairing vision.
 Type 1 diabetes mellitus is a chronic metabolic syndrome defined by an inability to produce insulin, a hormone which lowers blood sugar. This leads to inappropriate hyperglycaemia (increased blood sugar levels) and deranged metabolism of carbohydrates, fats and proteins. Insulin is normally produced in the pancreas, a glandular organ involved in the production of digestive enzymes and hormones such as insulin and glucagon. These functions are carried out in the exocrine and endocrine (Islets of Langerhans) pancreas respectively.
The genes identified so far in people with type 2 include many that affect the insulin-producing beta cells of the pancreas, says Craig Hanis, PhD, a professor at the Human Genetics Center at the University of Texas Health Science Center in Houston. And yet he emphasizes that why people get type 2 isn't at all clear yet: "What it tells us is that diabetes is a complicated disease."
In 2013, of the estimated 382 million people with diabetes globally, more than 80 per cent lived in LMIC. It was estimated that India had 65.1 million adults with diabetes in 2013, and had the 2nd position among the top 10 countries with the largest number of diabetes. This number is predicted to increase to 109 million by 2035 unless steps are taken to prevent new cases of diabetes1. Primary prevention of diabetes is feasible and strategies such as lifestyle modification are shown to be effective in populations of varied ethnicity2,3. However, for implementation of the strategies at the population level, national programmes which are culturally and socially acceptable and practical have to be formulated which are currently lacking in most of the developed and developing countries. Early diagnosis and institution of appropriate therapeutic measures yield the desired glycaemic outcomes and prevent the vascular complications4.
Type 1 and type 2 diabetes were identified as separate conditions for the first time by the Indian physicians Sushruta and Charaka in 400–500 AD with type 1 associated with youth and type 2 with being overweight.[110] The term "mellitus" or "from honey" was added by the Briton John Rolle in the late 1700s to separate the condition from diabetes insipidus which is also associated with frequent urination.[110] Effective treatment was not developed until the early part of the 20th century when the Canadians Frederick Banting and Charles Best discovered insulin in 1921 and 1922.[110] This was followed by the development of the long acting NPH insulin in the 1940s.[110]
Type 2 diabetes is typically a chronic disease associated with a ten-year-shorter life expectancy.[10] This is partly due to a number of complications with which it is associated, including: two to four times the risk of cardiovascular disease, including ischemic heart disease and stroke; a 20-fold increase in lower limb amputations, and increased rates of hospitalizations.[10] In the developed world, and increasingly elsewhere, type 2 diabetes is the largest cause of nontraumatic blindness and kidney failure.[24] It has also been associated with an increased risk of cognitive dysfunction and dementia through disease processes such as Alzheimer's disease and vascular dementia.[25] Other complications include acanthosis nigricans, sexual dysfunction, and frequent infections.[23]

Diabetes mellitus is a metabolic condition in which a person's blood sugar (glucose) levels are too high. Over 29.1 million children and adults in the US have diabetes. Of that, 8.1 million people have diabetes and don't even know it. Type 1 diabetes (insulin-dependent, juvenile) is caused by a problem with insulin production by the pancreas. Type 2 diabetes (non-insulin dependent) is caused by:
Different environmental effects on type 1 diabetes mellitus development complicate the influence of race, but racial differences are evident. Whites have the highest reported incidence, whereas Chinese individuals have the lowest. Type 1 diabetes mellitus is 1.5 times more likely to develop in American whites than in American blacks or Hispanics. Current evidence suggests that when immigrants from an area with low incidence move to an area with higher incidence, their rates of type 1 diabetes mellitus tend to increase toward the higher level.
Diabetes mellitus (DM) comprises a group of disorders characterized by hyperglycemia. It is the sixth leading cause of death in the United States and results in $132 billion in total direct and indirect costs. Although the incidence of Type 1 diabetes has doubled over the past 30 years, the increase in Type 2 diabetes has been even more dramatic. An estimated 20–40% of cases in large pediatric diabetes centers are now Type 2, and the rates are expected to rise along with the epidemic of childhood and adolescent obesity (Chapter 11).

Autonomic changes involving cardiovascular control (eg, heart rate, postural responses) have been described in as many as 40% of children with diabetes. Cardiovascular control changes become more likely with increasing duration and worsening control. [18] In a study by 253 patients with type 1 diabetes (mean age at baseline 14.4 y), Cho et al reported that the prevalence of cardiac autonomic dysfunction increases in association with higher body mass index and central adiposity. [19]
Is it your fault for getting type 2 diabetes? No – type 2 diabetes is not a personal failing. It develops through a combination of factors that are still being uncovered and better understood. Lifestyle (food, exercise, stress, sleep) certainly plays a major role, but genetics play a significant role as well. Type 2 diabetes is often described in the media as a result of being overweight, but the relationship is not that simple. Many overweight individuals never get type 2, and some people with type 2 were never overweight, (although obesity is probably an underlying cause of insulin resistance). To make matters worse, when someone gains weight (for whatever reason), the body makes it extremely difficult to lose the new weight and keep it off. If it were just a matter of choice or a bit of willpower, we would probably all be skinny. At its core, type 2 involves two physiological issues: resistance to the insulin made by the person’s beta cells and too little insulin production relative to the amount one needs.
The body will attempt to dilute the high level of glucose in the blood, a condition called hyperglycemia, by drawing water out of the cells and into the bloodstream in an effort to dilute the sugar and excrete it in the urine. It is not unusual for people with undiagnosed diabetes to be constantly thirsty, drink large quantities of water, and urinate frequently as their bodies try to get rid of the extra glucose. This creates high levels of glucose in the urine.
Talking to a counselor or therapist may help you cope with the lifestyle changes that come with a type 2 diabetes diagnosis. You may find encouragement and understanding in a type 2 diabetes support group. Although support groups aren't for everyone, they can be good sources of information. Group members often know about the latest treatments and tend to share their own experiences or helpful information, such as where to find carbohydrate counts for your favorite takeout restaurant. If you're interested, your doctor may be able to recommend a group in your area.
Many people, especially those with type 2 diabetes, are overweight or obese. Some people with type 2 diabetes may be able to avoid or delay the need to take drugs by achieving and maintaining a healthy weight. Weight loss is also important in these people because excess weight contributes to complications of diabetes. When people with diabetes have trouble losing weight with diet and exercise alone, doctors may give weight-loss drugs or recommend bariatric surgery (surgery to cause weight loss).
Exercise is very important if you have this health condition. Exercise makes cells more insulin sensitive, pulling glucose out of the blood. This brings down blood sugar, and more importantly, gives you better energy because the glucose is being transferred to the cells. Any type of exercise will do this, but extra benefit is gained when the activity helps build muscle, such as weight training or using resistance bands. The benefits of exercise on blood sugar last about 48-72 hours, so it is important for you to be physically active almost every day.
Oral medications are available to lower blood glucose in Type II diabetics. In 1990, 23.4 outpatient prescriptions for oral antidiabetic agents were dispensed. By 2001, the number had increased to 91.8 million prescriptions. Oral antidiabetic agents accounted for more than $5 billion dollars in worldwide retail sales per year in the early twenty-first century and were the fastest-growing segment of diabetes drugs. The drugs first prescribed for Type II diabetes are in a class of compounds called sulfonylureas and include tolbutamide, tolazamide, acetohexamide, and chlorpropamide. Newer drugs in the same class are now available and include glyburide, glimeperide, and glipizide. How these drugs work is not well understood, however, they seem to stimulate cells of the pancreas to produce more insulin. New medications that are available to treat diabetes include metformin, acarbose, and troglitizone. The choice of medication depends in part on the individual patient profile. All drugs have side effects that may make them inappropriate for particular patients. Some for example, may stimulate weight gain or cause stomach irritation, so they may not be the best treatment for someone who is already overweight or who has stomach ulcers. Others, like metformin, have been shown to have positive effects such as reduced cardiovascular mortality, but but increased risk in other situations. While these medications are an important aspect of treatment for Type II diabetes, they are not a substitute for a well planned diet and moderate exercise. Oral medications have not been shown effective for Type I diabetes, in which the patient produces little or no insulin.
Diabetes is a serious and costly disease which is becoming increasingly common, especially in developing countries and disadvantaged minorities. However, there are ways of preventing it and/or controlling its progress. Public and professional awareness of the risk factors for, and symptoms of diabetes are an important step towards its prevention and control.
Type 2 diabetes: Type 2 diabetes affects the way the body uses insulin. While the body still makes insulin, unlike in type I, the cells in the body do not respond to it as effectively as they once did. This is the most common type of diabetes, according to the National Institute of Diabetes and Digestive and Kidney Diseases, and it has strong links with obesity.
No single environmental trigger has been identified as causing diabetes mellitus, however both infectious agents and dietary factors are thought to be important. Various viruses have been implicated in the development of type I DM. They may act by initiating or modifying the autoimmune process. In particular, the rubella virus and coxsackie viruses have been closely studied. In particular, congenital rubella infection has shown direct relationships with the development of type 1 diabetes mellitus. This is presumably due to the virus (or antibodies against it) damaging the beta cells of the pancreas. Some research has looked at dietary factors that may be associated with type 1 diabetes. In particular, cow’s milk proteins (such as bovine serum albumin) which may have some similarities to pancreatic islet cell markers may be able to trigger the autoimmune process. Other chemicals including nitrosamines have been identified as causes of diabetes mellitus in animal models, but not in humans.
Patients with type 2 diabetes can still make insulin, but not enough to control their glucose levels. Type 2 diabetes is therefore initially treated with a combination of lifestyle changes (diet and exercise) which reduce the need for insulin and therefore lower glucose levels. If this is insufficient to achieve good glucose control, a range of tablets are available. These include metformin and pioglitazone, which, like diet and exercise, reduce insulin requirements; sulphonylureas (e.g. gliclazide), which stimulate insulin secretion; DPP4 inhibitors (e.g sitagliptin) and GLP-1 agonists (e.g. liraglutide), which stimulate insulin production and reduce appetite; and SGLT2 inhibitors (e.g. dapagliflozin), which lower blood sugar levels by causing sugar to pass out of the body in the urine. In many patients, particularly after several years of treatment, insulin production is so low or so insufficient compared with the patient's needs that patients with type 2 diabetes have to be treated with insulin injections, either alone or in combination with tablets.

There is currently no cure for diabetes. The condition, however, can be managed so that patients can live a relatively normal life. Treatment of diabetes focuses on two goals: keeping blood glucose within normal range and preventing the development of long-term complications. Careful monitoring of diet, exercise, and blood glucose levels are as important as the use of insulin or oral medications in preventing complications of diabetes. In 2003, the American Diabetes Association updated its Standards of Care for the management of diabetes. These standards help manage health care providers in the most recent recommendations for diagnosis and treatment of the disease.


Most pediatric patients with diabetes have type 1 diabetes mellitus (T1DM) and a lifetime dependence on exogenous insulin. Diabetes mellitus (DM) is a chronic metabolic disorder caused by an absolute or relative deficiency of insulin, an anabolic hormone. Insulin is produced by the beta cells of the islets of Langerhans located in the pancreas, and the absence, destruction, or other loss of these cells results in type 1 diabetes (insulin-dependent diabetes mellitus [IDDM]). A possible mechanism for the development of type 1 diabetes is shown in the image below. (See Etiology.)

Although age of onset and length of the disease process are related to the frequency with which vascular, renal, and neurologic complications develop, there are some patients who remain relatively free of sequelae even into the later years of their lives. Because diabetes mellitus is not a single disease but rather a complex constellation of syndromes, each patient has a unique response to the disease process.
Say that two people have the same genetic mutation. One of them eats well, watches their cholesterol, and stays physically fit, and the other is overweight (BMI greater than 25) and inactive. The person who is overweight and inactive is much more likely to develop type 2 diabetes because certain lifestyle choices greatly influence how well your body uses insulin.
The causes of diabetes mellitus are unclear, however, there seem to be both hereditary (genetic factors passed on in families) and environmental factors involved. Research has shown that some people who develop diabetes have common genetic markers. In Type I diabetes, the immune system, the body's defense system against infection, is believed to be triggered by a virus or another microorganism that destroys cells in the pancreas that produce insulin. In Type II diabetes, age, obesity, and family history of diabetes play a role.
Research continues on diabetes prevention and improved detection of those at risk for developing diabetes. While the onset of Type I diabetes is unpredictable, the risk of developing Type II diabetes can be reduced by maintaining ideal weight and exercising regularly. The physical and emotional stress of surgery, illness, pregnancy, and alcoholism can increase the risks of diabetes, so maintaining a healthy lifestyle is critical to preventing the onset of Type II diabetes and preventing further complications of the disease.

"Secondary" diabetes refers to elevated blood sugar levels from another medical condition. Secondary diabetes may develop when the pancreatic tissue responsible for the production of insulin is destroyed by disease, such as chronic pancreatitis (inflammation of the pancreas by toxins like excessive alcohol), trauma, or surgical removal of the pancreas.
The treatment of low blood sugar consists of administering a quickly absorbed glucose source. These include glucose containing drinks, such as orange juice, soft drinks (not sugar-free), or glucose tablets in doses of 15-20 grams at a time (for example, the equivalent of half a glass of juice). Even cake frosting applied inside the cheeks can work in a pinch if patient cooperation is difficult. If the individual becomes unconscious, glucagon can be given by intramuscular injection.

Can type 2 diabetes be cured? In the early stages of type 2 diabetes, it is possible to manage the diabetes to a level where symptoms go away and A1c reaches a normal level – this effectively “reverses” the progression of type 2 diabetes. According to research from Newcastle University, major weight loss can return insulin secretion to normal in people who had type 2 diabetes for four years or less. Indeed, it is commonly believed that significant weight loss and building muscle mass is the best way to reverse type 2 diabetes progression. However, it is important to note that reversing diabetes progression is not the same as curing type 2 diabetes – people still need to monitor their weight, diet, and exercise to ensure that type 2 diabetes does not progress. For many people who have had type 2 diabetes for a longer time, the damage to the beta cells progresses to the point at which it will never again be possible to make enough insulin to correctly control blood glucose, even with dramatic weight loss. But even in these people, weight loss is likely the best way to reduce the threat of complications.


In people with type 1 diabetes, the symptoms often begin abruptly and dramatically. A serious condition called diabetic ketoacidosis, a complication in which the body produces excess acid, may quickly develop. In addition to the usual diabetes symptoms of excessive thirst and urination, the initial symptoms of diabetic ketoacidosis also include nausea, vomiting, fatigue, and—particularly in children—abdominal pain. Breathing tends to become deep and rapid as the body attempts to correct the blood’s acidity (see Acidosis), and the breath smells fruity and like nail polish remover. Without treatment, diabetic ketoacidosis can progress to coma and death, sometimes very quickly.
According to the Mayo Clinic, doctors may use other tests to diagnose diabetes. For example, they may conduct a fasting blood glucose test, which is a blood glucose test done after a night of fasting. While a fasting blood sugar level of less than 100 milligrams per deciliter (mg/dL) is normal, one that is between 100 to 125 mg/dL signals prediabetes, and a reading that reaches 126 mg/dL on two separate occasions means you have diabetes.
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