Diabetes mellitus results mainly from a deficiency or diminished effectiveness of insulin that is normally produced by the beta cells of the pancreas. It is characterised by high blood sugar, altered sugar and glucose metabolism and this affects blood vessels and causes several organ damage. Causes of diabetes can be classified according to the types of diabetes.
Type 1 diabetes is always treated with insulin, a life-saving treatment. Patients will need to take insulin several times a day for the rest of their lives. They will usually learn how to self-administer this. Insulin is usually given through injections under the skin, normally two to four times a day. An increasing number of patients with type 1 diabetes are being treated with ‘insulin pumps’, which provide a continuous supply of insulin. 
Assemble a Medical Team: Whether you've had diabetes for a long time or you've just been diagnosed, there are certain doctors that are important to see. It is extremely important to have a good primary care physician. This type of doctor will help coordinate appointments for other physicians if they think that you need it. Some primary physicians treat diabetes themselves, whereas others will recommend that you visit an endocrinologist for diabetes treatment. An endocrinologist is a person who specializes in diseases of the endocrine system, diabetes being one of them.
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).
Considering that being overweight is a risk factor for diabetes, it sounds counterintuitive that shedding pounds could be one of the silent symptoms of diabetes. “Weight loss comes from two things,” says Dr. Cypess. “One, from the water that you lose [from urinating]. Two, you lose some calories in the urine and you don’t absorb all the calories from the sugar in your blood.” Once people learn they have diabetes and start controlling their blood sugar, they may even experience some weight gain—but “that’s a good thing,” says Dr. Cypess, because it means your blood sugar levels are more balanced.
With type 1, a disease that often seems to strike suddenly and unexpectedly, the effects of environment and lifestyle are far less clear. But several theories attempt to explain why cases of type 1 have increased so dramatically in recent decades, by around 5 percent per year since 1980. The three main suspects now are too little sun, too good hygiene, and too much cow's milk.
It is recommended that all people with type 2 diabetes get regular eye examination.[13] There is weak evidence suggesting that treating gum disease by scaling and root planing may result in a small short-term improvement in blood sugar levels for people with diabetes.[79] There is no evidence to suggest that this improvement in blood sugar levels is maintained longer than 4 months.[79] There is also not enough evidence to determine if medications to treat gum disease are effective at lowering blood sugar levels.[79]

We give you special kudos for managing your condition, as it is not always easy. If you've had diabetes for a long time, it's normal to burn out sometimes. You may get tired of your day to day tasks, such as counting carbohydrates or measuring your blood sugar. Lean on a loved one or a friend for support, or consider talking to someone else who has diabetes who can provide, perhaps, an even more understanding ear or ideas that can help you.
John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.
Jump up ^ Sattar N, Preiss D, Murray HM, Welsh P, Buckley BM, de Craen AJ, Seshasai SR, McMurray JJ, Freeman DJ, Jukema JW, Macfarlane PW, Packard CJ, Stott DJ, Westendorp RG, Shepherd J, Davis BR, Pressel SL, Marchioli R, Marfisi RM, Maggioni AP, Tavazzi L, Tognoni G, Kjekshus J, Pedersen TR, Cook TJ, Gotto AM, Clearfield MB, Downs JR, Nakamura H, Ohashi Y, Mizuno K, Ray KK, Ford I (February 2010). "Statins and risk of incident diabetes: a collaborative meta-analysis of randomised statin trials". Lancet. 375 (9716): 735–42. doi:10.1016/S0140-6736(09)61965-6. PMID 20167359.
This is specific to type 2 diabetes. It occurs when insulin is produced normally in the pancreas, but the body is still unable move glucose into the cells for fuel. At first, the pancreas will create more insulin to overcome the body’s resistance. Eventually the cells “wear out.” At that point the body slows insulin production, leaving too much glucose in the blood. This is known as prediabetes. A person with prediabetes has a blood sugar level higher than normal but not high enough for a diagnosis of diabetes. Unless tested, the person may not be aware, as there are no clear symptoms. Type 2 diabetes occurs as insulin production continues to decrease and resistance increases.
Jump up ^ Feinman, RD; Pogozelski, WK; Astrup, A; Bernstein, RK; Fine, EJ; Westman, EC; Accurso, A; Frassetto, L; Gower, BA; McFarlane, SI; Nielsen, JV; Krarup, T; Saslow, L; Roth, KS; Vernon, MC; Volek, JS; Wilshire, GB; Dahlqvist, A; Sundberg, R; Childers, A; Morrison, K; Manninen, AH; Dashti, HM; Wood, RJ; Wortman, J; Worm, N (January 2015). "Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base". Nutrition. Burbank, Los Angeles County, Calif. 31 (1): 1–13. doi:10.1016/j.nut.2014.06.011. PMID 25287761.
Incidence and Prevalence. It has been estimated that slightly over 6 per cent of the population is affected by some form of diabetes, or 17 million people in the USA and 1.2 to 1.4 million in Canada; many of these individuals are not diagnosed. Diabetes is ranked third as a cause of death, although the life span of patients with diabetes has increased due to improved methods of detection and better management. There is no cure for diabetes at the present time, but enormous strides have been made in the control of the disease. The patient must understand the importance of compliance with the entire treatment plan, including diet, exercise, and in some cases medication. The patient with diabetes is at increased risk for cardiovascular disease, renal failure, neuropathies, and diabetic retinopathy. Research studies such as the Diabetes Control and Complications Trial have indicated that tight control of blood glucose levels resulted in the delay or prevention of retinopathy, nephropathy, and neuropathy.
There are other factors that also fall into the category of environmental (as opposed to genetic) causes of diabetes. Certain injuries to the pancreas, from physical trauma or from drugs, can harm beta cells, leading to diabetes. Studies have also found that people who live in polluted areas are prone to type 2, perhaps because of inflammation. And an alternate theory of insulin resistance places the blame on damage caused by inflammation. Age also factors into type 2; beta cells can wear out over time and become less capable of producing enough insulin to overcome insulin resistance, which is why older people are at greater risk of type 2.

Another diabetes-related sexual dysfunction symptom in men is reduced amounts of ejaculation, or retrograde ejaculation. Retrograde ejaculation is a condition in which the semen goes into the bladder, rather than out of the body through the urethra. Diabetes and damage to the blood vessels causes nerve damage to the muscles that control the bladder and urethra, which results in this problem.

Diabetes can also result from other hormonal disturbances, such as excessive growth hormone production (acromegaly) and Cushing's syndrome. In acromegaly, a pituitary gland tumor at the base of the brain causes excessive production of growth hormone, leading to hyperglycemia. In Cushing's syndrome, the adrenal glands produce an excess of cortisol, which promotes blood sugar elevation.
 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.

ORAL GLUCOSE TOLERANCE TEST. Blood samples are taken from a vein before and after a patient drinks a thick, sweet syrup of glucose and other sugars. In a non-diabetic, the level of glucose in the blood goes up immediately after the drink and then decreases gradually as insulin is used by the body to metabolize, or absorb, the sugar. In a diabetic, the glucose in the blood goes up and stays high after drinking the sweetened liquid. A plasma glucose level of 11.1 mmol/L (200 mg/dL) or higher at two hours after drinking the syrup and at one other point during the two-hour test period confirms the diagnosis of diabetes.
When your blood sugar is out of whack, you just don’t feel well, says Cypress, and might become more short-tempered. In fact, high blood sugar can mimic depression-like symptoms. “You feel very tired, you don’t feel like doing anything, you don’t want to go out, you just want to sleep,” Cypress says. She’ll see patients who think they need to be treated for depression, but then experience mood improvement after their blood sugar normalizes.

Rates of type 2 diabetes have increased markedly since 1960 in parallel with obesity.[17] As of 2015 there were approximately 392 million people diagnosed with the disease compared to around 30 million in 1985.[11][18] Typically it begins in middle or older age,[6] although rates of type 2 diabetes are increasing in young people.[19][20] Type 2 diabetes is associated with a ten-year-shorter life expectancy.[10] Diabetes was one of the first diseases described.[21] The importance of insulin in the disease was determined in the 1920s.[22]
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).

In general, women live longer than men do because they have a lower risk of heart disease, but when women develop diabetes, their risk for heart disease skyrockets, and death by heart failure is more likely in women than in men. Another study also found that in people with diabetes, heart attacks are more often fatal for women than they are for men. Other examples of how diabetes affects women differently than men are:
Manage mild hypoglycemia by giving rapidly absorbed oral carbohydrate or glucose; for a comatose patient, administer an intramuscular injection of the hormone glucagon, which stimulates the release of liver glycogen and releases glucose into the circulation. Where appropriate, an alternative therapy is intravenous glucose (preferably no more than a 10% glucose solution). All treatments for hypoglycemia provide recovery in approximately 10 minutes. (See Treatment.)
Pre-clinical diabetes refers to the time during which destruction of pancreatic insulin-producing cells is occurring, but symptoms have not yet developed. This period may last for months to years. Normally, 80-90% of the pancreatic beta cells must be destroyed before any symptoms of diabetes develops. During this time, blood tests can identify some immunological markers of pancreatic cell destruction. However, there is currently no known treatment to prevent progression of pre-clinical diabetes to true diabetes mellitus.

Type 2 DM is characterized by insulin resistance, which may be combined with relatively reduced insulin secretion.[11] The defective responsiveness of body tissues to insulin is believed to involve the insulin receptor. However, the specific defects are not known. Diabetes mellitus cases due to a known defect are classified separately. Type 2 DM is the most common type of diabetes mellitus.[2]

Unexplained weight loss can happen for lots of reasons, and diabetes is one of them. Goundan explains that insulin helps your body move sugar from your blood to your cells, so when you have an insulin resistance, you don’t get enough energy into your cells despite all that sugar flowing through your body. “Because you’re unable to get enough energy from sugar, your body burns your own fat and muscle for energy," Kellis says. "Weight loss can be pretty significant, sometimes 10 to 20 pounds."