Excess glucose in the blood can damage small blood vessels in the nerves causing a tingling sensation or pain in the fingers, toes and limbs. Nerves that lie outside of the central nervous system may also be damaged, which is referred to as peripheral neuropathy. If nerves of the gastrointestinal tract are affected, this may cause vomiting, constipation and diarrhea.

The word diabetes (/ˌdaɪ.əˈbiːtiːz/ or /ˌdaɪ.əˈbiːtɪs/) comes from Latin diabētēs, which in turn comes from Ancient Greek διαβήτης (diabētēs), which literally means "a passer through; a siphon".[111] Ancient Greek physician Aretaeus of Cappadocia (fl. 1st century CE) used that word, with the intended meaning "excessive discharge of urine", as the name for the disease.[112][113] Ultimately, the word comes from Greek διαβαίνειν (diabainein), meaning "to pass through,"[111] which is composed of δια- (dia-), meaning "through" and βαίνειν (bainein), meaning "to go".[112] The word "diabetes" is first recorded in English, in the form diabete, in a medical text written around 1425.

observations The onset of type 1 diabetes mellitus is sudden in children. Type 2 diabetes often begins insidiously. Characteristically the course is progressive and includes polyuria, polydipsia, weight loss, polyphagia, hyperglycemia, and glycosuria. The eyes, kidneys, nervous system, skin, and circulatory system may be affected by the long-term complications of either type of diabetes; infections are common; and atherosclerosis often develops. In type 1 diabetes mellitus, when no endogenous insulin is being secreted, ketoacidosis is a constant danger. The diagnosis is confirmed by fasting plasma glucose and history.
How does high blood sugar (hyperglycemia) feel? To maintain the right amount of blood sugar, the body needs insulin, a hormone that delivers this sugar to the cells. When insulin is lacking, blood sugar builds up. We describe symptoms of high blood sugar, including fatigue, weight loss, and frequent urination. Learn who is at risk and when to see a doctor here. Read now
Jump up ^ Qaseem, Amir; Wilt, Timothy J.; Kansagara, Devan; Horwitch, Carrie; Barry, Michael J.; Forciea, Mary Ann (6 March 2018). "Hemoglobin A Targets for Glycemic Control With Pharmacologic Therapy for Nonpregnant Adults With Type 2 Diabetes Mellitus: A Guidance Statement Update From the American College of Physicians". Annals of Internal Medicine. doi:10.7326/M17-0939.
Several other signs and symptoms can mark the onset of diabetes although they are not specific to the disease. In addition to the known ones above, they include blurred vision, headache, fatigue, slow healing of cuts, and itchy skin. Prolonged high blood glucose can cause glucose absorption in the lens of the eye, which leads to changes in its shape, resulting in vision changes. Long-term vision loss can also be caused by diabetic retinopathy. A number of skin rashes that can occur in diabetes are collectively known as diabetic dermadromes.[23]
Watch for thirst or a very dry mouth, frequent urination, vomiting, shortness of breath, fatigue and fruity-smelling breath. You can check your urine for excess ketones with an over-the-counter ketones test kit. If you have excess ketones in your urine, consult your doctor right away or seek emergency care. This condition is more common in people with type 1 diabetes but can sometimes occur in people with type 2 diabetes.

Type 2 (formerly called 'adult-onset' or 'non insulin-dependent') diabetes results when the body doesn’t produce enough insulin and/or is unable to use insulin properly (this is also referred to as ‘insulin resistance’). This form of diabetes usually occurs in people who are over 40 years of age, overweight, and have a family history of diabetes, although today it is increasingly found in younger people.
If you recognize any of the symptoms, contact your doctor immediately. A simple in-office test for sugar in the urine is used for diagnosis. If that test is positive, then a drop of blood from the fingertip will confirm diabetes. Every day, thousands of adults and children around the world are diagnosed, but many go undetected. Early diagnosis cannot prevent Type 1, but it can head off potentially devastating, even fatal, health concerns.
Normally, blood glucose levels are tightly controlled by insulin, a hormone produced by the pancreas. Insulin lowers the blood glucose level. When the blood glucose elevates (for example, after eating food), insulin is released from the pancreas to normalize the glucose level by promoting the uptake of glucose into body cells. In patients with diabetes, the absence of insufficient production of or lack of response to insulin causes hyperglycemia. Diabetes is a chronic medical condition, meaning that although it can be controlled, it lasts a lifetime.
A third notion is that changes in how babies are fed may be stoking the spread of type 1. In the 1980s, researchers noticed a decreased risk of type 1 in children who had been breast-fed. This could mean that there is a component of breast milk that is particularly protective for diabetes. But it has also led to a hypothesis that proteins in cow's milk, a component of infant formula, somehow aggravate the immune system and cause type 1 in genetically susceptible people. If true, it might be possible to remove that risk by chopping those proteins up into little innocuous chunks through a process called hydrolyzation. A large-scale clinical trial, called TRIGR, is testing this hypothesis and scheduled for completion in 2017.
Because both yeast and bacteria multiply more quickly when blood sugar levels are elevated, women with diabetes are overall at a higher risk of feminine health issues, such as bacterial infections, yeast infections, and vaginal thrush, especially when blood sugar isn't well controlled. And a lack of awareness about having prediabetes or diabetes can make managing blood sugar impossible.