Diabetes Mellitus (DM) is impaired insulin secretion and variable degrees of peripheral insulin resistance leading to hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia, polyphagia, and polyuria. Later complications include vascular disease, peripheral neuropathy, and predisposition to infection. Diagnosis is by measuring plasma glucose. Treatment is diet, exercise, and drugs that reduce glucose levels, including insulin and oral antihyperglycemic drugs. Prognosis varies with degree of glucose control.
There are 2 main categories of DM—type 1 and type 2, which can be distinguished by a combination of features … Terms that describe the age of onset (juvenile or adult) or type of treatment (insulin- or non–insulin-dependent) are no longer accurate because of overlap in age groups and treatments between disease types.
Source – The Merck Manual