Diabetes mellitus is a condition characterized by hyperglycemia as a result of abnormalities in the secretion and/or action of insulin. It usually is a chronic and progressive disease that has profound effects on numerous aspects of metabolism, beyond those related to glucose homeostasis. The increasing incidence of pediatric diabetes and the severe consequences of missed diagnosis or suboptimal treatment underlie its interest for all pediatricians. Changes in the epidemiology and clinical characteristics of the different types of diabetes in the United States, in part due to shifts in demographics and lifestyle, have spurred a revision of some of the previous concepts. This chapter will review the diagnosis and classification of diabetes and describe in more detail the 2 most common types of pediatric diabetes: type 1 diabetes (T1D) and type 2 diabetes (T2D).
DIAGNOSIS OF DIABETES AND PREDIABETES
The American Diabetes Association’s criteria for diagnosis of diabetes are illustrated in Table 537-1.
TABLE 537-1CRITERIA FOR THE DIAGNOSIS OF DIABETES ||Download (.pdf) TABLE 537-1CRITERIA FOR THE DIAGNOSIS OF DIABETES
|Fastinga plasma glucose ≥ 126 mg/dL (7.0 mmol/L), or |
|2-hour plasma glucose ≥ 200 mg/dL (11.1 mmol/L) during an oral glucose tolerance test (OGTT). The test should be performed using a glucose load containing the equivalent of 75 g of anhydrous glucose dissolved in water for those weighing > 43 kg and 1.75 g/kg for those weighing < 43 kg, or |
|Classic symptoms of hyperglycemia or hyperglycemic crisis plus random plasma glucose ≥ 200 mg/dL (11.1 mmol/L), or |
|Hemoglobin A1c (A1c) ≥ 6.5% (48 mmol/mol)b |
Abnormal results should be confirmed before establishing a diagnosis of diabetes. Fluctuation of levels, in particular of 2-hour plasma glucose in the oral glucose tolerance test (OGTT), but also fasting plasma glucose and hemoglobin A1c (A1c), may happen, and the correlations among those 3 tests are not perfect. Therefore, except in patients with classical symptoms of hyperglycemia (ie, polyuria, polydipsia, weight loss) or hyperglycemic crisis (diabetic ketoacidosis [DKA] or hyperosmolar syndrome), the diagnosis requires 2 positive tests or the same test to be positive on 2 different samples.
The role of A1c and the current cutoffs for the diagnosis of diabetes are unclear in youth and currently limited to cases of suspected T2D. In addition, because of relatively large inter- and intra-assay variabilities, it should not be used as the sole criterion. An A1c value of 6.5% or less ...