Screening and Diagnosis of Pediatric Diabetes

Introduction

This article addresses issues related to the screening and diagnosis of diabetes among children. As is the case with adults, screening in children is done on the basis of risk. Generally, screening is only appropriate in asymptomatic populations when the following criteria are met:

• The disease is an important public health burden

• The natural history of the disease is well understood

• There is a recognized preclinical stage

• Tests that detect preclinical disease are available and reliable

• There are benefits to treatment when the disease has been detected early

• Screening is cost effective

Because many more of the above conditions are met for type 2 diabetes than for type 1, screening efforts are focused on type 2 diabetes. Screening for type 1 diabetes is typically done only in a research setting. In terms of diagnosis, one big challenge facing clinicians is distinguishing between type 1 and type 2 diabetes in youth. In the past, it could be safely assumed that a child presenting with diabetes could be given the diagnosis of type 1 diabetes. However, the rapidly rising rates of type 2 diabetes among youth now preclude such an assumption.

Type 1 diabetes

Screening

Although screening for type 1 diabetes is not generally done outside of a research context, there are a number of risk factors that are associated with the development of type 1 diabetes. Risk factors for type 1 diabetes are listed in Table 1.

Table 1. Risk factors for type 1 diabetes[1]

Diagnosis

For a child at high risk (with or without symptoms), fasting hyperglycemia should be tested. Criteria for diagnosing diabetes using fasting plasma glucose testing are listed in Table 2. When further diagnostic testing is performed, 85% to 90% generally have serological evidence of an autoimmune pathologic islet cell process. [4]

Table 2. ADA criteria for the diagnosis of diabetes mellitus [5]

Type 2 diabetes

Screening

Children should be screened if they are at substantial risk for type 2 diabetes, particularly if they are obese or have a family history of diabetes. Screening recommendations for type 2 diabetes in youth are listed in Table 3. Screening high-risk children every 2 years after age 10 can detect disease at an early asymptomatic stage.

Table 3. Screening recommendations for type 2 diabetes in youth [6]

Diagnosis

The diagnostic criteria for type 2 diabetes are shown in Table 4. Symptoms of type 2 diabetes often are slow to develop, whereas type 1 diabetes symptoms usually develop over a short period. About 90% of children with type 2 diabetes have acanthosis nigricans (dark shiny patches on the skin), which are most often found between the fingers, between the toes, on the back of the neck ("dirty neck"), and in axillary creases. Fasting plasma glucose and 2-hr postprandial glucose are used for diagnostic testing, with the former preferred because of cost and convenience.

Table 4. Diagnostic criteria for type 2 diabetes [6]

Distinguishing among types of diabetes

It is difficult to distinguish between various forms of diabetes because standard differentials such as ketoacidosis (type 1) or obesity (type 2) can occur in either group. Often only the presenting symptoms and clinical course of the disease fully determine its classification.[4]

Figure 1 depicts the general differential diagnosis between type 1 and type 2 diabetes. Maturity-onset diabetes of the young (MODY) is rare and occurs mainly in whites, but it can affect any ethnic group. [4,7] Until this form of diabetes is better understood, it cannot be ruled out unless the child is tested for β-cell autoantibodies.

Figure 1. Distinguishing between type 1 diabetes and type 2 diabetes [4]

Laboratory testing for C-peptide, which is formed during conversion of proinsulin to insulin, can differentially diagnose type 1 and type 2 diabetes. A low C-peptide level suggests type 1 diabetes. A high positive titer for glutamic acid decarboxylase antibodies also suggests type 1 diabetes, although there are exceptions.[7] Additionally, new diagnostic tests are being developed, such as that for adiponectin-to-leptin ratios (both are hormones released by adipocytes).[8]

References

1. Health Guide A-Z. Type 1 diabetes. What increases your risk? Available at: http://my.webmd.com/hw/diabetes_1_2/uq1456.asp. Accessed August 13, 2004.
2. Schroedor K. Risk factors for type 1 diabetes. Aurora Health Care. Available at: http://www.auroraheathcare.org/yourhealth/healthgate/getcontent.asp?URLhealthgate=%2220245.html%22
3. Kasimiotis H, Fida S, Rowley MJ, et al. Antibodies to SOX13 (ICA12) are associated with type 1 diabetes. Autoimmunity. 2001;33:95-101. 
4. American Diabetes Association. Type 2 diabetes in children and adolescents. Diabetes Care. 2000;23:381-389.
5. American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care. 2004;27(suppl 1):S5-S10
6. American Diabetes Association. Screening for type 2 diabetes. Diabetes Care. 2003;26(suppl 1):S21-S24.
7. Hussain AN, Vincent MT. Diabetes mellitus, type 1. Available at: http://www.emedicine.com/med/topic546.htm. Accessed August 24, 2004.
8. Morales A, Wasserfall C, Brusko T, et al. Adiponectin and leptin concentrations may aid in discriminating disease forms in children and adolescents with type 1 and type 2 diabetes. Diabetes Care. 2004;27:2010-2014.