First Glance

Fundamentals

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Gestational Diabetes Mellitus (GDM)

"Gestational diabetes mellitus" refers to the onset or first recognition of diabetes mellitus during pregnancy, most commonly during the third trimester. Women with GDM are characterized by insulin resistance and impaired insulin secretion, and approximately three - fourths have a family history of type 2 diabetes mellitus that was unmasked by the stress of pregnancy².

Clinical recognition of GDM is important because therapy including, insulin when necessary and antepartum maternal and fetal monitoring can reduce the well-described GDM associated perinatal morbidity and mortality.

They are at very high risk to develop type 2 diabetes mellitus within a 10 year period and require frequent long term follow up. Ideally all pregnant women should be tested to rule out gestational diabetes, but if this is not feasible all high risk patients (Table 3) must undergo this test.

Table 3 : High Risk Patients

Women who had GDM during a previous pregnancy.
Women with a first degree relative who is a diabetic.
Women who have given birth to a large weight baby in the previous pregnancy.
Women whose newborn in a previous pregnancy showed any complication known to be associated as arising from maternal GDM.
Women who gave birth to still born babies or infants with congenital abnormalities.
Women with bad obstetric history, including recurrent foetal wastage, hypertension, eclampsia, etc.
Women with repeated or persistent urinary tract infection.
Women manifesting glycosuria during pregnancy.
Women over the age of 30 years.

Table 4

Screening and diagnosis scheme for GDM

Plasma glucose

50-g

screening test

100-g

diagnostic test

Fasting

1-h

2-h

3-h

140 mg/dl

105 mg/dl

190 mg/dl

165 mg/dl

145 mg/dl

Screening for GDM may not be necessary in pregnant women who meet all of the following criteria: <25 years of age, normal body weight, no first degree relative with diabetes, and not Hispanic, Native American, Asian or African-American. The 100-g diagnosis test is performed on patients who have a positive screening test. The diagnosis of GDM required any two of the four plasma glucose values obtained during the test to meet or exceed the value shown above.

Other specific types of diabetes

This category of diabetes includes a wide variety of unrelated disorders, many with well defined etiologies like drug or chemical induced viral infections, endocrinopathies pancreastis, neoplasia, etc.

Impaired GlucoseTolerance (IGT) and Impaired Fasting Glucose (IFG)

The term IGT and IFG refer to a metabolic stage intermediate between normal glucose heomostasis and diabetes. These people have normal or only modestly elevated fasting blood glucose concentration and manifest hyperglycemia only when challenged with an oral glucose load used in the standardized OGTT. Approximately one third of individuals with IGT develop overt type 2 diabetes mellitus after 10 years. IGT is a risk factor for development of macrovascular disease.

Diagnosis of Diabetes Mellitus

It is important to detect diabetes at an early stage so that the associated complications may be prevented or delayed. New cases of diabetes can be diagnosed in a number of ways. It can be diagnosed when the patient has the classic symptoms such as excessive thirst and frequent urination and a clearly elevated blood glucose any time of the day.

Criteria for testing for diabetes

Testing for diabetes should be considered in all individuals at age 45 years and older. If the results are normal, it should be repeated at appropriate intervals.

Criteria for the diagnosis of diabetes mellitus ^1,3

Symptoms of diabetes plus casual plasma concentration >200 mg/dl (11.1 mmol/l)
FFG>126mf/dl (7.0 mmol/l). Fasting is defined as no caloric intake for at least 8h.
2-h PG>200 ml/dl (11.1 mmol/l) during an OGTT. The test should be performed as described by WHO², using a glucose load containing the equivalent of 75-g anhydrous glucose dissolved in water.

References :

American Diabetes Association : Report of the expert committee on the diagnosis and
classification of diabetes mellitus. Diabetes Care 1999;22 (Suppl 1): S 5-S 19.
Davidson MB. Diabetes Mellitus: Diagnosis and treatment, 4th edition,
W.B. Saunders Company:1998:1-15.
Defronzo RA: Current Therapy of Diabetes Mellitus. St.Louis 1998:1-4
Krall, L.P. and Beaser, R.S., Joslin Diabetes Manual, 12th edition, Lea and Febiger,
Philadelphia 1998:1-30.
Ramchandran A, Epidemiologicial research in diabetes in India,
NNDU Proceedings 1994:3:66- 68.

Opinion of Leading Doctors

"Diagnosis of diabetes has become more sensitive and simplified with the new and revised criteria. However the point that any test which is repeated again and again increases its sensitivity should not be forgotten. With better methods for diagnosis the detection of new cases are rapidly increasing. The three causes for the increased incidence are that Asian have a fertile genetic predisposition for the development of diabetes and then the current unhealthy lifestyle changes have not only increased the incidence in the entire population but also more & more new detections are happening with young adult.

-Dr. K. Kannan

Madurai.

"Physicians should be routinely testing for diabetes in all high risk individual e.g. elderly, obese, high-risk pregnant women, patient complaining of fatigue syndrome, stroke, CAD, those with positive family history".

-Dr A R Sircar

Lucknow

"Diabetes in India is an epidemic disease. For its proper management, early detection is a must. Why wait till patients develop complications. Detect diabetes today even though the patient is in his thirties."

-Dr Navneet Agarwal

Jhansi

"Indians belong to a race which is ethnically susceptible to diabetes. Countrywide screening for the detection of diabetes should be started on a war footing. The government should give a top priority."

-Dr Sarita Bajaj

Allahabad

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