Case Study: Latent Autoimmune Diabetes in Adults and Pregnancy: Foretelling the Future

PRESENTATiON W.S. is a 25-year-old woman referred for newly diagnosed gestational diabetes mellitus (GDM) after having a 1-hour plasma glucose (PG) of 150 mg/dl during a 50-g glucose challenge test at 28 weeks’ gestation. She denied any history of polyuria, polydipsia, polyphagia, or visual disturbances. During this pregnancy, she had gained only 5 lb by 31 weeks and denied any complications. Before the pregnancy, her baseline weight was 205 lb, and her BMI 33 kg/m. Overall, she was feeling well and tolerating her pregnancy well. Her medical history was significant for a single pregnancy 4 years ago that was not complicated by GDM. She delivered a healthy, full-term girl weighing 7 lb, 4 oz, by an uncomplicated spontaneous vaginal delivery (SVD). She denied any subsequent history of impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). She denied a family history of type 2 diabetes. However, her 4-year-old daughter had been diagnosed with type 1 diabetes. She denied any tobacco or alcohol use. After being diagnosed with GDM, she received appropriate dietary counseling and was instructed in home blood glucose monitoring. Secondary to persistent fasting hyperglycemia, she was started on human insulin NPH, 5 units subcutaneously daily at bedtime. She continued to monitor fasting and 2-hour postprandial blood glucose values. Her GDM was followed closely, and her NPH insulin was titrated to 14 units at bedtime. Because of ongoing postprandial hyperglycemia, insulin lispro was added for prandial coverage, in a dose of 1 unit/20 g of carbohydrate consumed. Her blood glucose control improved on intensive insulin therapy. Her hemoglobin A 1c (A1C) was excellent at 5.5%. At term, she delivered a healthy boy of 8 lb, 8 oz, by uncomplicated SVD. The patient was scheduled for a postpartum follow-up, including a 75-g oral glucose tolerance test (OGTT). She denied any symptoms of hyperglycemia, and sporadic blood glucose monitoring had revealed normal readings. She had lost a total of 17 lb since delivery and was close to her baseline weight at 207 lb. Her 75-g OGTT revealed a fasting blood glucose value of 117 mg/dl (normal 70–100 mg/dl) and a 2-hour value of 179 mg/dl (normal < 140 mg/dl). Her A1C was 5.8% (normal 4.0–6.5%). Since her test was consistent with IGT and she was still nursing, it was planned that she return to clinic in 8 weeks for a repeat OGTT and continue to monitor her blood glucose at home. Four weeks later, she called with symptoms of polyuria, polydipsia, and blurry vision. Her blood glucose values had been between 200 and 350 mg/dl for 3 days. W.S. was seen immediately in clinic. Insulin therapy was initiated with basal insulin glargine, 15 units at bedtime, and insulin lispro for bolus insulin coverage at meals. Because of the family history of type 1 diabetes in her daughter and acute exacerbation of hyperglycemia, an autoantibody test was ordered to evaluate her for type 1 diabetes. Results showed that the glutamic acid decarboxylase (GAD65) antibody was 34.2 U/ml (normal < 1.5 U/ml), the islet cell IgG autoantibody (ICA) was 80 JDF units (normal < 4.1), and the nonfasting C-peptide level was 794 pg/l (stimulated state 497–3,145 pg/l). Because of the presence of pancreatic antibodies, she was diagnosed with latent autoimmune diabetes in adults (LADA). Intensive insulin therapy was started with insulin lispro for prandial coverage and insulin glargine for basal coverage. Within the next 6 months, she was started on an insulin pump and had excellent glycemic control. One year after her diagnosis, she became pregnant with her third child. She had an uncomplicated pregnancy, and her diabetes was well controlled during pregnancy on insulin pump therapy.