Long-term hypothyroidism in patients started on levothyroxine during pregnancy.

Background: Current guidelines recommend different postpartum approaches for patients started on levothyroxine (LT4) during pregnancy. Objective: We studied the postpartum management of these patients and determined factors associated with long-term hypothyroidism. Methods: A retrospective study was conducted at a tertiary center between 2014 and 2020, with LT4 initiation according to 2014 ETA recommendations. We performed multivariate logistic regression (MVR) and a receiver operating characteristic curve analysis to determine variables associated with long-term hypothyroidism and their optimal cutoffs. Results: LT4 was initiated in 177 pregnant women, and 106/177 (60%) were followed at long-term (at least 6 months post partum) (28.5 (9.0-81.9) months). LT4 could have been stopped in 45% of patients who continued it immediately after delivery. Thirty-six out of 106 (34%) patients were long-term hypothyroid. In them, LT4 was initiated earlier during pregnancy than in euthyroid women (11.7 ± 4.7 vs 13.7 ± 6.5 weeks, P = 0.077), at a higher thyroid-stimulating hormone (TSH) level (4.1 (2.2-10.1) vs 3.5 (0.9-6.9) mU/L, P = 0.005), and reached a higher dose during pregnancy (62.8 ± 22.2 vs 50.7 ± 13.9 µg/day, P = 0.005). In the MVR, only the maximal LT4 dose during pregnancy was associated with long-term hypothyroidism (odds ratio (OR) = 1.03, 95% CI: 1.00-1.05, P = 0.003). The optimal cutoffs for predicting long-term hypothyroidism were an LT4 dose of 68.75 µg/day (87% specificity, 42% sensitivity; P = 0.013) and a TSH level ≥ 3.8 mU/L (68.5% specificity, 77% sensitivity; P = 0.019). Conclusion: One-third of the patients who started on LT4 during pregnancy had long-term hypothyroidism. The TSH level at treatment initiation and the LT4 dose during pregnancy could guide the decision for continuing long-term LT4.

Adult-onset nesidioblastosis: a challenging diagnosis revealed by glucagon-like-peptide-1 receptor imaging.

Summary: A 52-year-old female presented with recurrent episodes of fasting or post-absorptive hypoglycemia. A 72-h fasting test confirmed endogenous hyperinsulinemia. Conventional imaging was unremarkable. Selective pancreatic arterial calcium stimulation and hepatic venous sampling showed a maximum calcium-stimulated insulin concentration from several pancreatic areas, mainly the proximal splenic artery and the proximal gastroduodenal artery, suggesting the presence of one or more occult insulinoma(s) in the region of the pancreatic body. 68Ga-DOTA-exendin-4 PET/CT showed however generalized increased uptake in the pancreas and a diagnosis of nesidioblastosis was therefore suspected. The patient has been since successfully treated with dietetic measures and diazoxide. Treatment efficacy was confirmed by a flash glucose monitoring system with a follow-up of 7 months. Learning points: Adult nesidioblastosis is a rare cause of endogenous hyperinsulinemic hypoglycemia. The distinction between insulinoma and nesidioblastosis is essential since the therapeutic strategies are different. 68Ga-DOTA-exendin-4 PET/CT emerges as a new noninvasive diagnostic tool for the localization of an endogenous source of hyperinsulinemic hypoglycemia. Medical management with dietetic measures and diazoxide need to be considered as a valuable option to treat patients with adult nesidioblastosis. Flash glucose monitoring system is helpful for the evaluation of treatment efficacy.