Anterior and Posterior Pituitary Function in Patients with Sheehan Syndrome - Combining the use of Insulin Tolerance Test and Copeptin Assay.

Introduction: Sheehan syndrome (SS) typically involves the loss of anterior pituitary cells and rarely affects the posterior pituitary. The water deprivation test (WDT) is the gold standard for diagnosing central diabetes insipidus (CDI), but it is cumbersome. Serum copeptin measurements are an alternative for CDI diagnosis. In this study, we measured hypoglycaemia-stimulated serum copeptin in SS patients to assess posterior pituitary function alongside anterior pituitary hormone levels. Methods: This study recruited 43 patients with SS on stable hormonal replacement except for growth hormone (GH), 18 patients with CDI, and 19 body mass index (BMI) and parity-matched controls. All patients with SS and four patients with CDI underwent an insulin tolerance test (ITT), and hypoglycaemia-stimulated copeptin levels were measured at 0, 30, 45, and 90 minutes after insulin injection. Results: The mean serum copeptin level among patients with SS (26.01 ± 12.41 pmol/L) was significantly lower than that in healthy controls (31.92 ± 7.85 pmol/L) and higher than that in patients with CDI (1.81 ± 0.14 pmol/L). Using pre-defined cut-offs for CDI, basal serum copeptin <2.69 pmol/L and stimulated levels <4.92 pmol/L for complete central DI, and basal copeptin levels >2.69 pmol/L and stimulated copeptin <4.92 pmol/L for partial central DI, 9.2% (n = 4) of patients with SS had CDI, of which half had complete CDI and half had partial CDI. Conclusion: A significant number of patients with SS who are on hormone replacement therapy show involvement of the posterior pituitary, despite not displaying symptoms.

Thyroid Autoimmunity and Subclinical Hypothyroidism in Prolactinoma: A Case Control Study.

Background: This study was aimed at determining the frequency of thyroid autoimmunity and subclinical hypothyroidism in patients with hyperprolactinemia due to prolactinoma compared to well-matched healthy controls. Methods: This was a cross-sectional study wherein 78 treatment naïve prolactinoma patients and ninety-two healthy control subjects were recruited. Serum prolactin (PRL), thyroid-stimulating hormone (TSH), total thyroxine (T4), circulating anti-thyroid peroxidase (anti-TPO), and anti-thyroglobulin (anti-Tg) antibody levels were measured in all study subjects. Progression of the antibody-positive population to subclinical hypothyroidism was determined. Results: The median PRL level among patients was 166 ng/ml (IQR 85-467) compared to 11.4 ng/ml (IQR 8.5-15.9) in controls (P < 0.001). There was no significant difference in levels of T4 (P = 0.83) and TSH (P = 0.82) between the cases and controls. Overall, 25% of patients had the presence of anti-thyroid antibodies as compared to 20% of controls (P = 0.56). SCH was more common in antibody-positive hyperprolactinemia subjects compared with antibody-positive controls. Conclusion: We did not find an increased prevalence of thyroid autoimmunity among untreated prolactinoma patients compared to healthy controls. At the same time, subclinical hypothyroidism was more common in thyroid antibody-positive patients with hyperprolactinemia than positive controls.

Prolactinoma Outcome After Pregnancy and Lactation: A Cohort Study.

Context: Prolactinoma is the most frequent pituitary tumor among women of childbearing age. Fewer studies have addressed the outcome of prolactinomas after gestation. Objective: The aim was to study the spontaneous remission rate and change in tumor size after pregnancy and/or lactation in women with prolactinomas. Patients and Methods: Retrospective study conducted at a tertiary care center of north India. Records of 25 women with 31 pregnancies (20 microprolactinomas and 11 macroprolactinomas), who conceived on dopamine agonist (cabergoline) were studied. Cabergoline was stopped at conception in 24 pregnancies and continued in 7. Serum prolactin was noted 3 months after delivery and/or lactation. Magnetic resonance imaging available at last visit after delivery and/or lactation was also noted. Remission was defined as normal serum prolactin after pregnancy and/or lactation without use of cabergoline. Results: Among patients in whom cabergoline was stopped during pregnancy (n = 24), 41.6% (n = 10) had prolactin in normal range (achieved remission) after pregnancy and/or lactation. In 25% (n = 6) of women, adenoma size decreased by more than 50%, in 33%(n = 8), there was no change in adenoma size, and in 42% (n = 10), decrease in adenoma size was less than 50% after pregnancy and/or lactation. The median duration of cabergoline treatment before pregnancy among patients who achieved remission was 60 months against 24 months in those who did not achieve remission. The median pre-pregnancy adenoma size was 5.5 mm in women with remission against 8 mm in women who did not achieve remission. Conclusion: Pregnancy-induced remission of hyperprolactinemia was seen in 41.6% prolactinomas. Longer duration of dopamine agonist treatment before pregnancy, small pre-pregnancy adenoma size, and lower baseline prolactin were associated with high likelihood of remission, though not statistically significant.