A Rare Case of Severe Headache and Sudden-Onset Diabetes Insipidus During Pregnancy: Differential Diagnosis and Management of Lymphocytic Hypophysitis

ABSTRACT Objective: To present a case of lymphocytic hypophysitis (LH) during pregnancy. Methods: Clinical presentation before and after pregnancy and review of the pertinent literature are presented. Results: A 30-year-old woman, G3P2A0, presented at 30 weeks of gestation with headache, polyuria, and hypernatremia (156 mmol/L). Obstetrical history was significant for gestational diabetes mellitus, without previous infertility or autoimmune disorders. Magnetic resonance imaging of the head revealed an enlarged pituitary gland measuring 16 mm with slight compression of the optic chiasm. A clinical diagnosis of LH was made upon laboratory findings of diabetes insipidus, adrenal insufficiency, and central hypothyroidism. The patient was treated with desmopressin, hydrocortisone, and levothyroxine. There was rapid regression of the pituitary enlargement within 10 days. At 38 weeks, the patient gave birth to a healthy baby girl weighing 3,950 g. Post-delivery, she breastfed normally and continued to experience clinical, biochemical, and radiologic improvement at 1-year postpartum. Conclusion: The differential diagnosis of headache and sudden-onset endocrine dysfunction during pregnancy can be challenging, and rapid recognition and management are essential. LH, a rare autoimmune disease characterized by lymphocytic infiltration of the pituitary gland, is part of the differential diagnosis for headache and hypopituitarism during pregnancy. To our knowledge, very few cases of lymphocytic panhypophysitis have been described during pregnancy or the postpartum period. High clinical suspicion and proper hormone assessment are important to establish accurate diagnosis and treatment. A multidisciplinary approach involving endocrinologists and obstetricians can greatly reduce maternal and fetal morbidity resulting from pituitary dysfunction during pregnancy. Abbreviations: ACTH = adrenocorticotropic hormone DI = diabetes insipidus GDM = gestational diabetes mellitus GH = growth hormone IGF-1 = insulin-like growth factor 1 LH = lymphocytic hypophysitis MRI = magnetic resonance imaging