Endocrine Abstracts

JOINT2236

Background: Primary Hypoparathyroidism is a rare disorder characterized by hypocalcemia and hyperphosphatemia resulting from inadequate PTH synthesis and secretion. Even though neck surgery is the most common etiology, the non-surgical forms have been linked to autoimmune dysregulation and activation of humoral or cell-mediated immunity against parathyroid cells. Hashimoto’s thyroiditis, a common autoimmune cause of hypothyroidism. Both conditions can occur as an isolated endocrinopathy or as part of autoimmune polyglandular syndrome (APS), which is characterized by the functional impairment of multiple endocrine glands. Their coexistence is exceedingly rare but may suggest shared genetic and autoimmune mechanisms.

Case presentation: A 35-year-old Caucasian female was referred to the clinic with typical symptoms and complaints of hypocalcemia. For the past several years, patient had multiple hospitalizations due to episodes of hypocalcemia with tetany and seizures, requiring calcium infusions. Her medical history was remarkable for infertility with diminished ovarian reserve. The patient denied any history of neck surgery or irradiation. Regarding her family history, there was no evidence of cancer or genetic disorders among first-degree relatives. However, her father had type 2 diabetes. On Physical examination Trousseau’s and Chvosteck’s signs were positive. Laboratory studies revealed Primary Hypoparathyroidism with severe hypocalcemia—0.4mmol/l, low PTH levels – 2.64 pg/ml, high phosphorus—1.8 mmol/l, hypomagnesemia—0.63mmol/land low levels of Vitamin D-1,25—13ng/l. An electrocardiogram showed a prolonged QT interval. Brain MRI revealed no abnormalities. Infertility workup showed decreased ovarian reserve: AMH-0.527ng/ml FSH -14mIU/ml. transvaginal ultrasonography revealed low AFC. Combined calcium and calcitriol supplementation was commenced, with laboratory and clinical improvement. Assisted reproductive technology (ART) was used to aid in achieving pregnancy without success. The patient discontinued yearly checkups, and two years later, she was referred to an endocrinologist after a spontaneous pregnancy miscarriage. Laboratory tests revealed Hashimoto’s subclinical hypothyroidism (TSH – 4.94mIU/ml; FT4-14.53pmol/l; ANTI-TPO –221U/ml; ANTI-TG—1068 U/ml) and mild hypocalcemia due to irregular calcium supplement intake (Calcium – 1.02 mmol/L). Thyroid ultrasound showed an enlarged, heterogeneous thyroid (30cc) with hypoechoic nodules. Treatment with levothyroxine, calcium and calcitriol with lifestyle modifications resulted in symptom resolution. After several months of achieving laboratory and clinical improvement, infertility treatment is scheduled.

Conclusion: The coexistence of Primary hypoparathyroidism, Hashimoto’s thyroiditis, and diminished ovarian function is exceedingly rare, but suggests a potential shared autoimmune pathogenesis. Further research is needed to explore possible genetic and immunological links. Since disease is lifelong, essential follow-up is needed to avoid complications and recurrence.