Endocrine Abstracts

Objective: Postsurgical hypoparathyroidism (HypoPT) is the most common etiology of disease and often occurs after thyroid surgery. However, the differential diagnosis between different forms of HypoPT in some cases remains a challenge. We present the clinical case of postsurgical and functional HypoPT combination.

Case description: A 44-year-old female was referred to the Endocrinology Research Centre. She underwent total thyroidectomy for follicular adenoma performed in 2009. Hypoparathyroidism developed after surgery, so calcium carbonate 1000 mg/day and calcitriol 0.5–1 µg/day were prescribed. She continued this therapy for 2 years and then stopped in 2011. There were no clinical symptoms of hypocalcemia. Laboratory tests revealed albumin-corrected calcium level within 2.11–2.25 mmol/l (normal value 2.1–2.55) and PTH 16.7 pg/ml (15–65). Since 2019 her condition deteriorated with seizures, muscle cramps and paresthesia recurrence. She also had a history of stomach ulcer and therapy with proton pomp inhibitors over last months. Laboratory examination showed a decrease of PTH level less 3.0 pg/ml, hypocalcaemia (1.8 mmol/l), hyperphosphatemia (1.9 mmol/l (0.74–1.52) as well as hypomagnesemia 0.6 mmol/l (0.7–1.05). 25(OH)D blood test was normal – 37 ng/ml (30–100). Сalcium carbonate 1000 mg/day and calcitriol 1 mcg/day were immediately prescribed. Also she was started on magnesium supplements about 400–600 mg/day per os to control the hypomagnesaemia. After 6 months, lab. Test revealed normal magnesium (0.83 mmol/l), target calcium levels (2.32 mmol/l) and increased PTH to 24 pg/ml. There was complete symptom resolution. Step-by step the doses of calcium carbonate and calcitriol were reduced. Patient is currently receiving cholecalciferol in daily dose of 2000 IU. Her physical and laboratory examination remain normal.

Conclusion: Hypomagnesemia is recognized as a cause of hypoparathyroidism due to impaired parathyroid hormone secretion, with resultant hypocalcemia. This case demonstrates the importance of looking for all associated electrolyte abnormalities in patients with HypoPT.