Severe hypercalcaemia secondary to relapsed Graves' disease

Area of Science:

• Endocrinology
• Internal Medicine

Background:

• Graves' disease is an autoimmune disorder leading to hyperthyroidism.
• Hyperthyroidism can cause various metabolic disturbances.
• Hypercalcemia is a recognized, though uncommon, complication of thyrotoxicosis.

Observation:

• A 21-year-old woman with treated Graves' disease presented with severe hypercalcemia (3.69 mmol/L).
• Despite treatment for presumed Graves' relapse, calcium levels remained elevated.
• Intravenous bisphosphonate (pamidronate) administration successfully reduced serum calcium.

Findings:

• The patient experienced significant hypercalcemia attributed to thyrotoxicosis.
• Bisphosphonate therapy led to a subsequent risk of hypocalcemia.
• Pre-existing low vitamin D stores exacerbated the risk of hypocalcemia post-treatment.

Implications:

• Clinicians should consider hypercalcemia as a potential complication of thyrotoxicosis.
• Monitoring calcium and vitamin D levels is crucial during bisphosphonate therapy for hypercalcemic patients.
• Prompt recognition and management of hypercalcemia and subsequent hypocalcemia are vital in thyrotoxicosis patients.