Endocrine Abstracts

An 83-year-old man was admitted from rheumatology clinic with severe symptomatic hypocalcaemia and suppressed parathyroid hormone (PTH) having been referred with a 5-month history of worsening weakness, cramping and paraesthesia. Given the recent onset of symptoms and a record of a normal adjusted calcium in 2014 the diagnosis of new onset hypoparathyroidism was made and he was treated as per severe hypocalcaemia protocol. Admission blood tests showed low adjusted calcium (1.2mmol/l) and low PTH levels (<0.5 pmol/l), with normal phosphate, alkaline phosphatase, albumin and magnesium, and sufficient 25-hydroxyvitamin D levels. Underlying causes of hypoparathyroidism were considered. He had no history of surgery, irradiation or trauma to the neck. An HIV screen, iron studies, serum copper, and 9am serum cortisol were normal. Antiparathyroid antibodies were negative. A CT neck, thorax, abdomen and pelvis did not reveal any structural abnormalities in his neck or evidence of malignancy. Of note, he had received the first and second dose of the Oxford-AstraZeneca SARS-CoV-2 (ChAdOx1 nCoV-19) vaccines, three months and one month respectively, prior to the onset of his symptoms. Genetic syndromes were not considered given the late onset and absence of family history of hypoparathyroidism. His diagnosis is likely to be antibody-negative hypoparathyroidism and there has been no resolution on long-term follow up. It is rare to encounter new-onset hypoparathyroidism in the elderly and most cases occur after neck surgery or radiation. Autoimmune hypoparathyroidism, although rare, should still be considered in this age group after thorough investigation for other underlying causes. At present, there is only one other case report suggesting a possible link between the COVID-19 vaccine and development of hypoparathyroidism, however, whether this association is coincidental or causal remains to be elucidated. This is the first case report describing new-onset and persistent autoimmune hypoparathyroidism in an elderly patient after mRNA COVID-19 vaccination.