Endocrine Abstracts

We describe a 82 year old patient with background history of thyrotoxicosis (had total thyroidectomy), primary hyperparathyroidism (had parathyroidectomy 12 years back at another hospital – two glands removed). She was on L-thyroxine, alfacalcidiol 1 μg/day and CaCO₃ 500 mg BD. She remained stable for 7 years on this cocktail. In February 2017, she was admitted with acute confusion and was found to have adjusted ca level of 4.57 with AKI, normal magnesium. No recent changes in medications and there was no obvious precipitating event (apart from AKI although this may well be the other way round). Other workup for hypercalcemia was negative (including CT CAP). She was discharged prior to Endo review (CCa 2.68) with no alfacalcidiol/CaCO₃ at all. Her renal function was back to baseline. Understandably, she was readmitted after 3 days with paresthesia, pins and needles in both hands and her Adj Ca was 2.01. She was re-started on CaCO₃ 500 mg bd and alfacidiol 500 ng once daily with improvement in calcium levels (Adj Ca 2.2). However, 10 days post-discharge, she was readmitted with hypocalcemia (1.82; Mg 0.56). She was treated appropriately and discharged on CaCO₃ 500 bd, alfacalcidiol 1mcg daily. In April 2017, she was re-admitted with Adj calcium of 3.33. Her alfacalcidiol was reduced to 750 ng, CaCO₃ to 500 mg OD and Ca levels have been stable since (2.1–2.25). Corrected calcium levels: 4.57-3.30-2.68-2.01-2.2-1.82-1.90-3.33-2.21-2.18

Conclusion: This case clearly showed that dose requirements can change even after many years + the difficulties in maintaining calcium homeostasis post parathyroidectomy.

Questions: 1. What are the ideal calcium levels in patients with post-parathyroidectomy hypoparathyroidism?

2. What are the reasons for changes in dose requirements?