Endocrine Abstracts

Aim

To assess relationship between serum calcium level and localization studies and management outcome.

Methodology

Retrospective analysis of data for patients referred by primary care for hypercalcemia from 1/3/2019 to 1/3/2020 to the Endocrinology department at Royal Berkshire Hospital. The sample size was 63 which excluded normo-calcemic hyperparathyroidism as well as MEN1/2 patients.

Results

The average age of cohort was 68.6 years with female preponderance (80.5%). The average referral adjusted calcium was 2.8 mmol/l and PTH was 12.5 mmol/l. End organ damage in the form of osteopenia and osteoporosis was highly prevalent at 60.3%. The sensitivity for USS was 47.6% and MIBI was 50.8%. The concordance between the two modalities was 71.4%. The lower limit of adjusted serum calcium level cut off for positive USS was 2.65 mmol/l and for positive MIBI was 2.62 mmol/l with p value of 0.00025. In terms of management outcome, 57.1% of cohort were referred to ENT team for surgery and the rest were conservatively managed.

Discussion

Hypercalcemia forms a significant proportion of referrals to endocrinology service. Primary hyperparathyroidism is the most common cause of hypercalcaemia, with an estimated prevalence of about 1–7 cases per 1000 adults.[1] This study reiterated the established expected demographics of patients with primary hyperparathyroidism i.e., female preponderance with increasing prevalence in older adults [2]. Half of the referrals were asymptomatic. About two third of the cohort had osteopenia and osteoporosis, a criterion that enables eligibility for surgical intervention if appropriate. The pick-up rate of parathyroid USS and scintigraphy were comparable at around 50%, with a discordance of 28.6% between them. The lower limit for adjusted calcium above which both the USS and SestaMIBI provided positive finding was 2.62 mmol/l which is reassuringly just above the lower limit cut off for NICE diagnostic criteria for hypercalcemia. It is important to note though that normo-calcemic hypercalcemia were not included in this study. With respect to management outcome, a significant 57.1% of cohort were referred to ENT team for targeted (63.9%) or exploration surgery (36.1%) depending on image findings. The rest were conservatively managed with either cinacalcet (34.6%) or wait and watch approach (65.4%). It is interesting to note that 80% of patients with adenoma on USS translated to a surgical outcome. This held true even in the event of discordance with MIBI scan, revealing this modality being favoured by ENT team.