IMPE Abstracts

Introduction: Pediatric hypercalcemia is a rare condition. It occurs due to an imbalance between the endocrine system (PTH, calcitriol) and its target organs (bone, kidney and intestine). It is produced by multiple causes. Although it is usually asymptomatic, sometimes it could become an emergency, with increased morbidity and/or mortality.

Objective: To describe etiologies, biochemical profiles, clinical characteristics and treatments instituted in hypercalcemic children assisted at a tertiary center.

Methods: A retrospective descriptive study between 2008 and 2022 was conducted. Medical records of patients with confirmed hypercalcemia (>97 pc for age reference) were reviewed. Maximum calcemia with phosphatemia and PTH were analized. Patients were classified in 3 groups (G) according to the main suspected pathophysiological mechanism of hypercalcemia: G1: iatrogenic, G2: PTH-independent, G3: PTH-dependent. At the same time, groups were divided in subgroups according to specific etiologies involved. Symptomatic hypercalcemia was considered when there was at least one related symptom.

Results: 147 patients, 84 males (57%), median age 3.68 years (y) (IQR: 0.8-10.46) with confirmed hypercalcemia were included. G1: n76 (51.7%). G2: n58 (39.4%) (subgroups: oncologic: n21, granulomatous: n21 and genetic: n16). G3: n13 (8.8%) (subgroups: primary hyperparathyroidism: n7 and tertiary hyperparathyroidism: n6). In G3 median age was significantly greater than in G1 and G2 (9.9 vs 3.32 and 2.98 y respectively, P<0.03). While, median age in genetic subgroup of G2 was the lowest (0.81 y, P<0.005). Median calcemia was significantly lower in G1 than G2 and G3 (11.6 vs 12.6 and 12.3 mg/dl respectively, P<0.001). Mean phosphatemia was significantly lower in G3 than G1 and G2 (2.89 vs 5.25 and 4.96 mg/dl respectively, P<0.001). Symptoms of hypercalcemia were found in 34% of the patients (G1: 13%, G2: 50%, G3: 85%). Most patients were treated with reduced milk intake and hypercalcemic agents (vitamin D, calcium, parenteral nutrition), hyperhydratation and furosemide, however, 28% (G1: 10.5%, G2: 45% and G3: 54%) required additional treatments: corticoids, pamidronate, surgery, calcitonin, cinacalcet.

Conclusions: In our cohort, the iatrogenic group (G1) was the most numerous and the one with the lowest hypercalcemia and associated symptoms. Patients in the PTH-dependent group (G3) had the lowest phosphatemia and were the most symptomatic. The group of independent-PTH patients (G2) constitutes a diagnostic and therapeutic challenge due to the heterogeneity and severity of the etiologies included and the lack of a characteristic biochemical profile.