Severe hypocalcemia in the emergency department: a retrospective cohort study of prevalence, etiology, treatment and outcome.

The aim of this study was to evaluate the prevalence of severe hypocalcemia in patients attending the emergency department. Symptoms, causes, treatment, and outcome of severe hypocalcemia as well as course of calcium concentrations were assessed. This retrospective case series included all adult patients with measurements of serum calcium concentrations presenting to the emergency department of the Bürgerspital Solothurn between January 01 in 2017 and December 31 in 2020. Medical record reviews were performed of all patients with severe hypocalcemia, defined by a serum calcium concentration < 1.9 mmol/L, to assess clinical presentation and management. 1265 (3.95%) patients had a serum calcium concentration of < 2.1 mmol/L of which 139 (11%) had severe hypocalcemia of < 1.9 mmol/L. 113 patients had at least one measurement of albumin. Of these, 43 (3.4%) had an albumin-corrected serum calcium < 1.9 mmol/L defining true, severe hypocalcemia. Hypocalcemia was identified and documented in 35% of all cases. The mean serum calcium concentration was 1.74 ± 0.14 mmol/L. Calcium concentrations in malignancy-related hypocalcemia were similar to non-malignancy-related hypocalcemia. The main symptoms attributed to hypocalcemia were cardiac and neurologic. 12% of patients with severe hypocalcemia received intravenous and 23% oral calcium replacement. Active malignancy was the main cause of severe hypocalcemia in 28%, while in most cases, the main cause remained unclear. 41.9% of severely hypocalcemic patients reattended the emergency department for another episode of hypocalcemia within 1 year. Hypocalcemia is common in patients attending the emergency department, however, appears to be neglected frequently. The disorder is often a manifestation of severe disease, triggered by multiple causes. Calcium replacement was administered in less than half of the patients with severe hypocalcemia in this study. Due to frequent readmissions to the emergency department and a high mortality, increased awareness of the disorder and careful follow-up are desirable.