Hypomagnesaemia and hypocalcaemia in a patient with systemic sclerosis: role of proton pump inhibitors.

Proton pump inhibitors (PPI) are widely used in patients with systemic sclerosis (SSc) due to the chronic gastroesophageal reflux. The authors report a female patient with a 9-year history of SSc and long-term use of omeprazole, who complained of paresthesia and asthenia for 12 months. Physical examination revealed clinical signs of hypocalcaemia confirmed by laboratory tests that also showed hypomagnesaemia. After exclusion of possible causes, hypomagnesaemia secondary to PPI was diagnosed and omeprazole was replaced by a histamine H2-receptor antagonist: ranitidine. Despite continuous magnesium supplementation, the reintroduction of PPI at a lower dose due to worsening of dyspeptic symptoms led to recurrence of hypomagnesaemia. After definitive suspension of PPI, reintroduction of ranitidine and optimisation of anti-reflux environmental measures, the patient stabilised. In conclusion, SSc patients using PPIs should have their magnesium and calcium serum levels measured periodically, and non-specific symptoms such as asthenia, generalised paresthesia or life-threatening manifestations (seizures, arrhythmias) should not be neglected.