Vol.:(0123456789) 1 3 Internal and Emergency Medicine https://doi.org/10.1007/s11739-018-1898-7 IM - ORIGINAL Extreme hypomagnesemia: characteristics of 119 consecutive inpatients Geofrey Cheminet 1,2  · Gabrielle Clain 2,3  · Anne‑Sophie Jannot 2,3  · Brigitte Ranque 1,2  · Amélie Passeron 1,2  · Adrien Michon 1,2  · Gonzalo De Luna 1,2  · Jean‑Luc Diehl 2,4  · Stéphane Oudard 2,5  · Christophe Cellier 2,6  · Alexandre Karras 2,7  · Benoit Vedié 8  · Caroline Prot‑Bertoye 2,9  · Jacques Pouchot 1,2  · Jean‑Benoît Arlet 1,2 Received: 25 March 2018 / Accepted: 16 June 2018 © SIMI 2018 Abstract Extreme hypomagnesemia (hypoMg) can be encountered in many situations, but little data currently exist. Our aim is to describe the epidemiological, clinical, etiological characteristics, and the biological abnormalities of consecutive inpatients with extreme hypomagnesemia. In our observational monocentric study, between 1st July 2000 and April 2015, all inpatients with extreme hypomagnesemia, defned by at least one plasma magnesium concentration (P Mg ) below 0.3 mmol/L, were included. Demographic, clinical, biological characteristics and the drugs prescribed before the qualifying P Mg measurement were retrospectively collected. 41,069 patients had at least one P Mg assessment. The prevalence of extreme hypomagnesemia is 0.3% (119 inpatients). The median age is 70 years, 52% are women. The patients were mainly hospitalized in intensive care (n = 37, 31.1%), oncology (n = 21, 17.6%), gastroenterology (n = 18, 15.1%) and internal medicine (n = 16, 13.4%) departments. One hundred patients (84%) had a medical history of gastrointestinal disease (39% with bowel resections, 24% with stoma), and 50 (42%) had a cancer history. The drugs most commonly prescribed (known to induce hypoMg) are proton pump inhibitors (PPI) (n = 77, 70%), immunosuppressive regimens (n = 25, 22.5%), platinum salt-based chemo- therapies (n = 19, 17.1%), and diuretics (n = 22, 19.8%). The suspected causes of hypomagnesemia are often multiple, but drugs (46%, including PPI in 19%) and chronic gastrointestinal disorders (37%) are prominent. Associated electrolyte distur- bances include hypocalcemia (77%) and mild hypokalemia (51%). The 1-month mortality from all causes is 16%. Extreme hypomagnesemia is rare in inpatients, and is frequently associated with severe hypocalcemia. Digestive disorders and drugs are the main contributory causes. Keywords Hypomagnesemia · Hypocalcemia · Hypokalemia · Mortality · Proton pump inhibitors Abbreviations A Albumin CK Creatine kinase C ac Corrected plasma calcium concentration C am Measured plasma calcium concentration Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11739-018-1898-7) contains supplementary material, which is available to authorized users. * Jean-Benoît Arlet jean-benoit.arlet@aphp.fr 1 Service de Médecine Interne, Internal medicine Department, Georges Pompidou European Hospital, AP-HP, 20 rue Leblanc, 75015 Paris, France 2 Faculté de Médecine Paris Descartes, Sorbonne Paris-Cité, Paris, France 3 Medical Information Department, Georges Pompidou European Hospital, AP-HP, Paris, France 4 Medical Intensive Care Department, Georges Pompidou European Hospital, AP-HP, Paris, France 5 Oncology Department, Georges Pompidou European Hospital, AP-HP, Paris, France 6 Gastroenterology Department, Georges Pompidou European Hospital, AP-HP, Paris, France 7 Nephrology Department, Georges Pompidou European Hospital, AP-HP, Paris, France 8 Biochemistry Department, Georges Pompidou European Hospital, AP-HP, Paris, France 9 Renal Physiology Department, Georges Pompidou European Hospital, AP-HP, Paris, France