Hypomagnesemia in a department of internal medicine.

Background: Hypomagnesemia is frequently encountered in hospitalized patients. The aim of this study was to determine the underlying causes of hypomagnesemia as well as the clinical and biochemical characteristics, and concomitant electrolyte and acid-base abnormalities in patients with decreased serum magnesium (Mg(2+)) levels in an internal medicine clinic.

Methods: We prospectively studied adult patients who, either on admission to our clinic or during their hospitalization, were found to have hypomagnesemia (serum Mg(2+) concentration <1.3 mEq/L).

Results: One hundred and seven patients out of 2284 patients had hypomagnesemia. The incidence of hypomagnesemia was 4.7%. Malnutrition, drugs (mainly diuretics and aminoglycosides), respiratory alkalosis, diabetes mellitus, acute tubular necrosis, alcohol consumption and gastrointestinal losses were the main causes of the hypomagnesemia. In the majority of patients (80%), more than one condition may have contributed to the development of hypomagnesemia. Seventy-one patients (66.3%) exhibited at least one additional electrolyte disorder. Hypophosphatemia was the most frequent electrolyte abnormality (31.1%), followed by hypokalemia (26.1%), hyponatremia (21.5%), and hypocalcemia (22%). Seventy-eight patients (72.9%) exhibited pure or mixed acid-base disorders, mainly respiratory alkalosis (20.6%), metabolic acidosis (15.8%), and mixed metabolic alkalosis and respiratory alkalosis (18.7%).

Conclusions: Hypomagnesemia in patients hospitalized in an internal medicine clinic was of multifactorial origin. A wide array of concurrent acid-base and electrolyte disorders was evident in this population.