A study of hypermagnesaemia in a hospital population.

The purpose of this present study was to assess the prevalence of hypermagnesaemia in a hospital population. Furthermore, the relationship between hypermagnesaemia and other common electrolyte disturbances such as hypo- and hypercalcaemia, hypo- and hyperkalaemia and hypo- and hyperphosphataemia was studied. Twenty-seven percent of magnesium requests showed a serum magnesium concentration equal to, or greater than, 1.0 mmol/l. Hyperkalaemia (a plasma potassium concentration of equal to, or greater than, 5.0 mmol/l) was found in 18% of the patients with hypermagnesaemia and 25 % of these patients showed hyperphosphataemia (a plasma phosphate concentration of equal to, or greater than, 1.5 mmol/l). Of the serum magnesium requests, hypermagnesaemia was particularly common on the intensive care (23%) and the renal unit (43%). Hypermagnesaemia was also seen in patients undergoing cardiothoracic surgery (17 %) and who had an acute myocardial infarction (8 %). Seventy-three percent of patients with a plasma magnesium of greater than 1.0 mmol/l showed abnormal renal function. However, it was rare to find a serum magnesium of greater than 2.0 mmol/l (less than 1% of magnesium requests).