Hypophosphataemia and hypokalaemia in patients with hypomagnesaemia.

Experimental data suggest an association between hypomagnesaemia and hypokalaemia, and also with hypophosphataemia, but there have been few large studies using clinical results to study the prevalence of hypophosphataemia and/or hypokalaemia in patients with hypomagnesaemia. Our results show a two-fold increase in the prevalence of hypophosphataemia (plasma phosphate concentration < or = 0.80 mmol/l) in patients with hypomagnesaemia (plasma magnesium level < or = 0.70 mmol/l) compared with patients without this condition, and a six-fold increase in hypokalaemia (plasma potassium < or = 3.5 mmol/l). A triology consisting of hypomagnesaemia, hypophosphataemia and hypokalaemia is also described, which was found in 8% of patients with hypomagnesaemia and 17% of patients with severe hypomagnesaemia (plasma magnesium < or = 0.50 mmol/l). Patients most susceptible to this phenomenon include those in intensive therapy, post-operative patients, those with sepsis being treated with aminoglycosides, and oncology patients receiving chemotherapy.