[Magnesium and phosphorus--the forgotten electrolytes].

The clinical and pathophysiological significance and epidemiology of magnesium and phosphorus excess and deficit are discussed. In daily routine both ions largely remain "the forgotten electrolytes". With both elements deficits are clinically more important than excesses. Dietary intake, gastrointestinal and renal losses, shifts between intra- and extracellular fluid and sequestration within the extracellular compartment are the essential factors which determine body stores and the extracellular concentration of the electrolyte. The clinical signs of excess and deficit often lack specificity and - in the case of phosphorus deficiency - involve almost any organ. Since treatment of deficits is easy and success is rapid and involves virtually no risk a timely diagnosis is all the more important but often requires a high index of suspicion.