Pseudogout with low values of magnesium and low alkaline phosphatase activity in synovial fluid

A case of pseudogout associated with low values of magnesium and alkaline phosphatase activity in the synovial fluid is presented. The low magnesium concentration is believed to cause the low alkaline phosphatase activity, since adding magnesium in vitro raised the activity to normal. The reason for the low magnesium concentration in the synovial fluid remains unclear.