Lessons to be learned: a case study approach: pseudohyperkalaemia due to thrombocytosis in a case of tubo-ovarian abscess.

The case described here is that of a 48-year-old lady who presented with abdominal pain and fever; at a later stage she was found to have hyperkalaemia of uncertain origin. Blood examination revealed there to be marked elevation of the platelets (thrombocytosis) on some occasions. It was then realised that there was correlation between the platelet levels and serum potassium values. During the clotting process the release of potassium from the increased number of platelets caused the serum potassium to be elevated on account of an in vitro effect. The important point is that the raised serum potassium levels were not due to an in vivo phenomenon and, therefore, the patient did not need treatment for this; however, the presence of thrombocytosis was itself a clue to the diagnosis--which was eventually recognised as being due to an infection. At operation a tubo-ovarian abscess was discovered to be the cause of the problem.