Postsplenectomy thrombocytosis with pseudohyperkalaemia

Abstract

A 52-year old man developed hyperkalaemia on the 11th postoperative day following an extensive open retroperitoneal liposarcoma resection that included splenectomy. Despite thorough investigations, no aetiology for the hyperkalaemia was identified and standard empirical treatment was ineffective. On reconsideration, in view of the patient's concurrent thrombocytosis, a pseudofactual or artefactual hyperkalaemia was suspected. This was confirmed by contemporaneous testing of serum and plasma potassium levels, with the latter value lying within the normal range. Treatment for hyperkalaemia was discontinued, thus averting an iatrogenic and potentially dangerous hypokalaemia. This case highlights pseudohyperkalaemia as an often-neglected cause of elevated serum potassium levels and discusses its association with thrombocytosis following splenectomy.

Figure 1

Graph showing the rise in serum potassium levels as measured in Serum Separator (‘gold-top’) tubes (y axis) and blood platelet count (x axis) for the patient postsplenectomy. Each point represents a unique day on which measurements were carried out. The trend illustrates a strong and statistically significant positive correlation (R=0.91, p<0.0001****) between the two variables highlighting the link between thrombocytosis and pseudohyperkalaemia.