SHM Converge Scientific Abstract ePoster Gallery-Hyperkalemia or Pseudohyperkalemia? Management in a Renal Cell Carcinoma Patient

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A 46-year-old man with heart failure and newly diagnosed renal cell carcinoma was admitted with fatigue, pain, and initially normal potassium and platelet counts. Over the next two weeks, his potassium increased to 6.0 with peaked T waves on EKG, and his platelets rose markedly to 810,000/µL. He was treated aggressively for presumed hyperkalemia with Lasix, Lokelma, insulin shifts, and discontinuation of Entresto. Despite about a week of therapy, his potassium remained elevated.<br /><br />Workup for other causes, including tumor lysis syndrome, hemolysis, and lab abnormalities, was unrevealing. Nephrology noted the significant thrombocytosis and suspected pseudohyperkalemia, so a plasma potassium level was drawn in a heparinized tube. This result was close to 4.0, confirming pseudohyperkalemia. His thrombocytosis improved with IV fluids and better pain control, and his potassium normalized over the following days.<br /><br />The case highlights the importance of interpreting abnormal lab values in clinical context and considering pseudohyperkalemia, especially in patients with marked thrombocytosis. Platelet elevation can cause falsely high serum potassium because potassium is released during clotting or sample processing. It also underscores the risk of prolonged treatment for presumed hyperkalemia, which can lead to dangerous hypokalemia if the elevated potassium is not real. The authors note that true hyperkalemia may have been present initially, possibly related to Entresto, but the persistent elevation was most consistent with pseudohyperkalemia.<br /><br />Overall, clinicians should verify unexpectedly high potassium levels, especially when platelet counts are very elevated, by checking plasma potassium in a heparinized sample before escalating treatment.

Asset Subtitle

Kazi T. Haque

Meta Tag

Author List Kazi T. Haque, Mubeen Khan

Category Clinical Vignettes

Concept Hyperkalemia

Concept Pseudohyperkalemia

Concept Plasma Potassium

Concept Thrombocytosis

Concept Clinical Context

Distinguished Non-Finalist

Presenter Organization University of Texas Health Science Center at Houston

Presenting Author Kazi T. Haque

Track Adult

Keywords

pseudohyperkalemia

thrombocytosis

hyperkalemia

renal cell carcinoma

heart failure

potassium

platelet count

heparinized plasma

EKG peaked T waves

Entresto

Hyperkalemia

Pseudohyperkalemia

Plasma Potassium

Thrombocytosis

Clinical Context