Differentiating Pseudohyperkalemia From True Hyperkalemia in a Patient With Chronic Lymphocytic Leukemia and...

Area of Science:

• Internal Medicine
• Hematology
• Clinical Chemistry

Background:

• Acute electrolyte disturbances, particularly hyperkalemia, pose significant risks, including fatal cardiac arrhythmias.
• Prompt management of elevated serum potassium is crucial in clinical practice.
• Falsely elevated serum potassium can arise from pre-analytical errors like fist clenching or hemolysis, and analytical interferences.

Observation:

• An elderly woman with chronic lymphocytic leukemia presented with lower left quadrant pain and hematochezia.
• Initial laboratory tests showed a markedly elevated serum potassium level (7.5 mmol/L).
• The patient lacked typical hyperkalemia symptoms, EKG changes, and evidence of hemolysis in the blood specimen.

Findings:

• Abdominal CT scan indicated inflammatory changes consistent with diverticulitis.
• The patient received initial treatment for hyperkalemia with intravenous calcium, insulin, glucose, and bicarbonate.
• A subsequent serum potassium measurement normalized (3.9 mmol/L), and leukolysis-induced pseudohyperkalemia was diagnosed, leading to cessation of hyperkalemia treatment.

Implications:

• This case underscores the critical need for physicians to correlate laboratory findings with clinical presentation.
• Recognizing pseudohyperkalemia, specifically leukolysis-induced, is vital to prevent overtreatment and iatrogenic complications.
• Maintaining clinical suspicion and thorough investigation of unexpected laboratory results are paramount in patient care.