A case of severe pseudohyperkalaemia due to muscle contraction
Jan Van Elslande
; Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium
Toon Dominicus ; Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium
Jaan Toelen ; Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium; Department of Development and Regeneration, University of Leuven, Leuven, Belgium
Glynis Frans ; Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium
Pieter Vermeersch orcid.org/0000-0001-7076-061X ; Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium; Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
Introduction: Severe hyperkalaemia is a serious medical condition requiring immediate medical attention. Before medical treatment is started,
pseudohyperkalaemia has to be ruled out.
Case description: A 10-month old infant presented to the emergency department with fever and coughing since 1 week. Routine venous blood testing
revealed a severe hyperkalaemia of 6.9 mmol/L without any indication of haemolysis. Reanalysis of the plasma sample confirmed the hyperkalaemia
(7.1 mmol/L). Based on these results, the clinical pathologist suggested to perform a venous blood gas analysis and electrocardiogram (ECG)
which revealed a normal potassium of 3.7 mmol/L and normal ECG, ruling out a potentially life-treating hyperkalaemia. The child was diagnosed
with pneumonia. The paediatrician had difficulty to perform the first venous blood collection due to excessive movement of the infant during venipuncture.
The muscle contractions of the child in combination with venous stasis most probably led to a local increase of potassium in the sampled
limbs. The second sample collected under optimal preanalytical circumstances had a normal potassium. Since muscle contraction typically does not
cause severe hyperkalaemia, other causes of pseudohyperkalaemia were excluded. K3-EDTA contamination and familial hyperkalaemia were ruled
out and the patient did not have extreme leucocytosis or thrombocytosis. By exclusion a diagnosis of pseudohyperkalaemia due to intense muscle
movement and venous stasis was made.
Conclusion: This case suggests that intense muscle contraction and venous stasis can cause severe pseudohyperkalemia without hemolysis. Once
true hyperkalemia has been ruled out, a laboratory work-up can help identify the cause of pseudohyperkalaemia.
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