A case of severe pseudohyperkalaemia due to muscle contraction

Abstract

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.

Pseudohyperkalemia associated with essential thrombocytosis; a hint for better clinical practice

“…11 In contrast, a tube containing an anticoagulant, such as heparin, is used to measure plasma electrolytes, and the release of potassium from platelets is prevented. 3 Therefore, numerous platelets in thrombocytosis cause more release of intracellular potassium from thrombocytes in the measurement of serum potassium while no elevation in plasma levels, leading to pseudohyperkalemia.…”

“…In this situation, the in vitro potassium concentration raises without any actual increase in the in vivo values (which is called true hyperkalemia). 3 Hyperkalemia without any related clinical symptoms or obvious risk factors strongly raised the suspicion of pseudohyperkalemia. Substantially, pseudohyperkalemia must be noted, because the wrong administration of hyperkalemia treatment in this condition can lead the patient to severe hypokalemia and cause serious complications such as tachycardia, ventricular fibrillation, and hypoventilation.…”

“…Pseudohyperkalemia is defined as a raised serum potassium with concurrent normal plasma potassium levels. In this situation, the in vitro potassium concentration raises without any actual increase in the in vivo values (which is called true hyperkalemia) 3 . Hyperkalemia without any related clinical symptoms or obvious risk factors strongly raised the suspicion of pseudohyperkalemia.…”

Pseudohyperkalaemia in essential thrombocytosis: an important clinical reminder

“…Plasma electrolytes are taken in a specialised lithium heparinised bottle where tube inversions ensure mixing of anticoagulant (heparin) with blood to prevent clotting. ( 1 ) Prevention of clotting, therefore, prevents the release of intracellular potassium from platelets. The increase in serum potassium, from platelets, initially shows a linear increase at higher platelet concentrations in thrombocytosis.…”

“…Serum electrolytes are often taken as standard routine blood tests for almost all patients undergoing investigations, frequently daily in hospitalised patients. Pseudohyperkalaemia occurs when there is a raised serum potassium ( 1 ), with concomitant normal plasma potassium levels. A key understanding of pseudohyperkalaemia is essential for interpreting these investigations as true hyperkalaemia is potentially life-threatening and often presents insidiously.…”