A 61-year-old man was admitted to the emergency department (ED) for increased potassium concentration of 6.3 mmol/L (reference interval, 3.5–5.0 mmol/L) that was ordered by the general practitioner as part of a yearly medical checkup. Physical examination did not reveal any symptoms associated with hyperkalemia.
Student Discussion Document (pdf)
Michel J. Vos,1,2* Jolande W. Bouwhuis,3 and Lambert D. Dikkeschei1
1Department of Clinical Chemistry, Isala Hospital, Zwolle, the Netherlands; 2Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands; 3Department of Internal Medicine, Isala Hospital, Zwolle, the Netherlands.
*Address correspondence to this author at: Isala Hospital, Dokter van Heesweg 2, 8025 AB Zwolle, the Netherlands. Fax 31 20 –5661983; e-mail firstname.lastname@example.org
A 61-year-old man was admitted to the emergency department (ED) for increased potassium concentration of 6.3 mmol/L (reference interval, 3.5–5.0 mmol/L) that was ordered by the general practitioner as part of a yearly medical checkup. Physical examination did not reveal any symptoms associated with hyperkalemia. Reanalysis of potassium in a new blood sample drawn in the hospital resulted in a value of 3.7 mmol/L. Remarkably, his visit to the ED had been the third one in 3 years’ time, all taking place after a yearly medical checkup during the winter season with increased potassium at each visit that was within the reference interval after reanalysis of a new blood sample drawn in the hospital. The patient was referred to an internist for further examination who ordered a potassium analysis 1 month after the last visit to the ED. Again, an increased concentration was noticed (6.6 mmol/L) followed by admission to the emergency room. Reanalysis of potassium in the hospital again showed a healthy potassium concentration (3.6 mmol/L). The patient did not use any medication. On his visit to the internist, he mentioned that 1 year ago his sister was also admitted to the ED for an increased potassium concentration (7.9 mmol/L) that could not be confirmed in a newly drawn blood sample.
Questions to Consider
- What are possible causes of discrepant potassium results?
- What is the differential diagnosis of hyperkalemia?
- Which erythrocyte enzyme deficiencies can result in hemolysis?
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