QJM Advance Access originally published online on February 9, 2006
QJM 2006 99(3):181-192; doi:10.1093/qjmed/hcl011
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Masterclasses in medicine |
Unusual causes of hypokalaemia and paralysis
From the 1Division of Nephrology, St. Michael's Hospital, University of Toronto, Toronto, Canada, 2Renal Division, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (ROC), and 3Nephrology Unit and Department of Internal Medicine, Stellenbosch University, Cape Town, South Africa
Address correspondence to Professor M.L. Halperin, University of Toronto, St Michael's Hospital Annex, Lab #1, Research Wing, 38 Shuter Street, Toronto, Ontario, M5B 1A6, Canada. email: mitchell.halperin{at}utoronto.ca
We demonstrate how the application of physiological principles may help to identify unusual causes of a very low plasma potassium (K+) concentration (PK) and paralysis. In the two patients described, the short time course of the illness suggested that there was an acute shift of K+ into cells. The combination of a low rate of excretion of K+, the absence of a metabolic acid-base disorder, and the fact that the clinical findings occurred very soon after a large intake of carbohydrate supported this impression. Surprisingly, the PK remained low for many hours after these stimuli to shift K+ into cells had abated. The missing link in this story was eventually provided by the attending medical team with the help of their mentor, Professor McCance.