QJM Advance Access originally published online on March 10, 2005
QJM 2005 98(4):305-316; doi:10.1093/qjmed/hci046
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Masterclasses in medicine |
An approach to the patient with severe hypokalaemia: the potassium quiz
From the 1Department of Nephrology, Leiden University Medical Center, The Netherlands, 2Renal division, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (ROC), 3Nephrology Unit and Department of Internal Medicine, Stellenbosch University, Cape Town, South Africa, and 4Division of Nephrology, St. Michael's Hospital, University of Toronto, Toronto, Canada
The objective of this teaching session with Professor McCance is to develop an approach to the management of patients with a very low plasma potassium (K+) concentration (PK). The session begins with a quiz based on six recent medical consultations for a PK < 2 mmol/l. Professor McCance outlined how he would proceed with his diagnosis and therapy, using the synopsis that described each patient. This approach was then applied to a new patient, a 69-year-old woman who had a large volume of dependant oedema and developed a severe degree of weakness and hypokalaemia during more aggressive diuretic therapy that included a K+-sparing diuretic. The initial challenge for Professor McCance was to deduce why the K+-sparing diuretic was not effective in this patient. He also needed to explain why the PK was so low on admission.
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