Be on the lookout for this life threatening condition
- By: Humera Sarwar, AM Brooke
- Published: 15 November 2012
- DOI: 10.1136/sbmj.e6998
- Cite this as: Student BMJ 2012;20:e6998
Hyperkalaemia is defined as a serum potassium concentration [K+] of more than 5.5 mmol/L (normal range 3.5 to 5.5 mmol/L). It is common, occurring in up to 10% of hospital inpatients,1234 and high potassium concentrations have a high mortality if not treated rapidly.24 Hyperkalaemia is usually an incidental finding on regular tests.
As cardiac arrest can be the first definitive sign of hyperkalaemia,45doctors need to be aware of the condition and to understand the need for urgent treatment.
Potassium is the most abundant positive ion in the human body, with most of it found intracellularly.267 It has important roles within the body; it is integral to the propagation of nerve impulses via action potentials.27
Serum potassium must be tightly regulated, as the ratio of intracellular to extracellular potassium is important in determining cell membrane potential.2 As potassium is a key player in neuromuscular systems, small changes in potassium concentration have