James talks to Associate Professor Darren Roberts about hyperkalaemia on the wards.
Summary Writer: Elizabeth Campbell
Editor: James Edwards
Interviewee: Darren Roberts
Darren Roberts is a physician working in both clinical pharmacology/toxicology and nephrology in Sydney and Canberra and an Associate Professor at the Australian National University. He is the current Chair of the clinical pharmacology Special Interest Group and a member of various national and international government, professional and clinical committees. Darren’s research interests include pharmacokinetics and drug dosing in impaired renal function, influence of dialysis on xenobiotic clearance and evidence-based clinical toxicology. He works part-time at Royal Prince Alfred Hospital as a clinical pharmacologist and toxicologist, and undertook a portion of his renal training in Royal Prince Alfred Hospital and Concord Hospitals.
With Associate Professor Darren Roberts, Physician in Clinical Pharmacology, Toxicology, and Nephrology, at Canberra Hospital
The definition of hyperkalaemia may vary, depending on where you work. A serum potassium concentration greater than 5.5 is abnormal, and levels greater than 6-6.5 are very concerning. It is important to consider the reason for the hyperkalaemia and whether the potassium level is likely to continue to increase. If you have doubts about a result (e.g. suspecting a haemolysed blood sample), repeat the test. Blood gas testing is an accurate and quick way to confirm the serum potassium concentration.
When considering the causes of hyperkalaemia, it is helpful to think of either too much potassium getting into the blood (e.g. tissue damage), or difficulty getting the potassium out of the body (e.g. acute kidney injury). There may be a combination of factors leading to hyperkalaemia, for example, drug side effects (ACE inhibitors, spironolactone) with an associated acute kidney injury.
A 70-year-old man with end-stage renal failure presents to ED, unwell after missing dialysis for several days. He has a serum potassium concentration of 9 mmol/L.
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