Hyperkalaemia ( Greek hyper- - over, much; -emia - in the blood) (also potassium excess ) describes a sometimes life-threatening electrolyte disorder in which the concentration of potassium in the blood is increased. Hyperkalemia is spoken of in the blood serum above 5.0 mmol / l (5.4 in children) . A lack of potassium in the blood is known as hypokalemia .
Sources of error in incorrectly elevated values (pseudohyperkalemia) can be:
- The blood sample has been jammed for too long or has been pumped by hand for too long. This has resulted in hemolysis. The intracellular potassium of the erythrocytes is transferred to the serum through hemolysis.
- Rapid aspiration due to a cannula that is too small
- The blood was left to stand too long before centrifugation and has already decomposed too much. Hemolysis occurs.
- Potassium release in the blood sample in the event of excessive thrombocytosis or leukocytosis (e.g. in CML )
In the case of hyperkalemia, a sharp, high T-wave, the loss of the P-wave and a broadening of the entire QRS complex (especially right bundle branch block ) are noticeable in the ECG . The ECG changes, however, show only low sensitivity and specificity . ECG controls are therefore not a substitute for regular potassium controls when monitoring potassium-lowering therapy.
Increased potassium levels occur when not enough potassium can be excreted through the kidneys. This happens with acute kidney failure , chronic kidney failure and adrenal insufficiency ( Addison's disease ). Various medications can also increase blood potassium levels. These include ACE inhibitors and sartanes , aldosterone antagonists , triamterene , cytostatics , cold packed red blood cells and hormonal contraceptives containing the progestin drospirenone (Yasmin / Petibelle) because drospirenone structurally similar to spironolactone .
The serum potassium level is acutely affected by changes in the pH value of the blood. A change in the pH value by 0.1 leads to an opposite change in the potassium level of about 0.5 mmol / l. If the pH drops, acidosis occurs . In an effort to compensate for this, redistributive hyperkalemia occurs. Excess H + ions are redistributed from intravascular to intracellular and the potassium ions are redistributed in the opposite direction. Acidosis caused by organic acids such as lactate and ketone bodies does not lead to an increase in the potassium level in the blood, as these can penetrate the cell and so the potassium shift into the extracellular space does not occur. Respiratory acidosis leads to less pronounced hyperkalemia than metabolic acidosis.
Particularly in combination with reduced excretion, an increased intake can also lead to hyperkalemia. Potassium-rich infusions and, in the case of advanced kidney failure , even larger quantities of dried fruit or potassium-rich fruits (bananas) can contribute to this.
Therapy: potassium redistribution and potassium lowering measures
- Calcium gluconate 10% 10 ml iv, duration of action approx. 30 minutes. Stabilizes the resting membrane potential of the heart muscle cells and the conduction system, thereby preventing arrhythmias .
- high-dose inhalation with β 2 mimetics, e.g. B. Salbutamol . Shift from potassium to intracellular.
- Glucose solution + old insulin , onset of action after 30 minutes, duration of action 4 to 6 hours. Insulin induces a simultaneous intracellular shift of glucose and potassium.
- Sodium hydrogen carbonate , onset of action after approx. 10 minutes, duration of action 2 hours. Alkalosis → sodium proton exchanger (NHE) active → shift from sodium to intracellular → increased activity of the sodium-potassium pump → extracellular lowering of potassium
- Furosemide intravenously with 0.9% NaCl solution to specifically promote the elimination of potassium
- Restriction of enteral potassium intake
- Cation exchangers (either oral or rectal)
- Hemodialysis for 2 to 4 hours or hemofiltration
- Withdrawal from eplerenone , spironolactone , triamterene , ACE inhibitors
- Other medicines: patiromer , sodium zirconium cyclosilicate .
- Ian R Bailey, Vanessa R Thurlow: Is suboptimal phlebotomy technique impacting on potassium results for primary care? In: Annals of Clinical Biochemistry. May 2008, pp. 266-269. doi: 10.1258 / acb.2007.007123 .
- Brian T. Montague et al .: Retrospective Review of the Frequency of ECG Changes in Hyperkalemia . In: Clin J Am Soc Nephrol . No. 3 , 2008, p. 324-330 ( abstract ).
- Ulrich Kuhlmann, Joachim Böhler, Friedrich C. Luft, Mark Dominik Alscher, Ulrich Kunzendorf: Nephrology - Pathophysiology - Clinic - Renal Replacement Procedure , Stuttgart, 2015, p. 327
- Herbert Renz-Polster among others: Basic textbook internal medicine. 3. Edition. Urban & Fischer-Verlag, ISBN 3-437-41052-0 .
- M. M. Sood, AR Sood, R. Richardson: Emergency management and commonly encountered outpatient scenarios in patients with hyperkalemia. In: Mayo Clinic proceedings. Volume 82, Number 12, December 2007, pp. 1553-1561, doi : 10.1016 / S0025-6196 (11) 61102-6 . PMID 18053465 . (Review). .
- A. Rastegar, M. Soleimani, A. Rastergar: Hypokalaemia and hyperkalaemia. In: Postgraduate medical journal. Volume 77, Number 914, December 2001, pp. 759-764, PMID 11723313 . PMC 1742191 (free full text). (Review). .
- KS Kamel, C. Wei: Controversial issues in the treatment of hyperkalaemia. In: Nephrology Dialysis Transplantation . 2003, Volume 18, pp. 2215-2218. PMID 14551344 . (Review).
- Amitava Majumder, Anne Paschen: Medical working techniques. In: Jörg Braun, Roland Preuss (Ed.): Clinic Guide Intensive Care Medicine. 9th edition. Elsevier, Munich 2016, ISBN 978-3-437-23763-8 , pp. 29-93, here: pp. 62-66 ( dialysis method ).
- VELTASSA (powder for oral suspension) . European Medicines Agency .
- LOKELMA (powder for oral suspension) . European Medicines Agency .
- Danilo Fliser: Symptomatic hyperkalaemia: what to do in an emergency. In: Dtsch Arztebl. 2003; 100 (24), pp. A-1657 / B-1374 / C-1290.