HyperkalemiaE87.5

Hyperkalemia is an electrolyte disturbance and is defined as plasma potassium concentration > 5.0 mmol/l in adults and >5.4 mmol/l in children.

The following factors can be considered as etiopathogenesis here:

External balance disturbance:

• increased oral or venous K+ supply

Decreased K+ excretion:

• Acute renal failure: In anuria, serum potassium increases by about 1mmol/l daily as a result of cell catabolism.
• Chronic renal failure
• Hypoaldosteronism

Iatrogenically induced hyperkalemia:

• Renin inhibitors, ACE inhibitors and sartans inhibit the renin-angiotensin system.
• Aldosterone antagonists such as spironolactone and eplerenone inhibit the effects of aldosterone
• Potassium-sparing diuretics such as amiloride and triamterene retain potassium in the kidney
• Beta-blockers inhibit the RAS by inhibiting renin formation
• NSAIDs decrease renin secretion and renal blood flow
• Potassium chloride increases the exogenous supply of potassium as a drug
• Numerous other drugs have the potential to cause hyperkalemia. These include amino acids, azole antifungals, benzylpenicillin potassium (penicillin G), ciclosporin, digoxin, heparins, pentamidine, succinylcholine, tacrolimus, and trimethoprim.

Internal balance disorders (distribution hyperkalaemia): due to the transfer of intracellular potassium to the extracellular space.

• Acidosis
• release of potassium in case of cell damage (large soft tissue injuries with myolysis, rhabdomyolysis, burns, etc.)

Often with few symptoms. High concentrations, on the other hand, are potentially life-threatening and manifest themselves in muscle weakness, paralysis and cardiac arrhythmias. Elderly people with kidney disease are particularly at risk. Numerous drugs can promote the metabolic disorder because they inhibit the renin-angiotensin system, which promotes potassium excretion at the kidney.

The clinic, similar to hypokalemia, consists of muscular, neurologic, and cardiac symptoms with muscle weakness, paralysis, and cardiac arrhythmias.

ECG: QT shortened, branch block-like QRS widening; ventricular flutter/fibrillation or asystole.

Cation exchange resins, forced diuresis, hemodialysis

Serum potassium levels >6mmol/l are acutely threatening and require immediate potassium lowering.