EXCESSIVE HYPOKALEMIA AND HYPERKALEMIA FOLLOWING HEAD-INJURY

A sudden decrease of serum potassium below 2.5 mmol/l carries the risk of dangerous arrhythmias and requires immediate replacement therapy [ 6]. We refer to a patient with a brain stem compression after head inj ury, who developed a profound hypokalemia (K+ = 1.2 mmol/l) with life- threatening arrhythmias, probably due to a catecholamine induced intra cellular potassium shift (beta-2-stimulation). Only by aggressive pota ssium replacement up to 80 mmol/h (610 mmol/16 h) could potassium leve ls be increased and cardiac arrhythmias terminated. Although replaceme nt therapy was stopped when the serum K+ -level increased to 2.4 mmol/ l, 3.5 h later the patient became hyperkalemic (8.1 mmol/l). This was probably due to a secondary shift of potassium from intra- to extracel lular space. In patients with severe head trauma and the potential ris k of excessive catecholamine release special attention must be paid to changes in potassium balance.