Final answer:
Life-threatening hyperkalemia can lead to severe cardiac issues, muscle paralysis, and nervous system impairments, all of which are due to high potassium levels in the blood that disrupt normal cell function.
Step-by-step explanation:
A patient with life-threatening hyperkalemia is likely experiencing severe cardiac arrhythmias, muscular paralysis, and nervous system depression. These symptoms stem from the excessively high levels of potassium in the blood, which lead to partial depolarization of cell membranes and an impaired ability of the cells to repolarize. In particularly severe cases, this can result in cardiac cells failing to relax after a contraction, a serious condition that can cause the heart to stop pumping effectively, which is potentially fatal.