What mechanism causes life-threatening complications with succinylcholine in Guillain-Barré Syndrome?

The correct answer highlights a critical aspect of succinylcholine administration in patients with Guillain-Barré Syndrome (GBS). Succinylcholine is a depolarizing neuromuscular blocker that can lead to significant complications in patients with neuromuscular disorders, particularly due to its effect on potassium levels.

In Guillain-Barré Syndrome, a condition characterized by progressive muscle weakness and paralysis due to autoimmune damage to the peripheral nervous system, there is often associated neuronal damage. This can result in an increased risk of elevated potassium levels in the bloodstream. When succinylcholine is administered, it causes the release of potassium from the intracellular space into the extracellular fluid, potentially leading to hyperkalemia. In patients with GBS, who may already have unstable muscle membranes and altered potassium handling, this can precipitate life-threatening complications such as cardiac arrest or arrhythmias.

Thus, the mechanism behind the severe risk associated with succinylcholine in Guillain-Barré Syndrome centers around the increased potassium release and subsequent hyperkalemia, confirming the selection as the correct answer.