What is the primary danger in both Myasthenic and Cholinergic crisis?

The primary danger in both Myasthenic and Cholinergic crises is respiratory arrest. Myasthenic crisis occurs when there is an inadequate amount of acetylcholine available at the neuromuscular junction, leading to muscle weakness, particularly affecting the respiratory muscles. This inadequacy can compromise the ability to breathe adequately, ultimately leading to respiratory failure if not treated properly.

In a Cholinergic crisis, which is caused by an excessive accumulation of acetylcholine due to overmedication with cholinergic drugs, there is also significant respiratory compromise. The overstimulation of acetylcholine receptors can lead to muscle weakness, including the muscles responsible for respiration, further risking respiratory arrest.

The other options, while they may be potential complications in various medical scenarios, are not the primary concerns in these specific crises. Hence, the focus on respiratory arrest as the correct answer emphasizes the critical need for monitoring respiratory function in patients experiencing either Myasthenic or Cholinergic crises.