Final answer:
Hyperkalemia is the most significant clinical finding associated with acute adrenal crisis and fluid and electrolyte balance, characterized by elevated blood potassium levels due to reduced adrenal hormone secretion.
Step-by-step explanation:
The most significant clinical finding of acute adrenal crisis associated with fluid and electrolyte balance is hyperkalemia. An acute adrenal crisis can often result in hyperkalemia due to the hypofunction of the adrenal cortex, commonly seen in conditions such as Addison's disease. This disorder is characterized by a reduced secretion of adrenal hormones, which leads to excessive sodium and chloride loss, low blood pressure, and elevated blood potassium levels. Hyperkalemia can be accompanied by severe symptoms, including arrhythmias which can be fatal if not treated promptly.
In contrast, hypernatremia, or high serum sodium levels, are more commonly associated with hyperactivity of the adrenal cortex, as seen in Cushing's syndrome or in cases of prolonged treatment with cortisone, ACTH, or sex hormones. These conditions can lead to increased retention of water, increased blood volume, and increased blood pressure. As such, hypernatremia is not typically associated with acute adrenal crisis, where there is a deficiency rather than an excess of adrenal hormones.