PLAB Practice Exam 2025 – Complete Test Prep

In primary adrenal insufficiency, also known as Addison's disease, the adrenal glands do not produce sufficient amounts of cortisol due to damage or dysfunction of the adrenal cortex. This results in decreased levels of cortisol in the bloodstream, which is crucial for various physiological processes, including metabolism, immune response, and regulating blood pressure.

The body relies on cortisol to help manage stress and maintain glucose levels in the blood. When cortisol levels are insufficient, the effects can be widespread, including fatigue, weakness, and low blood pressure. The primary issue in this condition is directly related to the production of cortisol, making it the most relevant and decreased factor in primary adrenal insufficiency.

Other substances such as thyroid hormones, glucose levels, and epinephrine are not directly involved in primary adrenal insufficiency and do not exhibit the same predictable changes as cortisol does in this context.