Final answer:
Thyroid storm in Graves' disease can be triggered by a stressful event or illness, causing a sudden release of large amounts of thyroid hormones into the bloodstream.
Step-by-step explanation:
Thyroid storm is a life-threatening condition that can occur in patients with Graves' disease. It is triggered by a sudden release of large amounts of thyroid hormones into the bloodstream. The primary factor that can trigger thyroid storm in a patient with Graves' disease is a stressful event or illness, such as an infection or surgery. This triggers the release of stored thyroid hormones, leading to symptoms such as fever, rapid heartbeat, sweating, and confusion.