What is a notable symptom during an insulinoma episode?

During an insulinoma episode, the release of insulin from the tumor leads to a notable drop in blood glucose levels, resulting in hypoglycemic symptoms. Patients typically experience signs such as shakiness, sweating, palpitations, confusion, irritability, and, in severe cases, loss of consciousness or seizures. These symptoms arise because the body's glucose levels fall below normal, which is critical for brain function and overall metabolic processes.

Weight gain typically does not align with the symptoms of an insulinoma, as the condition is characterized by the opposite effect: hypoglycemia may lead to repeated cycles of poor dietary intake and potentially weight loss. Nausea and vomiting can be seen in various other gastrointestinal or metabolic disorders but are not the hallmark symptoms of insulinoma. Similarly, while severe headaches can occur due to multiple reasons, they are not specifically associated with hypoglycemic episodes resulting from insulinoma. Thus, the presence of hypoglycemic symptoms is the definitive feature during an insulinoma episode, making it the correct choice.