What adverse effect can result from untreated hyperthyroidism?

Thyroid storm, also known as thyrotoxic crisis, is a severe and life-threatening condition that can occur as a complication of untreated hyperthyroidism. It is characterized by an exacerbation of hyperthyroid symptoms, including profound hypermetabolism, extreme restlessness, agitation, fever, tachycardia, and even cardiovascular collapse. The rapid release of thyroid hormones into the bloodstream during this crisis causes significant stress on the body, potentially leading to severe complications if not treated urgently.

The development of thyroid storm highlights the importance of managing hyperthyroidism effectively to prevent such extreme adverse effects. While other options, like myxedema coma, relate to thyroid dysfunction, they are associated with hypothyroidism, not hyperthyroidism. Diabetes insipidus is not directly connected to thyroid conditions, and goiter is a physical manifestation rather than an acute adverse effect of untreated hyperthyroidism. Thus, the identification of thyroid storm as the correct adverse effect emphasizes the critical need for timely intervention in hyperthyroid patients.