The thyroid is a butterfly-shaped gland. But for some, it can be more like a bullet to the neck. The number of systems that our thyroid helps regulate truly is incredible, and an over or under-active thyroid can cause a whole host of acute and chronic issues. On the one hand, imagine a patient who has a thyroid history and is cold, weak, and has a depressed level of consciousness. Why is this occurring, and what's the diagnosis and treatment? On the other hand, imagine an anxious, hyperpyrexic patient in atrial fibrillation. Both patients have thyroid issues, but why do these patients present so differently? Let's see what happens when the scales tip either way for a few of the systems that the thyroid helps control!