The patient is a 47 year old man who presents with complaints of weakness, weight loss, and pounding in his chest. On further questioning he says that his hand writing has become illegible and that his hands "shake".

On physical exam he has a notable tremor when his hand is outstretched. His eyes are mildly proptotic and his pulse is 115 although he appears in no distress.

1. What is your differential diagnosis?

2. What areas of the exam should you focus on?

3. What laboratory tests will you order?