"Although commonly done, thyrotoxicosis should not be confused with, nor is it synonymous with hyperthyroidism. The latter term solely means that a patient has abnormally-elevated thyroid hormone levels, and maybe subclinical. This may in turn lead to overt symptoms and signs, which is called thyrotoxicosis."
"In subclinical thyrotoxicosis (normal serum free T4 and T3 with low TSH), the patient may not have any symptoms."
"palpitations, tachycardia or atrial arrhythmia, systolic hypertension"
"There are multiple causes of thyrotoxicosis 1:"
"excessive exogenous thyroid hormone iatrogenesis or ingestion (e.g. hamburger thyrotoxicosis, thyrotoxicosis factitia)"