Adrenal high refers to increased levels of epinephrine, a hormone secreted by the adrenal medullary pheochromocytes. Increased levels of the hormone are most commonly seen in pheochromocytomas, which can be 2-20 times higher than normal. Hormone levels are normal during attacks and require repeated testing for a definitive diagnosis. Adrenal hormones can be secreted by parasympathetic pheochromocytes, and their increased levels can be seen in paragangliomas. It can be seen in adrenal medullary hyperplasia of unknown etiology. Patients with hyperthyroidism also have increased levels of adrenal hormones, mainly due to increased secretion of thyroid hormones, which indirectly leads to increased adrenal hormones, also known as interhormonal synergism.