The adrenal glands produce the hormone norepinephrine, a potent form of the "fight or flight" hormone epinephrine. Tumors of the adrenal glands called pheochromocytomas produce abnormally high levels of norepinephrine. These tumors can occur sporadically or with the hereditary disorders multiple endocrine neoplasia types 2A and 2B, von Hippel-Lindau disease and neurofibromatosis type 1. Occasionally, elevated norepinephrine levels occur with adrenal medullary hyperplasia, an overgrowth of the tissues that produce the hormone. The majority of pheochromocytomas are noncancerous.
High Blood Pressure
Markedly elevated blood pressure levels characterize pheochromocytomas. In the online medical reference, Endotext.org, Dr. Marybeth Hughes and colleagues report that more than 98 percent of people with pheochromocytoma have high blood pressure. Approximately half of those affected exhibit persistently high blood pressure; others experience high blood pressure spikes with normal blood pressure between attacks.
Headaches
Severe, throbbing headaches occur in most people with elevated norepinephrine levels, notes Merck.com. The headaches typically correlate to the marked elevation in blood pressure caused by norepinephrine.
Profuse Sweating
The Mayo Clinic notes that profuse sweating, especially in the trunk of the body, is a common occurrence with pheochromocytoma. According to Hughes and colleagues, excessive sweating is a complaint in 60 to 70 percent of patients with this disorder. Heat intolerance typically accompanies this symptom.
Heart Palpitations
A heart palpitation refers to a conscious awareness of the heartbeat, usually due to an abnormal rhythm, rate or force. Heart palpitations commonly occur among people with elevated norepinephrine levels. Increased heart rate and forcefulness typify the disorder. Chest pain may accompany heart palpitations. The American Urological Association points out that approximately 90 percent of people presenting with heart palpitations, profuse sweating, headaches and high blood pressure harbor a pheochromocytoma.
Anxiety and Nervousness
As noted by the University of Virginia Health System, profound anxiety may accompany the elevated norepinephrine levels seen among people with pheochromocytoma. In some patients, the anxiety may progresses to the threshold of panic. Hughes and colleagues note in their instructional chapter on pheochromocytoma that anxiety and nervousness occur in approximately 20 percent and 40 percent of patients, respectively.
Nausea and Vomiting
A significant number of people with elevated norepinephrine levels experience nausea and vomiting, notes Merck.com. Abdominal pain may also occur, often in the epigastric region between the lowest ribs.
Pallor
Norepinephrine causes narrowing of the blood vessel near the skin and in the extremities. This effect often leads to pallor, or paleness of the skin. The skin also commonly feels cool to the touch. According to Hughes and colleagues, pallor occurs in up to 60 percent of people with symptomatic pheochromocytoma.
