A 44 year-old female patient visited our department for the treatment of diabetes. Her diabetes was pointed out 1 year before and was resistant to the treatment with oral hypoglycemic agents. From around the same time, she complained of repeated attacks consist of headache, palpitation, sweating and nausea. She had suffered from obsessive compulsive disorder for 20 years and her psychiatrist recognized that these attacks were caused by some psychological problems such as panic disorder. However, neither anti-depressant nor anxiolytic agent was effective to improve her recurrent symptoms. Because her diabetes was resistant to the treatment, abdominal ultrasonography was done. It showed large left adrenal mass (approximately 10 cm in diameter). Plasma levels of cortisol and aldosterone were normal. However, 24 h urine excretions of epinephrine, norepinephrine and total metanephrines were markedly increased (epinephrine 171 μg/d, norepinephrine 934 μg/d and total metanephrines 29.9 mg/d). Scintigraphy with 131I-metaiodobenzylguanidine (MIBG) revealed high levels of accumulation at left adrenal mass. From these results, left adrenal mass was diagnosed as pheochomocytoma. The left adrenal mass was removed surgically and the pathological findings revealed typical characteristics of pheochomocytoma. Both blood pressure and blood glucose levels were normalized after surgery. Furthermore, her recurrent panic attack-like symptoms disappeared.
In conclusion, this case shows us the importance of excluding physical abnormalities before making a diagnosis of panic attack-like symptoms. Among a number of medical conditions mimicking symptoms of panic attacks, endocrine disorders such as pheochromocytoma and hyperthyroidism especially should be taken into consideration because they are unnoticeable if not to be careful enough. Many symptoms caused by pheochromocytoma highly resemble to those of panic disorder, but new-onset diabetes could be useful clues in making proper diagnosis. Furthermore, our patient did not complain of intense anticipatory anxiety and agoraphobia which are characteristic of panic disorder. These could also be useful findings to get exact diagnosis.