A case of thyroid storm caused by Graves' disease misdiagnosed as panic attack due to panic disorder.

Background: Graves' disease is characterized by hyperthyroidism and its symptoms often overlap with those of panic disorder, which may make it difficult to distinguish between the two conditions. In this report, we describe how proper diagnosis of thyroid disease in patients with mental illness can lead to appropriate treatment.

Case Presentation: We encountered a 34-year-old woman in whom thyroid crisis from Graves' disease was misdiagnosed as panic attack. The patient was being managed as a case of panic disorder and bipolar disorder in a psychiatric outpatient setting. About 6 months before presentation she had lost about 16 kg in weight, and a month before presentation she developed several unpleasant symptoms as her condition worsened. Several weeks before she had had severe palpitations, tachycardia, and discomfort in her throat. She became unable to eat solids, ate only yogurt and gelatin, and felt it difficult to take psychiatric drugs. She visited our emergency outpatient department on a Sunday morning, presenting with nausea, severe tachycardia, fever, and restlessness with anxiety. We treated her as panic disorder with fever, but noted proptosis and considered the possibility of Graves' disease. Thyroid function tests were performed even though data from her clinic was not available because it was a weekend. Because there was no improvement in her condition after her first visit, she returned to our hospital early the next morning. We had misdiagnosed her as having severe panic attacks due to panic disorder, and after a diazepam injection had allowed her to go home. Later that day, the thyroid function test results became available, and her symptoms and the results strongly indicated a thyroid storm. The endocrinology department was consulted immediately, and she was referred for hospitalization the next day. During hospitalization, she was treated with steroid and radioactive iodine therapy and was discharged from hospital in 3 weeks.

Conclusion: Psychiatrists and doctors engaged in psychosomatic medicine need to consider the possibility of severe hyperthyroidism as a differential diagnosis of panic disorder.