A patient with Graves’ disease showing only psychiatric symptoms and negativity for both TSH receptor autoantibody and thyroid stimulating antibody

A 76–year-old woman was admitted to the Department of Psychiatry in our hospital because she denied medications and suffered from irritability and delusion. She had no complaints of somatic symptoms. Her thyroid function was normal at least four months before the admission, however, laboratory data on the admission revealed hyperthyroidism. She was pointed out to have thyroid disease thirty years ago, however, she was not diagnosed definitively at that time, and also did not take any medicine. She had also type 2 diabetes, hypertension, dyslipidemia, hyperuricemia and schizophrenia. The members of her family did not have thyroid disorders. She has been taking clonazepam (0.5 mg/day), trazodone (50 mg/day), nitrazepam (5 mg/day), 0.1% aripiprazole (6 ml/day), propranolol (30 mg/day) and telmisartan (40 mg/day), for the treatment for hypertension, psychiatric symptoms and schizophrenia.

Her body temperature was 35.7°C, blood pressure was 158/86 mmHg, and heart rate was 89 per minute and regular. Her thyroid was not swelled. She did not have tremor and exophthalmos. The serum TSH level was suppressed to < 0.03 μIU/mL (normal: 0.54-4.26 μIU/mL), free triiodothyronine (T3) and free thyroxine (T4) levels were elevated to 11.70 pg/mL (normal: 2.39-4.06 pg/mL) and 3.07 ng/dL (normal: 0.71-1.52 ng/dL), respectively (Figure 1). Plasma glucose level was 116 mg/dL (normal: 80–112 mg/dL), and HbA1c level was 6.6% (normal: 4.7-6.2%). Her liver and renal functions were normal, and leukocyte counts and C-reactive protein (CRP) level were not elevated.

Her serum levels of TRAb1 (7.7%; the cutoff point: 15%) and TSAb (155%; the cutoff point: 180%) were not elevated (Figure 2). Serum anti-thyroid peroxidase (TPO) antibody was elevated to 174 IU/mL (normal: < 16 IU/mL). At first, we diagnosed her as having painless thyroiditis, and did not give her an anti-thyroid drug. Her psychiatric symptoms continued and we re-evaluated her thyroid function one month later. The serum TSH level was still suppressed to < 0.03 μIU/mL (normal: 0.54-4.26 μIU/mL), and free T3 and free T4 levels were further elevated to 15.88 pg/mL and 4.75 ng/dL, respectively (Figure 1). Thyroid echography showed slight swelling of the thyroid gland (right lobe: 52.4 mm × 21.8 mm × 16.4 mm, left lobe: 46.6 mm × 18.7 mm × 12.8 mm, isthmus size: 4.3 mm) and slightly increased blood flow (Figure 3). Thyroid scintigraphy demonstrated a diffuse and significantly elevated uptake of ¹²³I uptake in her thyroid gland (Figure 4). Uptake rate 3 and 24 hours after injection of ¹²³I was 111% and 63%, respectively Her serum levels of TRAb1 and TSAb were still not elevated (Figure 2), in spite of elevation of anti-TPO antibody (210 IU/mL; normal: < 16 IU/mL). We evaluated second generation TRAb (TRAb2), and found that her serum level of TRAb2 was very weakly positive (2.0 IU/mL; the cutoff point: 1.0 IU/mL). Because results of thyroid echography and scintigraphy strongly suggested the development of GD, we treated her by using methimazole (30 mg/day). Her thyroid function was promptly normalized one month later (Figure 1), and her psychiatric symptoms also were ameliorated. Further, the values of TRAb1, TRAb2 and TSAb were also promptly decreased under each cutoff point (Figure 2).

Written informed consent was obtained from the patient's relatives for publication of this case report. A copy of the written consent is available for review by the Eitor-in-Chief of this jounal.