Silent thyroiditis with thyroid-stimulation-blocking antibodies (TSBAb).
A 24-year-old man showed thyrotoxic symptoms with hypokalemic periodic paralysis. Serum thyroid hormone levels were high and thyrotropin (TSH) was undetectable. 123I-thyroidal uptake was suppressed. TSH-binding inhibitor immunoglobulin (TBII) was positive. After a month without any treatment, he became hypothyroid. Thyroid hormone level was decreased and TSH was increased to above the normal range. 123I-thyroidal uptake was increased. TBII activity was still positive. From the clinical findings, a diagnosis of silent thyroiditis was made. Sera obtained in the hypothyroid state revealed the presence of thyroid-stimulation-blocking antibodies (TSBAb), but there were no thyroid-stimulating antibodies (TSAb). These results suggest that the hypothyroidism in this patient was due to the presence of TSBAb with TBII activity.
Nakamura
S
S
Department of Internal Medicine, Gifu Red Cross Hospital, Japan.
Sugimoto
M
M
Kosaka
J
J
Watanabe
H
H
Shima
H
H
Kawahira
S
S
D000328:Adult; D001323:Autoantibodies / Q000032:analysis* / Q000276:immunology; D006801:Humans; D007008:Hypokalemia / Q000209:etiology; D007037:Hypothyroidism / Q000097:blood / Q000209:etiology; D018828:Immunoglobulins, Thyroid-Stimulating; D007457:Iodine Radioisotopes; D008297:Male; D010243:Paralysis / Q000209:etiology; D013963:Thyroid Hormones / Q000097:blood; D013967:Thyroiditis, Autoimmune / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000276:immunology*; D013971:Thyrotoxicosis / Q000097:blood / Q000209:etiology; D013972:Thyrotropin / Q000097:blood* / Q000172:deficiency / Q000276:immunology
D001323:Autoantibodies; D018828:Immunoglobulins, Thyroid-Stimulating; D007457:Iodine Radioisotopes; D013963:Thyroid Hormones; D013972:Thyrotropin