Thyroid storm with encephalopathic symptoms due to Graves' disease and inappropriate secretion of thyrotropin

A 41-year-old woman is described, first hospitalized in the neurosurgical department for a transient ischemic attack with left hemiparesis followed after 6 hours by tonic-clonic seizures starting from the left hemiface and quickly generalized. Brain computed tomography (CT) scan and magnetic resonance imaging were normal. Clinically the patient presented tremor, tachycardia, generalized muscle weakness, and profuse diaphoresis. T4 and T3 were elevated. The patient was transferred from the neurosurgical to the medical department where a thyroid storm due to autoimmune Graves' disease with normal thyrotropin (TSH) values responsive to thyrotropin-releasing hormone (TRH) stimulation was diagnosed. A syndrome of inappropriate secretion of TSH was suspected in an unusual presentation as autoimmune Graves' hyperthyroidism. The TSH alpha-subunit and alpha-subunit/TSH molar ratio were normal, which supported the diagnosis of non-neoplastic inappropriate secretion of TSH. However, severe autoimmune Graves' hyperthyroidism is very rare indeed because autoantibodies to thyroid antigens are generally non-detectable in such patients. Our patient was treated initially with barbiturates, then with dexamethasone, Lugol's solution, methimazole and propranolol. Treatment of this patient proved difficult, and definitive improvement was obtained only after triiodothyroacetic acid administration, but methimazole and propranolol administration could not be discontinued. Fine needle aspiration biopsies of the thyroid in 2 occasions showed follicular or follicular-papillary proliferation with lymphocytic infiltration as in chronic thyroiditis. The patient is now in good clinical conditions and is followed up regularly. Autoimmune Graves' hyperthyroidism may be associated in extremely rare instances with non neoplastic inappropriate secretion of TSH.