Generalized Convulsions with Diffuse Spike and Wave Bursts Emerging with Graves' Disease

Abstract

Thyroid hormone lowers the seizure threshold. We present the case of a female patient who developed generalized convulsions emerging with Graves' disease, and clarified the clinico-electroencephalographic characteristics. Before treatment, electroencephalography (EEG) showed 2- to 2.5-Hz diffuse spike and wave (SW) bursts, apparent during and after hyperventilation without any distinct absence seizure. Thiamazole treatment without any anticonvulsant led to a euthyroid state, convulsions resolved and EEG abnormalities normalized promptly. Clinical seizures were generalized tonic-clonic convulsions during sleep, and EEG showed diffuse SW bursts induced by hyperventilation. These characteristics suggested that epilepsy might correspond to idiopathic generalized epilepsy (IGE). IGE might be susceptible to hyperthyroidism. Cases of IGE emerging with hyperthyroidism, even if EEG paroxysms are advanced, may be improved using antithyroid pharmacotherapy alone.

Key words

Graves' disease - idiopathic generalized epilepsy - hyperventilation

References

• 1 Hoffmann G, Dietzel I D. Thyroid hormone regulates excitability in central neurons from postnatal rats.  Neuroscience. 2004;  125 369-379
• 2 Jabbari B, Huott A D. Seizures in thyrotoxicosis.  Epilepsia. 1980;  21 91-96
• 3 Leubuscher H J, Herrmann F, Hambsch K, Langpeter D, Mueller P, Sorger D. EEG changes in untreated hyperthyroidism and under the conditions of thyreostatic treatment.  Exp Clin Endocrinol. 1988;  92 85-90
• 4 Macdonald R L, Gallagher M J, Feng H J, Kang J. GABA(A) receptor epilepsy mutations.  Biochem Pharmacol. 2004;  68 1497-1506
• 5 Martin J V, Williams D B, Fitzgerald R M, Im H K, Vonvoigtlander P F. Thyroid hormonal modulation of the binding and activity of the GABA_A receptor complex of brain.  Neuroscience. 1996;  73 705-713
• 6 Obeid T, Awada A, Rajeh S A, Chaballout A. Thyroxine exacerbates absence seizures in juvenile myoclonic epilepsy.  Neurology. 1996;  47 605-606
• 7 Radetti G, Dordi B, Mengarda G, Biscaldi I, Larizza D, Severi F. Thyrotoxicosis presenting with seizure and coma in two children.  Am J Dis Child. 1993;  147 925-927
• 8 Su Y H, Izumi T, Kitsu M, Fukuyama Y. Seizure threshold in juvenile myoclonic epilepsy with Graves' disease.  Epilepsia. 1993;  34 488-492
• 9 Sundaram M BM, Hill A, Lowry N. Thyroxine-induced petit mal status epilepticus.  Neurology. 1985;  35 1792-1793
• 10 Utku U, Asil T, Celik Y, Tucer D. Reversible MR angiographic findings in a patient with autoimmune Graves' disease.  AJNR Am J Neuroradiol. 2004;  25 1541-1543