Neuropsychiatric Disease and Treatment (Apr 2017)
Hashimoto encephalopathy with high plasma monoamine metabolite levels: a case report
Abstract
Sho Horikoshi,1,2 Itaru Miura,2 Yasuto Kunii,3 Satoko Asano,4 Keiko Kanno-Nozaki,2 Hirobumi Mashiko,5 Hirooki Yabe2 1Department of Neuropsychiatry, Hoshi General Hospital, 2Department of Neuropsychiatry, Fukushima Medical University School of Medicine, 3Department of Neuropsychiatry, Fukushima Medical University School of Aizu Medical Center, 4Department of Neuropsychiatry, Japan Red Cross Fukushima Hospital, 5Department of Neuropsychiatry, Fukushima Prefectural General Rehabilitation Center, Fukushima, Japan Abstract: Hashimoto encephalopathy (HE) is believed to be an immune-mediated disorder associated with Hashimoto’s thyroiditis. It was suggested that neuropsychiatric symptoms, the presence of antithyroid antibody, and good response to steroids were important for the diagnosis of HE. It has been reported that homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG), which are monoamine metabolites of dopamine and noradrenaline, respectively, are the possible biomarkers of neuropsychiatric diseases. We report a case of Hashimoto encephalopathy, in which we longitudinally measured the plasma levels of monoamine metabolites. A 52-year-old woman developed acute psychosis, and was admitted to the psychiatric ward of our hospital due to psychotic state, 6 days after a traffic accident. An extensive evaluation showed no remarkable findings, except an increase in antithyroglobulin antibodies. Plasma levels of HVA and MHPG were extremely high at 66.5 and 41.8 ng/mL, respectively. On day 16, 50 mg/day oral prednisolone was administered, which improved her psychotic symptoms. Plasma levels of HVA and MHPG decreased to 7.2 and 9.9 ng/mL, respectively, on day 19. After the temporary worsening of psychosis and increase in plasma levels of HVA and MHPG, the dosage of prednisolone was tapered and low-dose risperidone was started. Her psychiatric symptoms gradually improved and plasma monoamine metabolite levels decreased again (HVA: 17.9 ng/mL; MHPG: 7.7 ng/mL). Although autoimmune mechanism has been suggested to be involved in HE, neural mechanism and pathogenesis of HE remain unknown. Our findings suggest that monoaminergic neural activity might be associated with psychotic symptoms in patients with HE and plasma levels of monoamine metabolites might be useful as state markers. Keywords: Hashimoto encephalopathy, monoamine metabolite, homovanillic acid, 3-methoxy-4-hydroxyphenylglycol, symptomatic psychosis
