Arquivos de neuro-psiquiatria | 2019
Transient global amnesia. Have you considered hyperhomocysteinemia?
Abstract
Dear Editor, I read with great interest the article by Alessandro et al.1 about the predictors of recurrence among patients having previously experienced transient global amnesia (TGA). With this letter, I would like to present the characteristics (medical history, clinical and laboratory findings) of five patients (three women, two men) diagnosed with TGA according to all known Hodges and Warlow criteria in a Greek hospital during the last five years. All patients were young, nonsmokers, with negative personal medical history for cardiovascular disease, seizures, brain tumor or migraine. Two of the three women reported two consecutive spontaneous early pregnancy losses and one possible previous TGA event. The memory loss during TGA episodes was sudden, unrelated to previous intense psychological stress, and its duration was between 12 and 24 hours (Table). Neurological examination of the patients was normal; a mild polyneuropathy was diagnosed in the two men. Brain magnetic resonance imaging, including diffusion weighted imaging sequences, electroencephalography, electrocardiography and echocardiography, were also normal. An ultrasound examination of both sides of the carotid arteries showed only a mild arteriosclerosis, but no plaques or severe stenosis. Laboratory investigations revealed normal values of hemoglobin and hematocrit, normal renal, liver and thyroid functions, normal serum total cholesterol and low-density lipoprotein levels, low serum folate (<4 ng/mL) and vitamin B12 (<300 pg/mL) levels, and high serum total homocysteine (tHcy) levels (>15 μmol/L) (Table). All the patients were diagnosed with mutations of methylenetetrahydrofolate reductase (MTHFR) gene (hereditary hyperhomocysteinemia) (Table) and received initially L-methylfolate (1 gr per os daily) and hydroxocobalamin acetate (1 gr IM; daily for seven days, weekly for four weeks, then monthly). After four months of treatment, serum folate and vitamin B12 levels were increased, but serum tHcy levels had decreased significantly (Table). However, a lifelong intake of L-methylfolate supplement to control the MTHFR mutation gene-induced hyperhomocysteinemia was suggested to all patients. Although a causal relationship between TGA episodes and