Treatment outcomes for infantile spasms in Japanese children with Down syndrome.

BACKGROUND: The aim of this study was to assess the treatment response to conventional antiepileptic drugs and low-dose adrenocorticotropic hormone therapy for infantile spasms in children with Down syndrome. METHODS: We retrospectively investigated the response and relapse rates, electroencephalography findings, patient characteristics during drug withdrawal, and developmental outcome in 10 children with Down syndrome treated for infantile spasms in our hospital. RESULTS: All patients showed cessation of infantile spasms and achieved electroencephalographic normalization. Spasm relapse occurred in one of 10 patients (10%). Antiepileptic drugs have been withdrawn for seven of 10 patients (70%), none of whom have experienced seizure relapse since drug withdrawal. The median developmental quotient (n = 8) was 20.5, which shows that the developmental outcome was unfavorable. Low-dose adrenocorticotropic hormone therapy achieved a low seizure remission rate of 28.6%. CONCLUSIONS: Elucidation of the optimal treatment for infantile spasms in children with Down syndrome is needed to reduce the duration of infantile spasms and improve the developmental outcome.

Prognostic factors in the early phase of acute encephalopathy.

BACKGROUND: Neurological sequelae occur in 40% of patients with acute encephalopathy (AE). The early prediction of poor outcomes is critical to the initiation of appropriate treatment. The aim of the present study was therefore to elucidate prognostic factors that can be quickly and feasibly evaluated on hospital admission in patients with AE. METHODS: We analyzed data from 51 AE patients admitted to Hirakata City Hospital between January 2005 and December 2014. Age at onset, sex, underlying disease, status epilepticus (SE), presence of benzodiazepine-resistant SE (BZD-resistant SE), and basic blood serum parameters on admission were evaluated in relation to each patient's outcome. RESULTS: On univariate analysis age at onset, BZD-resistant SE, and serum aspartate aminotransferase (AST), alanine aminotransferase, lactate dehydrogenase, and platelet count varied significantly according to outcome. On multivariate analysis age at onset (≤21 months), presence of BZD-resistant SE, and AST (≥46 IU/L) were identified as independent variables associated with poor outcome. CONCLUSION: Age at onset, presence of BZD-resistant SE, and AST are associated with a poor prognosis in AE.

Parents'opinions of the changes in their children's epilepsy treatment during the transition from childhood to adulthood.

Objective: Patients with childhood-onset epilepsy often need continued epilepsy treatment into adulthood. We investigated parents' opinions of the changes in their children's epilepsy treatment during the transition from childhood to adulthood using questionnaires and formulated agendas to build the appropriate medical treatment system for epilepsy. Methods: We distributed questionnaires to parents of patients with epilepsy who were 12 to 18 years old. Results: We distributed 176 questionnaires, and analyzed 79 (45%) questionnaires. Most parents (59%) wanted their child to continue treatment for epilepsy in the pediatrics department because of confidence in the current treatment environment. Most parents (73%) were anxious about their child not being treated in the pediatrics department during future epilepsy medical treatments because of concerns about whether a proper handover from the pediatrics department to other departments is possible. No parent was recommended the departmental transition by the primary pediatrician to other courses for future epilepsy treatment, while 19% of par-ents had a sense of incongruity regarding epilepsy treatment at the current pediatrics department. Parents who were anxious about future epilepsy treatments had significantly fewer general-school students than parents without anxiety. In addition, their children had more seizures than children of parents who were not anxious. Furthermore, they wanted their child to continue treatment for epilepsy in the pediatrics department more than the parents without anxiety. Conclusions: Approximately 70% of the parents were anxious about obtaining future epilepsy treatment in clinical departments other than the pediatrics department. To build a satisfactory medical treatment system for patients with epilepsy having different backgrounds and requiring continued treatment in adulthood, it is important to create a cooperating network consisting of pediatricians, neurologists, neurosurgeons, psychiatrists, and epileptologists.

Delirious behavior or mild reduction of consciousness mimicking influenza-associated encephalopathy.

BACKGROUND: During the A/H1N1 pandemic, patients suffered from impaired consciousness. They were suspected of or diagnosed as having influenza-associated encephalopathy (IAE) in an emergency situation. Their symptoms resembled those of a recently described 'unique clinical group', which were reported to have a favorable prognosis. METHODS: We retrospectively examined 46 patients and divided them into two groups. Group IC contained the 26 patients with persisting impaired consciousness. The remainder of the patients were categorized into group R, consisting of patients with only neurological symptoms without impaired consciousness. RESULTS: Male predominance (22 male/four female) was noted in group IC. Patient age ranged from 5 to 12 years old (mean ± SD, 7.7 ± 2.3 years). Impaired consciousness such as delirious behavior or mild reduction of consciousness lasted continuously or intermittently from 5 min to 2.5 days. On electroencephalogram, semi-rhythmic high-voltage slow waves in the parieto-occipital regions and diffuse high-voltage slow waves were observed in eight and in two patients, respectively. In group R, there was no gender predominance. Patient age ranged from 1 to 9 years old (mean ± SD, 4.1 ± 2.5 years). All group R patients were clinically diagnosed with febrile seizure. CONCLUSIONS: Some of the characteristics in group IC resembled those of the unique clinical group, and are part of a continuous clinical spectrum. Some patients may have favorable outcome without specific treatment.

Focal seizures during adrenocorticotropic hormone therapy in a school-aged boy: a case report.

BACKGROUND: Adrenocorticotropic hormone therapy for infantile spasms, including West syndrome, has been previously reported to induce seizures. We present the findings for a school-aged child with epilepsy who developed new focal seizures during adrenocorticotropic hormone therapy. CASE PRESENTATION: The Japanese patient had posttraumatic epilepsy and developed intractable focal seizures at the age of 13 years. Adrenocorticotropic hormone therapy was administered when the patient was 14 years of age. On day 10 of treatment, he developed new focal seizures, which were characterized by left arm contractions followed by movements of touching things with his right hand and writhing and rocking his body left and right and back and forth as automatisms. The focal seizures clustered for 40 minutes and disappeared after suppository administration of 10 mg diazepam. These focal seizures did not reoccur after more than 2 years of follow-up. CONCLUSION: Adrenocorticotropic hormone-induced seizures can occur in children older than previously reported, and can occur in children with intractable seizures other than epileptic spasms.

[Neuropsychological profile of children with cryptogenic localization-related epilepsy and its association with age at onset].

The aim of this study was to investigate the neuropsychological profile of children with cryptogenic localization-related epilepsy (CLRE). Neuropsychological evaluations were performed in 16 CLRE children and 14 children with idiopathic localization-related epilepsy (ILRE) for control within 8 months (average 2.1 months) of initial seizure. The neuropsychological tests used in this study are as follows: the Wechsler Intelligence Scale for Children-Third Edition, Wechsler Intelligence Scale for Children-Revised, and Wechsler Preschool and Primary Scale of Intelligence. Age at onset and test differed significantly between CLRE and ILRE, while the duration between onset and test and the number of seizures before test did not. No marked difference was observed in the neuropsychological profile between 2 groups; however, the discrepancy between VIQ and PIQ was significantly larger in CLRE than in ILRE. This discrepancy was negatively correlated with age at the time of seizure onset (r = -0.615, and p = 0.011). The laterality in discrepancy between VIQ and PIQ was associated with the dominance of interictal discharge. In conclusion, children with lower age at the time of seizure onset were likely to have had a larger discrepancy between VIQ and PIQ.

[Efficacy of topiramate for relapsed epileptic spasms with tuberous sclerosis: report of three cases].

Topiramate (TPM) has been shown to be effective for epileptic spasms (ES) in children, but there is little clinical experience with TPM use in Japan. We report three tuberous sclerosis (TS) patients with relapsed ES, who became spasm-free while receiving TPM treatment. All three patients were treated with a starting dose of 0.5 mg/kg/day. The dosage was increased by 0.5 mg/kg/day every 2 weeks. Although the dose of TPM and the period until the relapsed ES subsided differed among these patients, spasm frequency was clearly reduced by a 1 mg/kg/day dose of TPM. Therefore, efficacy against relapsed ES appeared within one month in all three patients. All three became spasm-free, and there have been no ES relapses for more than 5 months to date. In case 2, seizures were well controlled by TPM alone. Cases 2 and 3 were able to discontinue zonisamide treatment. No adverse effects occurred in any of these patients.

Reversible splenial lesions during febrile illness with or without white matter lesions.

OBJECTIVE: Reversible splenium lesions during febrile illness (RESLEF) are found in a spectrum. There are two types of corpus callosum (CC) lesions: CC-only type, with limited lesions and the CC (+) type, with extensive white-matter lesions. This retrospective study aimed to describe the differences in clinical findings between CC-only and CC (+) lesions and the association between onset age and clinico-radiological features in RESLEF. METHODS: Fifty-two episodes of CC-only or CC (+) lesions accompanied by neurological symptoms, e.g., seizures, delirious behavior (DB), and disturbance of consciousness (DC), from January 2008 to October 2019 were included. We analyzed the etiology (pathogen), clinical course, laboratory data, magnetic resonance imaging and electroencephalography findings, therapy, and prognosis. RESULTS: The rate of DC in the CC (+) was significantly higher than that in the CC-only group (5/6 [83%] vs 7/46 [15%]; p = 0.0016). The median number of seizures in the CC (+) was also significantly higher than that in the CC-only group (4 [0-7] vs 0 [0-7]; p = 0.034). Further, in RESLEF, the median onset age (months) in the seizure was significantly lower than that in the no-seizure group (39 [12-74] vs 83 [28-174]; p = 0.0007). The median onset age (months) in the DB was significantly higher than that in the no-DB group (74.5 [26-174] vs 28 [12-139]; p = 0.003). CONCLUSIONS: In RESLEF, CC (+) is a more severe neurological symptom than CC-only. Furthermore, the onset age is related to the type of neurological symptoms that appear.

Rapid-onset dystonia-parkinsonism with ATP1A3 mutation and left lower limb paroxysmal dystonia.

BACKGROUND: Rapid-onset dystonia-parkinsonism (RDP) is a disease characterized by an abrupt onset of dystonia accompanied by signs of parkinsonism and prominent bulbar symptoms. CASE REPORT: We describe a case of a female patient, born after normal delivery, but diagnosed with mild intellectual disability at age 7. She presented with an abrupt onset of upper limb dystonia and bradykinesia without tremor in parkinsonism, as well as dysarthria and dysphagia caused by prominent bulbar symptoms, at age 9. She had normal findings on brain magnetic resonance imaging, electroencephalography, and blood examination but was diagnosed with a psychogenic disorder. At age 10, she developed left lower limb paroxysmal stiffness with pain, and at 14, she was hospitalized due to lasting paroxysmal symptoms. Whole-exome sequencing was performed for this index case and her parents, and a de novo missense variant c.829G > A, p.Glu277Lys in ATP1A3 was identified. DISCUSSION: This RDP case highlights a rare clinical feature of paroxysmal dystonia that affects the lower left limb and develops after the abrupt onset of permanent dystonia. Currently, there are only three reported RDP cases associated with the same missense mutation, and we summarized the clinical features of all cases including ours, such as onset of age, time for stable, RDP score, relapse and exacerbation. Various symptoms owing to ATP1A3 mutation could develop as ATP1A3-related neurological disorders beyond classical phenotypes such as alternating hemiplegia of childhood (AHC) or RDP. Although RDP is extremely rare during childhood, it is important to understand its clinical characteristics in children.

Acute encephalopathy in children with tuberous sclerosis complex.

OBJECTIVE: We examined the clinical manifestations of acute encephalopathy (AE) and identify risk factors for AE in children with tuberous sclerosis complex (TSC). METHODS: The clinical data of 11 children with clinically diagnosed TSC associated with AE and 109 children with clinically diagnosed TSC alone aged 4 years or older were collected from 13 hospitals. RESULTS: Of the 11 children with AE, 5 had histories of febrile seizures (FS), and all had histories of febrile status epilepticus (FSE). AE developed within 24 h after fever onset in all children with seizures lasting 30 min or longer. All children developed coma after seizure cessation. Head magnetic resonance imaging (MRI) revealed widespread abnormalities in the cerebral cortex, subcortical white matter, corpus callosum, basal ganglia, and thalamus. One child died; seven had severe neurological sequelae; and the other three, mild sequelae. Logistic regression analysis revealed that a history of FSE was correlated with the development of AE. SIGNIFICANCE: AE in children with TSC was characterized by sudden onset after fever, followed by coma, widespread brain edema evident on MRI, and poor outcomes. A history of FSE was a risk factor for the development of AE.

Clinical findings in patients with febrile seizure after 5 years of age: A retrospective study.

OBJECTIVE: Febrile seizures (FSs) typically occur in infants and children between 6 and 60 months of age. Rarely, FS can occur in late childhood (late FS [LFS]; >5 years of age); however, the clinical features of LFS remain unclear. We aimed to clarify the clinical features of LFS. METHODS: We retrospectively analyzed data from patients with LFS who visited Hirakata City Hospital between January 2004 and December 2014. We defined LFS as a seizure accompanied by fever (temperature ≥38 °C) occurring after 5 years of age, without a central nervous system infection. RESULTS: A total of 505 patients (349 boys, 156 girls: 5-14 years old) were included. A history of FS before 60 months of age was observed in 319 of 460 patients (69.3%) with sufficient information about previous FS history among the 505 patients enrolled. LFS was more likely to occur in males (69.1%). Seizure duration was ≤15 min in 87.4% of cases. A family history of FS in first-degree relatives was observed in 103/327 cases (31.5%). Among LFS cases, 45% occurred at 5 years of age, and 92.1% experienced only one seizure after 5 years of age. The number of seizure episodes gradually lessened with age, decreasing drastically to 5.6% of cases older than 9 years. CONCLUSIONS: Our findings suggest that sex differences, seizure duration, and family history were similar for LFS and FS. Over 90% patients with LFS experienced no recurrence after 5 years of age. Further study is needed to verify the recurrence rate of LFS.

[Simple and useful evaluation of motor difficulty in childhood (9-12 years old children ) by interview score on motor skills and soft neurological signs--aim for the diagnosis of developmental coordination disorder].

Many children with developmental disorders are known to have motor impairment such as clumsiness and poor physical ability;however, the objective evaluation of such difficulties is not easy in routine clinical practice. In this study, we aimed to establish a simple method for evaluating motor difficulty of childhood. This method employs a scored interview and examination for detecting soft neurological signs (SNSs). After a preliminary survey with 22 normal children, we set the items and the cutoffs for the interview and SNSs. The interview consisted of questions pertaining to 12 items related to a child's motor skills in his/her past and current life, such as skipping, jumping a rope, ball sports, origami, and using chopsticks. The SNS evaluation included 5 tests, namely, standing on one leg with eyes closed, diadochokinesia, associated movements during diadochokinesia, finger opposition test, and laterally fixed gaze. We applied this method to 43 children, including 25 cases of developmental disorders. Children showing significantly high scores in both the interview and SNS were assigned to the "with motor difficulty" group, while those with low scores in both the tests were assigned to the "without motor difficulty" group. The remaining children were assigned to the "with suspicious motor difficulty" group. More than 90% of the children in the "with motor difficulty" group had high impairment scores in Movement Assessment Battery for Children (M-ABC), a standardized motor test, whereas 82% of the children in the "without motor difficulty" group revealed no motor impairment. Thus, we conclude that our simple method and criteria would be useful for the evaluation of motor difficulty of childhood. Further, we have discussed the diagnostic process for developmental coordination disorder using our evaluation method.

[Attempt for development of rapid word reading test for children--evaluation of reliability and validity].

We developed a rapid word reading test for examining the phonological processing ability of Japanese children. We prepared two versions of the test, version A and B. Each test has word and non-word tasks. Twenty-two healthy boys of third grade in primary schools participated in this validation study. For criterion related validity, we performed the serial Hiragana reading test, the sentence reading test, Raven's coloured progressive matrices (RCPM), the Token test for children, the Kana word dictation test, the standardized comprehension test of abstract words (SCTAW), and Trail Circle test. The reading times of the newly developed test correlated moderately or highly with those of the serial Hiragana reading test and the sentence reading test. However, the scores of the other tests (RCPM, Token test for children, Kana word dictation test, SCTAW, Trail Circle test) did not correlated with the reading time of the rapid word reading test. Test-retest reliabilities in the word tasks were more than moderate: 0.52 and 0.76 in versions A and B, while those in the non-word tasks were high: 0.91 and 0.88 in versions A and B. The correlation coefficient between versions A and B was 0.7 for the word tasks and 0.92 for the non-word tasks. This study showed that the rapid word reading test has substantial validity and reliability for testing the phonological processing ability of Japanese children. In addition, the non-word tasks were more suitable for selectively examining the speed of the grapheme to phoneme conversion process.

The efficacy of adrenocorticotropic hormone in a girl with anti-N-methyl-D-aspartate receptor encephalitis.

BACKGROUND: Immunomodulatory therapy has shown some therapeutic benefits in patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. In this report, we describe the use of adrenocorticotropic hormone (ACTH) immunotherapy with good outcome in a patient with anti-NMDAR encephalitis. SUBJECT AND METHODS: A 4-year-old girl developed convulsions in her right arm and leg without impaired consciousness. These convulsions occurred frequently in clusters of 10-20 events of 10-20 s duration. She was admitted to our hospital on the 6th day following her initial series of convulsions. Flaccid paralysis of the right hand and leg was also found. Interictal electroencephalography showed high-amplitude slow waves. No abnormal findings were shown on MRI. 99mTc-ECD brain SPECT on the 14th day showed hyperperfusion in the left hemisphere, including the left basal ganglia. The convulsions ceased following the oral administration of valproic acid on the 10th day; however, paralysis associated with choreic dyskinesia of the right arm and leg remained. ACTH immunotherapy was then performed on the 15th day. We identified the presence of N-methyl-D-aspartate receptor antibody in CSF samples taken on the 6th day. After ACTH therapy, the patient fully recovered from the paralysis associated with choreic dyskinesia of the right arm and leg. She has not had a relapse and has not required medication for over a year. CONCLUSION: ACTH immunotherapy may be a useful treatment option for patients with anti-NMDAR encephalitis, although further evaluation is required.

Acetaminophen and Febrile Seizure Recurrences During the Same Fever Episode.

OBJECTIVES: To confirm the safety of using acetaminophen for febrile seizures (FSs) and to assess its efficacy in preventing FS recurrence during the same fever episode. METHODS: In this single-center, prospective, open, randomized controlled study, we included children and infants (age range: 6-60 months) with FSs who visited our hospital between May 1, 2015, and April 30, 2017. The effectiveness of acetaminophen was examined by comparing the recurrence rates of patients in whom rectal acetaminophen (10 mg/kg) was administered every 6 hours until 24 hours after the first convulsion (if the fever remained >38.0°C) to the rates of patients in whom no antipyretics were administered. No placebo was administered to controls. The primary outcome measure was FS recurrence during the same fever episode. RESULTS: We evaluated 423 patients; of these, 219 were in the rectal acetaminophen group, and 204 were in the no antipyretics group. In the univariate analysis, the FS recurrence rate was significantly lower in the rectal acetaminophen group (9.1%) than in the no antipyretics group (23.5%; P < .001). Among the variables in the final multiple logistic regression analysis, rectal acetaminophen use was the largest contributor to the prevention of FS recurrence during the same fever episode (odds ratio: 5.6; 95% confidence interval: 2.3-13.3). CONCLUSIONS: Acetaminophen is a safe antipyretic against FSs and has the potential to prevent FS recurrence during the same fever episode.

Classification of benign infantile afebrile seizures.

PURPOSE: The aim of this study is to classify infantile cases with benign seizures into known epileptic syndromes, thereby facilitating discussion of clinical factors that could play an important role in diagnosis. SUBJECTS: Fifty-seven patients with afebrile seizures fulfilling all of the following criteria were enrolled: (1) normal development prior to the onset, (2) no underlying disorders nor neurological abnormalities, (3) onset before the age of four and (4) normal interictal EEG and neuroimaging findings. RESULTS: Thirty-nine cases (Group A) were characterized by an association of mild gastroenteritis. The remaining 18 cases were divided into two groups according to the seizure type. One group had partial seizures (Group B, 13 cases) while the other was suspected to have generalized seizures (Group C, 5 cases). Age at onset was significantly higher for Group A (19.5 +/- 5.5 months) than Groups B (5.3 +/- 1.8 months) (p<0.001) and C (5.8 +/- 3.5 months) (p=0.038). Positive family history of seizure disorder, seizure cluster tendency, and the efficacy of lidocaine against seizure clusters were common in the three groups. CONCLUSIONS: Features in Group A were consistent with benign convulsions with mild gastroenteritis (proposed by Morooka) [Morooka, K., 1982. Mild diarrhea and convulsions. Shonika 23, 134-137 (in Japanese)], those of Group B with benign partial epilepsy in infancy [Watanabe, K., Yamamoto, N., Negoro, T., Takaesu, E., Aso, K., Furune, S., Takahashi, I., 1987. Benign complex partial epilepsies in infancy. Pediatr. Neurol. 3, 208-211], and those of Group C with benign infantile convulsions [Fukuyama, Y., 1963. Borderland of epilepsy with special reference to febrile convulsions and so-called infantile convulsions. Seishin Igaku 5, 211-223 (in Japanese)]. The distinction between these syndromes depends upon age at onset, association with gastroenteritis, and ictal symptomatology. In our experience, however, it was not easy to catch seizure type accurately in clinical situations. As far as the results of ictal video-EEG monitoring ever carried out concern, focal initiation of parxysmal discharges was demonstrated in all cases, not only of BPEI but also of apparent generalized seizures examined without exception. These observations led the authors to conclude that the identity of BIC is dubious, most probably it will represent a subtype of BPEI.

[Changes of electroencephalographic findings in a case of migraine with various neurological symptoms].

We report here an 1-year-old boy who was diagnosed as sporadic hemiplegic migraine demonstrated transient changes in electroencephalographic (EEG) background activity accompanied with migraine attacks. The attacks were associated with various neurological complications such as impairment of consciousness and hemiplegia and so on, which coincided with the changes of EEG findings. When his first headache developed with fever and impairment of consciousness, diffuse slow waves (1-2 Hz, 250-300 microV) appeared transiently. The slow wave gradually improved thereafter, and disappeared on the 24th day. On the 25th day, when he had the second attack with left hemiplegia and impairment of consciousness and sensation, slow waves, (2-3 Hz, 250-300 microV) appeared on right side of the brain. Constriction of the right middle cerebral artery was found on MR angiography at that time. The EEG change had improved to normal background activity 3 days after the episode. This unique case demonstrated that transient EEG changes seem to be correlated with the existence of unconsciousness and the laterality of the ischemic insult. We may assume that the changes of electroencephalographic findings may represent the cortical dysfunction caused by vascular constriction.

[Symptomatic hypersomnia due to orexin deficiency in hypothalamic lesions].

Narcolepsy is characterized by excessive daytime sleepiness (EDS), cataplexy and other abnormal manifestations of REM sleep. Recently, it was discovered that the pathophysiology of idiopathic narcolepsy-cataplexy is linked to orexin ligand deficiency in the brain and cerebrospinal fluid. Orexin neurons localize in the posterior hypothalamic area, which was previously described as "waking center" by von Economo in 1920s. Hypersomnia due to orexin ligand deficiency can also occur during the course of other neurological conditions, such as hypothalamic tumor, encephalopathy and demyelinating disorder (i.e. symptomatic hypersomnia). We experienced 8 pediatric cases with symptomatic hypersomnia. These cases were diagnosed as brain tumor (n = 2), head trauma (n = 1), encephalopathy (n = 1), demyelinating disorder (n = 3) and infarction (n = 1). Six pediatric cases with orexin measurements from the literatures were additionally included and total 14 cases were studied. Although it is difficult to rule out the comorbidity of idiopathic narcolepsy in some cases, a review of the case histories reveals numerous unquestionable cases of symptomatic hypersomnia. In these cases, the occurrences of the hypersomnia run parallel with the rise and fall of the causative diseases. Most of symptomatic hypersomnia cases show both extended nocturnal sleep time and EDS consisting of prolonged sleep episodes of NREM sleep. The features of nocturnal sleep and EDS in symptomatic hypersomnia are more similar to idiopathic hypersomnia than to narcolepsy.

Post-vaccination MDEM associated with MOG antibody in a subclinical Chlamydia infected boy.

The mechanism of post-vaccination acute disseminated encephalomyelitis (ADEM) has been hypothesized as resulting from vaccination-injected antigens cross-reacting with myelin components, however, a precise etiology has been uncertain. In this report, we describe the case of a 6-year-old Japanese boy who had multiphasic disseminated encephalomyelitis (MDEM), and was positive for both anti-myelin oligodendrocyte glycoprotein (MOG) antibodies and Chlamydophila pneumoniae antibodies. After vaccinations that were the second one for measles and rubella, and the booster immunization for Japanese encephalitis, the patient presented with fever, headache, vomiting, and a change in personality. He was treated with a high-dose of intravenous methylprednisolone in the diagnosis of ADEM. However, these symptoms recurred with different magnetic resonance imaging lesion, and he was diagnosed as MDEM. Retrospective testing for pathogens revealed C. pneumoniae IgM and IgG antibodies, and it was considered that he was infected with C. pneumoniae subclinically. The patient's serum indicated a positive response for the anti-MOG antibody from the onset of the ADEM diagnosis and in all recurrent episodes. Chlamydia species infection has been known to play a role in demyelinating diseases. It is also known that the anti-MOG antibody may be present but not exhibit its pathogenesis in the absence of a cell-mediated inflammatory response; however, the precise mechanism of action of the anti-MOG antibodies is not yet determined. We propose the possibility that post-vaccination demyelinating disease may result from the synergistic effects of a preceding anti-MOG antibody, possibly produced in response to a subclinical Chlamydia species infection.