title: Overlapping MERS and mild AESD caused by HHV-6 infection.
abstract: We report the case of an overlapping encephalopathy syndrome consisting of clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) and a mild form of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) caused by human herpesvirus-6. A previously healthy 17-month-old girl was admitted to our hospital as a precaution because of seizures that had developed more than 25 hours (h) after fever. Brain diffusion-weighted images (DWI) showed high signal intensity in the central splenial region on Day 2. She regained consciousness 16 h after the second seizure. On Day 6, she had a secondary cluster of partial seizures. DWI showed resolution of the splenial lesion and revealed reduced diffusion in the fronto-subcortical white matter. She regained consciousness 36 h after the secondary cluster of seizures without any sequelae. A third DWI performed on Day 15 showed that the fronto-subcortical white matter lesions had completely disappeared. Based on the clinicoradiological findings, we diagnosed the patient with overlapping MERS and mild AESD. Our case, together with previous reports, suggests that patients can develop combined encephalopathy syndromes as a phenotype. Many encephalopathy syndromes have been established and classified; however, some may not present as independent syndromes.
authors.affiliation: Department of Pediatrics, Rakuwakai Otowa Hospital, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Hatanaka
authors.affiliation: Department of Pediatrics, Hirakata City Hospital, Japan. Electronic address: dbs003@art.osaka-med.ac.jp.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kashiwagi
authors.affiliation: Department of Child Neurology, Tanabe Children's Clinic, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Tanabe
authors.affiliation: Department of Pediatrics, Nakahara Hiroshi Kids Clinic, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakahara
authors.affiliation: Department of Pediatrics, Rakuwakai Otowa Hospital, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Ohta
authors.affiliation: Department of Pediatrics, Osaka Medical College, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tamai
mesh_terms: D000208:Acute Disease; D003337:Corpus Callosum / Q000473:pathology*; D018792:Encephalitis, Viral / Q000209:etiology* / Q000473:pathology; D005260:Female; D015654:Herpesvirus 6, Human / Q000472:pathogenicity*; D006801:Humans; D007223:Infant; D019349:Roseolovirus Infections / Q000150:complications*; D012640:Seizures / Q000209:etiology* / Q000473:pathology; D013577:Syndrome; D066127:White Matter / Q000473:pathology*
keywords: Acute encephalopathy with biphasic seizures and late reduced diffusion; Clinically mild encephalitis/encephalopathy with a reversible splenial lesion; Human herpesvirus 6; Overlap