case report

1. A case of mumps-related acute encephalopathy with
biphasic seizures and late reduced diffusion
Takashi SHIIHARA 1, Kyoko HAZAMA 1, Hiroyuki TSUKAGOSHI 2, Shunji HASEGAWA 3, Yuri DOWA 1, Mio WATANABE 1
1 Department of Neurology, Gunma Children’s Medical Center, Shibukawa, Japan 2 Gunma Prefectural Institute of Public Health and Environmental Science, Maebashi,
Japan3 Department of Pediatrics, Yamaguchi University Graduate School of Medicine, Ube, Japan
Background
Mumps is a common childhood viral disease characterized by fever and swelling of the parotid gland. The
prognosis is generally good, although some complications, such as encephalitis (0.1%), exist. Acute
encephalopathy with biphasic seizures and late reduced diffusion is the most common type of acute
encephalopathy. However, this type of encephalopathy has not been reported in association with mumps infection.
Patient
A previously healthy 3-year-old Japanese boy had a brief convulsion after fever for 3 days, and then had conscious
disturbance and parotitis. After several days, he had a second brief convulsion and was admitted. Increased serum
amylase levels and presence of anti-mumps immunoglobulin M antibody confirmed mumps parotitis. The patient
had another brief seizure one day after his admission. He did not have status or cluster seizures, although the
biphasic nature of his seizures, conscious disturbance between the seizures, no pleocytosis in cerebrospinal fluid,
and brain magnetic resonance images were consistent with acute encephalopathy with biphasic seizures and late
reduced diffusion. Two courses of methylprednisolone pulse therapy (30 mg/kg/day for 3 consecutive days) were
administered and he was discharged nearly one month after the onset. His developmental quotient, determined
using the Kyoto Scale of Psychological Development (http://www.kiswec.com/), was 68, and his social interaction
and communication were impaired, and corresponded to autism spectrum disorder.
Discussion
In Japan, the mumps vaccine is not administered as a part of routine immunizations. It thus has low coverage (30–
40%), and as a result, mumps infections are still common. However, this is the first case of mumps-related acute
encephalopathy with biphasic seizures and late reduced diffusion. This case may be representative of only a
minority of patients with mumps-associated central nervous system involvement. Nevertheless, this diagnostic
possibility may be considered. In order to prevent mumps-related complications, routine mumps vaccination might
be warranted.
References
This case report was published in Brain Dev. 2017;39:808-810. If you need the pdf file,
please let me know. My E-mail address is; shiihara-ind@umin.net
Fig. 1: MRI findings, top to bottom rows: axial T2-weighted images,
diffusion-weighted images (DWI), and apparent diffusion coefficient
(ADC) maps at the basal ganglia-thalamus level, obtained on, left to
right column: days of illness (DOI) 6, 13, and 27. On DOI 6, fronto-
parietal high-intensity lesions with perirolandic sparing, which
involved the cortex, caudate heads, and subcortical to deep white
matter, were evident on T2-weighted images and DWI. Reduced
diffusion in the corresponding subcortical to deep white matter was
verified on the ADC maps. On DOI 13, the aforementioned high
intensity lesions and the white matter reduced diffusion became less
apparent. On DOI 27, the signal and diffusion abnormalities had
almost disappeared and cerebral atrophy had emerged.
T-061