Dokkyo Journal of Medical Sciences
44（3）：235 〜 238，2017
44（3）（2017）MERS with mumps virus infection

235Case Report

Clinically Mild Encephalopathy with a Reversible
Splenial Lesion Accompanying Mumps Virus Infection：
a 5-Year-Old Girl Report
Junpei Ishii, George Imataka, Sayuri Kajitani, Junko Ichikawa, Shigemi Yoshihara
Department of Pediatrics, Dokkyo Medical University

SUMMARY
Aseptic meningitis is known as a mumps complication. However, there are few cases of clinically mild
encephalopathy with a reversible splenial lesion（MERS）associated with mumps infection. We report aMERS related to mumps infection in a girl. In the early clinical course, repeating convulsion and consciousness disturbance with hallucination were recognized. Initially, we suspected aseptic meningitis due tomumps, because of her swollen right parotid gland. Cerebrospinal fluid test was performed, but the result
was normal. After that, diffusion weighted image of magnetic resonance imaging was added and abnormal
signal intensity was recognized in the corpus callosum, so she was diagnosed as MERS. Treatment wasperformed with steroid pulse therapy and patients was discharged without neurologic sequelae. We needto pay attention to MERS as complication although rare in a mumps infection.
Key Words：clinically mild encephalopathy with a reversible splenial lesion, acute encephalitis, magnetic
resonance image

teristic MRI findings of corpus callosum are improved

INTRODUCTION

within one week in many cases of MERS 5）. In recent

Clinically mild encephalitis/encephalopathy with ayears, Diffusion weighted image（DWI）of MRI has

reversible splenial lesion（MERS）is a type of acutebecome widespread and reports have increased that

encephalitic encephalopathy reported recently byMERS is related to various infectious diseases such

Tada et al in 2004 . It has long been known about

as；mycoplasma 6）, staphylococcus aureus bactere-

the concern with anti-epileptic drugs

reported withmia 7）, legionella 8）, dengue fever 9）, rubella 10）, rotavi-

acute mountain sickness 4）, related to this characteris-rus 11）, HHV-6 12） and adeno virus 13） in children 6～12）

tic magnetic resonance imaging（MRI）findings. The

and adult 13）. Influenza virus type A 14） including 2009clinical feature of MERS is mild compared with otherH 1 N 1 influenza 1 5 , 1 6） are the most reported MERS

types of acute encephalopathy. Furthermore, charac-

related to childhood infectious diseases, and other vari-1）

2,3）

ous types of viruses are also reported 6～13）. Here in wewill report about MERS in a 5-year-girl with mumps
Received March 1, 2017；accepted November 8, 2017
Reprint requests to：George Imataka
Department of Pediatrics, Dokkyo MedicalUniversity, 8 8 0 Kitakobayashi, Mibu, Shimotsuga, Tochigi 321-0293 Japanvirus infection.

CASE REPORTThe patient is a healthy five year old girl. There
were several children with epidemic parotitis in a236

Junpei Ishii

DJMS

estimated her consciousness level was JCS 3. Basedon convulsions with clusters and delirium state, we
tentatively diagnosed it as aseptic meningitis due tomumps. In the neurological examination, meningitis
signs were not noted. To investigate the cause of thissymptom, we performed blood examination but found
no abnormality other than high amylase level of 872
IU/L and the sodium value was 133 mEq/L. The IgMvalue of mumps virus by the enzyme immunoassay（EIA）method was positive as 1.84（reference valueless than 0.08）. The cerebrospinal fluid（CSF）examination showed a cell count of 2/3, glucose level of
43 mg/dl, and other values were all normal. The cerebrospinal fluid pressure was also normal. Virus isolation from CSF by polymerase chain reaction（PCR）
Figure 1
Diffusion weighted image of magnetic resonance imaging（Spin echo；TE＝3900 msec；TR＝88 msec, FA＝90）of
the patient on admission showed high abnormal intensitywith callsal splenial liesion. MRI of MERS is separated
into type 1 which shows abnormality in the corpus callosum and type 2 which observes the lesion besides thecorpus callosum. Her MRI is diagnosed as MERS type 1.

method was performed, and the result was negative.
Radiological examination with the DWI of brain MRI
detected an abnormal intensity in the corpus callosum（Figure 1）. Thus, she was diagnosed with MERS dueto mumps. She was then given steroid mini-pulse
therapy with 1 0 mg/kg of methyl-prednisolone（mPSL）for 3 days. Starting with mPSL pulse therapy, her consciousness improved completely the following day. After 3 days of mPSL therapy, she was discharged without convulsion recurrence. Electroen-nursery school where she is enrolled. She had no his-cephalogram showed normal background activity on

tory of mumps vaccination nor mumps infection. She

3rd day from the admission. The abnormality of thehad a fever over 38 degrees since morning. The rightcorpus callosum was improved when examined byparotid gland was painful and swollen. Moreover, she

MRI on the 11 th day.

suddenly laughed out loud several times. On the sameevening, she developed the first febrile seizure withDISCUSSION

bilateral symmetry for 5 minutes during sleep. After

In mumps infection, aseptic meningitis, hearing loss,

about an hour, she had a second tonic-convulsion oforchitis, and other complications are known. Among

bilateral symmetry, after which she was transported

them, the most frequent complication of childhood

to our hospital. While being transported in an ambu-mumps infection is aseptic meningitis. The increase inlance, she developed myoclonic seizures for a fewthe cell count of CSF is recognized in 65％ or more ofminutes. When she arrived at the hospital, her level ofchildren with mumps. However, clinically diagnosed as

consciousness almost improved（Japan Coma Scale；sterile meningitis is in 1 to 3％ of childhood mumps

JCS 1）and conversation with doctors and parents

infection. In addition 2.5/1000 cases（0.0025％）of

was possible. After observing for several hours at achildhood mumps may complicate to meningoencepha-outpatient department, she was able to walk and golitis that causes neurological sequelae. Importantly,back home. But she was brought back and hospital-

the mortality of meningoencephalitis associated withized after having a 3-minute tonic-clonic convulsion

childhood mumps is 0.5 to 2.3％ 17）. Our patients also

in her car on her way home. While being hospitalized,

had a parotid gland swelling, disturbance of conscious-

she suddenly pointed to the wall and said“There is aness and repeated seizures. CSF examination was per-fish”, after which she could not answer her name. We

formed, but the number of cell count did not rise.

44（3）（2017）MERS with mumps virus infection

Hoshino et al. reported clinical statistical study on237

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Junpei Ishii

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