The primary aims of this study were to relate HHV-7 infection with clinical manifestations of encephalitis, transient hip synovitis and hepatic changes in childhood and to evidence the effectiveness of early diagnosis and treatment in patients with encephalitis. 

A 2-year-old male patient reported persistent high fever, coughing and rhinorrhea starting 1 week ago. They sought outpatient pediatric care and was prescribed ceftriaxone and prednisolone, with no satisfactory response. The symptoms evolved to vomiting and dehydration. During the physical exam, he showed irritation, with constant cervical stiffness and hyperextension, photophobia, and convergent strabismus. On arrival, he had been taking ceftriaxone, acyclovir and desloratadine. Laboratory tests were very altered in leukocytes, platelets, PCR, AST, ALT and GGT. During the ophthalmologic examination, a paresis of cranial nerve VI on the right was identified as secondary to a probable meningitis. After 21 days of treatment with acyclovir, the patient had a good prognosis, however, he had claudication upon movement of the left hip. 

The CSF results were colorless, cloudy, pH 8, Glucose 58, Leukocytes 40, Proteins 81. To confirm this observation, the molecular panel detected the presence of HHV-7. The imaging tests helped and added to the results of the blood count and CSF. Cranial MRI showed a hyperintensity in the FLAIR sequence of the perimesencephalic subarachnoid space and small accumulation of liquid. In addition, the abdomen CT found a bit of fluid in the hip region. 

Encephalitis is an inflammation of the brain parenchyma that leads to neurological dysfunction caused by infection or autoimmunity. In this occasion, the patient had a rare case of HHV-7 encephalitis. Basically, the treatment was carried out with acyclovir and ketoprofen, obtaining a progressive improvement of the clinical picture. Consequently, further research on the complications of HHV-7 is essential to develop a good characterization of this disease.