Opsoclonus–myoclonus syndrome associated with human herpes virus-6 rhomboencephalitis

Clinical Analysis of Pediatric Opsoclonus-Myoclonus Syndrome in One of the National Children's Medical Center in China

Objective: To study the clinical characteristics and treatment of pediatric opsoclonus-myoclonus syndrome (OMS).

Methods: We analyzed the clinical data of nine children OMS between June 2017 and Nov 2020.

Results: Nine children (M/F = 3:6, median onset age was 18 months) diagnosed with OMS were included in the study. Before onset, human rhinovirus and respiratory syncytial virus were seen in one patient, respectively. And one patient received Japanese encephalitis vaccination. Three patients had neuroblastoma, and one patient had ganglioneuroblastoma. All patients' symptoms were improved after receiving surgery (for four patients with tumor), intravenous human immunoglobulin and pulsed methylprednisolone. However, four patients without mass relapsed and became relapse free after rituximab treatment. The relapse rate was 44.4% (4/9). The OMS severity score at the last follow-up was significantly lower than the OMS severity score at onset (3.0 ± 1.0 vs. 11.0 ± 2.2, paired-samples t-test, P < 0.001). All patients had at least one item of neurological symptoms or neuropsychological disturbances.

Conclusion: For pediatric OMS, human rhinovirus infection and respiratory syncytial virus infection can be seen before onset. Rituximab is effective in reducing relapse. Improving recognition and long-term prognosis in OMS is urgent.

Human Herpes Virus 6 Detection in Children With Suspected Central Nervous System Infection

Human herpes virus 6 (HHV-6) infection is considered a self-limited disease in immunocompetent children. However, HHV-6 could be associated with various neurologic diseases. We describe 8 children with suspected central nervous system infection and detection of HHV-6 in cerebrospinal fluid. The clinical significance of HHV-6 detection is controversial because it may be caused by primary infection, reactivation or latency.

Human herpesvirus 6 encephalitis in a patient treated with everolimus for renal cell carcinoma

INTRODUCTION

Everolimus is a mammalian target of rapamycin inhibitor and is approved as second-line treatment or beyond for renal cell carcinoma. We report a case of a 75-year-old male treated with everolimus for metastatic renal cell carcinoma, after sunitinib treatment, who was diagnosed with human herpesvirus 6 encephalitis.

CASE REPORT

After 39 months of everolimus, 10 mg per day, our patient was admitted with fever, consciousness disorders and a partial epileptic crisis. Laboratory tests revealed lymphopenia (170 lymphocytes/mm³), and polymerase chain reaction in cerebrospinal fluid was positive for human herpesvirus 6. Brain magnetic resonance imaging study demonstrated hippocampal abnormality and a pontine lesion.

MANAGEMENT AND OUTCOME

The patient stopped everolimus treatment indefinitely. He received ganciclovir initially intravenously, with a rapid clinical improvement, as well as polyvalent immunoglobulins were given to correct hypogammaglobulinemia. Two months later, antiviral therapy was switched to oral ganciclovir, which was never stopped. A new lumbar puncture was performed one month after the initiation of antiviral treatment, which did not reveal human herpesvirus 6 DNA anymore.

DISCUSSION

Human herpesvirus 6 encephalitis is more common in hematopoietic stem cell transplant recipients and HIV patients. This is the first case probably associated to everolimus treatment. In contrast to most patients diagnosed with this infection, who either die or develop neurologic sequelae, our patient almost fully recovered two months later.

Acute transverse myelitis following an opsoclonus-myoclonus syndrome: An unusual presentation

Opso-myoclonus syndrome (OMS) is a very rare and severe condition. Ataxia, opsoclonus, myoclonus and/or behavioral and sleeping disturbances define that autoimmune disorder syndrome which is paraneoplastic or triggered by an infection. Here, we report a 3 year-old immunocompetent boy who developed an atypical OMS which was later complicated by an acute transverse myelitis. Screening for neuroblastoma was negative and extensive infectious screening revealed an active HHV-6 infection confirmed by blood and cerebrospinal fluid PCR. A parainfectious disease was suggested and immunosuppressive treatment was initiated. After 2 years of follow-up, the patient has a left leg paresia needing a splint and is otherwise normal. Transverse myelitis can be associated with parainfectious OMS and earlier immunosuppressive treatment in these cases may be useful especially in young and immunocompetent children.