Case Report: Guillain-Barré Syndrome Characterized by Severe Headache Associated With Metabotropic Glutamate Receptor 5 Antibody

Anti-metabolic glutamate receptor 5 encephalitis with gangliocytoma: a case and review of the literature

BACKGROUND

There are very limited reports on anti-metabolic glutamate receptor5 (mGluR5) encephalitis, especially lacking of pediatric research. The disease was mostly accompanied by tumors, mainly Hodgkin's lymphoma. No reports of other tumors, such as gangliocytoma have been reported to associate with anti-mGluR5 encephalitis so far.

CASE PRESENTATION AND LITERATURE REVIEWS

We reported a case of a 12-year-old boy with anti-mGluR5 encephalitis complicated with gangliocytoma. The patient suffered from mental disorders including auditory hallucination, and sleep disorders. His cranial magnetic resonance imaging (MRI) showed an abnormality in the right insular lobe. Autoimmune encephalitis antibodies testing was positive for mGluR5 IgG antibody both in cerebrospinal fluid and serum (1:3.2, 1:100 respectively). Abdominal CT indicated a mass in left retroperitoneal confirmed with gangliocytoma via pathology. The patient underwent resection of gangliocytoma. After first-line immunotherapy (glucocorticoid, gamma globulin), his condition was improved. Furthermore, we provide a summary of 6 pediatric cases of Anti-mGluR5 encephalitis. Most of them complicated with Hodgkin's lymphoma, except the case currently reported comorbid with gangliocytoma. The curative effect is satisfactory.

CONCLUSIONS

We report the first patient with anti-mGlur5 encephalitis complicated with gangliocytoma. It suggests that in addition to paying attention to the common lymphoma associated with anti-mGlur5 encephalitis, we should also screen the possibility of other tumors for early detection of the cause, active treatment and prevention of recurrence.

Autoimmune encephalitis with mGluR5 antibodies: A case series from China and review of the literature

Background

Only 15 patients of autoimmune encephalitis with metabotropic glutamate receptor 5 (mGluR5) antibodies have been reported worldwide since 2011, mostly from western countries. Patients with different genetic backgrounds are necessary to further clarify the clinical phenotype and prognosis of this rare disease.

Objective

We initially describe a case series from China to confirm the previous findings, expand the clinical phenotype, and identify the prognostic factors of autoimmune encephalitis with mGluR5 antibodies.

Methods

Observational data with follow-up were prospectively collected from autoimmune encephalitis patients with mGluR5 antibodies. Clinical information and outcomes on current and previously reported cases were combined and analyzed.

Results

We identified five patients (median age 35 years); two were female. The main clinical manifestations were behavioral/personality changes (five of five, 100%) and cognitive disorders (four of five, 80%), accompanied with other neurologic symptoms. Hypoventilation occurred in two (40%) patients, which was life-threatening. One patient had meningoencephalitis, suggesting a new phenotype in anti-mGluR5 encephalitis. All patients received immunotherapy. At the last follow-up (median 18 months), two (40%) patients showed complete recovery, two (40%) patients showed partial recovery, and one (20%) patient died. One (20%) patient had multiple relapses. Together with the 15 previously reported cases, associated tumors occurred in seven of 12 (58%) Western patients vs. one of eight (13%) Chinese patients. Modified Rankin Scale (mRS) scores at the last follow-up (median 31 months) were available in 16 patients. Patients with bad outcomes (mRS > 2, n = 4) were more likely to have hypoventilation at onset and higher mRS scores at peak of the disease.

Conclusions

In patients with different genetic background, as Chinese, the clinical phenotype of anti-mGluR5 encephalitis is similar. Fewer paraneoplastic cases were observed in Chinese patients. Most patients showed good responses to immunotherapy and cancer treatment. The clinical outcomes were favorable in most patients.