Neuromyelitis optica spectrum disorders (NMOSD) are a group of relapsing inflammatory autoimmune CNS diseases and as its known the coexistence of other autoimmune disorders such as Sjogren’s Syndrome is not rare. Here we report a patient whose initial diagnosis was NMOSD and Sjogren's Syndrome, but with immunosuppresive treatment she presented with anti-NMDAR encephalitis triggered by HSV Encephalitis.
The most interesting point about this case is that it draws the attention to the coexistance of NMOSD and anti-NMDAR encephalitis. There are only 11 adult cases in the previous literature that have been reported anti-NMDAR encephalitis with NMOSD. Previous studies suggested that autologous immunity triggers AQP4 antibody releated cytotoxicity and meantime activation of NMDAR which end up with comorbidity. But the pathophysiology of this comorbidity has not been clearly established yet.
A unique case of NMOSD coexisting with Sjogren's Syndrome and anti-NMDAR encephalitis triggered by HSV encephalitis was reported.
Our patient, who is a 52-year-old otherwise healthy female patient, applied to our clinic with paraparesis, and anesthesia under T2 level. Aqp-4 positive NMOSD was our initial diagnosis. In addition, her anti-Ro/SSA antibody was positive and salivatory gland biopsy showed Grade 4 changes so she also had Sjogren’s Syndrome diagnosis. After induction treatment, she received CTX regimen; but due to difficulty of use, AZA and hydroxychloroquine were started.
While using AZA, she presented with HSV Encephalitis approximately one month later. No case of HSV type 1 encephalitis after NMOSD has been reported in the literature. But as is known, immunosuppresive treatments might trigger possible viral infections. MRI was suggestive for HSV encephalitis and diagnosis was also confirmed by cerebrospinal fluid HSV PCR. On this time limbic panel from blood and CSF was negative. While she was in the hospital for IV treatment of acyclovir, the follow-up brain MRI which performed with the purpose of starting maintenence therapy for NMOSD, showed increased T2 hyperintensity and contrast enhancement on the left limbic area. In new CSF evaluation, anti-NMDAR antibody was found to be positive.
As reported in the literature before, herpes simplex encephalitis is a widely accepted risk factor for anti-NMDAR encephalitis. For treatment, seizure control and immunotherapy (first-line immunotherapy: steroids, IVIG, plasmapheresis, and second-line: RTX, CTX) are recommended. So after induction therapy, our patient was given RTX; and with the controlling of the seizures, her neurologic examination got better
This case provides evidence for the coexistance of NMOSD with anti-NMDAR encephalitis. Regarding previous case reports and studies, it is necessary to improve our understanding of effect relationship and pathogenesis of this comorbidity to guide both treatment and the prognosis.