Unusual Case of NMDA-R Encephalitis and Autoimmune Polyglandular Syndrome

Presentation Number: MON 296
Date of Presentation: April 3rd, 2017

Simona Frunza-Stefan*1, Hilary Whitlatch2 and Rana Malek1
1University of Maryland Medical Center, Baltimore, MD, 2University of Maryland School of Medicine, Baltimore, MD

Abstract

Introduction:

Anti-N-methyl-D-aspartic acid-receptor (NMDA-R) encephalitis is a rare autoimmune –antibody mediated form of limbic encephalitis. Reported immunologic triggers of this autoimmune encephalopathy include benign tumors, malignancy, and preceding infection. Here we describe an unusual case of NMDA-R encephalitis in a woman with autoimmune polyglandular syndrome type 2 variant (APS3v).

Case report:

A 58 year old female was transferred to our tertiary medical center with altered mental status. Symptoms began 8 months prior to presentation and included weight loss and change in personality and behavior. She appeared older than stated age, pale, cachectic with a flat affect. Right eye proptosis was notable with no thyromegaly or nodules. She was afebrile but tachycardic. Laboratory evaluation was notable for TSH <0.005 uIU/mL (0.47 - 4.68), free T4 3.3 ng/dL (0.6 - 2.5) and elevated serum TSI 479 % (0 - 139), consistent with thyrotoxicosis due to Graves’ disease. She was noted to be hyperglycemic requiring insulin therapy. Her A1C was 9.7 % with GAD antibodies titer 1702.3 U/mL (0.0 - 5.0) and C-peptide 0.5 ng/mL (1.1 - 4.4), consistent with type 1 diabetes. Adrenal insufficiency was ruled out. CT scan of the brain showed no acute intracranial process.

She was treated with methimazole and insulin therapy. Given fluctuating mental status with psychotic features, she underwent a work-up for paraneoplastic disease. An abdominal CT showed a cystic lobular left adnexal mass with peripheral enhancing soft tissue. Serum anti-NMDAR antibody was positive with titer 1:160. She underwent bilateral salpingo-oophorectomy and pelvic washing. Pathology was consistent with a left serous cystadenofibroma. Within hours of surgery, she had marked clinical improvement. Serial anti-NMDAR antibody testing showed a clearance of the serum antibodies within 2 months of surgery.

Conclusion:

The co-occurrence of multiple autoimmune conditions suggests common genetic, immunologic, and/or environmental factors play critical roles in the induction of organ-specific autoimmunity. A correlation between NMDA encephalitis and autoimmune thyroid disease has been reported but coexisting with polyendocrine autoimmunity has not been observed yet. Our case of coincident APS3v and NMDA receptor encephalitis underscores the importance of considering autoimmune encephalopathy in those patients with a personal or family history of autoimmunity.

 

Nothing to Disclose: SF, HW, RM