Internal Medicine University of Tennessee Graduate School of Medicine Knoxville, Tennessee, United States
Clinical Scenario or Case: 67yoWF who initially presented with acute altered mental status, fevers and bullous skin lesions. PMH significant for DM2 and recent COVID infection. There was concern for sepsis from skin infection and broad-spectrum antibiotics were started. She also had LP performed which demonstrated lymphocyte predominant leukocytosis though her infectious PCR was negative. Due to concern for worsening, acyclovir was started while awaiting an MRI. She had minimal improvement overall. MRI later resulted with significant limbic enhancement. These findings being much more indicative of autoimmune encephalopathy (AE) than infectious, however testing of her CSF was completely negative of all AE drivers. She was started on high dose dexamethasone and had rapid improvement. She remained stable following conclusion of steroids and was discharged home.
Evidence/Literature Review: In many autoimmune encephalitis cases, no clear antibody is found. Criteria for antibody negative encephalitis is available given the relative newness of AE. Nonetheless, connections to autoimmune blistering disease (AIBD) flaring with encephalitis is not well documented. A case series from Emory was able to find 3 AE with concurrent AIBD. While AIBD can be associated with paraneoplastic syndromes, which is a strong trigger of AE, there was no correlation appreciated in the literature.
Unique Aspects of Case: This case demonstrates a unique presentation of AE and AIBD triggered by a recent viral illness. While her autoimmune testing was negative, her rapid improvement with steroids gives validity to being an antibody negative disease of which may be known in the future. We hope to highlight the connection to AIBD being an exceptionally rare presentation regardless of whether an antibody is determined.
Recommendations/Conclusions: Post infectious AE is an increasingly common condition post COVID. Physicians should be aware that other autoimmune conditions can be sparked by viral illnesses. We hope to highlight our rare case as a way to avoid chasing red herrings on diagnosis.
