Paroxysmal Sympathetic Hyperactivity in Severe Anti-N-Methyl-d-Aspartate Receptor Encephalitis: A Single Center Retrospective Observational Study

Approach to acute encephalitis in the intensive care unit

PURPOSE OF REVIEW

Recent years have seen a dramatic increase in the identification of autoimmune encephalitis (AE) and the emergence of new causes of infectious encephalitis (IE). However, management of these patients remains challenging, with many requiring care in intensive care units. Here, we describe recent advances in the diagnosis and management of acute encephalitis.

RECENT FINDINGS

Advances in the identification of clinical presentations, neuroimaging biomarkers, and electroencephalogram patterns have enabled more rapid diagnosis of encephalitis. Newer modalities such as meningitis/encephalitis multiplex PCR panels, metagenomic next-generation sequencing, and phage display-based assays are being evaluated in an effort to improve detection of autoantibodies and pathogens. Specific advances in the treatment of AE include establishment of a systematic approach to first-line therapies and the development of newer second-line modalities. The role of immunomodulation and its applications in IE are actively being investigated. In the ICU, particular attention to status epilepticus, cerebral edema, and dysautonomia may improve outcomes.

SUMMARY

Substantial diagnostic delays still occur, with many cases left without an identified etiology. Antiviral therapies remain scarce, and optimal treatment regimens for AE still need to be clarified. Nevertheless, our understanding of diagnostic and therapeutic approaches to encephalitis is rapidly evolving.

Thymic Hyperplasia-Associated Autoimmune Encephalitis Mimicking Neuroleptic Malignant Syndrome: A Case Report

Anti-NMDA (N-methyl-D-aspartate) receptor encephalitis is a common autoimmune encephalitis. It is commonly associated with underlying malignancy. We present a 24-year-old patient with sudden onset of behavioral changes and acute psychosis who was treated with antipsychotics followed by the development of generalized rigidity, facial twitching, and sympathetic overactivity. MRI and EEG were inconclusive. The neuroleptic malignant syndrome was presumed and bromocriptine was started. Multiple antiepileptics were started to control this twitching without success. NMDA receptor reactivity in the CSF established the diagnosis. Searching for underlying malignancy was unyielding except for an anterior mediastinal mass seen on the CT chest. The patient had only mild improvement in response to corticosteroids, plasmapheresis, and intravenous immunoglobulin (IVIG). Significant improvement was achieved after the thymectomy. This case serves to remind clinicians of key aspects of the disease including general rigidity and paroxysmal sympathetic hyperactivity, and the potential to confuse these with other diagnoses including neuroleptic malignant syndrome. This case is also unique in that the association with thymic hyperplasia is very rare and only a few cases were reported in English literature.