A Case of Acute Necrotizing Encephalopathy in a Patient With Influenza
Kristen Watkins1, Catherine Imossi1, Eddie Louie2, Kristen Thomas3, Laura Methvin4, Christopher William3, Ilya Kister1, Kara Melmed5
1Neurology, 2Infectious Disease, 3Pathology, 4Cardiology, 5Neurocritical Care, NYU Langone Health
Objective:
We present a case of rapidly progressive encephalitis originating in the pons and radiating superiorly to involve the hippocampi, accompanied by severe myotonia with profound electrolyte derangement.
Background:

This is a 57-year old-female with seronegative lupus (on hydroxychloroquine and belimumab) who presented with acute onset dysarthria and gait instability. Stroke code imaging was negative. She tested positive for Influenza A and oseltamivir was started, later changed to peramivir. Her mental status declined within hours requiring intubation.

Magnetic resonance imaging (MRI) demonstrated symmetrical T2 hyperintense lesions with diffusion restriction at the pons. Repeat MRI two days after disclosed marked progression of the symmetrical brainstem edema, involving the temporal lobes through the hippocampi. Cerebrospinal fluid (CSF) revealed protein of 181. She was transferred to a tertiary care hospital.

Patient was unresponsive on unsedated exam. Diffuse myotonia was observed, with creatinine kinase (CK) over 70,000. EEG revealed multiple generalized seizures with focal onset over the left temporal lobe. Repeat CSF disclosed protein of 665 and few cells. Serum and CSF revealed elevations in interleukin-6 in the serum (213) and CSF (104) and was negative for toxins, ganglioside antibodies, and antibodies associated with autoimmune encephalitis (Mayo Clinic ENC2 panel). Profound refractory hyperkalemia resulted in cardiac arrest.

Autopsy revealed multifocal cerebral and cord hemorrhage with bland coagulative necrosis consistent with infarction without lymphocytic or neutrophilic infiltration or malignancy. There was acute lung injury attributed to influenza, and renal changes consistent with Class II lupus nephritis.

Design/Methods:
NA
Results:
NA
Conclusions:
Her cause of death was determined to be acute necrotizing encephalopathy (ANE), a severe neurologic condition involving fulminant cerebral edema usually triggered by a viral infection. Pathophysiology has not been entirely characterized but is thought to involve a cytokine storm in susceptible hosts. Prompt identification is essential so that high-dose steroids, plasmapheresis, tocilizumab, and/or intravenous immunoglobulin can be initiated.
10.1212/WNL.0000000000216475
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