Clinical Course of a Patient with Radiographically Described Acute Necrotizing Encephalopathy

Editor:

We write in reference to a reported case of acute necrotizing encephalopathy (ANE) associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection published in the August 2020 issue of Radiology (1). A 58-year-old woman with hypertension presented with cough, fever, and altered mental status. She was somnolent but arousable, with bilateral ptosis and conjugate tonic downgaze. She initially was right hemiparetic, and over days became quadriplegic. SARS-CoV-2 real-time reverse-transcription polymerase chain reaction (RT-PCR) testing was positive via nasopharyngeal swab. Initial cerebrospinal fluid (CSF) testing was unavailable. Later, SARS-CoV-2 RT-PCR was performed in the CSF and was negative.

Initial treatment was with 2 g/kg of intravenous immunoglobulin in divided doses, without clinical improvement. High-dose steroids (intravenous methylprednisolone, 1000 mg daily for a total of 5 days) were then administered, followed by 40 mg of prednisone for 5 days via percutaneous endoscopic gastrostomy tube. After supportive care, the patient demonstrated physical and cognitive improvement, with decreasing ophthalmoplegia, speaking in short answers, and participating with physical therapy. She was discharged to subacute rehabilitation.

The patient recovered considerably; 4 months after hospitalization, her sensory and motor examination were normal. There was residual psychomotor slowing. She was able to perform activities of daily living, although she was not yet driving. Modified Rankin scale score was 3. Repeat MRI of the brain without contrast agent enhancement showed residual T2 hyperintensities and hemosiderin deposition in the medial thalami; T2 hyperintensities significantly improved and hemosiderin deposition remained unchanged. MRI T2 hyperintensities in the bilateral medial temporal lobes had resolved (Figure).

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Several cases of coronavirus disease 2019 (COVID-19)–associated ANE have now been reported (Table). Most show MRI abnormalities in the thalamus, putamen, hippocampus, medial temporal lobes, and amygdala, associated with illnesses (1–5). The brainstem, cerebellum, cerebral peduncles, and pons may also be involved (2–5). The neuroinvasive mechanism of ANE is not known; there are two possible hypotheses, the immune-mediated neurotoxicity and neuronal retrograde dissemination (6). SARS-CoV and SARS-CoV-2 are similar in structure, and both can penetrate through the neuroepithelium of the olfactory nerve and olfactory bulb by an interaction between the viral spike protein and host cell surface protein angiotensin-converting enzyme 2 (ACE2). In the brain, ACE2 is expressed in the brainstem, hypothalamus, motor cortex, and raphe nucleus (7). Immunotherapy has some role in the treatment of COVID-19–associated ANE, as described in the literature (1,4,5).

Disclosures of Conflicts of Interest: P.B. disclosed no relevant relationships. E.K.F. disclosed no relevant relationships. S.M. disclosed no relevant relationships. A.B.M. disclosed no relevant relationships.