A 53-year-old woman was admitted to an American clinic complaining of fever and abdominal pain. A month prior, she had undergone a kidney transplant, after which she regularly took the immunosuppressants cyclosporine and tacrolimus. Soon after, the patient developed right-sided hemiparesis and progressive encephalopathy, rendering her speechless but occasionally responsive to her doctor's commands. An MRI revealed mesencephalic hyperintensities in the thalamus, tegmentum, and substantia nigra, forming a pattern known as the panda sign. Dr. Carlton Watson and colleagues at Vassar Brothers and Westchester Medical Centers shared the case in Neurology.
Panda sign is most often observed in Wilson's disease, and less commonly in Leigh syndrome, acute disseminated encephalomyelitis, rabies, and toxic leukoencephalopathy. However, the woman's etiology turned out to be different: PCR testing of her cerebrospinal fluid revealed West Nile fever virus. She was prescribed five doses of antiviral immunoglobulin and a month-long course of the antiviral drug remdesivir, after which she was referred for rehabilitation. There, her speech recovered, but hemiparesis persisted. Therefore, although panda sign is not specific for West Nile fever, this infection should be considered when it is detected, especially in immunocompromised patients.
