A reversible lesion of the corpus callosum splenium with adult influenza-associated encephalitis/encephalopathy: a case report.
BACKGROUND
Influenza virus-associated encephalitis/encephalopathy is a severe childhood illness with a poor prognosis. Adult case reports are rare and, to date, there have been no reports of adults with a mild subcortical encephalopathy with reversible lesions of the corpus callosum splenium.


METHODS
A previously healthy 35-year-old man presented with acute progressive tetraplegia, transcortical motor aphasia and a mild decrease in his consciousness during his recovery after receiving oseltamivir phosphate treatment, and influenza type A antiviral medication. The initial magnetic resonance imaging study at day 1 showed symmetrical diffuse lesions in the white matter and a lesion on the central portion of the corpus callosum splenium. These findings had resolved on follow-up studies at day 8 and day 146. His neurological deficits mostly recovered within 12 hours following methylprednisolone pulse therapy. The levels of interleukin-6 and interleukin-10 in his blood and cerebrospinal fluid were initially elevated, but rapidly decreased to normal levels by day 8.


CONCLUSIONS
It is important for clinicians to recognize that even in adulthood, the subcortical encephalopathy observed during the therapeutic treatment for influenza type A infection can occur in conjunction with a reversible lesion of the corpus callosum, which may recover quickly. In addition, the cytokine storm in the blood system and the corticospinal cavity may play an important role in the etiology of the disease process.
Kimura
En
E
Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, Honjo, Kumamoto, Japan. enkimura-ku@umin.net
Okamoto
Sadahisa
S
Uchida
Yuji
Y
Hirahara
Tomoo
T
Ikeda
Tokunori
T
Hirano
Teruyuki
T
Uchino
Makoto
M