Transient Splenial Lesion of the Corpus Callosum in H1N1 Influenza Virus-Associated Encephalitis/Encephalopathy

Abstract

A 26-year-old man was admitted to our hospital because of high fever, drowsiness, memory disturbance, and disorientation due to H1N1 influenza virus-associated encephalitis/encephalopathy. All of his symptoms rapidly improved following methylprednisolone pulse therapy. The diffusion-weighted image of brain magnetic resonance imaging (MRI) revealed a large transient hyperintense signal lesion on the central splenium of the corpus callosum. This MRI finding in conjunction with a complete clinical recovery has been previously observed in cases of clinically mild seasonal influenza-associated encephalitis/encephalopathy, and can be also a useful clue for the diagnosis of new type of influenza, H1N1 influenza virus infection complicated by encephalitis/encephalopathy.

The hidden burden of influenza: A review of the extra‐pulmonary complications of influenza infection

“…Three patients (30%) were diagnosed with PRES based on findings of vasogenic edema in the frontal cortex in one and in the parietal and occipital cortex in the other two; only one of these patients had follow‐up MRI imaging which demonstrated resolution at day 24 . Two patients’ MRIs had the hyperintense signal on the central splenium of the corpus callosum typical of MERS; follow‐up MRI at day 11 was normal in the only patient with follow‐up imaging reported . Electroencephalography (EEG) testing revealed diffuse slowing typical of encephalitis in 11/14 (79%), epileptic discharges in 1/14 (7%), and was normal in 1/14 (7%).…”

“…All patients were treated with supportive care, and 21 of the 28 patients reported were treated with neuraminidase inhibitors including oseltamivir, peramivir, and/or zanamivir. Three patients (11%) were additionally treated with corticosteroids, and one patient underwent plasma exchange . Overall, 79% (22/28) of adult patients with IAE survived.…”

Acute influenza virus-associated encephalitis and encephalopathy in adults: a challenging diagnosis

“…2. In total, 44 cases of IAE in adults were identified from 31 reports (Ak et al , 2012; Akins et al , 2010; Alakare et al , 2010; Bartynski et al , 2009; Bulakbasi et al , 2006; Chen et al , 2010; Cheng et al , 2011; Cunha et al , 2012; Fukami et al , 2005; Gadoth et al , 2010; Goenka et al , 2014; Gonzalez & Brust, 2009; Hakoda & Nakatani, 2000; Hawkins et al , 1987; Hjalmarsson et al , 2009; Iijima et al , 2002; Ishii et al , 2015; Ito et al , 2011; Jeganathan et al , 2013; Khosla et al , 2011; Kimura et al , 2008; Lee et al , 2010; Salonen et al , 1997; Santini et al , 2012; Simon et al , 2013; Steinberg et al , 1972; Steininger et al , 2003; Tsai et al , 2011; Wang et al , 2011, 2015; Yamashita et al , 2008). The cases are summarized in the supplementary material.…”

The Pattern of Brain Microhemorrhages After Severe Lung Failure Resembles the One Seen in High-Altitude Cerebral Edema

“…An involvement of the corpus callosum was thus far not mentioned. Reversible signal alterations in MRI, but no MH, have been observed in patients with encephalopathies caused by various mainly viral infections (18)(19)(20). The mechanism has been speculated as intramyelinic edema caused by a cytokine storm.…”