Clinical and Radiological Predictors of Outcome for Murray Valley Encephalitis

Abstract

A review of the laboratory-confirmed cases of Murray Valley encephalitis (MVE) from Western Australia between 2009 and 2011 was conducted to describe the clinical, laboratory, and radiological features of the disease. The nine encephalitis patients presented with altered mental state and seizures, tremor, weakness, or paralysis. All patients developed a raised C-reactive protein, whereas most developed acute liver injury, neutrophilia, and thrombocytosis. All patients with encephalitis developed cerebral peduncle involvement on early magnetic resonance imaging (MRI). The absence of thalamic MRI hyperintensity during the acute illness, with or without leptomeningeal enhancement, predicted a better neurological outcome, whereas those patients with widespread abnormalities involving the thalamus, midbrain, and cerebral cortex or the cerebellum had devastating neurological outcomes. MRI scans repeated months after acute illness showed destruction of the thalamus and basal ganglia, cortex, or cerebellum. These findings may help clinicians predict the neurological outcome when evaluating patients with MVE.

Case Report: Zika Virus Meningoencephalitis and Myelitis and Associated Magnetic Resonance Imaging Findings

“…The purely cortical pattern of encephalitis in this case differs from the typical locations of other viral infections such as multifocal or diffuse (Epstein-Barr virus, Japanese encephalitis, varicella zoster virus), limbic system (herpes simplex virus type 1), basal ganglia and/or thalamic (eastern equine encephalitis, Japanese encephalitis, HIV-1, Murray Valley encephalitis, WNV), cerebral white matter (cytomegalovirus, HIV-1, Nipah viral encephalitis, WNV), cerebral peduncles (Murray Valley encephalitis), or substantia nigra (St. Louis encephalitis, WNV). 11,[13][14][15] Furthermore, this is also the first demonstration of the rapid resolution of MRI findings coincident with the patient's clinical recovery from her encephalitis. In addition, based on signs of upper motor neuron dysfunction most prominent in the lower extremities that lasted longer than her encephalitis, our patient probably also had mild myelitis, another as yet rarely described adult complication.…”

“…9 Although the rapidity of resolution of an initially severe clinical presentation was unexpected, similar cases of rapidly improving meningoencephalitis have been described in a subset of patients with meningoencephalitis due to infection with other flaviviruses, including WNV, 10 and Murray Valley encephalitis virus. 11 Given the increasing prevalence and geographic distribution of ZIKV infection, ZIKV should be considered in patients with acute meningoencephalitis and appropriate environmental exposures.…”

Extended detection and isolation of Murray Valley encephalitis virus in whole blood and urine

“…CSF typically shows elevated protein and leucocytosis, with a predominance of mononuclear cells . The case we present here was unusual in that the MRI findings were subtle and the neurological outcome was excellent, although longer term mild sequelae are sometimes identified …”

Long‐term outcomes of Murray Valley encephalitis cases in Western Australia: what have we learnt?

“…PathWest undertakes all of the testing for suspected MVEV infection within WA and information was retrieved from clinical and laboratory data held in clinical files by one of us (D. Smith). The criteria for laboratory confirmation of MVEV infection have been described previously . Briefly, serological testing was performed by an in‐house haemagglutination inhibition assay, a monoclonal antibody epitope blocking enzyme immunoassay and an IgM in‐house indirect immunofluorescence immunoassay.…”

“…The criteria for laboratory confirmation of MVEV infection have been described previously. 16 Briefly, serological testing was performed by an in-house haemagglutination inhibition assay, a monoclonal antibody epitope blocking enzyme immunoassay and an IgM in-house indirect immunofluorescence immunoassay. From 2000, molecular testing was performed using an in-house nested or tandem reverse transcriptase polymerase chain reaction using primers for the MVEV envelope and NS5 gene, respectively.…”