Letter to the EditorDelayed imaging abnormalities of neuro-invasive West Nile virus in cancer patients
Introduction
West Nile virus (WNV) is a single-stranded ribonucleic acid virus of the genus Flavivirus and the most significant cause of epidemic encephalitis in the western hemisphere [1]. The majority of infections are clinically silent. Seroprevalence following large human epidemics is low and frequently between 2 and 3% per year [2]. Clinical presentation is most commonly a self-limited illness called West Nile fever [3]. Symptoms can include fever, headache, malaise, back pain, myalgias, anorexia and rash persisting for three to six days [3]. Less than 1% of people infected with WNV develop neuroinvasive disease with encephalitis, meningitis, or flaccid paralysis. Still, WNV is the third most common infectious cause of encephalitis in hospitalized patients in the U.S. [1], [4]. Diagnosis is best established through IgM antibody to WNV in serum or cerebrospinal fluid (CSF) [3]. Magnetic resonance imaging (MRI) can reveal hyperintensities in the basal ganglia, thalami, caudate nuclei, brainstem, and spinal cord on T2-weighted and fluid-attenuated inversion recovery images [5], [6]. WNV patients with this particular pattern of abnormality on MRI may have a worse prognosis than patients with normal or other MRI abnormalities [6].
We present 2 cases of cancer patients with WNV encephalitis who developed devastating neurological complications. Imaging initially was unremarkable in both cases but later showed features of WNV on repeat imaging.
Section snippets
Patient #1
The first patient was a 65-year-old male with history of relapsed chronic lymphocytic leukemia. He was initially diagnosed seven years prior and treated with pentostatin, cyclophosphamide and rituximab. Five years later he received an allogenic stem cell transplant from an unrelated donor. Following relapse he received four doses of rituximab followed by a donor lymphocyte infusion. He subsequently presented with a three day history of fever, diarrhea, and upper respiratory symptoms and started
Discussion
People who are immunosuppressed are at a higher risk for WNV neuro-invasive disease and can have an increased severity of disease [7], [8]. A case–control study revealed that cancer and chemotherapy increased at least sixfold the risk of developing neuroinvasive disease [9]. Particular cancers, predominantly hematological malignancies undergoing stem cell transplantation are at increased risk for severe disease after an infection [10]. Unfortunately, treatment with IFN, IVIG and ribavirin has
Funding
No funding was obtained for this project.
Conflict of interest
No conflict of interests to report.
References (10)
- et al.
Epidemic West Nile encephalitis, New York, 1999: results of a household-based seroepidemiological survey
Lancet
(Jul 28 2001) - et al.
Manifestations of West Nile neuroinvasive disease
Rev Med Virol
(Jul-Aug 2006) - et al.
West Nile virus: a primer for the clinician
Ann Intern Med
(Aug 6 2002) - et al.
Encephalitis hospitalization rates and inpatient mortality in the United States, 2000–2010
PLoS One
(Sep 5 2014) - et al.
West Nile virus: case report with MR imaging findings
AJNR Am J Neuroradiol
(Aug 2003)
Cited by (1)
Pediatric West Nile Virus-Associated Neuroinvasive Disease: A Review of the Literature
2019, Pediatric NeurologyCitation Excerpt :A significant number of patients with WNV meningoencephalitis may have normal brain imaging findings even with significant symptoms such as alteration in mental status and dysphasia.62 Several reports, including one pediatric, have documented that imaging may be initially normal with follow-up imaging proving abnormal; therefore, an initial normal imaging pattern may be a function of time bias.56,63,64 On conventional sequences, T2 signal (with corresponding low T1 signal) abnormality with or without diffusion signal abnormality may be seen in the lobar gray and white matter, basal ganglia, thalami, brainstem, and even cerebellum.