Rabies encephalitis: immunohistochemical investigations

Three cases of human rabies encephalitis were studied immunohistochemically using a specific antiserum to rabies ribonucleoprotein (RNP) and the peroxidase-antiperoxidase method. In this way, RNP could be specifically demonstrated in all cerebral regions and the spinal cord with a predilection for virus attack on the diencephalon and the brain stem according to the clinical course of the disease, and possibly reflecting the phenomenon of pathoclisis. Virus antigen was mainly present in the nerve cell bodies and processes, and in glial cells, especially in the interfascicular oligodendroglia, which seems to be a route of rabies virus infection in the later course of this fatal disease. Immunohistochemically, virus antigen was not limited to the Negri bodies: it was also traceable in the cytoplasm. Altogether, many more virus infected cells were established by immunostaining than were to be expected by the presence of Negri bodies in hematoxylin-eosin stained sections.     

Symmetrical brainstem encephalitis caused by herpes simplex virus

We describe a 53-year-old man with herpes simplex virus (HSV) brainstem encephalitis diagnosed based by positive HSV immunoglobulin M antibodies from cerebrospinal fluid. The MRI findings of this case had three unique features. First, the lesions were symmetrical. Second, the lesions may have been associated with reactivation of HSV infection in the region of the trigeminal nerve. Third, diffusion-weighted and apparent diffusion coefficient (ADC) imaging, conducted for the first time on an HSV brainstem encephalitis case, suggested that the lesions were associated with vasogenic edema.     

Hantavirus pulmonary syndrome: encephalitis caused by virus Andes

Hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome (HPS) are rodent-borne emerging diseases caused by members of the genus Hantavirus, family Bunyaviridae. Some species of hantavirus may cause encephalitis, but this is the first report in Andes virus associated to HPS.     

Atypical brainstem encephalitis caused by herpes simplex virus 2

BACKGROUND: Herpes simplex encephalitis is one of the most common and serious sporadic encephalitides of immunocompetent adults. Herpes simplex virus 2 (HSV-2) infections of the central nervous system usually manifest as subacute encephalitis, recurrent meningitis, myelitis, and forms resembling psychiatric syndromes. OBJECTIVES: To report and discuss magnetic resonance imaging (MRI) findings and clinical features in atypical brainstem encephalitis and facial palsy associated with HSV-2. SETTING: Neurology department of a tertiary referral center. PATIENT: A 37-year-old woman was admitted to the hospital with fever, diplopia, left hemiparesis, sensory change in the face and limbs, personality changes, frontal dysexecutive syndrome, and a stiff neck. Brain MRI showed multifocal high-signal intensities in the pons, midbrain, and frontal lobe white matter on T2-weighted and fluid-attenuated inversion recovery images. Cerebrospinal fluid (CSF) polymerase chain reaction (PCR) amplification analysis was positive for HSV-2. Acyclovir therapy was started, and the encephalitic symptoms disappeared with a negative conversion of HSV-2 PCR in the CSF. However, after the discontinuation of acyclovir therapy, peripheral facial palsy occurred on the left side. A possible relapse or delayed manifestation of the HSV-2 infection was suspected, and the acyclovir therapy was restarted. A complete remission was achieved 3 days after the treatment. She was discharged without any neurologic sequelae. CONCLUSIONS: We describe a patient who developed atypical encephalitis due to HSV-2 and peripheral facial palsy, which could also be related to the HSV-2. This case suggests that HSV-2 should be considered among the possible causes of atypical or brainstem encephalitis and that the PCR amplification method of the CSF can help reveal the possible cause of HSV-2.     

Human encephalitis caused by pseudorabies virus infection: a case report

Pseudorabies virus (PRV) primarily infects swine but can infect cattle, dogs, and cats. Several studies have reported that PRV can cross the specie barrier and induce human encephalitis, but a definitive diagnosis of human PRV encephalitis is debatable due to the lack of PRV DNA detection. Here, we report a case of human PRV encephalitis diagnosed by the next-generation sequencing (NGS) of PRV sequences in the cerebrospinal fluid (CSF) of a patient. A male pork vendor developed fever and seizures for 6 days. NGS results showed PRV sequences in his CSF and blood. Sanger sequencing showed that PRV DNA in the CSF and PRV antibodies in both the CSF and blood were positive. MRI results revealed multiple inflammatory lesions in the bilateral hemisphere. Based on the clinical and laboratory data, we diagnosed the patient with PRV encephalitis. This case suggests that PRV can infect humans, causing severe viral encephalitis. People at risk of PRV infection should improve their self-protection awareness.

     

Electro-clinical evolution of refractory non-convulsive status epilepticus caused by West Nile virus encephalitis.

West Nile virus (WNV) has re-emerged with a much wider geographic distribution and a higher incidence than ever. In spite of some recent reports on the neurological manifestations and EEG changes caused by WNV encephalitis, there are few data on the incidence of seizures, status epilepticus or post-encephalitic epilepsy. There is also no systematic review of EEG changes caused by WNV encephalitis that is based on a large series of patients. Here, we review the pertinent literature, and report the electroclinical evolution and therapeutic complexity of a patient with WNV encephalitis who developed refractory, non-convulsive status epilepticus.     

Brainstem encephalitis caused by Coxiella burnetii

Coxiella burnetii is the causative agent of Q fever, which rarely causes neurologic symptoms. We describe a patient who presented with progressive sensory changes, dizziness, and motor weakness. The cerebrospinal fluid revealed pleocytosis, and MRI indicated the presence of a diffuse brain stem lesion. An indirect immunofluorescence test revealed antibodies against C. burnetii. The symptoms improved with antibiotics against C. burnetii. Q fever should be considered as a possible etiology of brainstem encephalitis.     

Reversible limbic encephalitis caused by ovarian teratoma

A 19-year-old woman developed memory loss followed by psychosis, coma, convulsion, and central hypoventilation requiring mechanical ventilation. MRI of the brain showed minimal changes, and SPECT imaging revealed a small region of increased uptake in the cortex. Intravenous acyclovir and high-dose corticosteroids were administered without any effect. An extensive work-up revealed an elevated serum alpha-fetoprotein (AFP) concentration and the presence of an ovarian tumor. Following resection of the tumor, an immature teratoma by pathology, the patient had significant recovery of her cognitive function with some psychotic sequela. Serum anti-neuronal antibody (anti-Hu) was negative both by immunohistochemistry and by Western blot analysis. A rare combination of paraneoplastic limbic encephalitis and brainstem encephalitis was the suspected diagnosis. Because the tumor contained a neuronal component, we propose an immunologic cross-reaction as the pathomechanism, but the lack of a specific antibody may suggest cell-mediated rather than globulin-mediated immunity.     

Endogenous paranoid-hallucinatory syndrome caused by Borrelia encephalitis

We describe a case with no neurological signs but marked psychiatric symptoms induced by borrelia burgdorferi, whose clinical picture was indistinguishable from an endogenous schizophrenia. The symptoms within one week under antibiotic treatment with ceftriaxon, but afterwards the patient showed a mild organic brain syndrome. The case demonstrated the aetiologic nonspecificity of paranoid symptoms and hallucinations and emphasizes that in psychotic patients without psychiatric history additional diagnostic measures should be performed.     

Acute fatal necrotizing hemorrhagic encephalitis caused by Epstein-Barr virus in a young adult immunocompetent man

Epstein-Barr Virus (EBV) encephalitis is a rare (<1%) and generally self-limited disease with few sequelae. This neurological complication has been reported almost exclusively in the course of acute primary infection and in paediatric patients. We describe a case of a young adult immunocompetent man who developed an acute fatal necrotizing haemorrhagic encephalitis as the only manifestation of an acute EBV infection. EBV-DNA was tested positive in several CSF samples by qualitative and quantitative PCR. Serological profile showed: absence of IgM against Viral Capsid Antigen (VCA) in three different consecutive samples, presence of IgG against VCA and IgG seroconversion for Epstein Barr Nuclear Antigen (EBNA). EBV-DNA was detected by qualitative PCR in autoptic brain material. Clinical course was not influenced by antiviral therapy with acyclovir. In conclusion to our knowledge, this is the only case of acute necrotizing haemorrhagic EBV encephalitis with a fatal outcome, in an adult immunocompetent man.