Dengue in patients with central nervous system manifestations, Brazil.

We investigated the prevalence of dengue in patients with suspected viral meningitis/meningoencephalitis in a dengue-endemic area. Cerebrospinal fluid analysis showed positive results and a 6.74× greater likelihood of identifying positive fluid in patients who died. Our findings support testing patients with neurologic manifestations for the virus in dengue-endemic areas.

MR findings in Murray Valley encephalitis.

Murray Valley encephalitis (MVE) is caused by a flavivirus related to West Nile and St. Louis encephalitis viruses. We report a case of MVE resulting in quadriplegia and respiratory failure. MR imaging demonstrated thalamic hyperintensity on T2-weighted images, with similar involvement of the red nucleus, substantia nigra, and cervical cord. These findings preceded serologic diagnosis and are similar to those of Japanese encephalitis. In the appropriate setting, thalamic T2 hyperintensity is suggestive of flavivirus infection.

Demonstration of Akabane virus antigen using immunohistochemistry in naturally infected newborn calves.

Eight newborn calves showing ataxia were necropsied and examined histologically. Six of seven cerebrospinal fluid samples collected from these animals had neutralizing antibody for Akabane virus (AKV). All examined calves had nonsuppurative encephalomyelitis, localized mainly in the midbrain and spinal cord. Corresponding to the encephalitic lesion, AKV antigen was demonstrated in neuroglial cells in the brain stem and neuronal cells in the ventral horn of the spinal cord. This is the first study to demonstrate AKV antigen by immunohistochemistry in naturally infected newborn calves.

Early diagnosis of Murray Valley encephalitis by reverse transcriptase-polymerase chain reaction.

A 4-year-old aboriginal boy developed encephalitis due to Murray Valley encephalitis virus (MVE) following an earlier infection with Kunjin virus (KUN). The illness was severe, resulting in cerebral atrophy and profound physical and intellectual disability. The earlier KUN infection complicated his serological profile and delayed antibody responses to MVE. By contrast, the reverse transcriptase-polymerase chain reaction (RT-PCR) assay detected MVE in serum 3 days after the onset of illness and 4 days before the appearance of MVE-specific IgM. We suggest that MVE-specific RT-PCR provides rapid and specific diagnosis of MVE and should be used more widely for the diagnosis of acute viral encephalitis in cases originating from flavivirus endemic areas.

[Diagnostic value of cytological examination of the cerebrospinal fluid with the millipore membrane filter technique].

With the millipore membrane filter (MP) technic 280 samples of CSF from 203 cases with different diseases involving the central nervous system were studied. 76 of these samples were examined with the slide centrifuge technic simultaneously for comparison. In accordance with the pathological cell components (transformed lymphocytes, plasmocytes, different phagocytes, granular neurocytes and tumor cells) as well as the clinical data, the diagnostic results could be divided into three groups. The diagnoses were definitely established in 19.6% of the cases with the cytological examination of the CSF. The diagnoses were suggestive in 50.7% and not established with the cytological examination of the CSF in 29.6%. With intracranial infection, demyelinating disease, cerebrovascular accidents and brain tumors an overall higher positive diagnostic rate of 76.8% was obtained and with other neurological disorders it was only 19.2% (P less than 0.001). The advantages and disadvantages of the MP technic were compared with those of the slide centrifuge and sedimentation chamber technics. The limitation of the staining method for the MP slides remained to be further studied. More than two technics for concentrating CSF cells were recommended to be in use for the time being.

Factors in serum and cerebrospinal fluid from children with viral encephalopathies impair glucose transport.

Since glucose transport appears to be inhibited in viral infections, we looked for inhibitors in cerebrospinal fluid (CSF) and serum of children with febrile convulsions (FC) and Singapore syndrome (SS). When incubated with rat and human adipocytes both fluids from FCs inhibited the utilization of glucose supplied in the medium as exhibited by decreased synthesis of triglycerides. Sera in the acute stage of the illness were more inhibitory than those from convalescents. There was competition between 3-0 methyl glucose and the CSF factors suggesting competitive inhibition at the plasma membrane. This may be due to anti-idiotypic antibodies. The likelihood of a second inhibitor is suggested by (1) the inhibitory activity of the larger of two fractions (about 80,000 molecular weight, corresponding to albumin) obtained in gel filtration chromatography of pooled CSF and (2) failure to observe a decrease in inhibitory activity with recovery from SS following management with hyperglycaemia-producing infusions. These observations are consistent with glycated albumin as a possible factor. Further characterization is called for to ascertain the genesis of viral encephalopathies.

Computed tomographic findings in acute viral encephalitis in adults with emphasis on herpes simplex encephalitis.

Nine patients with acute viral encephalitis were diagnosed by CT. Seven had herpes simplex and two had nonherpetic acute viral encephalitis. All patients with herpes simplex encephalitis initially were febrile. They developed confusion and seizures. Five had focal neurological deficit and two had papilledema. The CT scan showed an abnormality on the initial CT in 6 of 7 cases. In one case initial CT study was normal; however follow-up scan (performed 5 days later) showed a definite abnormality. CT showed the characteristic pattern of herpes simplex encephalitis in all cases. This is a temporal lobe hypodense lesion (unilateral, 5 cases; bilateral, 2 cases) with a small interspersed hyperdense region. The hyperdense component represents hemorrhage. Mass effect was seen in all cases. Two patients showed enhancement which was diffuse or patchy in one case and cisternal-gyral in the other; however enhancement was absent in 5 cases. One patient showed progression of the size of the hypodense lesion despite antiviral treatment. Follow-up CT showed hypodense lesion(s) in the temporal lobe region with enlargement of the temporal horns and contiguous basal cisterns in 4 cases. In 2 other cases of acute viral encephalitis the patients initially developed fever, confusion and seizures. CT showed basal ganglia calcification or hypodense lesions.

The role of lumbar puncture in the evaluation of dementia: the University of Pittsburgh Study.

In a retrospective study of 80 patients over 55 years old, the efficacy of lumbar puncture in evaluating elderly demented patients was examined. Despite a cost of $381 per procedure, in addition to cerebrospinal fluid (CSF) evaluation, no diagnosis was made on the basis of the information obtained in any of the patients (53 per cent) who underwent lumbar puncture. The only abnormalities found were 11 cases of nonspecific elevations in CSF protein and one case of abnormal cellularity not related to bacterial infection. An additional 422 cases of dementia from other series were reviewed, and only four patients were found whose diagnosis could have been made by lumbar puncture--one patient had neurosyphilis, and the other three were postencephalitic. In addition, the literature on complications of lumbar puncture was reviewed. There were no serious complications of lumbar puncture in the present study. The authors concluded that although it is low-risk, lumbar puncture cannot currently be recommended for routine use in the evaluation of elderly demented patients, but should be used in evaluating demented patients under 55 years of age, patients with rapid onset or progression of dementia, patients with syphilis serology in suspected cases of viral encephalitis, and patients with signs and symptoms of fungal meningitis.

Acute viral encephalitis: its diagnosis and outcome.

Sixty patients with acute viral encephalitis admitted to The London Hospital in the last fifteen years have been reviewed. These consisted of 12 patients with known viral infection, 29 patients with acute viral infection of undetermined type, and 19 patients in whom an encephalitic illness followed a viral infection (post-infection encephalitis). The patients with primary viral encephalitis presented with an inflammatory brain disorder, including headaches and fever, and developed focal or diffuse neurological signs. Patients with post-infection encephalitis, usually following a 'flu'-like illness, presented with an acute neurological disturbance. The results of investigations, including virological studies, CSF examination, electroencephalography and neuroradiology, are described. Biopsy or autopsy material was available in 11 patients and these pathological findings supported the clinical classification of these patients. The mortality was highest in patients with herpes simplex virus encephalitis and lowest in patients with post-infection encephalitis. A considerable morbidity was found, not only in patients with primary viral encephalitis, but also in patients with encephalitis of unknown aetiology and post-infection encephalitis.

Comparison of protein values in cerebrospinal fluid by nephelometry and radial immunodiffusion.

Various parameters of three radial immunodiffusion systems, a kinetic nephelometer and two laser nephelometers were compared in a measurement of IgG and albumin in cerebrospinal fluid. Greater precision for IgG and albumin determinations was found with two RID systems. Correlation coefficients between methods ranged from 0.71 to 0.94. The generally poor correlations of methods, combined with the results of accuracy studies employing WHO standard reference dilutions and proportional errors demonstrated by linear regression equations, illustrate graphically the need for standardization in the field of immunochemical determinations. Our preliminary studies of the IgG/Alb ratio in cerebrospinal fluid of multiple sclerosis patients agreed with the work of others. In each case, the ratio was elevated or borderline high.

Uptake of 5(125I) iodo-2-deoxyuridine (IDU) in plasma and cerebrospinal fluid in a case of herpes encephalitis with a comparative study on the uptake in plasma, cerebrospinal fluid and brain tissue in dogs.

A case of herpes encephalitis diagnosed by brain biopsy and treated with 5-iodo-2-deoxyuridine (IDU) is presented. The infection occurred in a previously well 19-year-old female patient. Plasma and cerebrospinal fluid (CSF) uptake of the substance was determined using 125I labelled IDU. Top CSF levels of IUD and metabolites of less than 4 microgram/ml, about 1/10 of the corresponding plasma level, were obtained after 6 hours of continuous infusion. The result is discussed and compared with a similar study made on 5 healthy beagle dogs where in addition the levels obtained in various parts of the brain were determined. In the animal experiment a mean value of 2.5 microgram/ml of IDU and metabolites was obtained in the CSF after 8 hours, less than 1/20 of the plasma level. The levels in brain tissue were only slightly higher than in the CSF. The causes of therapeutic failures with IDU treatment are discussed.