Classical and modern methods of cerebrospinal fluid analysis. Report on the First All-German Symposium of the Society for Laboratory Medicine (FRG) and the Study Group for CSF Analysis and Clinical Neurochemistry of the Society for Psychiatry and Neurology (formerly GDR) in Marburg a. d. Lahn, October 5-6, 1990

The aim of the symposium was to prepare an inventory of cerebrospinal fluid (CSF) analysis used in Germany, and to evaluate them in comparison with modern methods. From the large field of CSF analysis, four main topics were selected, all related to the practical application of the methods. The following conclusions were drawn: Classical techniques of cytodiagnosis are clinically important. Therefore, manual and mechanized techniques must be further improved with respect to counting, collection, and differentiating of CSF cells. As cytokines and complement factors are early mediators of diverse processes in CNS, highly sensitive techniques must be developed for their routine analysis e.g. in CNS inflammation. Recent efforts to detect specifically viral and bacterial agents (e.g. by polymerase chain reaction, Particle Counting Immuno-Assay, Enzyme Immuno-Assay) or antibodies (e.g. affinity-mediated immunoblot, specific antibody index) in CSF must be continued in order to develop definite and practicable assays for daily routine. For the detection of intrathecally produced antibodies, qualitative procedures appear to be more reliable then quantitative ones, provided that the former are highly sensitive and specific.

Detection of viral DNA in neonatal herpes simplex virus infections: frequent and prolonged presence in serum and cerebrospinal fluid

Polymerase chain reaction (PCR) assay was used to detect herpes simplex virus (HSV) DNA in mouth, skin, sera, or cerebrospinal fluid (CSF) from seven neonates with HSV infection. In a culture-negative patient, the diagnosis was confirmed by detection of HSV DNA. Serial examinations revealed that HSV DNA remained in the serum and/or CSF from several patients for 1-2 weeks after the beginning of treatment. Next, the results of PCR assay in neonatal HSV infections were compared with those in older children with herpes simplex encephalitis (HSE). HSV DNA was detected in CSF from four neonates with central nervous system involvement and in CSF from all nine children with HSE. Sera were positive for HSV DNA in five of seven neonates, including two cases of localized infections, but in none of the children with HSE. These results suggest that HSV may be spread principally via viremia in neonates. PCR assay could be useful for the confirmative diagnosis of neonatal HSV infections, especially in culture-negative cases.

Detection of varicella-zoster virus DNA by polymerase chain reaction in the cerebrospinal fluid of patients suffering from neurological complications associated with chicken pox or herpes zoster

The polymerase chain reaction (PCR) was used to detect varicella-zoster virus (VZV) DNA in the cerebrospinal fluid of patients with VZV infection associated with neurological symptoms. Positive results were obtained in three of five children with post-chicken pox cerebellitis and in seven of seven herpes zoster patients with neurological symptoms. The PCR thus provides a useful tool for the early diagnosis of VZV-associated neurological disease.

Cytomegalovirus encephalitis in a non-immunocompromised patient: CSF diagnosis by in situ hybridization cells

Cytomegalovirus (CMV) encephalitis in immunologically normal patients is rarely reported in the literature. CMV infection was diagnosed by viral DNA probe techniques on CSF cells in a 32-year-old, immunologically normal male presenting with a severe clinical picture due to encephalitis. Administration of ganciclovir was followed by an immediate improvement in the patient's condition. More sensitive techniques for CMV detection could allow to discover more cases of CMV encephalitis in non-immunocompromised patients than previously recognized.

Cerebrospinal dehydrogenases in central nervous system infections

Cerebrospinal fluid (CSF) dehydrogenases were studied in 42 controls, 23 children with pyogenic meningitis, 22 with tuberculous meningitis and 19 with encephalitis to assess their usefulness in differentiating between the different central nervous system infections. CSF-LDH and ICD activity was increased in CNS infections (p less than 0.0001), LDH being significantly higher (p less than 0.001) in pyogenic meningitis than in tuberculous meningitis or encephalitis. However, ICD activity was significantly different in each of these conditions (p less than 0.001). The dehydrogenase activity declined with subsequent clinical improvement, in all children with meningitis. A significant direct relationship was found between the enzyme activity and CSF protein content as well as total cell count. The 95% confidence interval confirms the utility of assaying CSF dehydrogenase activity to differentiate various CNS infections, thus improving the diagnostic ability.

Rapid diagnosis of herpes simplex encephalitis by nested polymerase chain reaction assay of cerebrospinal fluid

With the aim of improving early diagnosis of herpes simplex encephalitis a polymerase chain reaction (PCR) assay with two "nested" primer pairs was developed for the amplification of herpes simplex virus DNA in cerebrospinal fluid (CSF). Southern blotting was used to confirm the specificity of the amplification. The assay was applied to 151 CSF samples from 43 consecutive patients with herpes simplex encephalitis verified by the finding of herpes simplex virus/viral antigen in a brain biopsy sample or at necropsy (13) and/or intrathecal production of IgG antibody to the virus (40). As controls, 87 CSF samples from 60 patients with acute febrile focal encephalopathy (initially suspected to be herpes simplex encephalitis but excluded by the absence of intrathecal antibody synthesis) were tested. PCR detected herpes simplex virus DNA in 42 of the 43 patients with proven herpes simplex encephalitis; all but 1 were positive in the first CSF sample taken. The 1 PCR-negative patient had been treated with acyclovir from 20 h after the onset of symptoms. All the control subjects were PCR negative, as were 270 internal contamination controls. The PCR result remained positive in samples drawn up to 27 days after the onset of neurological symptoms. This method is a rapid and non-invasive means to diagnose herpes simplex encephalitis; it is highly sensitive and specific.

Correlation of early MRI with CT scan, EEG, and CSF: analyses in a case of biopsy-proven herpes simplex encephalitis

Herpes simplex encephalitis (HSE) carries a high mortality rate. Therefore, an early diagnosis and institution of acyclovir are essential. We report a case of biopsy-proven HSE with 2 negative cerebrospinal fluid (CSF) analyses and 2 normal CT scans. However, MRI together with EEG were abnormal early in the disease stressing their significant role in any suspected case of HSE. Although brain biopsy remains controversial, CSF herpes simplex antigen detection offers hope in providing an early or retrospective diagnosis while specific antiviral therapy with acyclovir is initiated. Overdependency on routine CSF analysis or head CT scan can result in unnecessary delays in diagnosis and treatment.

Listeria brainstem encephalitis: two own cases and literature review

We analysed two of our own and 21 patients described in the literature with listeria brainstem encephalitis. The disease was characterised by a prodromal state with fever, nausea and headache followed by severe brainstem dysfunction with multiple cranial nerve palsies, ataxia, respiratory insufficiency and coma. The diagnosis was established by isolation of Listeria monocytogenes from CSF and/or serum. Serological tests are without diagnostic evidence. Cerebrospinal fluid examination may not initially point to a bacterial infection. Computed tomography and magnetic resonance imaging technique might supply evidence of brainstem involvement and contribute to an early diagnosis. There is a high percentage of lethal outcome without early antibiotic therapy.

A sensitive ELISA system for the rapid detection of virus specific IgM antibodies in the cerebrospinal fluid

The intrathecal production of IgM antibodies to different viral antigens was measured by a modification of ELISA that was both sensitive and specific. Suitably diluted CSF and homologous serum samples containing similar amount of IgM were examined, and a comparison of the photometric signals permitted the detection of specific antibodies secreted from activated lymphocytes into the CSF compartment during the course of viral infections of the central nervous system. Polyvinyl chloride (PVC) microtitre plates were activated by glutaraldehyde and then coated with different viral antigens. Test samples were incubated on these solid-phase antigens and virus-specific IgM antibodies were detected using a peroxidase-conjugated F (ab')2 fragment of anti-human IgM antibody to avoid interference from rheumatoid factors.

[Detection of specific IgM in the CSF for early and rapid diagnosis of herpes simplex virus encephalitis]

A capture-ELISA for detecting IgM in CSF was developed for the purpose of rapid and early diagnosis of herpes simplex virus (HSV) encephalitis. In 37 cases with sporadic HSV encephalitis the CSF IgM was measured. In 13 cases the results were positive, in the others it was negative. 17 cases with other central nervous system disorders were taken as control group in which only one case with Guillain-Barré syndrome showed positive test and all the others were HSV antibody negative except one with IgG positive in CSF who had undergone a brain operation two weeks prior to the test.

[Eosinophilic granulocytes in the cerebrospinal fluid]

The first section of the paper presents the morphology, structure and function of the eosinophilic granulocytes, while the second part deals with major neurologic diseases in which eosinophils are present or represent significant findings. These data are compared with the results of the author's own examinations of 1,000 unselected cerebrospinal fluid (CSF) samples. Eosinophils appeared usually in conjunction with infection, followed by foreign body inflammation. If the proportion of eosinophils exceeds 4%, the condition is termed CSF-eosinophilia, which usually develops in the presence of foreign bodies. However, infection may produce similar findings, especially in parasitic disease, and tumours of the central nervous system occasionally present with CSF eosinophilia.

Demonstration of herpes simplex virus DNA in CSF cells by in situ hybridization for early diagnosis of herpes encephalitis

Herpes simplex virus (HSV) was studied by in situ DNA hybridization with a biotinylated cDNA probe in 56 air-dried methanol-fixed cerebrospinal fluid (CSF) cell preparations which had been collected from 12 patients with herpes simplex encephalitis (HSE) during the previous 5 years. In three additional HSE cases, freshly prepared acetone-fixed CSF cell preparations were available. In all cases, CSF cell preparations were obtained by cytocentrifugation. Herpes simplex virus DNA could be demonstrated in 8 of the 12 HSE cases with methanol-fixed cells (66%) and in all 3 cases with fresh acetone-fixed CSF cells. The earliest CSF sample was available at the onset of symptoms and showed positive DNA hybridization. In three cases hybridization was positive after a clinical course of more than 5 weeks but was usually found in the 1st week of illness before the beginning of specific inthrathecal IgG synthesis. In 54 control cases with other acute inflammatory diseases of the CNS, including 14 cases of varicella-zoster meningitis, no positive hybridization was detected. These findings strongly suggest that in situ hybridization in CSF cells is a reliable tool for the early and rapid diagnosis of HSE, especially at the onset of the disease, when no antibodies can be detected.

Specific in vitro IgG subclass synthesis and lymphocyte proliferation responses in herpes virus encephalitis

Cerebrospinal fluid, peripheral blood lymphocytes (PBL) and sera from 5 patients with herpes simplex encephalitis (HSVE), 3 with varicellae zoster (VZV) meningoencephalitis and 5 with encephalitis of unknown origin (NUD) were analyzed. Lymphocytes from both blood and CSF were shown to synthesize anti-VZV IgG subclasses in VZV meningoencephalitis and anti-HSV IgG subclasses in HSVE. The subclass patterns of CSF and in vitro synthesized anti-viral IgG were similar, suggesting that a considerable portion of the antiviral IgG subclasses detected are synthesized in the CNS compartment. Antigen presentation in vitro seemed to produce a heterologous IgG4 and/or 3 response in 3 patients. Lymphocyte proliferation was detectable in response to HSV and VZV, respectively.

Central-nervous-system methyl-group metabolism in children with neurological complications of HIV infection

To assess methyl-group metabolism in the central nervous system in infection with human immunodeficiency virus (HIV), levels of 5-methyltetrahydrofolate, methionine, and S-adenosylmethionine were measured by high-performance liquid chromatography in cerebrospinal fluid (CSF) from six children with congenital HIV infection and neurological complications. Total neopterins were also measured, as a marker of macrophage activation. In all six children concentrations of one or more methyl-group carriers were lower than those in a reference population of children, and all of the five in whom CSF neopterins were measured had higher than normal levels. Defective methylation may play a part in the neurological damage caused by HIV infection.

Rapid detection of herpes-simplex-virus DNA in cerebrospinal fluid of patients with herpes simplex encephalitis

Herpes-simplex-virus (HSV) DNA in cerebrospinal fluid was amplified by use of the polymerase chain reaction and identified by hybridisation to a specific oligonucleotide probe. Specimens of cerebrospinal fluid (CSF) from 4 of 4 patients with herpes simplex encephalitis were positive for HSV DNA, whereas CSF specimens from 6 patients with other central-nervous-system infections were negative. This technique may expedite diagnosis of herpes simplex encephalitis.

Spread of herpes simplex virus type 1 in the central nervous system during experimentally reactivated encephalitis

Because many of the features of reactivated herpes simplex virus type 1 (HSV-1) central nervous systems (CNS) infections in vivo are incompletely understood, we used an animal model to study the development of the morphological, ultrastructural, radiological and immunological changes which occurred during acute and experimentally reactivated diseases. Rabbits were intranasally inoculated with HSV-1, and their latent trigeminal ganglionic and CNS infections were reactivated by intravenous injection of cyclophosphamide and dexamethasone. Technetium brain scans were performed to localize areas of blood-brain barrier breakdown, and cerebrospinal fluid (CSF) was analysed for IgG content by radial immunodiffusion assays. Nervous system tissues were studied by in situ hybridization and by immunofluorescent, light and electron microscopic techniques. Diffuse uptake of technetium was observed as HSV-1 spread transsynaptically into the brain during the acute phase of infection, and viral antigens and nucleic acids were detected in both the CNS olfactory and trigeminal systems. During latency, viral RNA was detected in the nuclei of neurons within the CNS olfactory cerebral and entorhinal cortices, indicating that HSV-1 became latent within the same CNS structures that were involved during the acute phase of infection. Following drug-induced reactivation, the brain scans revealed a more focal breakdown of the blood-brain barrier, and both neurons and neuronal processes in the entorhinal and olfactory cortices contained viral nucleic acids which correlated with the ultrastructural presence of HSV-1 virions. During the reactivated phase of infection a marked increase in the CSF IgG index occurred without an increase in the CSF: serum albumen ratio indicating a prompt intrathecal response in infected rabbits as compared to controls. To some extent, the CSF IgG index reflected the degree of histopathological damage.

Misleading CT scans: a report of two cases

Two patients who appeared to have suffered from intracranial haemorrhage are presented. Their clinical histories and computed tomographic scans were supportive of the diagnosis of intracranial haemorrhage. However, both patients were found to have infected cerebrospinal fluid.

Beta-2-microglobulin in the cerebrospinal fluid of patients with infections of the central nervous system

Beta-2-microglobulin was determined in 147 patients admitted to hospital because of suspicion of CNS disease. Patients with meningism were chosen as control group. The concentration of beta-2-microglobulin in the spinal fluid of control patients was correlated with age. Reference values for 0-40 years were 0.34-1.58 mg/l. Above 40 years of age the values were 0.46-3.14 mg/l. CSF beta-2-microglobulin levels of patients with meningism, aseptic and bacterial meningitis overlap too much to be relevant in distinguishing between these entities. Five patients with herpes simplex encephalitis had markedly elevated levels ranging from 4.4 to 9.0 mg/l. Ten patients with herpes zoster-associated encephalitis had values from 1.1 to 6.1 mg/l. In the patient groups with CNS infections, the ratio of serum to spinal fluid beta-2-microglobulin was significantly more frequently less than 1 as compared with the meningism group, indicating intrathecal production of the protein. Further studies on the clinical relevance of CSF beta-2-microglobulin in the diagnosis of encephalitis seem warranted.

Increased endotoxin and interleukin-1 beta concentrations in cerebrospinal fluid of infants with coliform meningitis and ventriculitis associated with intraventricular gentamicin therapy

Intraventricular gentamicin therapy in infants with gram-negative enteric bacillary meningitis and ventriculitis is associated with increased mortality. Therefore, endotoxin, interleukin-1 beta, and cachectin (tumor necrosis factor) concentrations in ventricular cerebrospinal fluid from 21 infants (11 received intravenous antibiotics alone and 10 received intraventricular gentamicin also) were determined and correlated with outcome and other ventricular cerebrospinal fluid indexes of inflammation. Mean interleukin-1 beta concentrations in ventricular cerebrospinal fluid correlated significantly with adverse outcome and with mean concentrations of endotoxin, white blood cells, and protein and inversely with glucose concentrations. Mean and peak endotoxin and interleukin-1 beta concentrations were significantly higher in infants who received intraventricular gentamicin and intravenous antibiotics than in infants given intravenous antibiotics alone. Intraventricular gentamicin may have caused release of endotoxin from gram-negative bacilli in ventricular cerebrospinal fluid, resulting in increased interleukin-1 beta concentrations and inflammation, which could have contributed to the poor outcome in these patients.