SARS-CoV-2 infection and spontaneous spinal hemorrhage: a systematic review

The neurological manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, including spontaneous spinal hemorrhage (SSH), are diverse. SSH is a detrimental neurosurgical event requiring immediate medical attention. We aimed to investigate the association between SARS-CoV-2 and SSH and delineate a rational clinical approach. The authors searched PubMed, Scopus, Web of Science, and Google Scholar for studies published up to January 25, 2023, on SSH and SARS-CoV-2 infection. For each dataset, the authors performed pooled estimates examining three outcomes of interest: (1) early post-intervention neurological status, (2) mortality, and (3) post-intervention neurological rehabilitation outcomes. After reviewing 1341 results, seven datasets were identified for the final analysis. Fifty-seven percent of patients were females. Twenty-eight percent of the patients experienced severe systemic infection. The mean interval between the SARS-CoV-2 infection and neurological presentation was 18 days. Pain and sensorimotor deficits were the most common (57%). Spinal epidural hematoma (EDH) was the most common presentation (71.4%). Three patients were treated conservatively, while 4 received neurosurgical intervention. Pain and sensorimotor deficits had the best treatment response (100%), while the sphincter had the worst response (0%). Long-term follow-up showed that 71% of patients had good recovery. SARS-CoV-2-associated SSH is a rare complication of infection, with an often insidious presentation that requires high clinical suspicion. Patients with SARS-CoV-2 infection and new neurological symptoms or disproportionate neck or back pain require a neuroaxis evaluation. Neurosurgical intervention and conservative management are both viable options to treat SSH following COVID-19. Still, a homogenous approach to the treatment paradigm of SSH cannot be obtained, but lesions with space-occupying effects are suitable for neurosurgical evacuation-decompression while more indolent lesions could be treated conservatively. These options should be tailored individually until larger studies provide a consensus.

Clinical Features, Laboratory, and Radiological Findings of Patients With Acute Inflammatory Myelopathy After COVID-19 Infection: A Narrative Review

ABSTRACT

The objective of this review was to analyze the existing data on acute inflammatory myelopathies associated with coronavirus disease 2019 infection, which were reported globally in 2020. PubMed, CENTRAL, MEDLINE, and online publication databases were searched. Thirty-three acute inflammatory myelopathy cases (among them, seven cases had associated brain lesions) associated with coronavirus disease 2019 infection were reported. Demyelinating change was seen in cervical and thoracic regions (27.3% each, separately). Simultaneous involvement of both regions, cervical and thoracic, was seen in 45.4% of the patients. Most acute inflammatory myelopathy disorders reported sensory motor and bowel bladder dysfunctions. On cerebrospinal fluid analysis, pleocytosis and increased protein were reported in 56.7% and 76.7% of the patients, respectively. Cerebrospinal fluid severe acute respiratory syndrome coronavirus 2 reverse transcriptase-polymerase chain reaction was positive in five patients. On T2-weighted imaging, longitudinally extensive transverse myelitis and short-segment demyelinating lesions were reported in 76% and 21%, respectively. Among the patients with longitudinally extensive transverse myelitis, 61% reported "moderate to significant" improvement and 26% demonstrated "no improvement" in the motor function of lower limbs. Demyelinating changes in the entire spinal cord were observed in three patients. Most of the patients with acute inflammatory myelopathy (including brain lesions) were treated with methylprednisolone (81.8%) and plasma-exchange therapy (42.4%). An early treatment, especially with intravenous methylprednisolone with or without immunoglobulin and plasma-exchange therapy, helped improve motor recovery in the patients with acute inflammatory myelopathy associated with coronavirus disease 2019.

Infectious Myelopathies

PURPOSE OF REVIEW

This article reviews bacterial, viral, fungal, and parasitic pathogens associated with myelopathy. Infectious myelopathies may be due to direct infection or parainfectious autoimmune-mediated mechanisms; this article focuses primarily on the former.

RECENT FINDINGS

Some microorganisms exhibit neurotropism for the spinal cord (eg, enteroviruses such as poliovirus and flaviviruses such as West Nile virus), while others are more protean in neurologic manifestations (eg, herpesviruses such as varicella-zoster virus), and others are only rarely reported to cause myelopathy (eg, certain fungal and parasitic infections). Individuals who are immunocompromised are at increased risk of disseminated infection to the central nervous system. Within the last few years, an enterovirus D68 outbreak has been associated with cases of acute flaccid paralysis in children, and emerging Zika virus infection has been concurrent with cases of acute flaccid paralysis due to Guillain-Barré syndrome, although cases of myelitis have also been reported. Associated pathogens differ by geographic distribution, with myelopathies related to Borrelia burgdorferi (Lyme disease) and West Nile virus more commonly seen in the United States and parasitic infections encountered more often in Latin America, Southeast Asia, and Africa. Characteristic CSF and MRI patterns have been identified with many of these infections.

SUMMARY

A myriad of pathogens are associated with infectious myelopathies. Host factors, geographic distribution, clinical features, CSF profiles, and MRI findings can assist in formulating the differential diagnosis and ultimately guide management.

Temporal trends in Human T-Lymphotropic virus 1 (HTLV-1) associated myelopathy/tropical spastic paraparesis (HAM/TSP) incidence in Martinique over 25 years (1986-2010)

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1) has been discovered in 1980 and has been linked to tropical spastic paraparesis (HAM/TSP) in 1985 in Martinique. There is no data on HAM/TSP incidence trends. We report, in the present work, the temporal trends incidence of HAM/TSP in Martinique over 25 years.

METHODS

Martinique is a Caribbean French West Indies island deserved by a unique Neurology Department involved in HAM/TSP diagnosis and management. A registry has been set up since 1986 and patients diagnosed for a HAM/TSP were prospectively registered. Only patients with a definite HAM/TSP onset between 1986 and 2010 were included in the present study. The 25-year study time was stratified in five-year periods. Crude incidence rates with 95% confidence interval (95%CI) were calculated using Poisson distribution for each period. Age-standardized rates were calculated using the direct method and the Martinique population census of 1990 as reference. Standardized incidence rate ratios with 95% CIs and P trends were assessed from simple Poisson regression models. Number of HTLV-1 infection among first-time blood donors was retrospectively collected from the central computer data system of the Martinique blood bank. The HTLV-1 seroprevalence into this population has been calculated for four 5-year periods between 1996 and 2015.

RESULTS

Overall, 153 patients were identified (mean age at onset, 53+/-13.1 years; female:male ratio, 4:1). Crude HAM/TSP incidence rates per 100,000 per 5 years (95%CI) in 1986-1990, 1991-1995, 1996-2000, 2001-2005 and 2006-2010 periods were 10.01 (6.78-13.28), 13.02 (9.34-16.70), 11.54 (8.13-14.95), 4.27 (2.24-6.28) and 2.03 (0.62-3.43). Age-standardized 5-year incidence rates significantly decreased by 69% and 87% in 2001-2005 and 2006-2010 study periods. Patients characteristics did not differ regarding 1986-2000 and 2001-2010 onset periods. Between 1996-2000 and 2011-2015 study periods, the HTLV-1 seroprevalence significantly decreased by 63%.

CONCLUSION

Martinique faces a sudden and rapid decline of HAM/TSP incidence from 2001 in comparison to 1986-2000 periods. Reduction of HTLV-1 seroprevalence, that may result from transmission prevention strategy, could account for HAM/TSP incidence decrease.

Myelopathy associated with microorganisms

PURPOSE OF REVIEW

This article reviews the common infectious etiologies of spinal cord dysfunction that span the globe epidemiologically and vary pathophysiologically.

RECENT FINDINGS

Many microorganisms have the ability to directly or indirectly result in spinal cord dysfunction. These agents may have the ability to infect the spinal cord itself, but frequently cause indirect damage by parainfectious or postinfectious immune-mediated destruction or external compression of the spinal cord.

SUMMARY

Infectious myelopathies can pose diagnostic difficulty but are potentially reversible causes of spinal cord dysfunction. The often complex relationship among the infectious agent, the immune system, and the neuraxis can create a difficult management conundrum whereby immune modulation may be the preferred approach.

[Neurological manifestations of HIV-infection (review)]

Current data on the etiology, pathogenesis, diagnosis and treatment principles of HIV are reviewed. The special attention is focused on affections of the nervous system (neuro-AIDS). Primary and secondary manifestations of these affections are described.

Non-traumatic myelopathy at the Chris Hani Baragwanath Hospital, South Africa--the influence of HIV

BACKGROUND

Non-traumatic myelopathy from developing regions has been described widely. In these regions infections, mainly tuberculosis, followed by acute transverse myelitis and neoplasms, dominate. These are also regions of high HIV prevalence. In developed regions, the most prominent reported spinal cord disease in HIV/AIDS is vacuolar myelopathy (VM). Other myelopathy causes in HIV/AIDS include opportunistic infections, neoplasms, vascular lesions and metabolic disease. In developing regions, opportunistic infections are more commonly encountered with VM occurring less frequently.

AIM

To determine the influence of HIV on the myelopathy spectrum in an HIV endemic region.

DESIGN

Prospective case series.

METHODS

Hundred unselected consecutive in-patients admitted with myelopathy were studied. Myelopathy aetiologies were established by collating information obtained from magnetic resonance imaging (MRI) scans, CSF and blood studies, CXR findings, non-neurological illness and response to treatment. Data were analysed in terms of two cohorts, HIV positive and HIV negative.

RESULTS

Approximately 50% of the patients presenting and admitted to our hospital with non-traumatic myelopathy are HIV positive. The HIV positive myelopathy patients were younger (20-40 years) and had infectious aetiologies. Tuberculosis was the most frequently identified cause of myelopathy. The majority of HIV-positive patients had advanced HIV infection. Anti-retroviral treatment did not influence myelopathy aetiologies. The HIV-negative patients were older and had neoplasms, followed by degenerative spondylosis as the main myelopathy causes.

CONCLUSION

HIV influences the non-traumatic myelopathy spectrum in regions with high HIV prevalence. Empiric treatment of HIV-myelopathy patients with anti-tuberculous medications where resources are severely limited has merit.

HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP): the role of HTLV-I-infected Th1 cells in the pathogenesis, and therapeutic strategy

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic progressive myelopathy characterized by bilateral pyramidal tract involvement with sphincteric disturbances. The primary neuropathological feature of HAM/TSP is chronic myelitis characterized by perivascular cuffing and parenchymal infiltration of lymphocytes. Although the exact cellular and molecular events underlying the induction of chronic inflammation in the spinal cord by HTLV-I are still unclear, a long-standing bystander mechanism, such as the destruction of surrounding nervous tissue by the interaction between HTLV-I-infected CD4+ T cells and HTLV-I-specific cytotoxic T cells in the spinal cord, is probably critical in the immunopathogenesis of HAM/TSP. In this review, the role of HTLV-I-infected CD4+ T cells as activated Th1 cells in the peripheral blood will be discussed as the first responders of this mechanism in the immunopathogenesis of HAM/TSP. Since the discovery of HAM/TSP, various therapeutic approaches, such as immunomodulatory or anti-viral drugs, have been used for HAM/TSP patients. However, an effective therapeutic strategy against HAM/TSP is still unavailable. As HTLV-I-infected CD4+ T cells are the first responders in the immunopathogenesis of HAM/TSP, the ideal treatment is the elimination of HTLV-I-infected cells from the peripheral blood. In this review, the focus will be on therapeutic strategies aimed at targeting HTLV-I-infected CD4+ T cells in HAM/TSP patients.

West nile poliomyelitis in a 7-year-old child

West Nile poliomyelitis is a well-described neurologic manifestation of West Nile viral infection in adults. However, few reports have described this manifestation in children infected with West Nile virus. We describe a 7-year-old boy who developed West Nile poliomyelitis with flaccid paralysis of his left leg. Electrodiagnostic testing and radiologic imaging confirmed anterior horn cell injury. We report on his course clinically and electrodiagnostically over 20 months.

VZV vasculopathy associated with myelo-radiculoganglio-meningo-encephalitis: an autopsy case of an immunocompetent 66-year-old male

Encephalitis is the most severe manifestation of central nervous system (CNS) infection by Varicella-Zoster-Virus (VZV). VZV associated encephalitis is now recognized to be a vasculopathy that affects large or small cerebral arteries. This report describes an autopsy case of an immunocompetent 66-year-old male who developed a progressive small vessel vasculopathy and clinically presented with a zosteriform rash and myelo-radiculoganglio-meningo-encephalitis followed by subarachnoid bleeding. This is an extremely rare manifestation of VZV vasculopathy associated with widespread CNS damage, and what is more, the spinal lesions were different from those of the cerebrum, brainstem and cerebellum, where the former were predominantly demyelinative changes and the latter were ischemic. To the best of our knowledge, few cases have been described pathologically in an immunocompetent individual. Further studies are needed to investigate the pathogenesis and treatment of VZV vasculopathy.

Immunohistochemical screening for viral agents in cheetahs (Acinonyx jubatus) with myelopathy

Numerous cases of acute-onset progressive ataxia, hindlimb paresis and paralysis of unknown aetiology occurred during 1993 to 2003 in cheetahs (Acinonyx jubatus) within the European Endangered Species Programme (eep). This study describes the immunohistochemical investigation of a possible viral aetiology of the "cheetah myelopathy". Antibodies to feline herpesvirus type 1, canine distemper virus, canine parvovirus and Borna disease virus were applied to formalin-fixed and paraffin-embedded brain and spinal cord sections from 25 affected cheetahs aged between three-and-a-half months and 13 years. Using the avidin-biotin complex technique, none of the antibodies gave positive immunosignals in either the brain or the spinal cord tissue.

Modulation of dendritic cell maturation and function by the Tax protein of human T cell leukemia virus type 1

Human T cell leukemia virus type 1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is characterized by the generation of an intense CTL cell response directed against the viral transactivator protein Tax. In addition, patients diagnosed with HAM/TSP exhibit rapid activation and maturation of dendritic cells (DC), likely contributing to the robust, Tax-specific CTL response. In this study, extracellular Tax has been shown to induce maturation and functional alterations in human monocyte-derived DC, critical observations being confirmed in freshly isolated myeloid DC. Tax was shown to promote the production of proinflammatory cytokines and chemokines involved in the DC activation process in a dose- and time-dependent manner. Furthermore, Tax induced the expression of DC activation (CD40, CD80, and CD86) and maturation (CD83) markers and enhanced the T cell proliferation capability of DC. Heat inactivation of Tax resulted in abrogation of these effects, indicating a requirement for the native structure of Tax, which was found to bind efficiently to the DC membrane and was internalized within a few hours, suggesting that extracellular Tax may possess an intracellular mechanism of action subsequent to entry. Finally, inhibitors of cellular signaling pathways, NF-kappaB, protein kinase, tyrosine kinase, and phospholipase C, were shown to inhibit Tax-mediated DC activation. This is the first study reporting the immunomodulatory effects of extracellular Tax in the DC compartment. These results suggest that DC, once exposed to Tax by uptake from the extracellular environment, can undergo activation, providing constant antigen presentation and costimulation to T cells, leading to the intense T cell proliferation and inflammatory responses underlying HAM/TSP.

Natural history of human T-lymphotropic virus 1-associated myelopathy: a 14-year follow-up study

BACKGROUND

The progression of neurological disability in human T-lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) remains undefined.

OBJECTIVES

To determine the time course of disability scores and to identify predictors of outcome among patients with HAM/TSP.

DESIGN

Clinical 14-year follow-up study.

SETTING

University hospital. Patients One hundred twenty-three patients with HAM/TSP.

MAIN OUTCOME MEASURES

We determined time from onset to the following 4 Kurtzke Disability Status Scale (DSS) end points: scores of 6 (unilateral aid required), 6.5 (bilateral aid required), 8 (wheelchair confinement), and 10 (death related to the disease). Times to reach selected DSS scores were estimated using the Kaplan-Meier method. Univariate and multivariate analyses identified variables related to the rate of progression to DSS 8. The HTLV-1 proviral loads were also assessed.

RESULTS

The disability of the cohort progressed throughout the follow-up period. The median times from onset to DSS 6, 6.5, and 8 were 6, 13, and 21 years, respectively. The median time from DSS 6 to DSS 8 was 8 years; DSS 10 was reached by one fourth of the patients within 20 years. Age at onset of 50 years or older and high HTLV-1 proviral load were associated with a shorter time to DSS 8 (P = .01 and P = .02, respectively). A shorter time to DSS 6 significantly adversely affected the time to progression from DSS 6 to DSS 8.

CONCLUSIONS

Human T-lymphotropic virus 1-associated myelopathy/tropical spastic paraparesis is a rapidly disabling disease. Monitoring for HTLV-1 proviral load is recommended in future therapeutic trials.

Role of neuronal interferon-gamma in the development of myelopathy in rats infected with human T-cell leukemia virus type 1

Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of not only adult T-cell leukemia but also HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Among the rat strains infected with HTLV-1, chronic progressive myelopathy, named HAM rat disease, occurs exclusively in WKAH rats. In the present study, we found that HTLV-1 infection induces interferon (IFN)-gamma production in the spinal cords of HAM-resistant strains but not in those of WKAH rats. Neurons were the major cells that produced IFN-gamma in HTLV-1-infected, HAM-resistant strains. Administration of IFN-gamma suppressed expression of pX, the gene critically involved in the onset of HAM rat disease, in an HTLV-1-immortalized rat T-cell line, indicating that IFN-gamma protects against the development of HAM rat disease. The inability of WKAH spinal cord neurons to produce IFN-gamma after infection appeared to stem from defects in signaling through the interleukin (IL)-12 receptor. Specifically, WKAH-derived spinal cord cells were unable to up-regulate the IL-12 receptor beta2 gene in response to IL-12 stimulation. We suggest that the failure of spinal cord neurons to produce IFN-gamma through the IL-12 pathway is involved in the development of HAM rat disease.

Neurological and neuropsychiatric syndromes associated with liver disease

The clinical presentation of acute liver failure and hepatic encephalopathy (HE) in patients with cirrhosis differs significantly. The most serious neurological complication of acute liver failure is the development of devastating brain oedema. Therefore, intracranial pressure monitoring is urgently needed in these patients. Brain oedema is amplified by hypoglycemia, hypoxia and seizures, which are also frequent complications of acute liver failure. Therefore, these parameters must also be monitored. In contrast to acute liver failure in which cerebral dysfunction progresses rapidly, cognitive decline may be clinically undetectable for a long time in cirrhotic patients, until clinically overt symptoms such as psychomotor slowing, disorientation, confusion, extrapyramidal and cerebellar symptoms or a decrease in consciousness occur. Clinically, overt HE is preceded by minimal alterations of cerebral function that can only be detected by neuropsychological or neurophysiological measures, but which nevertheless interfere with the patient's daily living. Rapidly progressing spastic paraparesis (hepatic myelopathy) is a rare complication of cirrhosis. In contrast to HE, it does not respond to blood ammonia lowering therapies but must be considered as an indication for urgent liver transplantation. Cognitive dysfunction has recently been detected in hepatitis C virus (HCV)-infected patients with normal liver function. The patients presented with severe fatigue, cognitive dysfunction and mood disorders. Alterations in brain metabolites, as detected by magnetic resonance spectroscopy, indicated central nervous system alteration in these patients. In contrast to patients with HE, HCV-infected patients did not show motor symptoms or deficits in visual perception, but considerable deficits in attention and concentration ability.

Neurological complications of HIV infection

Cognitive disorders, vacuolar myelopathy, and sensory neuropathies associated with HIV are the most common disorders in patients with HIV AIDS, and are the focus of this review. These disorders are treatable and of those associated with HIV AIDS the pathogenic mechanisms are the most understood. Although triggered by productive HIV macrophage infections, aberrant immune activation plays a major role in inducing the CNS disorders. Novel therapies aimed at these inflammatory mechanisms can be effective. The sensory neuropathies associated with HIV infection are a major cause of morbidity; incidence may be increased by the toxic effects of specific antiretroviral drugs within the peripheral nervous system.

[Neurological manifestations of dengue: study of 41 cases]

The increase of encephalitis and meningoencephalitis in patients with dengue, diagnosed at a public hospital, Neurology State reference, we adopted systematic data collection.

OBJECTIVE

The objective was to present 41 cases of neurological manifestations of dengue and to compare data with literature.

METHOD

This is a descriptive study, retrospective from March to July 1997 and, prospective, from February to May 2002, analyzing damaged neurological regions and diagnostic of 41 patients.

RESULTS

Involved regions were brain (5/7 cases - 71.4%, in 1997, and 20/34 cases - 58.8%, in 2002), spinal cord (2/34 cases - 5.9% in 2002) and peripheral nerves (2/7 cases - 28.6% in 1997 and 12/34 cases - 35.3% in 2002). There was no meningeal involvement. According to topography, there was encephalic and peripheral nerves diagnosis in both periods and, exclusively in 2002, spinal cord damage. Cerebral hemorrhage and acute disseminated encephalomyelitis were diagnosed for the first time, as well as hemifacial spasm worsening as possible neurological manifestation of dengue.

CONCLUSION

This is the third casuistics in dengue and nervous system. Three dengue complications were diagnosed, for the first time registered on the literature.

Erectile dysfunction and HTLV-I infection: a silent problem

The human T-lymphotropic virus type I (HTLV-I) is a retrovirus associated with a chronic myelopathy known as HTLV-I-Associated Myelopathy or Tropical Spastic Paraparesis (HAM/TSP). The main objective was to assess the frequency of erectile dysfunction (ED) in HTLV-I-infected individuals from Salvador and other cities from Bahia, Brazil, as well as to verify if sexual dysfunction correlates with urinary symptoms and overall neurological impairment. From January 2001 to April 2004, 218 HTLV-I carriers (111 male and 107 female subjects) had complete clinical, neurological, and urological evaluation. They were assessed using standardized questionnaires to determine urinary complaints (Urinary Distress Inventory) and ED (Brief Male Sexual Function Inventory). Neurological impairment was established by Expanded Disability Status Scale (EDSS) from 0 to 10. HAM/TSP was considered as EDSS> or =2. A total of 17 males had clinically defined HAM/TSP (group 1). From the 94 HTLV-I-infected males, 62 were selected (group 2) and paired by age with patients in group 1. A total of 79 individuals were selected for this study. The age ranged from 35 to 81 y (mean=47.9+/-9.65). The percentage of ED in the studied population was 40.5%. In the HAM/TSP group, ED frequency was 88.2%. The associations among sexual dissatisfaction, erectile dysfunction, urinary symptoms (frequency, nocturia, and urgency) and EDSS> or =2 were statistically significant. In HAM/TSP, there is a slow and progressive degeneration of the lateral funiculus of the spinal cord. HTLV-I-infected individuals present a high frequency of ED and it is closely associated to urinary symptoms and the overall neurological picture. The HTLV-I carriers already had prominent compromise of the sexual activity.

Treatment of AIDS-associated myelopathy with L-methionine: A placebo-controlled study

BACKGROUND

The histopathology of AIDS-associated myelopathy (AM) closely resembles that of myelopathies due to cobalamin or folate deficiency, with white matter vacuolization in the spinal cord. The pathogenesis of AM appears unrelated to direct HIV infection of the spinal cord. There is abnormal trans-methylation metabolism in AM, with decreased availability of the methyl group donor S-adenosyl-methionine (SAM). The authors hypothesized that treatment with l-methionine, the direct metabolic precursor of SAM, might improve AM.

OBJECTIVE

To determine the safety and efficacy of l-methionine treatment in AM.

METHODS

Fifty-six patients with clinical diagnosis of AM were randomized to a Phase II, double-blind, placebo-controlled study comparing the effect of l-methionine 6 g/day in two divided doses with that of placebo. Study duration was 12 weeks. All patients had somatosensory evoked potentials with prolonged central conduction time (CCT) at entry. Change in CCT was the primary endpoint of the study. Frequency of adverse events (AEs) was used to assess safety. Secondary endpoints were strength, spasticity, and urinary function. Biochemical measurements included serum methionine and homocysteine and CSF SAM.

RESULTS

There were no significant differences in AEs between the two groups. Serum homocysteine increased in l-methionine-treated patients from 7.2 (+/-5.2 SD) to 12.6 (+/-6.15 SD) micromol/L. The mean CCT at baseline was 25.9 milliseconds (+/-7.3 SD) for the treatment group and 24.1 milliseconds (+/-7.0 SD) for the placebo group. At completion, it was 3.0 milliseconds (+/-6.1 SD) for the treatment group and 23.6 milliseconds (+/-5.5 SD) for the placebo group (p = 0.17). In a subset of 15 patients with CSF studies, SAM levels increased in the l-methionine but not in the placebo group (p = 0.07). There was no significant effect of treatment on strength, spasticity, or urinary function.

CONCLUSIONS

l-methionine was safe and well tolerated although in some patients induced an increase of serum homocysteine. There was a nonsignificant improvement in CCT in treated patients but no benefit in any of the clinical measures.

The epidemiology and disease outcomes of human T-lymphotropic virus type II

Human T-lymphotropic virus type II (HTLV-II) is a human retrovirus which is endemic in Amerindian and pygmy tribes. Molecular subtypes show geographic segregation consistent with an ancient origin of this virus within humans in Africa or South America. More recently, injection drug users in the United States and Europe have become infected with HTLV-II, and secondary sexual transmission has introduced the virus at low levels into the general population and blood donors. HTLV-II has been linked with a spastic paraparesis called HTLV-associated myelopathy / tropical spastic paraparesis (HAM/TSP), and perhaps with other neurological syndromes. It is also associated with an increased incidence of pneumonia and bronchitis, inflammatory conditions such as arthritis, and perhaps with increased mortality. Except for a few cases of cutaneous lymphoma in patients coinfected with HIV, there is no evidence that HTLV-II causes lymphoproliferative disease. HTLV-II and HIV coinfection has not been proven to alter the course of HIV disease, but such patients may have altered levels of CD4+ and CD8+ lymphocytes, and antiretroviral therapy may paradoxically increase HTLV-II proviral load.

Remission of HIV-associated myelopathy after highly active antiretroviral therapy

HIV-associated myelopathy is the leading cause of spinal cord disease in HIV-infected patients. Typically, it affects individuals with low CD4 T cell counts, presenting with slowly progressive spastic paraparesis associated with dorsal column sensory loss as well as urinary disturbances. Other aetiologies must be first ruled out before establishing the diagnosis. We report here the case of a 37-year-old woman with advanced HIV disease, who developed HIV-associated myelopathy. The patient showed a gradual improvement after beginning with highly active antiretroviral therapy and, finally, she achieved a complete functional recovery. In addition, neuroimaging and neurophysiological tests normalized.

Immunopathogensis of HTLV-I associated neurologic disease: molecular, histopathologic, and immunologic approaches

Human T-cell lymphotropic virus type I (HTLV-I) infection is associated with a variety of human diseases including HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic progressive inflammatory neurological disease. An important risk factor for the development of HAM/TSP is thought to be a high HTLV-I proviral load. Histopathological studies have demonstrated the presence of HTLV-I virus in the affected areas of spinal cords from HAM/TSP patients. Furthermore, T-cell infiltrations have been shown in spinal cord lesions. The precise mechanism for disease development is still unknown. Virus-host immune interactions are considered to play an important role in disease pathogenesis. This review focuses on current molecular, histopathological, and immunological approaches to understand the immunopathogenesis of HAM/TSP.

The Role of CD4+ T Cells in Biphasic Hind Limb Paralysis Induced by the D Variant of Encephalomyocarditis Virus (EMC-D) in DBA/2 Mice

DBA/2 CrSlc mice infected with the D variant of encephalomyocarditis virus (EMC-D) (10 PFU/head) developed biphasic hind limb paralysis due to spinal cord lesion. The early phase lesion was characterized by demyelination with infiltration of macrophages in the funiculus lateraris and the late phase lesion by degeneration of motor neurons with infiltration of CD4(+) T cells in the cornu ventrale. In the present study, treatment with anti-Mac1 monoclonal antibody (MAb) or anti-CD4 MAb prior to virus infection (-3 to -1 days) reduced the early phase lesion and the incidence of the first paralysis. Signals of viral RNAs were observed only in a few oligodendrocytes in the funiculus lateraris. Treatment with anti-CD4 MAb from 31 to 33 days post infection when mice showed recovery from the first paralysis reduced the late phase lesion and prevented the second paralysis. Signals of viral RNAs were still detected in a few degenerated neurons in the cornu ventrale. These results indicate that while macrophages and CD4(+) T cells participate in the early phase lesion and paralysis and only CD4(+) T cells in the late phase lesion and paralysis.

Oligodendrocyte-specific expression of human immunodeficiency virus type 1 Nef in transgenic mice leads to vacuolar myelopathy and alters oligodendrocyte phenotype in vitro

Vacuolar myelopathy (VM) is a frequent central nervous system complication of human immunodeficiency virus type 1 (HIV-1) infection. We report here that transgenic (Tg) mice expressing even low levels of Nef in oligodendrocytes under the regulation of the myelin basic protein (MBP) promoter (MBP/HIV(Nef)) developed VM similar to the human disease in its appearance and topography. The spinal cords of these Tg mice showed lower levels of the myelin proteins MAG and CNPase and of the 21-kDa isoform of MBP prior to the development of vacuoles. In addition, Tg oligodendrocytes in primary in vitro cultures appeared morphologically more mature but, paradoxically, exhibited a less mature phenotype based on O4, O1, CNPase, and MBP staining. In particular, mature CNPase(+) MBP(+) Tg oligodendrocytes were less numerous than non-Tg oligodendrocytes. Therefore, Nef appears to affect the proper differentiation of oligodendrocytes. These data suggest that even low levels of Nef expression in human oligodendrocytes may be responsible for the development of VM in HIV-1-infected individuals.

Chronic active VZV infection manifesting as zoster sine herpete, zoster paresis and myelopathy

After lumbar-distribution zoster, an HTLV-1-seropositive woman developed chronic radicular sacral-distribution pain (zoster sine herpete), cervical-distribution zoster paresis and thoracic-distribution myelopathy. Detection of anti-varicella zoster virus (VZV) IgM and VZV IgG antibody in cerebrospinal fluid (CSF), with reduced serum/CSF ratios of anti-VZV IgG compared to normal serum/CSF ratios for albumin and total IgG, proved that VZV caused the protracted neurological complications. Diagnosis by antibody testing led to aggressive antiviral treatment and a favorable outcome.

Acute flaccid paralysis and West Nile virus infection

Acute weakness associated with West Nile virus (WNV) infection has previously been attributed to a peripheral demyelinating process (Guillain-Barré syndrome); however, the exact etiology of this acute flaccid paralysis has not been systematically assessed. To thoroughly describe the clinical, laboratory, and electrodiagnostic features of this paralysis syndrome, we evaluated acute flaccid paralysis that developed in seven patients in the setting of acute WNV infection, consecutively identified in four hospitals in St. Tammany Parish and New Orleans, Louisiana, and Jackson, Mississippi. All patients had acute onset of asymmetric weakness and areflexia but no sensory abnormalities. Clinical and electrodiagnostic data suggested the involvement of spinal anterior horn cells, resulting in a poliomyelitis-like syndrome. In areas in which transmission is occurring, WNV infection should be considered in patients with acute flaccid paralysis. Recognition that such weakness may be of spinal origin may prevent inappropriate treatment and diagnostic testing.

The pathogenesis of spinal cord involvement in dengue virus infection

To investigate the mechanisms of dengue (DEN) virus transmission within the spinal cord, severe combined immunodeficient mice were intracerebrally inoculated with DEN virus type 2. After inoculation, a high virus titer and antigens were detected in the brain and spinal cord. At early stages of the infection, ultrastructural examinations showed that a few virions were present in the cytoplasm of ependymal cells lining the central canal. As the infection progressed, virions were observed in the lumen of the rough endoplasmic reticulum (RER), RER-derived vesicles and the Golgi region of infected neurons. These data suggest that the inoculated DEN virus might spread to the neurons of the spinal cord via the cerebral spinal fluid and cause several neuronal pathological responses. Moreover, DEN virus was also observed in myelinated and unmyelinated nerve fibers and typical neuronal synapses. Some virion-containing vesicles appeared to be fused with the membrane of presynapses, indicating that neuron-to-neuron transport of DEN virus might occur in the spinal cord. Additionally, anterior, lateral and posterior horns of the spinal cord exhibited different numbers of the positive neurons and different staining intensities of the DEN antigen during the infection. This difference likely represents variation of susceptibility to the DEN virus among the neurons of the spinal cord.

Feline leukemia virus-associated myelopathy in cats

Feline leukemia virus (FeLV) infection is associated with distinct neoplastic, hematologic, and immunosuppressive diseases. Here we report on a novel neurologic syndrome in 16 cats infected with FeLV for more than 2 years. Clinical signs consisted of abnormal vocalization, hyperesthesia, and paresis progressing to paralysis. The clinical course of affected cats involved gradually progressive neurologic dysfunction invariably resulting in euthanasia. Microscopically, white-matter degeneration with dilation of myelin sheaths and swollen axons was identified in the spinal cord and brain stem of affected animals. Neither neoplastic nor hematologic diseases commonly associated with FeLV infection were present. Fungal and protozoal infection in one animal was suggestive of impaired immune competence. Immunohistochemical staining of affected tissues revealed consistent expression of FeLV p27 antigens in neurons, endothelial cells, and glial cells. Furthermore, proviral DNA was amplified from multiple sections of spinal cord as well as intestine, spleen, and lymph nodes. These findings suggest that in a proportion of chronically FeLV-infected cats, a virus evolved with cytopathic potential for cells in the central nervous system.

Human T cell leukaemia virus type I associated neuromuscular disease causing respiratory failure

Polymyositis and inclusion body myositis have rarely been described in association with human T cell leukaemia virus type I (HTLV-I) infection. Most of such patients have coexisting HTLV-I associated myelopathy (HAM). Two patients with HTLV-I infection, myopathy, and respiratory failure are described. The muscle biopsy specimen of the first patient bore the histological features of inclusion body myositis and there was no evidence of concurrent myelopathy. The second patient had HAM, and her muscle biopsy showed non-specific myopathic and neuropathic changes. Both patients developed respiratory muscle weakness over eight years after diagnosis of myopathy, leading to hypercapnic respiratory failure requiring mechanical ventilatory support. Respiratory failure as a complication of HTLV-I associated myopathy has not previously been described.

Axonal damage is a late component of vacuolar myelopathy

The role of axonopathy in myelin disorders recently has been examined. To investigate axonal pathologic changes in vacuolar myelopathy (VM), semiquantitative immunohistochemical stains for inflammation, axonal damage, and gliosis were performed on spinal cord sections from patients with AIDS with and without VM and from HIV-negative controls. Significant axonal damage was present in only moderate to severe VM, despite inflammation at all stages. The authors conclude that axonal damage is not present in early disease; it is present in moderate to severe vacuolar myelopathy and may contribute to clinical deficits in late stages of this disorder.

Mechanisms of central nervous system viral persistence: the critical role of antibody and B cells

Contributions of humoral and cellular immunity in controlling neurotropic mouse hepatitis virus persistence within the CNS were determined in B cell-deficient J(H)D and syngeneic H-2(d) B cell+ Ab-deficient mice. Virus clearance followed similar kinetics in all mice, confirming initial control of virus replication by cellular immunity. Nevertheless, virus reemerged within the CNS of all Ab-deficient mice. In contrast to diminished T cell responses in H-2(b) B cell-deficient muMT mice, the absence of B cells or Ab in the H-2(d) mice did not compromise expansion, recruitment into the CNS, or function of virus-specific CD4+ and CD8+ T cells. The lack of B cells and lymphoid architecture thus appears to manifest itself on T cell responses in a genetically biased manner. Increasing viral load did not enhance frequencies or effector function of virus-specific T cells within the CNS, indicating down-regulation of T cell responses. Although an Ab-independent antiviral function of B cells was not evident during acute infection, the presence of B cells altered CNS cellular tropism during viral recrudescence. Reemerging virus localized almost exclusively to oligodendroglia in B cell+ Ab-deficient mice, whereas it also replicated in astrocytes in B cell-deficient mice. Altered tropism coincided with distinct regulation of CNS virus-specific CD4+ T cells. These data conclusively demonstrate that the Ab component of humoral immunity is critical in preventing virus reactivation within CNS glial cells. B cells themselves may also play a subtle role in modulating pathogenesis by influencing tropism.

[HIV-associated myelopathy: an uncommon indicator of AIDS]

INTRODUCTION

Spinal cord lesions are an uncommon mode of discovering acquired immunodeficiency syndrome because they usually appear at a later stage.

EXEGESIS

We report a 58-year-old patient who had a spastic paraparesia and sphincter dysfunction. The spinal cord magnetic resonance imaging showed spontaneous hypersignals on T2-weighted images at the cervical and thoracic levels, enhanced with gadolinium, and without swelling. No cause was found. The HIV serology was positive and allowed us to consider an HIV-associated myelopathy. The antiretroviral therapy led to functional recovery.

CONCLUSION

An HIV serology is suggested whenever an unexplained intramedullary lesion is discovered. Indeed, the diagnosis of HIV-associated myelopathy implies a specific therapeutic approach.

Expression of CCR-5/CXCR-4 in spinal cord of patients with AIDS

The discovery that chemokines and their receptors (in particular CXCR-4 and CCR-5) play a role in HIV infection challenges traditional views on the pathogenesis of HIV infection in man and identifies new potential targets for therapeutic intervention. Several groups as well as our pilot study have found that increased numbers of CCR-5 positive macrophage/microglia correlate with disease severity in brains of patients with AIDS. Among HIV-related disorders, vacuolar myelopathy (VM) is the most common spinal cord disorder in patients with AIDS. The purpose of this study was to investigate the possible relationship between the expression of CCR-5/CXCR-4 and spinal cord pathology in patients with AIDS. Thirty-four spinal cords (forming two groups: without and with VM) of patients with AIDS and 6 HIV-1-negative controls were investigated by routine histological examination and immunohistochemistry. Elevated expression of CXCR-4 was found in most AIDS cases with/without neuropathological disorders (8/17 and 13/16, respectively). No CCR-5 expression was detected in HIV-1-negative controls. Among 34 cases with AIDS, expression of CCR-5 was detected in 1/16 HIV-1-positive normal spinal cords and 5/18 with VM. Despite the lack of statistical significance between the two groups (P=0.1019), our results suggest that CCR-5/CXCR-4 are present in spinal cord of patients with AIDS and that CCR-5 is more frequently found in association with VM.

[Spinal cord infections]

Although infectious myelopathies are rare, appropriate aetiological diagnosis is of crucial importance to improve outcome. Lyme disease causes a myelomeningoradiculitis during the second stages and a progressive encephalomyelitis during the third stage. Serum and cerebrospinal fluid antibody tests are the basis of diagnosis. Myelopathy usually responds to treatment with ceftriaxone or doxycycline. Vacuole myelopathy occurs in patients with human immunodeficiency virus infection. It is characterised by a progressive spastic and ataxic paraparesis. About half of patients have symptoms of dementia. No specific treatment is available. Human T-cell lymphotropic virus type I is endemic in tropical areas and particularly in French West Indies. It causes a chronic spastic paraparesis with sexual and bladder dysfunction. Diagnosis depends on the positive antibody response in both serum and cerebrospinal fluid, and on the exclusion of other causes of spinal cord disease. There is no specific treatment.

Myelopathy in a previously asymptomatic HIV-1-infected patient

A wide variety of disorders of diverse pathogenic mechanisms can trigger spinal cord dysfunction in HIV-1-infected patients. The most common such condition is HIV-1-associated myelopathy (HM) which characteristically complicates advanced HIV-1 disease in patients with low CD4 cell counts and previous AIDS-defining diagnoses. We describe an unusual presentation of HM in a previously asymptomatic patient with a relatively preserved CD4 cell count (458 cells/mm3) who was even unaware of his serological status. The patient presented with a clinically severe, slowly progressive myelopathy and could not walk unassisted. Significant neurological improvement could be obtained as rapidly as within 4 weeks after the institution of an antiretroviral combination of only two nucleoside analog HIV-1 reverse transcriptase inhibitors (zidovudine and didanosine). An HIV-1 protease inhibitor was also prescribed at that point but could only be added to intensify the regimen 3 months later, when significant neurological improvement had already been recorded. We also review the disorders reported to derange spinal cord function in previously asymptomatic HIV-1-infected patients.

[Adenovirus myelitis and Epstein-Barr myelitis: two unusual viral causes with similar presentations]

We report two cases of viral myelitis, one associated with adenovirus and the other with Epstein-Barr virus. The clinical presentation and course were similar, with viral illness, paraplegia with a D4 sensory level, and fever. Spinal magnetic resonance imaging showed a T2 cervico-dorsal high intensity signal. Cerebrospinal fluid examination showed pleocytosis without oligoclonal bands. Both patients recovered after treatment with high-dose methylprednisolone. These two cases suggest a similar clinical and paraclinical pattern in viral transverse myelitis. Moreover, treatment with corticosteroids seems to be useful in viral myelitis.

AIDS myelopathy is not associated with elevated HIV viral load in cerebrospinal fluid

The pathogenesis of AIDS-associated myelopathy is unknown. Elevated HIV-1 viral load in CSF has been associated with cognitive impairment. The authors investigated if a similar association exists in patients with myelopathy. The authors evaluated levels of HIV-1 RNA in the CSF of 16 individuals with AIDS myelopathy and in 16 nonmyelopathic HIV-infected control subjects. There was no correlation between levels of HIV-1 RNA and the presence or severity of myelopathy.

Passage of human T-cell leukemia virus type-1 during progression to cutaneous T-cell lymphoma results in myelopathic disease in an HTLV-1 infection model

Studies comparing functional differences in human T-cell leukemia virus type 1 (HTLV-1) clones that mediate distinct outcomes in experimentally infected rabbits, resulted in a dermatopathic smoldering adult T-cell leukemia/lymphoma following chronic infection with HTLV-1 strain RH/K34. During the 3.5 years' follow-up, HTLV-1 skin disease progressed to cutaneous T-cell lymphoma. When infection was passed to several naive rabbits, progressive paraparesis due to myelopathic neurodegeneration, analogous to HTLV-associated myelopathy, resulted in one of 4 transfusion recipients. Similar proviral loads were detected in the two diseases, regardless of stage of progression or tissue compartment of infection. Complete proviral sequences obtained from the donor and affected recipient aligned identically with each other and with the inoculated virus clone. Existence of disparate pathogenic outcomes following infectious transmission further extends the analogy of using rabbits to model human infection and disease. Although the experimental outcomes shown are limited by numbers of animals affected, they mimic the infrequency of HTLV-1 disease and authenticate epidemiological evidence of virus sequence stability regardless of disease phenotype. The findings suggest that further investigation of a possible role for HTLV-1 in some forms of cutaneous T-cell lymphoma is warranted.

[HIV-1 associated encephalopathy and myelopathy]

HIV-1-associated encephalopathy (HIVE) remains an important manifestation of advanced HIV infection despite recent progress in antiretroviral therapy. This is in part due to particular pharmacological and virological characteristics of the central nervous system (CNS). HIVE is characterized by a "subcortical" dementia with psychomotor slowing as well as memory and concentration deficits. An invariable finding are deficits of central motor function. Pathogenetically, an enhanced viral replication in immunocompetent CNS cells is believed to be a requirement. This leads to neurotoxic effects directly elicited by viral products as well as indirectly by the immune response to virus infection. HIV-1 myelopathy (HIVM) is the other CNS manifestation of late HIV infection. The present consensus paper recommends diagnostic and therapeutic procedures in HIVE and HIVM and outlines the current research.

Age-dependent neurologic manifestations of HIV infection in childhood

Although the neurologic complications of HIV- 1 infection during the first two years of life have been defined, the neurologic features in older children are not so well described. The present report is focused on the age-dependent neurologic presentation of HIV-1 infection. Sixty-two vertically HIV-1 infected children underwent detailed serial evaluations: neurologic assessment, neuropsychological tests, neuroimaging studies, and cerebrospinal fluid analysis. Neurologic involvement was found in 30 patients (48.3%). This population was divided into two groups, exhibiting progressive (83.3%) or nonprogressive (16.6%) neurologic signs and symptoms. In the first group of patients, progressive encephalopathy was distinguished from spastic paraparesis, possibly due to spinal cord involvement. The second group, represented by long-term survivors, requires clinical monitoring due to the possible prognostic value of acquired but presently nonprogressive signs of brain involvement. In contrast with the stereotyped features of the early form of progressive encephalopathy, the late form showed a polymorphic picture, with age-dependent neurologic manifestations. Multifocal white matter alterations and cerebral calcifications (sometimes with delayed onset and progression) were the prominent imaging findings. A correlation between cerebrospinal fluid HIV RNA levels, suggestive of viral replication within the central nervous system, and progressive neurological disease were also found.

Axonal loss results in spinal cord atrophy, electrophysiological abnormalities and neurological deficits following demyelination in a chronic inflammatory model of multiple sclerosis

Recent pathological studies have re-emphasized that axonal injury is present in patients with multiple sclerosis, the most common demyelinating disease of the CNS in humans. However, the temporal profile of demyelination and axonal loss in multiple sclerosis patients and their independent contributions to clinical and electrophysiological abnormalities are not completely understood. In this study, we used the Theiler's murine encephalomyelitis virus model of progressive CNS inflammatory demyelination to demonstrate that demyelination in the spinal cord is followed by a loss of medium to large myelinated fibres. By measuring spinal cord areas, motor-evoked potentials, and motor coordination and balance, we determined that axonal loss following demyelination was associated with electrophysiological abnormalities and correlated strongly with reduced motor coordination and spinal cord atrophy. These findings demonstrate that axonal loss can follow primary, immune-mediated demyelination in the CNS and that the severity of axonal loss correlates almost perfectly with the degree of spinal cord atrophy and neurological deficits.