Characteristics of Patients with Acute Flaccid Myelitis, United States, 2015-2018

Differences between years with and without increased activity suggest differences in viral etiologies.

Observed peaks of acute flaccid myelitis (AFM) cases have occurred biennially since 2014 in the United States. We aimed to determine if AFM etiology differed between peak and nonpeak years, considering that clinical features of AFM differ by virus etiology. We compared clinical and laboratory characteristics of AFM cases that occurred during peak (2016 and 2018, n = 366) and nonpeak (2015 and 2017, n = 50) years. AFM patients in peak years were younger (5.2 years) than those in nonpeak years (8.3 years). A higher percentage of patients in peak years than nonpeak years had pleocytosis (86% vs. 60%), upper extremity involvement (33% vs. 16%), and an illness preceding limb weakness (90% vs. 62%) and were positive for enterovirus or rhinovirus RNA (38% vs. 16%). Enterovirus D68 infection was associated with AFM only in peak years. Our findings suggest AFM etiology differs between peak and nonpeak years.

Uncommon acute neurologic presentation of canine distemper in 4 adult dogs

Four uncommon cases of canine distemper (CD) were diagnosed in vaccinated adult dogs. All dogs had acute onset of neurologic signs, including seizures, abnormal mentation, ataxia, and proprioceptive deficits. Polymerase chain reaction for CD virus was positive on cerebrospinal fluid in 2 cases. Due to rapid deterioration the dogs were euthanized and CD was confirmed by postmortem examination.

[Affection of central nervous system in hemorrhagic fever with renal syndrome]

The authors report results of comparative analysis of 897 cases of hemorrhagic fever with renal syndrome diagnosed in the Upper Amur region in 1960-2005. All the patients were grouped by 5-year intervals depending on the severity of clinical condition. The frequency of CNS affection accompanied by acute psychic disorders, convulsive and meningeal syndromes varied significantly in different years. Pituitary hemorrhage was revealed at autopsy in 36.8% of the patients, pituitary necrosis in 5.2%, brainstem hemorrhage in 68.4%. A case of severe hemorrhagic fever with renal syndrome is described characterized by acute renal insufficiency and eclamptic convulsions with moderately manifest hemorrhagic syndrome preceding the favourable outcome.

Influence of proinflammatory cytokines and chemokines on the neuropathogenesis of oncornavirus and immunosuppressive lentivirus infections

Retroviral infection of the CNS can lead to severe debilitating neurological diseases in humans and other animals. Four general types of pathogenic effects with various retroviruses have been observed including: hemorrhage (TR1.3), spongiform encephalopathy (CasBrE, FrCasE, PVC211, NT40, Mol-ts1), demyelination with inflammatory lesions (HTLV-1, visna, CAEV), and encephalopathy with gliosis and proinflammatory chemokines and cytokines, usually with microglial giant cells and nodules [human immunodeficiencyvirus (HIV), feline immunodeficiencyvirus (FIV), simian immunodeficiency virus (SIV), Fr98]. This review focuses on this fourth group of retroviruses. In this latter group, proinflammatory cytokine and chemokine upregulation accompanies the disease process, and may influence pathogenesis by direct effects on resident CNS cells. The review first discusses the Fr98 murine polytropic virus system with particular reference to the roles of cytokines and chemokines in the pathogenic process. The Fr98 data are then compared and contrasted to the cytokine and chemokine data in the lentivirus systems, HIV, SIV, and FIV. Finally, various mechanisms are presented by which tumor necrosis factor (TNF) and several chemokines may alter the pathogenesis of retrovirus infection of the CNS.

Highlights from 5th International Conference on HHV-6 and -7

This article reports on key presentations at the 5th International Conference on Human Herpesvirus (HHV)-6 and -7, organized by the HHV-6 Foundation. New assays for HHV-6 and -7 promise to be more accurate and better able to distinguish between HHV-6A and B or differentiate active from latent infection. Nevertheless, more research is needed to enhance the sensitivity and specificity of these assays. Cellular receptors for both HHV-6 and -7 have been identified. Both viruses have in vitro tropism for neurons and dendritic cells of the central nervous system (CNS), and their role in producing CNS disease in the immunocompromised (particularly transplant recipients and the HIV-infected) is well established. HHV-6 may enhance the progression of simian immunodeficiency virus in monkeys, as suggested by in vivo data. In immunocompetent children and adults, HHV-6 and/or -7 may play a role in triggering and perpetuating several diseases of the nervous system, namely encephalitis, multiple sclerosis, chronic fatigue syndrome and epilepsy.

HIV-TAT protein upregulates expression of multidrug resistance protein 1 in the blood-brain barrier

Central nervous system (CNS) complications of human immunodeficiency virus (HIV) infection remain a serious health risk in HIV/acquired immunodeficiency syndrome despite significant advances in highly active antiretroviral therapy (HAART). Specific drugs used for HAART are substrates for the efflux transport systems, such as the multidrug resistance-associated proteins (MRPs), which are present on brain microvascular endothelial cells (BMEC) and astrocytes, that is, the main cell types that form the blood-brain barrier (BBB). Thus, drugs employed in HAART are actively removed from the CNS and do not efficiently inhibit HIV replication in the brain. To study the potential mechanisms of this process, the aim of the present research was to address the hypothesis that HIV Tat protein can contribute to upregulation of MRP expression at the BBB level. Tat is a protein produced and released by HIV-infected cells, which may play an important role in brain vascular pathology in the course of HIV infection. Among the family of MRPs, exposure to Tat specifically induced MRP1 messenger ribonucleic acid and protein expression both in BMEC and astrocytes. These alterations were accompanied by enhanced MRP1-mediated efflux functions. Furthermore, activation of the mitogen-activated protein kinase signaling cascade was identified as the mechanism involved in Tat-mediated overexpression of MRP1. These results indicate that Tat exposure can lead to alterations of the BBB functions and decrease HAART efficacy in the CNS through overexpression of drug efflux transporters.

Clinical features and factors of unfavorable outcomes for non-polio enterovirus infection of the central nervous system in northern Taiwan, 1994-2003

This study investigated the clinical manifestations and outcomes of central nervous system (CNS) infection by enteroviruses. Cases with CNS involvement among all enterovirus-culture-positive cases from January 1995 to June 2003 were retrospectively reviewed. Among 1028 enterovirus-culture-positive cases, there were 333 cases involving the CNS. Of these, the ratio of male to female subjects was 1.78, and the mean (+/- standard deviation) age was 6.83 +/- 5.9 years; 21 were premature neonates, and 10 failed to thrive. Disease entities included 282 cases of aseptic meningitis (84.7%), 44 cases of encephalitis (13.2%), and 7 cases of encephalomyelitis/polio-like syndrome (2.1%). Of these cases, 97.9% (326/333) had fever with peak body temperature at 38.9 degrees C, 85% had headache and vomiting, 70% had meningeal signs, 64% had neck stiffness, 16.6% (55/333) had change of consciousness, 5.4% (18/333) had seizures and 5.2% (17/333) had myoclonic jerks. Mannitol was administered in 77.2% of patients (257/333), along with intravenous immunoglobulin in 6.6% (22/333). Twelve cases received ventilator support. One patient died of hand-foot-and-mouth disease, encephalitis plus cardiopulmonary failure, and 2 premature neonates died of hepatic failure, disseminated intravascular coagulation, sepsis-like syndrome and myocarditis. Eighteen had neurologic sequelae, including 7 with limb weakness, 5 with epilepsy, 2 with sixth cranial nerve palsy, 3 with cerebral palsy, 4 with psychomotor retardation, 2 with spasticity, and 1 with hearing loss. Factors associated with unfavorable outcomes (death or sequelae) included younger age (p=0.0003), higher peak white blood cell count (WBC) [p=0.0009] and skin rash (p=0.005). Younger age and higher peak WBC were poor prognostic factors of severe enterovirus CNS infection. Death was related to neonatal enterovirus infection and enterovirus 71 infection in young children.

Neurological complications in kidney transplant recipients

Neurological complications are frequent in renal transplant recipients and may largely contribute to morbidity and mortality. The postransplant neurological complications may be categorized into five areas: 1) Immunosuppressive medications, 2) stroke, 3) peripheral neuropathies, 4) infection, and 5) malignancies. A number of complications are directly caused by the neurotoxicity of immunosuppressive agents. Calcineurin-inhibitors may cause mild symptoms, such as tremors and paresthesia, or severe symptoms, such as disabling pain syndrome and leukoencephalopathy. Severe neurological syndromes may also be caused by the monoclonal antibody OKT3. Stroke may occur in about 8% of renal transplant patients. It may be favored by hypertension, diabetes, and accelerated atherosclerosis which may be acquired during dialysis or after transplantation. Peripheral mononeuritis and polyneuritis may also occur. An acute femoral neuropathy may occur in about 2% of patients as a result of nerve compression after operation. Guillain-Barré syndrome may also develop, triggered in some cases by cytomegalovirus (CMV) or Campylobacter jejuni infection. Lymphomas are the most frequent brain tumors. They are usually associated to a Epstein Barr virus (EBV) infection and are more frequent in patients who received an aggressive immunosuppressive therapy. Infection represents the most frequent neurological complication. Acute meningitis usually caused by Listeria monocytogenes, subacute and chronic meningitis caused by Cryptococcus neoformans, focal brain infection caused by Aspergillus fumigatus, Toxoplasma gondii or Nocardia asteroids, and progressive dementia caused by polyoma J virus or other viruses are the most frequent types of neurological infections.

Cardiac troponin I: a reliable marker and early myocardial involvement with meningoencephalitis after fatal enterovirus-71 infection

OBJECTIVES

A major outbreak of enterovirus 71 (EV71) in Taiwan in 1998 caused many severe cases and 78 deaths. Our purpose was to find reliable markers and early indicators of fatal EV71 central nervous system (CNS) infection.

METHODS

From June 2000 to November 2001, 21 patients with hand foot mouth disease or herpangina with CNS infection were admitted to Kaohsiung Veterans General Hospital. All 21 had culture-confirmed EV71 infection or were EV71 IgM positive. Patients were divided into two groups: group I included the five fatalities at our institution and group II, the 16 surviving patients.

RESULTS

Of the 21 infants and children with EV71 infection with CNS involvement, MR imaging studies were completed on 17, and 15 showed hyperintensity in the posterior portions of brain stem. All patients received intravenous immunoglobulin (IVIG) 1 g/day for two days and supportive care. Five patients rapidly deteriorated owing to irreversible hypotension and died. The other 16 patients recovered completely without sequel. In group I patients, the decrease of cardiac ejection function is significant and laboratory findings showed lower platelet count (P=0.0192). The mean of initial cTnI level for groups I and II was 10.6+/-11.6 and 0.48+/-0.55 ng/dl, respectively, higher in group I than in II (P=0.0019).

CONCLUSION

We hypothesized that like patients with severe burns, those with severe EV-71 CNS meningoencephalitis have varying degrees of non-ischemic cardiac injury, manifesting as leakage of cTnI from myocytes into the circulation. EV-71 CNS meningoencephalitis likely to die with an early myocardial involvement evidenced by reduced ejection fraction and release of cTnI. We conclude that fatal EV71 CNS infection quickly leads to death due to severe encephalopathy associated with cardiomyopathy.

Emergence of late cytomegalovirus central nervous system disease in hematopoietic stem cell transplant recipients

Preemptive ganciclovir therapy has reduced the occurrence of early cytomegalovirus (CMV) disease after hematopoietic stem cell (HSC) transplantation. However, late disease is increasingly reported. We describe 2 patients who developed late CMV central nervous system (CNS) disease after haploidentical HSC transplantation. Direct genotypic analysis was used to examine the presence of ganciclovir resistance. One patient had a mixed viral population in the cerebrospinal fluid (CSF), with coexistent wild-type and mutant UL97 sequences. The presence of 2 different strains was confirmed by subclone sequencing of the UL54 gene. One of the strains was different from the concurrent blood strain. The second patient had resistant variant in the lungs. These cases raise concern about the changing natural history of CMV disease in HSC transplantation, with emergence of previously uncommon manifestations following prolonged prophylaxis. Under these circumstances the CNS may be a sanctuary site, where viral persistence and antiviral drug resistance could result from limited drug penetration.

Epstein-Barr virus infections of the central nervous system

OBJECTIVE

Epstein-Barr virus (EBV), a lymphotropic herpes virus causing infectious mononucleosis (IM), also causes various central nervous system (CNS) infections. In the present study, EBV CNS infections were investigated.

PATIENTS AND METHODS

For adult inpatients in our hospital and related hospitals between 1984-2002, CNS syndromes with IM symptoms were examined, and serologic positives were assessed according to established criteria. Polymerase chain reaction (PCR) was performed for cerebrospinal fluid (CSF) from seven patients.

RESULTS

Ten patients with EBV-related CNS infections were found; their mean age was 36 years (20-79 years). The neurologic forms were as follows: acute encephalitis (4 patients), acute cerebellar ataxia (1), acute disseminated encephalomyelitis (ADEM) (2), myelitis (1), and meningitis (2). The PCR from CSF was positive in two patients with meningitis, one patient with ADEM, and one patient with encephalitis-associated chronic EVB infection. One case of encephalitis and another of relapsing ADEM were attributed to chronic EBV infection.

CONCLUSION

Our study identified a variety of EBV-related CNS infections. EBV CNS infections are divided into two groups: 1) CNS syndromes associated with primary EBV or reactivated infection, and 2) those associated with chronic EBV infection; it is notable that in the former, diverse CNS syndromes including ADEM can occur, whereas in the latter, chronic or recurrent CNS syndromes are produced.

Acute central nervous system complications in varicella zoster virus infections

BACKGROUND

In a previous multicenter study on central nervous system (CNS) viral infections varicella zoster virus (VZV) appeared the most frequent etiologic agent and appeared often without rash.

OBJECTIVE

To evaluate the appearance and diagnostics of VZV in CNS more thoroughly, we studied the cases systematically by using sensitive and specific methods to learn the best diagnostic approach in order to start specific therapy.

STUDY DESIGN

We analyzed all serum and cerebrospinal fluid samples of 174 patients, 88 females and 86 males, with acute CNS symptoms associated with VZV infection diagnosed in the multicenter study on viral CNS infections.

RESULTS

About 38 patients (22%) had chickenpox, 59 (34%) had shingles, and 77 (44%) had no cutaneous symptoms at all. The mean age of chickenpox patients was 8.6 years, of the others 46.6 and 41.4 years. VZV-specific nucleic acid was detected in the CSF in one fourth of the patients in all groups, primarily during the first week of illness. In serum specimens, specific IgM was present in two thirds of the patients with chickenpox, whereas in the others in one third of the cases. In CSF, specific IgM was present in 15-17% of patients with skin manifestations, compared with 6% of those without rash.

CONCLUSIONS

The role of VZV infections in CNS complications seems remarkable, often presenting without rash. Even these cases should be promptly recognized in order to conduct proper antiviral therapy. In children, a combination of PCR and IgM tests is the best approach. In adults, PCR, together with the measurement of intrathecal antibody production yields best results.

Murine coronavirus spike glycoprotein mediates degree of viral spread, inflammation, and virus-induced immunopathology in the central nervous system

The mouse hepatitis virus (MHV) spike glycoprotein is a major determinant of neurovirulence. We investigated how alterations in spike affect neurovirulence using two isogenic recombinant viruses differing exclusively in spike. S(4)R, containing the MHV-4 spike gene, is dramatically more neurovirulent than S(A59)R, containing the MHV-A59 spike gene (J. J. Phillips, M. M. Chua, E. Lavi, and S. R. Weiss, 1999, J. Virol. 73, 7752-7760). We examined the contribution of differences in cellular tropism, viral spread, and the immune response to infection to the differential neurovirulence of S(4)R and S(A59)R. MHV-4 spike-mediated neurovirulence was associated with extensive viral spread in the brain in both neurons and astrocytes. Infection of primary hippocampal neuron cultures demonstrated that S(4)R spread more rapidly than S(A59)R and suggested that spread may occur between cells in close physical contact. In addition, S(4)R infection induced a massive influx of lymphocytes into the brain, a higher percentage of CD8(+) T cells, and a higher frequency of MHV-specific CD8(+) T cells relative S(A59)R infection. Despite this robust and viral-specific immune response to S(4)R infection, infection of RAG1-/- mice suggested that immune-mediated pathology also contributes to the high neurovirulence of S(4)R.

The role of interleukin-18 in vesicular stomatitis virus infection of the CNS

Intranasal application of vesicular stomatitis virus (VSV) results in the initial infection of the olfactory receptor neurons and a rapid progression of the virus through the mouse central nervous system (CNS). Interleukin-18 (IL-18) is an 18.3-kd cytokine that induces interferon gamma (IFN-gamma) production in mice. IL-18 is synthesized as an inactive precursor that is cleaved and activated by caspase-1/interleukin-1beta converting enzyme (ICE). IL-18 shares several biological properties with IL-12, including the ability to induce IFN-gamma production in T lymphocytes and natural killer (NK) cells. In the CNS, microglia and astrocytes produce IL-18 and IL-12. We have previously shown that IL-12 promotes recovery from VSV encephalitis. This led us to examine the potential role of IL-18 in the pathogenesis of VSV encephalitis. We show that both IL-18 and caspase-1 mRNA are consistently present in the CNS of mice. The addition of exogenous IL-18 to cell cultures does not affect the production of VSV, and addition of exogenous IL-18 at the time of infection does not alter the morbidity or mortality of BALB/c mice. In vitro studies with neutralizing monoclonal antibody to IL-18 had no effect. From these results we conclude that in this system and under the experimental conditions used, unlike IL-12 and IFN-gamma, IL-18 does not play a significant role in the host response to VSV infection.

Neurologic involvement in an outbreak of enterovirus 71 infection: a hospital-based study

Enterovirus (EV) can cause varied clinical manifestations. Involvement of the central nervous system (CNS) with the nonpolio EVs are common and important causes of morbidity in children. To investigate the manifestations of nonpolio enteroviral infections with CNS involvement during the EV outbreak, from February 1998 to January 1999, we collected 153 hospitalized patients in our pediatric ward caused by nonpolio EV infections which were diagnosed by history, clinical features, or detected from viral cultures. Fourteen patients (9.2%) had CNS presentations, 13 males and one female. The ages ranged from one month to 10.3 years. The spectrum of CNS presentations included aseptic meningitis (4 cases, 28.6%), encephalitis (5 case, 35.7%), encephalomyelitis (3 cases, 21.4%), and poliomyelitis-like syndrome (2 cases, 14.3%). Among these patients, 8 cases (57.1%) were isolated with EV71 from at least one site of rectal or throat swab sampling. Two fatal cases were presented as encephalitis and complicated with pulmonary edema. Generally, enteroviral infections are considered as a benign infectious disease in children. However, pediatricians should keep in mind that EV71 has caused several endemic outbreaks and continues to be an occasional cause of severe CNS disease. Early evaluation and appropriate treatment of CNS enteroviral infections may minimize the neurologic sequelae.

[Detection of viral aetiology in cerebral spinal fluid samples from 580 clinical cases]

OBJECTIVE

To investigate the viral aetiology in cerebral spinal fluid (Csf) from 580 cases of CNS infection or FUO in Yuedong district from 1990 to 1997.

METHODS

Virus isolation was done with Hep-2 and BHK-21 cells.

RESULTS

21 virus types of 5 kinds of viruses were isolated from 113 samples (19.5%). Clinically diagnosed diseases included viral encephalitis 17.8% (43/242), intracranial infection 20.2% (47/233), paralytic diseases 24.3% (9/37), FUO 37.5% (9/24), convulsion 16.0% (4/25), Guillain-Barre syndrome 5.3% (1/19). Virus infection included 11 cases of Poliovirus (constitutional ratio 0.0973, including 1 Polio-I, 8 Polio-II, 2 Polio-III); 54 cases of Coxsackie virus (0.477 9, including 11 CoxA24, 10 CoxBl, 2 Cox134, 3 CoxB5); 15 cases of ECHO virus (0.1327, including 4 ECHO-24, 3 ECRO-7, 2 ECHO-12 and each one of ECHO-3, 11,14,15,27,32); 25 cases of Enterovirus (0.2213, including 14 EV-70, 11 EV-71); 8 cases of Adenovirus (0.070 8, including 3 Adv-2, 3 Adv-3 and 2 Adv7). Results of different age groups indicated there was significant difference (P < 0.05) in virus detection rate in two age groups. Virus positive rates in different years were 1990-1991 14.2% (15/106), 1992-1993 14.1%(23/163), 1994-1995 26.1% (36/138), 1996-1997 22.5% (39/173), that showed a significant difference (P <0.05).

CONCLUSIONS

Virus infection rate of CNS diseases and FUO showed an a ascending trend, and the different virus types and kinds were isolated in different periods.

Complications of varicella in children: emphasis on skin and central nervous system disorders

A review of medical records at a tertiary hospital in southern Taiwan from June 1988 through May 1998 identified 136 children who had been hospitalized for varicella-related complications. Of the children, 83% (113/136) were healthy before the onset of varicella and 17% (23/136) had underlying illnesses. The mean age was 4.7 years (ranged from 1 day to 18 years) with a male predominance (1.7:1). The mean hospital stay was 5.5 days (ranged from 1 to 22 days). Secondary bacterial skin or soft tissue infections were the most common complications (44%), followed by central nervous system (CNS) involvement (23%), pneumonia (18%), thrombocytopenia (12%), and liver function impairment (10%). Among the 60 patients with secondary bacterial cutaneous infection, 16 (27%) had positive isolates, including 12 isolates of Staphylococcus aureus and four Streptococcus pyogenes. Age above 8 years was significantly associated with the development of varicella-associated CNS complications (p = 0.019). Of the 23 immunocompromised hosts, the most common underlying conditions were hematological diseases (11 patients, 48%), followed by neonatal varicella (7 patients, 30%) and chronic illness with steroid treatment (5 patients, 22%). All of the subjects in this study had a favorable outcome except for three lethal cases, resulting in a case-fatality rate of 2.2%. The cause of death was S. aureus septicemia in one patient, streptococcal toxic shock syndrome in one patient, and encephalitis with brain herniation in one patient. Our results demonstrate that varicella continues to be a serious disease that occasionally results in life-threatening complications in healthy and immunocompromised children. Routine immunization of all healthy children against varicella is recommended.

Opportunistic viral infections in the setting of human immunodeficiency virus

Human immunodeficiency virus (HIV) infection has provided a setting in which additional neurologic problems develop. The mechanism of these complications varies from agent to agent, but the added spectrum of diseases encountered has challenged diagnosticians and provided unparalleled opportunities to develop a deeper understanding of these conditions and their treatments. This review addresses the most prominent viral-associated complications, except for progressive multifocal leukoencephalopathy, which is addressed in a separate review. The complications of greatest importance both due to their frequency and severity are caused by cytomegalovirus, so these are discussed in greater depth. However, the association of Epstein-Barr virus with induction of central nervous system lymphoma represents an important viral linked complication of great importance. In addition, the increased activity of varicella zoster virus has been notable in the setting of HIV. Finally, human herpesvirus type 6 is an emerging virus of interest that has been identified in the setting of HIV infection, whose role in pathophysiology is only now being investigated.