Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human herpesvirus (HHV) 6 is a beta-herpes, DNA virus. This virus shows closest homology with cytomegalovirus and HHV-7. Infection usually occurs in infants 6 to 24 months of age, and primary infection may result in roseola. HHV-6 infection in infants is the commonest cause of fever-induced seizures. Infection in adults is seen primarily in immunocompromised hosts with solid organ transplants or in those with human immunodeficiency virus infection. The virus is capable of pronounced interaction in vitro with cytomegalovirus and human immunodeficiency virus and induces immunosuppression and apoptosis. The importance of these interactions in vivo necessitates further investigation. HHV-6 infection may contribute to the pathogenesis of multiple sclerosis. HHV-6 may be diagnosed by viral culture, serology, or polymerase chain reaction.
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PMID:Human herpesvirus 6. 1006 56

Three new members of the family of human herpesviruses (HHVs) have been identified in less than a decade, HHV 67 and 8. HHV-6 and HHV-7, both infecting T-lymphocytes and phylogenetically related to cytomegalovirus, were identified as causative agents of exanthema subitum. In addition, HHV-6 has been reported to manifest central nervous system tropism and to be frequently detected in normal brain tissue, but has also been associated with febrile seizures. HHV-7 has been suggested to be involved in the development of pityriasis rosea, but has also been found to occur in normal dermal tissue. HHV-8, related to Epstein-Barr virus and infecting B-lymphocytes, was the first herpesvirus to be identified with molecular techniques. Recent research has been focused on the involvement of proteins expressed by HHV-8 in the pathogenesis of two rare tumours, Kaposi's sarcoma and body-cavity B-cell lymphomas.
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PMID:[HHV 6,7 and 8. Recently discovered herpesviruses explain the etiology of well-known diseases]. 1042 75

The frequency was studied with which human herpesviruses types 6 and 7 (HHV-6 and HHV-7) occur in the cerebrospinal fluid (CSF) of patients with febrile seizures and matched control patients. CSF samples were prospectively collected from a case series of patients with febrile seizures and from age-, sex-, and race-matched control patients without febrile seizures, all of whom were evaluated in the emergency department of an urban, tertiary care, pediatric medical center. Using polymerase chain reaction, the samples were examined for the presence of viral DNA from HHV-6, HHV-7, herpes simplex viruses types 1 and 2 (HSV-1 and HSV-2), and cytomegalovirus (CMV). CSF from a subset of both groups was also examined for RNA from enteroviruses. During the 7-month, 2-week collection period, a total of 174 patients were evaluated for fever and seizures. Of these, 23 (13.2%) met the study criteria. Their mean age was 1.4 +/- 0.7 years. Sixteen (70%) of the 23 were male. The 23 patients were matched to 21 control subjects. None of the samples from the patients or control subjects had polymerase chain reaction evidence of HHV-6, HHV-7, HSV-1, or HSV-2. All samples from the patients were negative for CMV. One control subject was positive for CMV. The 10 patients and seven control subjects tested for enteroviral RNA were negative. Neither HHV-6 nor HHV-7 appears to be present in the CSF of patients with febrile seizures. What role, if any, they have in the pathogenesis of febrile seizures merits further study.
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PMID:Human herpesviruses types 6 and 7 and febrile seizures. 1058 Aug 81

Three new members of the family of human herpesviruses (HHVs) have been identified in less than a decade, HHV 6 7 and 8. HHV-6 and HHV-7, both infecting T-lymphocytes and phylogenetically related to cytomegalovirus, were identified as causative agents of exanthema subitum. In addition, HHV-6 has been reported to manifest central nervous system tropism and to be frequently detected in normal brain tissue, but has also been associated with febrile seizures. HHV-7 has been suggested to be involved in the development of pityriasis rosea, but has also been found to occur in normal dermal tissue. HHV-8, related to Epstein-Barr virus and infecting B-lymphocytes, was the first herpesvirus to be identified with molecular techniques. Recent research has been focused on the involvement of proteins expressed by HHV-8 in the pathogenesis of two rare tumours, Kaposi's sarcoma and body-cavity B-cell lymphomas.
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PMID:[Recently discovered herpes viruses explain the etiology of well-known diseases]. 1082 85

Human herpesvirus-6 (HHV-6) is the causative agent of the common childhood infectious disease, exanthem subitum. After the virus was recently isolated from humans, it was found to be closely related to human cytomegalovirus (CMV), and was thus classified within the beta subgroup of human herpesviruses. HHV-6 possesses neurotropism in vitro, and it has been suggested that primary infection can cause complications of the central nervous system (CNS), including febrile seizures and encephalitis/encephalopathy. There is also speculation that the direct invasion of the virus into the CNS may play an important role in causing these neurological complications. Moreover, there are several reports which have suggested an association between HHV-6 and a variety of neurological disorders in adults. This paper will briefly review our virological understanding of the virus, and summarize recent findings regarding HHV-6 as an etiologic agent for CNS infection.
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PMID:Central nervous system complications in human herpesvirus-6 infection. 1089 38

Central nervous system (CNS) complications occur more frequently in cystic fibrosis (CF) patients than other lung transplant recipients. The purpose of this study was to compare CF patients with and without CNS complications following lung transplantation, to identify risk factors for CNS events. Records of 21 patients with CF who underwent lung transplant between 1991-1996 were reviewed. Data were collected on multiple variables, including: age at transplant; gender; cytomegalovirus (CMV) status; cholesterol and triglyceride levels; sinusitis; percent ideal body weight (IBW); body mass index (BMI); augmented immunosuppression, acute lung rejection episodes (ALR); cyclosporine doses; electrolytes; magnesium, blood urea nitrogen (BUN), and creatinine levels; and 6-month survival. CNS complications identified were seizures, severe headaches (HA), strokes, or confusional episodes. Eleven of 21 patients (52%) with CF had CNS events: eight had seizures, five HA, three strokes, and one confusional episode. There was no difference in age at transplant, pretransplant percent IBW or BMI, cholesterol and triglyceride levels, or number of ALR. CMV mismatch and clinical sinusitis had no effect. Cyclosporine doses did not differ between groups at 30 days, or 3 or 6 months posttransplant. Both BUN and creatinine concentrations showed a rise over time that did not differ between groups. Potassium levels were within normal limits for both groups. While sodium levels did not differ between groups pretransplant, or at 30 days or 6 months posttransplant, a decrease in sodium values was seen at the time of CNS events. There was no difference in 6-month survival. We could not identify any pre- or posttransplant risk factors that predicted CNS events. It is likely that cyclosporine toxicity is the major cause of CNS complications. Despite the high rate of CNS events, the overall prognosis was good, and 6-month survival was not affected.
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PMID:Cystic fibrosis patients with and without central nervous system complications following lung transplantation. 1097 38

The diagnostic approach to the compromised host with CNS infection depends on an analysis of the patient's clinical manifestations of CNS disease, the acuteness or subacuteness of the clinical presentation, and an analysis of the type of immune defect compromising the patient's host defenses. Most patients with CNS infections may be grouped into those with meningeal signs, or those with mass lesions. Other common manifestations of CNS infection include encephalopathy, seizures, or a stroke-like presentation. Most pathogens have a predictable clinical presentation that differs from that of the normal host. CNS Aspergillus infections present either as mass lesions (e.g., brain abscess), or as cerebral infarcts, but rarely as meningitis. Cryptococcus neoformans, in contrast, usually presents as a meningitis but not as a cerebral mass lesion even when cryptococcal elements are present. Aspergillus and Cryptococcus CNS infections are manifestations of impaired host defenses, and rarely occur in immunocompetent hosts. In contrast, the clinical presentation of Nocardia infections in the CNS is the same in normal and compromised hosts, although more frequent in compromised hosts. The acuteness of the clinical presentation coupled with the CNS symptomatology further adds to limit differential diagnostic possibilities. Excluding stroke-like presentations, CNS mass lesions tend to present subacutely or chronically. Meningitis and encephalitis tend to present more acutely, which is of some assistance in limiting differential diagnostic possibilities. The analysis of the type of immune defect predicts the range of possible pathogens likely to be responsible for the patient's CNS signs and symptoms. Patients with diseases and disorders that decrease B-lymphocyte function are particularly susceptible to meningitis caused by encapsulated bacterial pathogens. The presentation of bacterial meningitis is essentially the same in normal and compromised hosts with impaired B-lymphocyte immunity. Compromised hosts with impaired T-lymphocyte or macrophage function are prone to develop CNS infections caused by intracellular pathogens. The most common intracellular pathogens are the fungi, particularly Aspergillus, other bacteria (e.g., Nocardia), viruses (i.e., HSV, JC, CMV, HHV-6), and parasites (e.g., T. gondii). The clinical syndromic approach is most accurate when combining the rapidity of clinical presentation and the expression of CNS infection with the defect in host defenses. The presence of extra-CNS sites of involvement also may be helpful in the diagnosis. A patient with impaired cellular immunity with mass lesions in the lungs and brain that have appeared subacutely or chronically should suggest Nocardia or Aspergillus rather than cryptococcosis or toxoplasmosis. Patients with T-lymphocyte defects presenting with meningitis generally have meningitis caused by Listeria or Cryptococcus rather than toxoplasmosis or CMV infection. The disorders that impair host defenses, and the therapeutic modalities used to treat these disorders, may have CNS manifestations that mimic infections of the CNS clinically. Clinicians must be ever vigilant to rule out the mimics of CNS infections caused by noninfectious etiologies. Although the syndromic approach is useful in limiting diagnostic possibilities, a specific diagnosis still is essential in compromised hosts in order to describe effective therapy. Bacterial meningitis, cryptococcal meningitis, and tuberculosis easily are diagnosed accurately from stain, culture, or serology of the CSF. In contrast, patients with CNS mass lesions usually require a tissue biopsy to arrive at a specific etiologic diagnosis. In a compromised host with impaired cellular immunity in which the differential diagnosis of a CNS mass lesion is between TB, lymphoma, and toxoplasmosis, a trial of empiric therapy is warranted. Antitoxoplasmosis therapy may be initiated empirically and usually results in clinical improvement after 2 to 3 weeks of therapy. The nonresponse to antitoxoplasmosis therapy in such a patient would warrant an empiric trial of antituberculous therapy. Lack of response to anti-Toxoplasma and antituberculous therapy should suggest a noninfectious etiology (e.g., CNS lymphoma). Fortunately, most infections in compromised hosts are similar in their clinical presentation to those in the normal host, particularly in the case of meningitis. The compromised host is different than the normal host in the distribution of pathogens, which is determined by the nature of the host defense defect. In compromised hosts, differential diagnostic possibilities are more extensive and the likelihood of noninfectious explanations for CNS symptomatology is greater. (ABSTRACT TRUNCATED)
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PMID:Central nervous system infections in the compromised host: a diagnostic approach. 1144 10

A 10-year-old girl with M2 acute myeloid leukemia underwent an unrelated cord blood transplantation in refractory first relapse. On day +13, after 48 hours with fever, she showed a measles-like rash, and on day +15, she began experiencing neurologic symptoms (headache, tremors, weakness, nystagmus, mild confusion, speaking, taste, and behavior disturbances, and focal seizures). She also had amnesia for recent events with disability to learn, mimicking Wernicke-Korsakoff syndrome. Computed tomography of the brain and cerebrospinal fluid (CSF) and electroencephalogram were nonspecific. We found human herpesvirus 6 (HHV-6) DNA in CSF and cytomegalovirus in bronchoalveolar lavage using polymerase chain reaction techniques. Treatment with ganciclovir and foscarnet was effective, with total resolution of symptoms.
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PMID:Herpesvirus-6 encephalitis complicated by Wernicke-Korsakoff syndrome in a pediatric recipient of unrelated cord blood transplantation. 1190 11

The possibility of amplification of human cytomegalovirus (HCMV) DNA in cerebrospinal fluid (CSF) for the diagnosis of HCMV central nervous system (CNS) infection in infants was studied. Single-step PCR, nested PCR and PCR-Digene were used to assay CSF specimens from 37 patients. Criteria for patient inclusion in the study were: 1. clinical manifestations suggesting CMV neuroinfection such as seizures, hypertonia, hypotonia, intracranial calcification, microcephaly, chorioretinitis; 2. any of the following symptoms: anaemia, hepetomegaly, prolonged cholestatic jaundice, or hepatitis, splenomegaly, thrombocytopenia, intrauterine hypotrophy; 3. serologic presentation, and/or positive results for CMV infection obtained by single-step PCR and PCR-Digene in urine and/or blood. PCR-Digene results were positive in 6 CSF samples. Four CSF samples were positive by nested PCR and 1 CSF sample by single step PCR. We found that the double PCR was about ten or more times more sensitive than single PCR and the PCR-Digene was only three times more sensitive than nested-PCR. The results were correlated with serology. Thirty-three out of 37 examined patients were seropositive (ELISA IgG); ELISA IgM gave positive results in 9 patients. In control studies, cells infected with other members of the herpes virus family were negative with these methods, which suggest that amplification combined with primers from the IE and the L-region of CMV is specific. In conclusion, nested-PCR seems to be the best method for early diagnosis of CMV infection in CSF due to an absence of false positive results and its high specificity and sensitivity.
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PMID:Detection of cytomegalovirus in infant cerebrospinal fluid by conventional PCR, nested PCR and PCR-Digene. 1193 Sep 94

Schizencephaly is an uncommon congenital brain malformation. We report our experience of 13 patients with schizencephaly and evaluate the clinical, neuroradiologic, electroencephalographic (EEG), and nosological features. Of these 13 patients, 8 were unilateral forms, 5 were bilateral forrms and 11 were open-lip type schizencephaly. One patient was proven to have cytomegalovirus (CMV) infection. The clinicalfeatures and neurodevelopmental outcomes are variable. Although seizure developed in 9 patients (5 patients from unilateral and 4 from bilateral forms), the severity of epilepsy was not totally related to the degree of malformations. The neurodevelopmental outcome depended on the extent of schizencephaly as well as the seizure control. Those with bilateral forms and intractable seizures had the worst outcome. Other central nervous system (CNS) anomalies were observed in 11 patients. Six out of 11 patients had focal cortical dysplasia. We conclude that children with schizencephaly usually have variable neurological impairment. Earlier diagnosis of schizencephaly and related CNS malformation with neuroimaging is helpful in predicting the neurodevelopmental outcomes in these patients.
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PMID:Schizencephaly: correlation between clinical and neuroimaging features. 1223 9


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