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Tom Solomon

Publications and source records attributed to Tom Solomon.

27 records · Page 2Linked to original sources
PubMed2003

Exotic and emerging viral encephalitides.

PURPOSE OF REVIEW: The exotic and emerging viral encephalitides are caused by animal or human viruses and characterised by sudden unexpected outbreaks of neurological disease, usually in tropical and sub-tropical regions, but sometimes spreading to temperate areas. Although a wide range of viruses come within this label, as this review highlights, there are common research questions as to the origin and spread of the viruses, the contribution of viral and host factors to the clinical presentations and outcome, and the possibilities for treatment and vaccination. RECENT FINDINGS: During 2002, North America experienced the largest ever outbreak of West Nile encephalitis; a poliomyelitis-like flaccid paralysis due to West Nile virus was recognised, and transfusion-related infections were documented. Globally, Japanese encephalitis virus is the most important emerging viral encephalitis; interferon alpha was not effective against Japanese encephalitis in a double-blind placebo-controlled trial, but new chimeric vaccines are in development. Recent work suggests Japanese encephalitis virus originated in the Indonesia-Malaysia region, and spread from there. The origin of Nipah virus, which caused an encephalitis outbreak in Malaysia in 1998, is not known, but flying foxes have been identified as a natural host. Enterovirus 71 continues to cause large outbreaks of hand foot and mouth disease across Asia, associated with neurological and systemic complications; recent work has focused on the pathogenesis of these complications. SUMMARY: Disease surveillance remains important for the early recognition and containment of encephalitis outbreaks. Detailed clinical and laboratory studies will help answer the key questions, but there is a need to ensure the results translate to real benefits for the communities affected by these diseases.

Animals↗
PubMed2003

Origin and evolution of Japanese encephalitis virus in southeast Asia.

Since it emerged in Japan in the 1870s, Japanese encephalitis has spread across Asia and has become the most important cause of epidemic encephalitis worldwide. Four genotypes of Japanese encephalitis virus (JEV) are presently recognized (representatives of genotypes I to III have been fully sequenced), but its origin is not known. We have determined the complete nucleotide and amino acid sequence of a genotype IV Indonesian isolate (JKT6468) which represents the oldest lineage, compared it with other fully sequenced genomes, and examined the geographical distribution of all known isolates. JKT6468 was the least similar, with nucleotide divergence ranging from 17.4 to 19.6% and amino acid divergence ranging from 4.7 to 6.5%. It included an unusual series of amino acids at the carboxy terminus of the core protein unlike that seen in other JEV strains. Three signature amino acids in the envelope protein (including E327 Leu-->Thr/Ser on the exposed lateral surface of the putative receptor binding domain) distinguished genotype IV strains from more recent genotypes. Analysis of all 290 JEV isolates for which sequence data are available showed that the Indonesia-Malaysia region has all genotypes of JEV circulating, whereas only more recent genotypes circulate in other areas (P < 0.0001). These results suggest that JEV originated from its ancestral virus in the Indonesia-Malaysia region and evolved there into the different genotypes which then spread across Asia. Our data, together with recent evidence on the origins of other emerging viruses, including dengue virus and Nipah virus, imply that tropical southeast Asia may be an important zone for emerging pathogens.

Amino Acid Sequence↗
PubMed2002

Treatment of severe diphtheritic myocarditis by temporary insertion of a cardiac pacemaker.

Vietnamese children and adolescents with diphtheritic myocarditis and severe conduction abnormalities were treated prospectively with temporary insertion of a cardiac pacemaker. Five of 32 patients died before the procedure could be performed; the remaining 27 patients underwent successful pacemaker insertion. In children and adolescents with diphtheritic myocarditis and severe conduction defects, temporary insertion of a cardiac pacemaker may improve the outcome.

Adolescent↗
PubMed2002

The role of lumbar puncture in children with suspected central nervous system infection.

BACKGROUND: The use of the lumbar puncture in the diagnosis of central nervous system infection in acutely ill children is controversial. Recommendations have been published but it is unclear whether they are being followed. METHODS: The medical case notes of 415 acute medical admissions in a children's hospital were examined to identify children with suspected central nervous system infection and suspected meningococcal septicaemia. We determined whether lumbar punctures were indicated or contraindicated, whether they had been performed, and whether the results contributed to the patients' management. RESULTS: Fifty-two children with suspected central nervous system infections, and 43 with suspected meningococcal septicaemia were identified. No lumbar punctures were performed in patients with contraindications, but only 25 (53%) of 47 children with suspected central nervous system infection and no contraindications received a lumbar puncture. Lumbar puncture findings contributed to the management in 18 (72%) of these patients, by identifying a causative organism or excluding bacterial meningitis. CONCLUSION: The recommendations for undertaking lumbar punctures in children with suspected central nervous system infection are not being followed because many children that should receive lumbar punctures are not getting them. When they are performed, lumbar puncture findings make a useful contribution to the patients' management.

Adolescent↗
PubMed2002

Japanese encephalitis vaccine for travelers: exploring the limits of risk.

The prevention of Japanese encephalitis in travelers presents the juxtaposition of 4 factors: a disease that is widespread throughout Asia, a disease with a low incidence in travelers, a vaccine about which there are safety concerns, and a clinical course that can result in death or permanent disability in two-thirds of symptomatic cases. Travel medicine practitioners often seem to be polarized into 2 groups: a group that gives more weight to the severity of the disease (and therefore often recommend vaccination) and another group that is more persuaded by the low occurrence of cases in travelers (and therefore rarely recommend vaccination). This review assesses the known risks of contracting Japanese encephalitis and the risks associated with the vaccine and tries to develop an appropriate way to recommend this vaccine to travelers who may be at significant risk.

Asia↗
PubMed2002

Evaluation of the World Health Organization standard tourniquet test and a modified tourniquet test in the diagnosis of dengue infection in Viet Nam.

OBJECTIVES: A positive tourniquet test is one of several clinical parameters considered by the World Health Organization to be important in the diagnosis of dengue haemorrhagic fever, but no formal evaluation of the test has been undertaken. As many doctors remain unconvinced of its usefulness, this study was designed to assess the diagnostic utility of both the standard test and a commonly employed modified test. METHODS: A prospective evaluation of the standard sphygmomanometer cuff tourniquet test, compared with a simple elastic cuff tourniquet test, was carried out in 1136 children with suspected dengue infection admitted to a provincial paediatric hospital in southern Viet Nam. RESULTS: There was good agreement between independent observers for both techniques, but the sphygmomanometer method resulted in consistently greater numbers of petechiae. This standard method had a sensitivity of 41.6% for dengue infection, with a specificity of 94.4%, positive predictive value of 98.3% and negative predictive value of 17.3%. The test differentiated poorly between dengue haemorrhagic fever (45% positive) and dengue fever (38% positive). The simple elastic tourniquet was less sensitive than the sphygmomanometer cuff, but at a threshold of 10 petechiae (compared with the WHO recommendation of 20) per 2.5 cm2 the sensitivity for the elastic tourniquet rose to 45% (specificity 85%). Other evidence of bleeding was frequently present and the tourniquet test provided additional information to aid diagnosis in only 5% of cases. CONCLUSION: The conventional tourniquet test adds little to the diagnosis of dengue in hospitalized children. The simple, cheap elastic tourniquet may be useful in diagnosing dengue infection in busy rural health stations in dengue endemic areas of the tropics. A positive test should prompt close observation or early hospital referral, but a negative test does not exclude dengue infection.

Adolescent↗
PubMed2002

Seizures and raised intracranial pressure in Vietnamese patients with Japanese encephalitis.

Japanese encephalitis (JE) causes at least 10 000 deaths each year. Death is presumed to result from infection, dysfunction and destruction of neurons. There is no antiviral treatment. Seizures and raised intracranial pressure (ICP) are potentially treatable complications, but their importance in the pathophysiology of JE is unknown. Between 1994 and 1997 we prospectively studied patients with suspected CNS infections referred to an infectious disease referral hospital in Ho Chi Minh City, Vietnam. We diagnosed Japanese encephalitis virus (JEV), using antibody detection, culture of serum and CSF, and immunohistochemistry of autopsy material. We observed patients for seizures and clinical signs of brainstem herniation, measured CSF opening pressures (OP) and, on a subset of patients, performed EEGs. Of 555 patients with suspected CNS infections, 144 (26%) were infected with JEV (134 children and 10 adults). Seventeen (12%) patients died and 33 (23%) had severe sequelae. Of the 40 patients with witnessed seizures, 24 (62%) died or had severe sequelae, compared with 26 (14%) of 104 with no witnessed seizures [odds ratio (OR) 4.50, 95% confidence interval (CI) 1.94-10.52, P < 0.0001]. Patients in status epilepticus (n = 25), including 15 with subtle motor seizures, were more likely to die than those with other seizures (P = 0.003). Patients with seizures were more likely to have an elevated CSF OP (P = 0.033) and to develop brainstem signs compatible with herniation syndromes (P < 0.0001). Of 11 patients with CSF OP > or =25 cm, five (46%) died, compared with seven (9%) of 80 patients with lower pressures [OR 8.69, 95% CI 1.73-45.39, P = 0.005). Of the 50 patients with a poor outcome, 35 (70%) had signs compatible with herniation syndromes (including 19 with signs of rostro-caudal progression), compared with nine (10%) of those with better outcomes (P < 0.0001). Of 11 patients with CSF OP > or =25 cm, five (46%) died, compared with seven (9%) of 80 patients with lower pressures (OR 8.69, 95% CI 1.73-45.39, P = 0.005). The combination of coma, multiple seizures, brainstem signs and illness for 7 or more days was an accurate predictor of outcome, correctly identifying 42 (84%) of 50 patients with a poor outcome and 82 (87%) of 94 with a better outcome. These findings suggest that in JE, seizures and raised ICP may be important causes of death. The outcome may be improved by measures aimed at controlling these secondary complications.

Adolescent↗
PubMed2002

Treatment of subacute sclerosing panencephalitis with interferon-alpha, ribavirin, and inosiplex.

Subacute sclerosing panencephalitis is an almost universally fatal late complication of measles infection for which there is no established treatment. We report a patient with subacute sclerosing panencephalitis who was bed-bound and ataxic and had a left hemiparesis and frequent myoclonus. He was started on a new regimen consisting of intraventricular interferon-alpha (starting at 100,000 U/m2/day, building up to 1 million U/m2/day), ribavirin (60 mg/kg/day intravenously), and inosiplex (3 g/day) and improved markedly. At 10 weeks, the intraventricular reservoir was removed because of bacterial infection, and he was discharged home on oral ribavirin (1200 mg/kg/day) and inosiplex. He continued to improve as judged by neurologic examination, functional independence measurement, neuropsychometry and single photon emission computed tomography (SPECT) imaging. However, after 10 months, he deteriorated suddenly and died before further intraventricular treatment could be instituted. Further trials are needed to evaluate long-term combination therapy in subacute sclerosing panencephalitis.

Administration, Oral↗