Clinical characteristics of febrile convulsions during primary HHV-6 infection

OBJECTIVE—To clarify clinical characteristics of children with febrile convulsions during primary human herpesvirus 6 (HHV-6) infection.SUBJECTS AND METHODS—The clinical characteristics of first febrile convulsion were compared between those with and without primary HHV-6 infection in 105 children. HHV-6 infection was verified by culture or acute/convalescent anti-HHV-6 antibody titres.RESULTS—Primary infection with HHV-6 was seen in 21 of 105 patients with febrile convulsions (3 upper respiratory infection, 1 lower respiratory infection, and 17 exanthem subitum). 13 of 23 patients < 1 year, 19 of 79 patients with first febrile convulsion, and 2 of 15 with second convulsion were infected with HHV-6. The median age of patients with first febrile convulsion and HHV-6 was significantly lower than those without infection. The frequency of clustering seizures, long lasting seizures, partial seizures, and postictal paralysis was significantly higher among those with primary HHV-6 infection than among those without. The frequency of atypical seizures in 19 patients with first febrile convulsion associated with primary infection was significantly higher than in 60 patients without primary infection. The frequency in infants younger than 1 year of age was also significantly higher than that in 10 age matched infants without primary infection.CONCLUSIONS—These findings suggest that primary infection with HHV-6 is frequently associated with febrile convulsions in infants and young children and that it often results in the development of a more severe form of convulsions, such as partial seizures, prolonged seizures, and repeated seizures, and might be a risk factor for subsequent development of epilepsy.     

Urinary tract infection in febrile convulsions.

A retrospective review of the casenotes of 403 children admitted to hospital with febrile convulsions was performed to estimate the frequency of symptomatic urinary tract infection and examine medical practice in making this diagnosis. A total of 228 (56%) children had urine cultured: 150 bag specimens, 76 clean voided samples, and two suprapubic aspirates. There were 13 'probable' and six 'possible' infected urine samples together representing 5% of the whole study population (n = 403), 8% of those having urine cultured (n = 228), and 12% of those providing uncontaminated urine samples (n = 155). Those with first febrile convulsions and those aged under 18 months were more likely to have urine examined. Practices varied significantly between different hospitals. These results suggest that there has indeed been a need for practice guidelines, and that further audit of practice is required to assess their impact.     

Human herpes virus-6 and febrile convulsions

Parents of 996 children aged 4-5 years identified consecutively from the Oxford health visitor register were asked to complete a questionnaire about breathing disorders during sleep. A total of 782 (78.5%) was returned. Ninety five (12.1%) children were reported to snore on most nights. Habitual snoring was significantly associated with daytime sleepiness, restless sleep, and hyperactivity. The questionnaire responses were used to select two subgroups, one at high risk of a sleep and breathing disorder and a control group. These children (132 in total) were monitored at home with overnight video recording and oximetry, and had formal behavioural assessment using the Conners scale. Seven (7/66) children from the high risk group and none from the control group had obvious sleep disturbance consequent on snoring and upper airway obstruction. Thus our estimate of the prevalence of sleep and breathing disorders in this age group is 7/996 or 0.7%. The high risk group had significantly higher nocturnal movement, oxygen saturation dip rates, and overnight pulse rates than the controls. Maternal but not paternal smoking was associated with the high risk group. Parents and teachers thought those in the high risk group were more hyperactive and inattentive than the controls, but only their parents thought them more aggressive. Significant sleep and breathing disorders occur in about 0.7% of 4-5 year olds. Children whose parents report snoring and sleep disturbance have objective evidence of sleep disruption and show more behaviour problems than controls.     

Pre-eclampsia and febrile convulsions.

An association between pre-eclampsia and febrile convulsions has been reported, but the association may not be causal. We compared the risk of febrile convulsions in 14 974 children who had been exposed to pre-eclampsia in fetal life with that of 39 210 unexposed children. Children exposed to pre-eclampsia had a slightly increased risk of febrile convulsions, but the association was apparently caused by a shorter gestation in pre-eclamptic women.     

Viruses and febrile convulsions.

In 276 children admitted to hospital with febrile convulsions a wide range of virus types was identified by means of nasopharyngeal secretions and cough/nasal swabs. The overall virus identification rate was 49%. Analysis of age, sex, family history, and past history showed no marked differences between the virus-positive and the virus-negative children. More than 80% had symptoms of respiratory infection in association with their convulsions, whether or not a virus was identified. Convulsions were not apparently more severe in the virus-positive group. Rapid virus diagnosis was found helpful in the management of children with febrile convulsions. The virus aetiology of many febrile convulsions has implications both for hospital cross-infection and for research into methods of prevention.     

幼儿急疹合并热性惊厥的临床特征

目的 探讨幼儿急疹合并热性惊厥的临床特征.方法 回顾性总结本院2005年1月至2008年2月确诊的幼儿急疹病例和热性惊厥病例,对幼儿急疹并热性惊厥的31例患儿的临床资料进行总结,与其他热性惊厥患儿及幼儿急疹未合并热性惊厥者对比,并结合文献进行分析.结果 幼儿急疹合并热性惊厥患儿占所有热性惊厥的17.1%(31/181),占2岁内热性惊厥的24.4%(31/127),占幼儿急疹患儿的15.7%(31/198);幼儿急疹并热性惊厥患儿出现热性惊厥的平均年龄为(0.85 4±0.38)岁,早于一般的热性惊厥患儿(2.41±1.30)岁,P<0.01;与不伴热性惊厥的幼儿急疹患儿比较,伴热性惊厥者的性别、年龄、最高体温、热程、出疹时间均无显著差别(P>0.05),而热性惊厥家族史有显著差别(P<0.05).结论 遗传因素是导致幼儿急疹并热性惊厥发作的一个危险因素;幼儿急疹并热性惊厥时一般预后良好,但要警惕发生严重中枢神经系统损伤的可能性,如癫痫.对于1岁内初次发热并出现热性惊厥的患儿要注意幼儿急疹的可能.     

Role of viruses in febrile convulsions.

A disseminated viral illness was demonstrated by isolating a virus from the CSF, blood or urine in 27% of 73 children who were admitted to hospital after a first febrile convulsion. However, a viral aetiology could be implicated for 86% of the children after combining results of tissue culture, electron microscopy, mouse inoculation, complement fixation tests, and interferon assay. Parallel bacterial cultures showed a possible pathogen in 29% of children, but in only 4% was the pathogen isolated from the CSF, blood, or urine. No correlation was found between the nature of the pathogen (or evidence of its dissemination) and the severity of the convulsion, degree of fever, CSF protein, CSF white cells, or the WBC. The results suggest that a febrile convulsion could be a response to invasion of the blood stream or central nervous system by a micro-organism which is usually a virus. Invasion may be of such brief duration that successful isolation of the virus from the blood, CSF, or urine in not more commonly achieved.     

Serum immunoglobulin concentrations in febrile convulsions.

The mean, age adjusted, serum IgA values of 47 children with febrile convulsions were almost identical to those of controls. Five children had serum IgA values less than 0.1 g/l by nephelometry, suggesting that in some cases at least there may be an association between a low serum IgA concentration and febrile convulsions.     

Hyponatraemia in children with febrile convulsions.

In a study of 23 children admitted to hospital with a febrile convulsion, mild hyponatraemia was found on 8 occasions. In 6 of these cases there was evidence of inappropriate secretion of antidiuretic hormone. The hyponatraemia is unlikely to be the cause of the convulsion, but probably predisposes the child to a subsequent convulsion during the same febrile illness.     

Treatment of febrile convulsions]

Information and reassurance of parents are essential before considering therapeutic measures following a first febrile seizure. It must be emphasized that, although impressive, febrile convulsions are essentially benign, and that in the majority of cases there will be no recurrence. Apart from that, therapeutic measures are of limited efficacy in order to prevent reocurrence. The correct use of antipyretic treatment during febrile episodes must be specified. Due to its several inconveniences, oral diazepam as an intermittent prophylaxis should be only considered in case of multiple reoccurrences. There is little place for continuous anticonvulsant treatment.