Cytomegalovirus infection and infantile spasms

Seizures and epilepsy secondary to viral infection in the central nervous system

Viral infection in the central nervous system (CNS) is a common cause of seizures and epilepsy. Acute symptomatic seizures can occur in the context of almost all types of acute CNS viral infection. However, late unprovoked seizures and epilepsy may not be frequent after viral infection of the CNS. The incidence of seizures and epilepsy after CNS viral infection is mainly dependent on the brain region of infection. It remains to be determined whether treatment of CNS viral infection using antiepileptic drugs (AEDs) can prevent seizures and subsequent epilepsy in patients, particularly with regard to the timing, drug choice and dosage, and duration of AEDs. The postoperative outcome of seizures in patients with intractable epilepsy caused by viral encephalitis primarily depends on the epileptogenic zone. In addition, neuroinflammation is known to be widely involved in the generation of seizures during CNS viral infection, and the effects of anti-inflammatory therapies in preventing seizures and epilepsy secondary to CNS viral infection require further studies. In this review, we discuss the incidence, mechanisms, clinical management and prognosis of seizures and epilepsy secondary to CNS viral infection, and summarize common CNS viral infections that cause seizures and epilepsy.

Intravenous immunoglobulin therapy is rarely effective as the initial treatment in West syndrome: A retrospective study of 70 patients

PURPOSE

To evaluate factors influencing the efficacy and safety of intravenous immunoglobulins (IVIG) therapy for West syndrome.

METHODS

We investigated seizure outcomes in 70 patients who received IVIG treatment for West Syndrome during the first 3months after the onset of epileptic spasms. IVIG was administered for 3 consecutive days (initial IVIG treatment) at dosages ranging from 100 to 500mg/kg/day. If spasms disappeared within 2weeks of the initial treatment, maintenance IVIG treatment was commenced. We evaluated seizure outcomes at 2weeks (initial evaluation), at 2years (long-term evaluation), and the last visit (last follow-up evaluation) after the initial IVIG treatment. We analyzed dosages of IVIG, age at onset of spasms, treatment lag, and etiologies between responders and non-responders.

RESULTS

Among the patients, 7/70 (10.0%) had cessation of spasms and resolution of hypsarrhythmia at the initial evaluation. Another 6/70 patients (8.6%) were found to have cessation of spasms at the long-term evaluations. The treatment lag in responders was shorter than that in non-responders (P<0.01). There were no significant differences between responders and non-responders in IVIG dosages, age at onset of spasms, and etiologies. Two patients had relapse of partial seizures after cessation of spasms at the last follow-up evaluation. Adverse effects occurred in 2/70 patients.

CONCLUSIONS

The efficacy of IVIG was so low that it should not be considered as first-line treatment in West syndrome. IVIG therapy has a good safety profile and we would recommend it for West syndrome cases with drug resistance, severe complications associated with profound brain damage, severe brain atrophy, and in immunocompromised patients.

Genetic and biologic classification of infantile spasms

Infantile spasms constitute an age-dependent epilepsy, highly associated with cognitive impairment, autism, and movement disorders. Previous classification systems focused on a distinction between symptomatic and cryptogenic etiologies, and have not kept pace with recent discoveries of mutations in genes in key pathways of central nervous system development in patients with infantile spasms. Children with certain genetic syndromes are much likelier to manifest infantile spasms, and we review the literature to propose a genetic classification of these disorders. Children demonstrating genetic associations with infantile spasms also manifest phenotypes beyond epilepsy that may be explained by recent advances in the understanding of underlying biological mechanisms. Therefore we propose a biologic classification of genes highly associated with infantile spasms, and articulate models for infantile spasms pathogenesis based on those data. The two best described pathways of pathogenesis involve abnormalities in the gene regulatory network of gamma-aminobutyric acidergic forebrain development and abnormalities in molecules expressed at the synapse. These genetic and biologic classifications are flexible, and they should encourage much needed progress in syndrome recognition, clinical genetic testing, and the development of new therapies targeting specific pathways of pathogenesis.

Epilepsy in patients with congenital cytomegalovirus infection

Patients with congenital cytomegalovirus (CMV) infection were at high risk for postnatal seizures, but little is known about epilepsy associated with congenital CMV infection. To define the features of epilepsy, we retrospectively reviewed the clinical, laboratory and neuroradiographic findings in 19 children (male 9) with congenital CMV infection. Seven (37%) patients had developed epilepsy (partial seizure 5 and epileptic spasms 2) at a mean age of 20 months (range 2-37 months). During the clinical course, West syndrome occurred in only three patients. The most common seizure type in our series was partial seizure. At the time of last follow-up (mean 96 months), seizures remained uncontrolled in six patients. Neonatal clinical manifestations (gestational age, gender distribution, birth asphyxia or symptoms at birth) were not predictive of the development of epilepsy. On the contrary, some neuroradiographic findings (ventricular dilatation and migration disorder) were significantly associated with the development of epilepsy.

Infantile spasms in an infant with cytomegalovirus infection treated with ganciclovir

A 3-month-old male infant with cytomegalovirus infection and intractable partial seizures was treated with ganciclovir for 6 weeks. The drug was well tolerated, and virus shedding in the cerebrospinal fluid and urine was eliminated, although infantile spasms at the age of 6 months appeared. At the age of 12 months, intractable seizures persisted, and the psychomotor development of the infant was markedly delayed. To our knowledge, no previous similar case has been reported. These findings suggest that treatment with ganciclovir of infants with cytomegalovirus infection results only in cessation of virus shedding in the cerebrospinal fluid and urine without having a preventive effect on the future appearance of infantile spasms. This may be due to the irreversibility of previous brain damage from the cytomegalovirus infection and the virostatic nature of the drug.

Magnetic resonance imaging findings in infantile spasms: etiologic and pathophysiologic aspects

An etiologic evaluation of 86 patients with infantile spasms is presented and the place of cranial magnetic resonance imaging (MRI) findings within this spectrum is discussed. A total of 103 cranial MRIs, performed between 4 and 72 months of age, were analyzed and classified according to the etiologic and pathophysiologic aspects. Ninety-one percent of cases were diagnosed as symptomatic infantile spasms, and hypoxic-ischemic encephalopathy was the primary cause (30%). The most common involvement was thinning of the corpus callosum in 43 patients (50%), followed by dilation of cerebral ventricles in 32 (36%), delayed myelination in 23 (26.7%), lesions of diencephalic deep gray matter in 17 (19.7%), and enlargement of the subarachnoid space in 12 (14%). Thin corpus callosum and diffuse atrophy were changes mainly associated with hypoxic-ischemic encephalopathy, whereas delayed myelination seemed to be independent from a specific etiology. The results showed that cranial MRI may provide considerable information regarding not only the etiology but also the pathophysiology of infantile spasms.

Human herpesviruses and neurological disorders of childhood

The human herpesviruses, a group of DNA viruses that includes herpes simplex viruses types 1 and 2, varicella zoster virus, cytomegalovirus, Epstein-Barr virus, and human herpes viruses types 6, 7, and 8, cause substantial neurological morbidity among infants and children. This review describes the biology of these viruses and summarizes the clinical manifestations and therapy of the diseases that result from childhood infection with these important pathogens.

Chronic encephalitis associated with epilepsy: immunohistochemical and ultrastructural studies

Chronic encephalitis has been recognized as a cause of epilepsy since the work of Rasmussen et al. in the late 1950s. Despite this, few immunohistochemical studies of the affected brain tissue have been attempted. We have studied specimens of brain tissue from seven patients with this condition who underwent therapeutic multilobar cortical resection or hemispherectomy. Immunohistochemical studies were carried out using antibodies to glial fibrillary acidic protein (GFAP), proliferating cell nuclear antigen (PCNA, PC10), T lymphocytes (UCHL-1), B lymphocytes (L26), macrophages and microglia (HAM-56), and major histocompatibility complex molecules (LN3 and beta 2-microglobulin). Additionally, the results of preliminary immunohistochemical and ultrastructural investigation of possible immune complex deposition in blood vessel walls of affected brain tissue are presented. The pattern of GFAP immunoreactivity suggested a patchy and/or laminar disease process in most patients. GFAP immunoreactive cells were especially prominent around microvessels in some cases, suggesting an abnormality and perivascular collections of inflammatory cells, seen to a variable extent in all cases, contained abundant cells immunolabelled with UCHL-1, LN3 and beta 2-microglobulin. L26-labelled B lymphocytes were extremely sparse. Anti-PCNA frequently labelled microvascular endothelial cells, rare pericytes and occasional cells with microglial/macrophage morphology. The data suggest that chronic encephalitis found in patients with epilepsy results from patchy but widespread parenchymal brain injury, in the course of which cells of both microglial and lymphocyte series accumulate or proliferate within brain.(ABSTRACT TRUNCATED AT 250 WORDS)

The epidemiology and natural history of infantile spasms

Few population-based studies of infantile spasms have been done, and most reports have not included comparison groups. In spite of these limitations, this review attempts to summarize what is known about the distribution, etiology, and natural history of infantile spasms in populations; discusses the limitations of current data; and includes suggestions for further population-based research. Most estimates of the incidence of infantile spasms are between 0.25 and 0.42 per 1000 live births per year. Among children less than 10 years of age, the annual prevalence of infantile spasms is 0.14 to 0.19 per 1000. The peak age at onset of spasms is 4 to 6 months, and there appears to be a slight excess of male cases. The etiology of infantile spasms is unknown for 40% to 50% of affected children. Selected syndromes (eg, Aicardi syndrome, Down syndrome, etc) and inherited disorders (eg, tuberous sclerosis) may account for as many as one third of cases. Other factors, such as intrauterine infection, "birth injury," and head trauma have not been systematically evaluated, and thus, their contribution to the etiology of infantile spasms is uncertain. Areas for future etiologic research include controlled studies of immunologic factors and in utero and postnatal infections and further exploration of the interrelationship between infantile spasms and Lennox-Gastaut syndrome.

Infantile spasms

Infantile spasms constitute a relatively rare disorder of infancy and early childhood; their onset is usually within the first 6 to 8 months of life. A large percentage of patients with this disorder (85-90 per cent) show various degrees of retardation. Infantile spasms typically occur in clusters immediately on arousal, or soon thereafter, but rarely occur while the infant is actually asleep. The usual interictal EEG pattern associated with infantile spasms is hypsarrhythmia, but infantile spasms may occur in the absence of this EEG pattern. The pathophysiology of infantile spasms is not known, but recent evidence suggests that certain regions in the brain stem that are associated with sleep cycling may be responsible for the clinical and EEG manifestations of this disorder. At present, the only known effective treatment for infantile spasms is ACTH or corticosteroids. The therapeutic efficacy of these two agents is relatively equal, and one drug may be effective if the other drug fails. The effectiveness of certain traditional anticonvulsants (valproic acid and the benzodiazepines) and pyridoxine in the treatment of infantile spasms has not been adequately assessed. The long-term mental and developmental outcome of patients with infantile spasms is poor. The only factor that appears to be important in terms of long-term outcome is whether the patient is initially classified as cryptogenic or symptomatic, with the cryptogenic patients having the better outcomes. Approximately half of the infantile spasm patients will continue to have other types of seizures after their spasms stop.

Immunological disturbance in West and Lennox-Gastaut syndromes

Cell-mediated and humoral immunity were investigated in 18 patients with West syndrome, 12 with Lennox-Gastaut syndrome and 19 healthy controls. The study included determination of T and B peripheral blood lymphocytes, serum levels of IgG, IgA and IgM, skin sensibilization with DNCB, intracutaneous PHA, leucocyte migration inhibition test and lymphocyte blastic transformation in the presence of PHA. Cell-mediated deficiency was detected in 28 children whereas low levels of immunoglobulins were observed only in 6 children. Immunological disturbances were more prominent in children with West syndrome.

Infantile spasms: modern practical aspects

Data on incidence, aetiology, therapy and prognosis of infantile spasms are reviewed. In a large proportion of cases the aetiological factors of infantile spasms can now be established with some certainty. Especially the new neuroradiological and virological investigative methods have enabled a more accurate diagnosis. There have been changes in the aetiologic pattern over the years. The optimal dosage and duration of ACTH or glucocorticoid therapy have not yet been established. In the Finnish study the large ACTH doses (120-160 IE) generally used in many Nordic countries did not carry a better prognosis than the smaller doses (20-40 IE). Side-effects of ACTH therapy are relatively common. They are more frequent with large doses than with smaller ones. Measures can be taken to prevent or treat part of them. The prognosis and related factors in infantile spasms as well as some recommendations to improve them are reviewed.

Nonfebrile seizures after febrile convulsions: possible role of chronic cytomegalovirus infection

Twelve hundred children with convulsions when feverish were studied during a period of five years. Among them 52 subjects (4.33%) developed nonfebrile seizures after a period of eight months to five years from the first febrile convulsion (group A). Twenty-three children had neither afebrile seizures nor EEG abnormalities during the period of observation (group B). The two groups were comparable for age of the first febrile convulsion onset, sex, and socioeconomic status. None had risk factors for subsequent epilepsy or clinical signs of congenital cytomegalovirus infection. The isolation rate of CMV from urine was 53.84% in patients of group A, 26.09% in children of group B, and 26.83% in healthy control children. Twelve CMV-positive children from group A were followed for one to more than three years. In five of seven children with persisting EEG abnormalities, cytomegaloviruria was still present 13 to 41 months after the first isolation, whereas none of five patients with normal electroencephalograms had viruria after a comparable period. We found that CMV-positive children generally lacked cell-mediated immunity to the virus, whereas CMV-negative patients had positive reactions. Our data suggest a correlation between persistence of neurologic abnormalities and CMV excretion in children with nonfebrile seizures and CMV infection.

Neurological and electroencephalographic abnormalities after febrile seizures. Possible association with cytomegalovirus

In order to assess the possible association of cytomegalovirus (CMV) with cerebral damage, 65 children aged between 2 and 10 years were tested for CMV isolation and antibody status. All of them had previously presented one or more episodes of febrile convulsions. At the time of our study, they were grouped according to their clinical features and electroencephalogram (EEG). 21 had typical and/or atypical absence attacks with 3 c/s spike-wave EEG (primary generalized epilepsy), 21 presented febrile seizures and spontaneous fits with focal EEG abnormalities, 23 had no seizures and a normal EEG. We performed the same investigation in 41 healthy children. The study showed a similar isolation rate of CMV in healthy subjects and in patients without neurological and EEG alterations, while a significantly higher isolation rate was observed in the groups with neurological and EEG abnormalities. As for serology, no significant difference was observed between the four groups, although the positivity rate of the healthy children was lower than in the other three groups. The study suggests a possible association of CMV with neurological and EEG abnormalities after febrile seizures.

Cell-mediated and humoral immunity in West syndrome

The immunological status of five children with West syndrome consequent to previous cerebral lesions was investigated. Three children had West syndrome and two were in transition from West to Lennox-Gastaut syndrome. All of them showed cellular immunological deficiencies in the following tests: sensitization to DNCB, intracutaneous reaction to PHA, inhibition of leucocyte migration, blastic transformation of lymphocytes, T and B lymphocytes in peripheric blood and levels of serum immunoglobulins. These immunological deficiencies, of different degrees of severity, were associated to frequent infections in these children. A possible association between the immunological deficiencies and autoimmunity is discussed.

ACTH therapy in infantile spasms: side effects

162 children with infantile spasms were treated with ACTH at the Children's Hospital, Helsinki, and at the Aurora Hospital, Helsinki, during 1960--76. In a large proportion (37%) of the children the treatment caused pronounced side effects, and the mortality was 4.9%. The most common complications were infections: septic infections, pneumonias, and urinary and gastrointestinal infections. Other side effects were arterial hypertension (11), osteoporosis (2), hypokalaemic alkalosis (2), and other marked electrolyte disturbances (10). In children necropsy showed fresh intracerebral haemorrhages. Four children developed oliguria and hyperkalaemia during and after withdrawal of ACTH. One of them had tubular necrosis confirmed by renal biopsy. Infections were significantly more common with large doses (120 units) of ACTH than with small ones (40 units). It is concluded that side effects, even severe ones, are more common during treatment than had been assumed. Careful watch is important before and after treatment. The benefit of very high dosages should also be reconsidered.

Incidence and aetiology of infantile spasms from 1960 to 1976: a population study in Finland

This series of cases of infantile spasms comprised 107 children born between 1960 and 1976 in the county of Uusimaa, Finland. The incidence of the syndrome was 0.38 to 0.42/1000 live births and has remained almost unchanged during those years, although there have been changes in the size of different aetiological groups. The importance of prenatal and perinatal factors, and especially of neonatal hypoglycaemia, as causal factors has decreased, whereas the numbers of cases due to infections and malformations has increased. Compared with investigations in other countries, this Finnish series differs in the incidence of familial cases and congenital cytomegalovirus infection, and especially in the higher incidence of neonatal hypoglycaemia and the lower incidence of tuberous sclerosis.