Kevin E. Gordon

Incidence of Epilepsy in Childhood and Adolescence: A Population-Based Study in Nova Scotia from 1977 to 1985

Summary: Data from a regional EEG laboratory allowed us to identify almost all children in Nova Scotia (population 850,000) with one or more unprovoked, afebrile seizures from 1977 through 1985. We then reviewed hospital and pediatric neurology physician charts to limit cases to those with two or more definite afebrile seizures between the ages of 1 month and 16 years. In all, 693 children developed epilepsy: typical childhood absence seizures (AS) (97), either generalized tonic‐clonic (GTCs) or partial seizures either secondarily generalized or not (511), and other generalized seizure types, including infantile spasms (IS) as well as myoclonic, akinetic, tonic, and atypical AS (85). The incidence of epilepsy was 118 in 100,000 for children aged < 1 year, 48 in 100,000 for those aged 1–5 years, 43 in 100,000 for those aged 6–10 years, and 21 in 100,000 for those aged 11–15 years. The incidence for each year of age between 1 and 10 years was remarkably constant (mean 46 in 100,000 ± 7 SD). Comparison of the incidence rates showed significant differences for those aged <1 year as compared with all others, and for those aged >10 years as compared with those aged 1–10 years. We conclude that the incidence of epilepsy is highest in the first year of life, plateaus in early childhood, and decreases markedly after age 10 years. The overall incidence of epilepsy in childhood is lower than that reported in previous studies.

Long-term prognosis of typical childhood absence epilepsy: Remission or progression to juvenile myoclonic epilepsy

Objective: To determine the proportion and characteristics of children presenting with childhood absence epilepsy (CAE) who were not taking anti-epileptic drugs (AEDs) and were seizure-free over the last year of long-term follow-up. Methods: For case finding, centralized EEG records for the province of Nova Scotia allowed identification of all children with typical CAE diagnosed between 1977 and 1985. Follow-up was done in 1994 to 1995. Results: Of 81 children with CAE, 72 (89%) were contacted for follow-up. Mean age at seizure onset was 5.7 years (range, 1 to 14 years) and at follow-up was 20.4 years (range, 12 to 31 years). Forty-seven (65%) were in remission. Twelve others (17%) were not taking AEDs but continued to have seizures. Thirteen (18%) were taking AEDs; five were seizure-free over the last year (in four of these a trial without AEDs had previously failed). Fifteen percent of the total cohort had progressed to juvenile myoclonic epilepsy (JME). Multiple clinical and EEG factors were examined as predictors of outcome. Factors predicting no remission (p < 0.05) included cognitive difficulties at diagnosis, absence status prior to or during AED treatment, development of generalized tonic clonic or myoclonic seizures after onset of AEDs, abnormal background on initial EEG, and family history of generalized seizures in first-degree relatives. Conclusions: Only 65% of children presenting with CAE had remission of their epilepsy. Forty-four percent of those without remission had developed JME. At the time of diagnosis, remission is difficult to predict accurately in most patients. However, development of generalized tonic-clonic seizures or myoclonic seizures during AED treatment is ominous, predicting both lack of remission of CAE and progression to JME. NEUROLOGY 1996;47: 912-918

If a first antiepileptic drug fails to control a child's epilepsy, what are the chances of success with the next drug ?

OBJECTIVE This study was carried out to determine how often a childs epilepsy is controlled and remits if a first antiepileptic drug (AED) fails to control seizures. STUDY DESIGN We used the Nova Scotia population-based epilepsy study, which identified children between 1977 and 1985 who had two or more unprovoked seizures without progressive cause and followed them up for at least 4 years. Seizure types were partial, primary, and secondarily generalized (excluding absence seizures). The study documented success or failure of the initial AED in the first year of treatment, as well as long-term seizure control and remission. RESULTS The number of eligible children was 417, with an average follow-up period of 8 years. The initial prescribed AEDs were phenobarbital (48%), carbamazepine (38%), and phenytoin (11%). Overall, 345 (83%) children received only one AED in the first year of treatment; 61% became free of seizures and no longer required AED treatment at the end of follow-up (remission). Only 4% of those treated with a single AED during the first year later experienced intractable epilepsy. In contrast, 72 of 417 (17%) had inadequate seizure control with their first AED and received a second AED, with only 42% having complete remission of their epilepsy. The 72 children in whom seizures were not controlled with the first AED were more likely to have neurologic deficits (p = 0.01) and complex partial seizures (p = 0.01), and 29% had intractable epilepsy (p < 0.0001). CONCLUSIONS If the first AED is not efficacious, the outcome is less favorable, although many children will have remission of their epilepsy. Invasive or complex treatments for epilepsy with partial and generalized tonic-clonic seizures should not be used until at least two AEDs have failed to control seizures.

Does the number of seizures before treatment influence ease of control or remission of childhood epilepsy? Not if the number is 10 or less

Article abstract-Using a population-based regional cohort of 479 children with epilepsy, we studied the effect of the number of pretreatment afebrile seizures on seizure control and remission. The number of pretreatment seizures varied from 1 to 20. For the first 10 pretreatment seizures, there was no significant difference or trend in (1) the proportion of children who were seizure free long enough to attempt stopping medication (mean, 70%), (2) the number of breakthrough seizures before control was achieved, or (3) the proportion of children who were seizure free after stopping medication for the first time (mean, 70%). More patients with more than 10 pretreatment seizures had complex partial seizures (59%) than those with 10 or fewer seizures (16%) (p < 0.00001). We conclude that there does not appear to be any penalty for seizure control or early remission of epilepsy if medication is delayed for up to 10 pretreatment seizures. NEUROLOGY 1996;46: 41-44

Discontinuation of anticonvulsant therapy in children free of seizures for 1 year A prospective study

We studied 97 children who were weaned from antiepileptic drug therapy 1 year after their last seizure.Medication was withdrawn over 4 to 8 weeks, and patients were followed for 12 to 57 months (32.4 plus minus 13.1; mean plus minus SD) or until seizure recurrence. The overall probability of remaining seizure free was 78% at 3 months, 71% at 6 months, 66% at 12 months, and 61% at 24 months (95% CI, 51, 71), similar to studies that have required longer treatment periods. Factors retained in multivariate analysis were female sex, age at seizure onset over 120 months of age, seizure type, and clinical evidence of neurologic abnormalities. Using these risk factors, a simple method of predicting the 24-month recurrence risk was possible. NEUROLOGY 1996;46: 969-974.

Benign Rolandic Epilepsy: Atypical Features Are Very Common:

The objective of this study was to determine the frequency of atypical clinical and electrographic features in children with benign rolandic epilepsy. A retrospective case series design was employed in the setting of a tertiary care pediatric hospital. Forty-two children with benign rolandic epilepsy were seen through our neurology department between January 1, 1991, and December 31, 1993. Their charts were reviewed for atypical clinical features, imaging studies and results, total number of seizures at initial presentation and last follow-up, and use of anticonvulsants. Atypical clinical features included status epilepticus, developmental delay, daytime-only seizures, screaming as a seizure component, and postictal Todds paresis. All children had at least one electroencephalogram, and these records were reviewed for atypical electrographic features such as unusual location, atypical spike morphology, and abnormal background. Atypical clinical features were seen in 50% of patients and atypical electrographic features in 31%. Computed tomographic scans were performed in 15 patients and were consistently normal. Treatment with anticonvulsant medication was initiated in 40%. Although patients with atypical features did not have an increased seizure frequency, they were more likely to undergo imaging studies (P < .01) and to be commenced on anticonvulsant medication (P < .02). Our experience suggests that atypical clinical and electrographic features are the rule rather than the exception in benign rolandic epilepsy. Further work must be done to develop a reliable definition of this common entity. (J Child Neurol 1995;10:455-458).

Acute Pancreatitis Causing Death in a Child on the Ketogenic Diet

The ketogenic diet has demonstrated good efficacy in children with pharmacologically resistant seizures. Relatively few serious complications have been reported in the more than 70 years in which the diet has been used. We report a child who developed acute pancreatitis and died. A 9-year-old girl had a seizure disorder with associated developmental delay owing to glucose transport protein deficiency. The ketogenic diet with medium chain triglyceride oil had been initiated shortly after diagnosis in infancy. She was not on anticonvulsants. She presented in coma with decreased respiratory effort and shock, requiring resuscitation. Investigations were consistent with pancreatitis. Despite fluid resuscitation and inotropic support, she had prolonged hypotension and acidosis. She subsequently had a cardiac arrest and died. A postmortem examination confirmed hemorrhagic pancreatitis. Hypertriglyceridemia is a risk factor for developing acute pancreatitis. The high fat content of the ketogenic diet often causes hyperlipidemia. The outcome for this patient raises concern regarding a potential consequence of the ketogenic diet. (J Child Neurol 2001;16:682).

Relation of Pregnancy and Neonatal Factors to Subsequent Development of Childhood Epilepsy: A Population-Based Cohort Study

OBJECTIVE. We examined the effect of pregnancy and neonatal factors on the subsequent development of childhood epilepsy in a population-based cohort study. PATIENTS AND METHODS. Children born between January 1986 and December 2000 in Nova Scotia, Canada were followed up to December 2001. Data on pregnancy and neonatal events and on diagnoses of childhood epilepsy were obtained through record linkage of 2 population-based databases: the Nova Scotia Atlee Perinatal Database and the Canadian Epilepsy Database and Registry. Factors analyzed included events during the prenatal, labor and delivery, and neonatal time periods. Cox proportional hazards regression models were used to estimate relative risks and 95% confidence intervals. RESULTS. There were 648 new cases of epilepsy diagnosed among 124207 live births, for an overall rate of 63 per 100000 person-years. Incidence rates were highest among children <1 year of age. In adjusted analyses, factors significantly associated with an increased risk of epilepsy included eclampsia, neonatal seizures, central nervous system (CNS) anomalies, placental abruption, major non-CNS anomalies, neonatal metabolic disorders, neonatal CNS diseases, previous low birth weight infant, infection in pregnancy, small for gestational age, unmarried, and not breastfeeding infant at the time of discharge from hospital. CONCLUSIONS. Our study supports the concept that prenatal factors contribute to the occurrence of subsequent childhood epilepsy.

LAMOTRIGINE-INDUCED RASH IN CHILDREN

Article abstract-Of 68 children treated with lamotrigine, a new antiepileptic medication, five developed a rash. One child developed Stevens-Johnson syndrome on lamotrigine monotherapy. Of the five patients with the rash, three were admitted to the hospital (two to the intensive care unit). All recovered completely, but one child had a recurrence of the rash within 30 minutes of reexposure to lamotrigine after 6 months. NEUROLOGY 1996;46: 240-242

Self‐Reported Headache Frequency and Features Associated With Frequent Headaches in Canadian Young Adolescents

Objective.—To explore the associated factors for frequent headache among young adolescent Canadians.