Absence seizures with evolution into generalized tonic-clonic activity: clinical and EEG features

PURPOSE: To report the clinical and electrographic features of absence seizures evolving into generalized tonic-clonic (GTC) activity in six patients with idiopathic generalized epilepsy. METHODS: All patients were referred for evaluation of refractory seizures and underwent video-EEG monitoring after discontinuation of their antiepileptic drugs (AEDs). We analyzed the video-EEG recordings for seizure semiology as well as ictal and interictal activity. We also reviewed the initial clinical data in all patients. RESULTS: All patients were women, with a mean age of 27 years (range, 14-43 years). The mean age at seizure onset was 12 years (range, 5-15 years). Family history was positive for epilepsy in four patients. All patients had recorded seizures with an onset that was characteristic of generalized absence clinically and electrographically, with evolution into GTC activity. The EEG onset was with generalized 2.5-to 5-Hz spike-and-wave discharges, with evolution into faster rhythmic activity. Interictal EEG recordings showed generalized 2-to 5-Hz spike-and-wave discharges. All had normal background activity. All patients were treated with divalproex monotherapy. Five patients have been seizure free, and one had a single breakthrough GTC seizure during a follow-up period of 12-36 months. CONCLUSIONS: GTC activity may evolve from typical absence seizures. This seizure type should be included in the International Classification of Seizures. Its recognition and distinction from complex partial seizures with secondary generalization are important for appropriate therapy.     

Short duration of benign partial epilepsy in infancy

It has previously been reported that benign partial epilepsy in infancy constitutes up to 29% of the epilepsies presenting in the first 2 years of life. To determine the proportion of benign partial epilepsy in our epilepsy population, we retrospectively reviewed 331 patients with greater than two afebrile seizures in the first 2 years of life between 1993 and 2000. Inclusion criteria were (1) partial seizures with or without secondary generalization, (2) normal development, (3) no other neurologic abnormalities, (4) normal interictal electroencephalograms (EEGs), and (5) good response to treatment. Exclusion criteria included seizures that (1) were caused by acute central nervous system insult, (2) occurred only within the first month of life, and (3) lasted longer than 30 minutes. Of 331 patients, 22 (6.6%) fulfilled the criteria with a minimum of 2 years and a mean of 4 years of follow-up off antiepilepsy drug treatment. Six (27%) had complex partial seizures, and 16 (73%) had complex partial seizures with secondary generalization. Neuroimaging studies were normal in all patients. Of the 6 patients with ictal EEGs, 3 had a temporal lobe focus, 1 had an occipital lobe focus, and the remaining 2 had dual foci. Median onset was 4.0 months (range 0.8-9.3). Seizures remitted within 4 months in 20 (91%). Mean duration of seizure persistence was 2.1 months (range 0-8.3) and was longer in treated patients. Median age at last seizure was 6.4 months (range 2-18). Nineteen were treated with antiepilepsy drugs. At last follow-up (mean duration of 52.2 months), all patients were seizure free and off antiepilepsy drugs. Benign partial epilepsy in infancy is an epilepsy syndrome of short duration and is easily recognized using accepted classification criteria. Benign partial epilepsy in infancy appears to be an idiopathic localization-related epilepsy with a favorable prognosis. The incidence in our population is not as common as previously reported. Based on our findings, we suggest weaning of antiepilepsy drugs 6 months after seizure onset.     

Northern Epilepsy Syndrome: Clinical Course and the Effect of Medication on Seizures

Summary: We describe the clinical course and treatment of 19 patients with the Northern epilepsy syndrome, an autosomal recessively inherited epilepsy with associated mental deterioration. The clinical course could be divided into three successive stages. The first stage continued from the onset of epilepsy until puberty. Seizures began at a mean age of 6.6 years and consisted predominantly of generalized tonic-clonic convulsions (GTC) and, transiently, also of complex partial seizures (CPS). Until puberty, seizure frequency increased in most patients from one attack in 1–2 months to one to two attacks weekly. Seizures did not respond to phenytoin (PHT) or carbamazepine (CBZ), were transiently controlled by valproate (VPA) and phenobarbital (PB), but were effectively treated only by clonazepam (CZP). Mental deterioration began 2–5 years after the onset of epilepsy and was most rapid before adulthood, a time when the seizures were also most frequent. The second stage is marked by fewer seizures, further mental deterioration, and less rapid progression. All patients were demented (I.Q.<70) by age of 30 years. The first signs of motor clumsiness also appeared then. The third stage was one of permanent disability and usually began in middle age. Seizures were few, but the patients were clumsy and had marked equilibrium difficulties.     

A Five-Year Follow-Up Study of 66 Epileptics

A follow-up study of 66 patients with epilepsy who had been pursued for about five years from onset of seizures was performed. The patients were selected according to the following criteria: the age of onset of seizures was over 10 years old, and medication started a year from the onset. The results were: controlled 23 (34.8%), improved 17 (25.80/0), unchanged 20 (30.3%), and worsened 6 (9.1%). The duration from the onset to the beginning of medication did not seem to play an important role in the patients whose age of onset was over 10 years old. Seizures had ceased in 19 of 23 of the controlled patients within three years after medication. Thus, the two-year terminal remission rate was 28.8% of the total 66 patients. The number of seizure types was 36 partial seizures in which included 25 secondarily generalized seizures, and 30 generalized seizures. The frequency according to type of seizure, which had been controlled or improved was 41.7% in the partial seizure, and 83.3% in the generalized seizure. The patients with generalized seizure had a better prognosis than those with partial seizures whether they had a past history with respect to suspected brain damage, or not. As to the type of complex seizures in the partial seizure type, the type of impaired consciousness alone frequently developed into secondarily generalized seizure, while a half of the psychomotor seizures did not.     

Do partial seizures predict an increased risk of seizure recurrence after antiepilepsy drugs are withdrawn?

Most children who are seizure free on antiepilepsy drugs for 2 or more years remain seizure free when taken off antiepilepsy drugs. We studied 27 children with well-controlled epilepsy in whom seizures unexpectedly recurred after antiepilepsy drug withdrawal. Seizures were focal in 20 of 27 cases (74%). In 11 of the 20 cases (55%), there was also a late onset of seizures (after 2 years) and an abnormal electroencephalogram (EEG) at antiepilepsy drug withdrawal. Of the remaining 9 patients with focal seizures, 3 (15%) had only a late seizure onset, 3 (15%) had only an abnormal EEG, and 3 (15%) had neither a late onset of seizures nor an abnormal EEG. In the 7 patients without focal seizures, 6 of 7 (86%) had a late seizure onset and/or an abnormal EEG. Our study suggests that partial seizures can be the most important predictor of unanticipated seizure recurrence when antiepilepsy drugs are withdrawn, particularly with late onset of seizures and an abnormal EEG at antiepilepsy drug withdrawal. A large, multicenter, prospective study looking at these and other potential risk factors for seizure recurrence is needed.     

Refractory grand mal seizures with onset during infancy including severe myoclonic epilepsy in infancy.

In 1978, Dravet proposed a clinical entity called severe myoclonic epilepsy in infancy (SMEI). In the same year, a patient group, which was later called high voltage slow wave-grand mal syndrome (HVSW-GM), is reported in Japan. Both syndromes are very similar, except for seizure manifestation: generalized tonic-clonic convulsions (GTC) with myoclonic and other polymorphic seizures in SMEI vs. GTC only in HVSW-GM. To study the pathophysiology of these refractory epilepsies, the author formulated new clinical diagnostic criteria common to both syndromes as follows: GTC with onset before the age of 1 year as the principal seizure type; an epilepsy entity unclassifiable either as partial or generalized by all the clinical data including EEG findings; mental and motor dysfunction absent prior to seizure onset but appearing later; absence of epileptiform activities on EEG in the initial stage; stubborn refractoriness to conventional antiepileptic medication. Twenty-two patients meeting all of five clinical criteria above mentioned were recruited in the study. Detailed analysis of clinico-electrical features and long-term follow-up of these patients led the author to the conclusion that GTC in combination with seizures of other types will contribute to an unfavorable pathophysiological or prognostic conditions, and, especially when GTC exists in combination with myoclonic seizures, the severity of epilepsy will increase. The author claimed that the three clinical entities, SMEI, HVSW-GM, and their variant form, share certain characteristics in common and may constitute a unique epilepsy syndrome for which a new name of infantile refractory grand mal syndrome (IRGMS) was offered. This is a more basic concept with broader spectrum than SMEI, encompassing not only SMEI but also related borderlands like HVSW-GM. More recently, the author observed that early zonisamide medication within 1 year after seizure onset may improve seizure prognosis in IRGMS, by preventing the development of myoclonic seizures.     

Rasmussen encephalitis in childhood

Six patients admitted to the Department of Pediatric Neurology at Hacettepe University Children’s Hospital between 1992 and 1997 with a clinical diagnosis of Rasmussen encephalitis received surgical treatment for their intractable epilepsy. MRI, SPECT and WADA tests were performed in patients with an epileptic focus demonstrated on routine or long-term video EEG monitoring. Viral studies using the PCR methodology were performed in cases with histopathological evidence of Rasmussen encephalitis. The ages of these patients ranged between 7 and 16 years, and the mean age at onset of seizures was 7.1±2.2 years. In four patients seizures presented as epilepsia partialis continua and were refractory to anticonvulsive drug therapy. In three cases intravenous immunoglobulin therapy yielded temporary and partial improvement in seizure control. The mean presurgical follow-up duration was 2.04+1.74 years, and early surgical intervention for epilepsy was performed in one case. The surgical approach selected for the treatment of epilepsy was resective surgery with electrocorticography. The mean postoperative follow-up duration was 32.3+17.2 months. Seizures were fully controlled in one patient, in whom surgery was performed 3 months after the seizures first started. Early surgical intervention may provide histopathological evidence for diagnosis as well as effective seizure control. Received: 25 October 1998     

Seizure Frequency and Duration of Epilepsy are Not Risk Factors for Postoperative Seizure Outcome in Patients with Hippocampal Sclerosis

PURPOSE: Despite accurate localization of the seizure focus, not all patients are seizure free after temporal lobectomy. This study determined risk factors for seizure recurrence in patients with proven hippocampal sclerosis. METHODS: The outcome from surgery was assessed in 56 consecutive patients with proven hippocampal sclerosis. The age at surgery, duration of epilepsy, history and age of febrile seizures, age of onset of epilepsy, sex ratio, laterality of seizure focus, and seizure frequency were compared between patients seizure free and those not seizure free, and those seizure and aura free and those with seizure recurrence including auras. RESULTS: During a mean follow-up of 38 months, 48 (86%) of 56 are seizure free. The mean age at surgery (37 vs. 36 years), duration of epilepsy (26 vs. 22 years), age (1.6 vs. 1.1 years), and occurrence (58 vs. 75%) of febrile seizures, age of onset of epilepsy (11 vs. 14 years), sex ratio (50 vs. 75% female), laterality of seizure focus (42 vs. 50% left), greater than weekly seizures (40 vs. 38%), and a history of (69 vs. 75%) and frequency of (2.10 vs. 2.38 per year) secondarily generalized seizures did not differ significantly between the two groups. Similarly there was no significant difference between patients seizure and aura free and those with seizure recurrence including auras. CONCLUSIONS: Clinical factors such as seizure frequency and duration of epilepsy are not risk factors for postoperative seizure recurrence.     

Increased secondary generalization of partial seizures after temporal lobectomy

OBJECTIVE: This study tests the primary hypothesis that secondary generalization of partial seizures is more likely after anterior temporal lobectomy (ATL) than before ATL, and the secondary hypothesis that antiepileptic drug withdrawal accounts for increased generalization of seizures postoperatively. BACKGROUND: The authors observed that some patients had generalized tonic-clonic (GTC) seizures after but not before ATL, by using a new classification of outcome that compares preoperative and postoperative seizure frequencies by seizure type. METHODS: Twenty patients with refractory temporal lobe epilepsy had postoperative GTC seizures or nongeneralizing complex partial (CP) seizures in a consecutive ATL series. All had reduced seizure frequency postoperatively and more than 2 years of follow-up on antiepileptic drugs. The authors calculated a generalization fraction, as (number of GTC seizures)/(number of CP and GTC seizures), for 2 years before and 2 years after surgery. RESULTS: Postoperative generalization fractions were greater than preoperative generalization fractions (Wilcoxon signed-rank test, p < 0.01). Most postoperative GTC seizures were not associated with antiepileptic drug withdrawal, and postoperative GTC seizures were not more associated with drug withdrawal than were postoperative CP seizures. Patients with more than two GTC seizures per year preoperatively were more likely than other patients to have postoperative GTC seizures. CONCLUSIONS: Patients with reduced seizure frequency after ATL have a greater tendency for partial seizures to secondarily generalize postoperatively. This phenomenon is not explained by antiepileptic drug withdrawal.     

The diversity of seizures related to alcohol use. A study of consecutive patients

The aim of this study was to investigate the influence of hazardous alcohol drinking on the occurrence of epileptic seizures, the semiology of such seizures, and the extent of the problem. A consecutive sample of 142 acute seizure patients (78 male and 64 female, mean age 46 (16-79) years) was studied. Control groups were 185 consecutive sciatica patients and 254 healthy individuals. Subjects with a hazardous alcohol drinking level were identified by a score >8 in the Alcohol Use Disorders Identification Test (AUDIT). Seizures in AUDIT-positive individuals occurring within 72 h of the last drink were considered to be related to alcohol withdrawal. Generalized or partial onset seizures were classified on the basis of history, electroencephalographic (EEG) and neuroradiological findings. Thirty-five percent of seizure patients were AUDIT-positive, whereas conversely 27% were abstainers. Two-thirds of AUDIT-positive seizure patients met the criteria for withdrawal seizures. Indications of partial onset seizures were found in 25 (51%) of AUDIT-positive patients, all secondarily generalized seizures. Sixty percent of generalized onset seizure patients were AUDIT-positive. In conclusion, seizure patients included significantly more AUDIT-positive subjects, as well as abstainers, than healthy Norwegian controls and consecutive sciatica patients from our hospital. Partial onset seizures are more frequent among hazardous drinkers than hitherto recognized. A generalized onset seizure in adults warrants a high suspicion of alcohol as a provoking factor. Routine screening of acute seizure admissions with the Alcohol Use Disorders Identification Test is recommended.