6
Epilepsy
AICARDI-GOUTIERES SYNDROME
Aicardi-Goutieres syndrome was first described in 1984 in a series of eight patients. The clinical picture is of infants with familial progressive encephalopathy, basal ganglia calcification, and chronic cerebrospinal fluid pleocytosis (Table 1). It is a very rare syndrome, suspected to be familial with autosomal-recessive inheritance, and occurrence in siblings has been reported. A majority of reported cases have elevated serum levels of α-interferon, which is of unclear pathogenic significance.
EARLY MYOCLONIC ENCEPHALOPATHY
Criteria for this syndrome have been developed by the International League Against Epilepsy (ILAE).
However, this epileptic syndrome is nonspecific with regard to origin, and not all patients fulfill all of the ILAE criteria. In particular, there may be clinical overlap with the syndrome of early infantile epileptic encephalopathy, which is recognized by the ILAE as distinct from early myoclonic epilepsy (Table 2).
IDIOPATHIC LOCALIZATION-RELATED EPILEPSIES
This group, known by the acronym ILRE, includes the so-called benign partial epilepsies in infancy and childhood. Entities originally falling into this category included benign childhood epilepsy with centrotemporal spikes, childhood epilepsy with occipital paroxysms, and primary reading epilepsy.
Some authors would now include benign partial epilepsies of infancy, and Panayiotopoulos-type early- onset benign childhood occipital epilepsy (also called benign childhood epilepsy with occipital paroxysms) (Table 3).
LENNOX-GASTAUT SYNDROME
Originally described in the 1930s, Lennox-Gastaut syndrome is a childhood-onset epileptic syn- drome almost always associated with developmental delay or congenital anomalies (Table 4).
MESIAL TEMPORAL LOBE EPILEPSY
Mesial temporal lobe epilepsy (MTLE) may occur with or without accompanying pathological lesions. One of the more common forms occurs in conjunction with hippocampal sclerosis. Diagnostic criteria for hippocampal sclerosis have been defined based on pathological examination, primarily from surgical specimens; autopsy material is relatively rare. The primary feature is that of neuronal cell loss and gliosis with relative sparing of transitional cortex in the mid-hippocampus. Hippocampal scle- rosis may be an isolated finding, without the individual having concomitant mesial temporal lobe epilepsy.
From: Current Clinical Neurology: Diagnostic Criteria in Neurology Edited by: A. J. Lerner © Humana Press Inc., Totowa, NJ
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No electroclinical feature per se distinguishes MTLE with or without hippocampal sclerosis, although the presence of olfactory–gustatory auras is felt to be more common in patients with MTLE secondary to a neoplasm (Table 5). MTLE also needs to be distinguished from neocortical temporal lobe epilepsy, with which it shares some broad features. History of febrile seizures, abdominal auras, contralateral dystonic posturing, and ipsilateral mesial temporal spike waves on electroencephalogram suggest MTLE.
In Pfander’s multiple logistic regression model, this combination yielded diagnostic accuracy of 73%, and positive and negative predictive values of 81 and 70%, respectively.
80 Diagnostic Criteria in Neurology
Table 1
Diagnostic Criteria for Aicardi-Goutieres Syndrome
1. Progressive encephalopathy with infantile onset (under 1 year of age).
2. Basal ganglia calcification.
3. Chronic cerebrospinal fluid pleocytosis.
4. Negative toxoplasmosis, rubella, cytomegalovirus, herpes simplex serology.
5. Exclusion of other toxic or metabolic disorders, such as lymphocytic choriomeningitis.
Table 2
Diagnostic Criteria for Early Myoclonic Encephalopathy 1. Electroencephalogram with suppression–burst pattern.
2. Occurrence of erratic, fragmentary myoclonus of early onset in association with other types of seizures.
3. The seizures are resistant to conventional antiepileptic therapy.
4. No known obstetric complications or perinatal insults.
Adapted with permission from Wang PJ, Lee WT, Hwu WL, et al. The controversy regarding diagnostic criteria for early myoclonic encephalopathy. Brain Dev 1998;20:530–535.
Table 4
Diagnostic Criteria for Lennox-Gastaut Syndrome
1. Multiple seizure types including atypical absence and seizures resulting in falls (axial tonic, massive myoclonic, and atonic seizures).
2. Electroencephalogram demonstrating slow spike and wave (<2.5 Hz) and bursts of fast rhythms at 10–12 Hz during sleep.
3. Static encephalopathy and learning disabilities, most often associated with profound mental retardation Other seizure types usually are present, including generalized tonic–clonic seizures and partial seizures.
Table 3
Diagnostic Criteria for Idiopathic Localization-Related Epilepsies Clinical features
1. Normal neurological examination.
2. Normal neuroimaging.
3. Family history of benign type epilepsy.
4. Brief stereotypes seizures.
5. Frequent nocturnal occurrences.
6. Easy to control epilepsy except with ethosuximide.
7. Remission before adolescence.
Electroencephalogram features 1. Normal background activity.
2. Spikes with a characteristic morphology and location.
3. Sleep activation.
4. Occasional generalized paroxysms.
Adapted with permission from Negoro T. Diagnosis and treatment of idiopathic
focal epilepsies (benign partial epilepsies) in infancy and childhood. Epilepsia
2005;46:S3–S38, and from Blackwell Publishing.
SUDDEN UNEXPECTED DEATH IN EPILEPSY
There are no universal guidelines in determining this diagnosis, which is by definition always made retrospectively (Table 6).
One proposed diagnosis is sudden unexpected, nontraumatic, and nondrowning death in an individ- ual with epilepsy with or without evidence for a seizure and excluding documented status epilepticus, where postmortem examination does not reveal a cause for death.
Common findings include pulmonary edema, bitten tongue, and incontinence. The relationship of sudden unexpected death in this population to suffocation is unknown.
SOURCES
Aicardi-Goutieres Syndrome
Goutieres F, Aicardi J, Barth PG, Lebon P. Aicardi-Goutieres syndrome: an update and results of interferon-alpha studies. Ann Neurol 1998;44:900–907.
Koul R, Chacko A, Joshi S, Sankhla D. Aicardi-Goutieres syndrome in siblings. J Child Neurol 2001;16:759–761.
Epilepsy 81
Table 5
Status of Various Criteria in the Diagnosis of Mesial Temporal Lobe Epilepsy With Hippocampal Sclerosis
Distinguishes Essential
Characteristic Does not May Does Yes No
History of initial precipitating incident + +
Family history + +
Latent period + +
Silent period + +
Seizure onset between 6 and 14 years + +
Predominantly unilateral HS on magnetic resonance imaging + +
Hypometabolism on positron-emission tomography + +
Characteristic seizure semiology + +
aCharacteristic interictal and ictal EEG + +
Memory disturbance + +
Pharmacoresistance + +
Good surgical outcome + +
Progressive course + +
a
