- Epilepsia partialis continua of Kozhevnikov
- Hemiconvulsion-hemiplegia epilepsy syndrome
- Kozhevnikov-Rasmussen syndrome
- Migrating focal seizures of infancy
The following are severe neocortical epileptic syndromes with onset in infancy and childhood:
- Epilepsia partialis continua of Kozhevnikov (a lengthy focal motor seizure-type or focal motor status epilepticus and not an epileptic syndrome)
- Hemiconvulsion-hemiplegia syndrome
- Kozhevnikov-Rasmussen syndrome
- Migrating partial epilepsy of early childhood
The epileptic syndromes and their significance
A major advance in recent epileptology is the recognition of epileptic syndromes that allows an accurate diagnosis and management of seizure disorders.[1-3]
Medical diagnosis is the identification of a disease by investigation of its symptoms and history, which provides a solid basis for the treatment and prognosis of the individual patient. An accurate diagnosis is the golden rule in medicine, and epilepsies should not be an exception to this. Like in any other disease, the recognition of non-fortuitous clustering of symptoms and signs in epilepsies requires the study of detailed clinical and laboratory data.[1-3] However, often in current practice, the diagnosis is limited to either epilepsy or seizures, which is unsatisfactory because this cannot provide guidance on important items such as severity of the disease, prognosis, short- and long-term therapeutic decisions, and genetics (research and counselling), which are all factors that crucially affect personal, family, and social life; education; and career choices of patients. Defining the type of epilepsy should now be considered mandatory as it offers the best guide to both management and prognosis. Most epileptic syndromes and diseases are well defined and easy to diagnose. The benefits of syndromic diagnosis over seizure/symptom diagnosis or an inclusive diagnosis such as epilepsy far outweigh any morbidity from incorrect categorization that may arise in difficult cases.[4]
Important clinical features of a syndrome include the type of seizures, their localization, frequency, sequence of events, circadian distribution, precipitating factors, age at onset, mode of inheritance, physical or mental symptoms and signs, prognosis, and response to treatment.
Epilepsies or epilepsy?
The clinical and practical significance of the syndromic diagnosis of epilepsies is well illustrated by 3 common epileptic disorders. Benign childhood focal epilepsies, juvenile myoclonic epilepsy (JME), and hippocampal epilepsy have nothing in common other than the fact that they may all be complicated by generalized tonic clonic seizures (GTCS), which are primarily GTCS in JME and secondarily GTCS in benign childhood focal epilepsies and hippocampal epilepsy.
Furthermore, the short-and long-term treatment strategies are entirely different for each disorder: benign childhood focal epilepsies may or may not require medication for a few years, appropriate anti-epileptic drug (AED) treatment is lifelong in JME while neurosurgery may be life-saving for patients with hippocampal epilepsy. What may be a life-saving drug such as carbamazepine for hippocampal epilepsy may be ill-advised for JME.
It should not be difficult to distinguish an intelligent child with benign focal seizures or childhood absence epilepsy from a child with Kozhevnikov-Rasmussen, Lennox-Gastaut, Down, or Sturge-Weber syndrome or a child with severe post-traumatic cerebral damage, brain anoxia, or catastrophic progressive myoclonic epilepsy. Describing all these children as simply having epilepsy just because they have seizures offers no more benefit than a diagnosis of febrile illness irrespective of cause, which may be a mild viral illness, a life-threatening acute bacterial meningitis, or a malignancy. Inappropriate generalizations with regard to terminology, diagnosis, and treatment are the single most important factor of mismanagement in epilepsies.[4]
C. P. Panayiotopoulos, MD, PhD, FRCP
Reviewed and revised June 2008 by Steven C. Schachter, MD
Back to topThis is a focal motor seizure type or focal motor status epilepticus and not an epileptic syndrome.
Prevalence
Very small.
Age at onset
Any age; 1/3 <16 years.
Sex
Males = females.
Neurological and mental state
Usually normal, depending on etiology.
Etiology
Multiple and diverse: focal or multifocal brain lesions, systemic diseases affecting the brain and metabolic or other derangements; Kozhevnikov-Rasmussen syndrome and malformations of cortical development are the main causes in children. Cerebrovascular disease and brain space occupying lesions are the main causes in adults. Non-ketotic hyperglycemia is the most common of the reversible causes. An ‘encephalitic process’ is found in >50%.
Russian spring-summer tick-borne encephalitis is an endemic cause.
Pathophysiology
The epileptogenic generators are mainly in the primary motor cortex.
Clinical manifestations
The cardinal and defining symptom is epilepsia partialis continua.
Nearly all patients also have other seizures such as motor focal seizures in the same side and secondarily generalized tonic-clonic seizures. These may start before or after the onset and more often interspersed with epilepsia partialis continua.
Precipitating factors
Sometimes movement action or sensory stimuli.
Diagnostic procedures
The yield of investigative procedures is cause dependent. Around 2/3 have an abnormal brain MRI and EEG that become worse in progressive disorders such as Kozhevnikov-Rasmussen syndrome. PET and SPECT scans often localize the abnormal region but they are not specific. Screening for metabolic and mitochondrial disorders may be needed.
Inter-ictal EEG
Normal initially but soon after deteriorates, with high-amplitude focal or diffuse slow waves often dominating in one hemisphere. Poverty of physiological rhythms in the affected side. Inter-ictal multifocal spikes or sharp and slow waves in nearly all EEGs.
Ictal EEG
Epilepsia partialis continua is notorious with regard to lack of clinico-EEG correlations; epileptiform abnormalities may or may not be concomitant with the jerks. Typically, jerk-locked back-averaged cortical potentials appear in the contralateral primary motor area preceding the jerks by a few msec, sensory evoked potentials are of high amplitude and there is a rostro-caudal pattern of muscle recruitment with co-contraction of agonists and antagonist muscles.
Prognosis
Usually bad, often associated with residual or progressive neurocognitive deficits.
Differential diagnosis
Encephalitis of any cause. Kozhevnikov-Rasmussen syndrome.
Management options*
Seizures are resistant to AEDs. Clonazepam, valproate, levetiracetam, or carbamazepine may be considered.
*Expert opinion, please check FDA-approved indications and prescribing information
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
Negligible today because of improved emergency care for status epilepticus. 0.06% in the American Collaborative Perinatal Project.
Age at onset
5 months to 4 years; peak at 6 months to 2 years.
Sex
Males = females.
Neurological and mental state
Usually normal prior to the onset of insult.
Etiology
Central nervous system (CNS) infection such as herpes encephalitis. A few may be traumatic or vascular. Frequently no cause is found. High family incidence of febrile seizures.
Clinical manifestations
Sudden unilateral clonic convulsions that last for hours or days if not appropriately treated. Consciousness may be intact. Post-convulsive flaccid hemiplegia follows in all cases; it lasts for more than 7 days and is permanent in more than 80%. The face is always involved and aphasia is present if the dominant side is affected. These signs distinguish acquired post-convulsive from congenital hemiplegia.
Diagnostic procedures
Should include CSF examination. Brain imaging, if possible, should precede lumbar puncture. In the acute stage, there is usually edema in the affected hemisphere. Later, a rather characteristic, uniform hemiatrophy appears. SPECT shows hyperperfusion in the acute stage followed later by hypoperfusion.
Inter-ictal EEG
EEG is not important at the acute stage, although grossly abnormal in the affected hemisphere.
Ictal EEG
Focal discharges of slow waves and spikes. There is no consistent relation between clonic convulsions and EEG discharges.
Prognosis
Depends on cause and speed of effective acute management. Focal seizures appear within 1 to 5 years in 80% of the patients. Secondarily generalized tonic-clonic seizures and often convulsive status epilepticus are common. Learning difficulties are probably the rule. Seizures are usually intractable to anti-epileptic medication.
Management options*
Immediate seizure control (treating status epilepticus with benzodiazepines) and treatment of the underlying illness are essential. Drug treatment is needed for focal epilepsy.
Hemispherectomy is beneficial.
*Expert opinion, please check FDA-approved indications and prescribing information
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
Very small; 1 case annually in specialized centers.
Age at onset
1 to 10 years; peak at 5 to 6 years.
Sex
Males = females.
Neurological and mental state
Normal.
Etiology
Unknown. Chronic viral infection? Abnormal immune response to viral infection? Autoimmune disorder unrelated to infection?
Clinical manifestations
Three stages:
- First stage with simple focal motor or somatosensory seizures or with epilepsia partialis continua (60%), complex focal seizures without automatisms or secondarily generalized tonic-clonic seizures (GTCS). Seizures deteriorate in weeks or months. Hemiparesis is initially post-ictal and later permanent.
- In the second stage (3 months to 10 years from onset), seizures become longer, more frequent, and widespread. Neurological and mental deficits: hemiparesis, hemihypesthesia, hemianopia, intellectual/language impairment.
- In the third stage, seizure severity and progression of deficits burn out.
Diagnostic procedures
No specific diagnostic procedure or abnormality. At onset, all functional and structural tests may be normal. It is the progression and the localization that may be consistent with this diagnosis.
CSF: non-specific abnormalities in half of patients. Oligoclonal or monoclonal banding may be found.
Serial CT brain scan and preferably MRI: progressive hemiatrophy, usually starting in the temporo-insular region.
Magnetic resonance spectroscopy: decreased relative N-acetylaspartate signal intensity over the affected hemisphere.
Functional brain imaging – single photon emission computed tomography (SPECT) and positron emission tomography (PET): inter-ictal hypoperfusion and hypometabolism in the affected side, which worsens with progression of the disease and may be abnormal at a stage that MRI is normal. Ictally, there is regional hyperperfusion corresponding to the epileptogenic region.
Inter-ictal EEG
Normal initially but gradually deteriorates to severe unilateral abnormalities (slow waves, poverty of physiological rhythms). Inter-ictal multifocal spikes, sharp waves in nearly all EEGs.
Ictal EEG
Multifocal onset. Focal motor seizures may occur without concomitant EEG changes. Conversely, ictal EEG paroxysms may frequently occur without discernible clinical manifestations. Epilepsia partialis continua often lacks clinico-EEG correlations.
Prognosis
Devastating, with intractable seizures and fixed neurological deficits.
Differential diagnosis
Initially focal seizures and later encephalitis.
Management options*
Seizures are refractory to AEDs. Intravenous immunoglobulin, steroids, and plasma exchange give equivocal results.
Functional hemispherectomy.
*Expert opinion, please check FDA-approved indications and prescribing information
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
Very small; ~20 infants have been reported.
Age at onset
First week to 7 months of life; mean age 3 months.
Sex
Males = females.
Neurological and mental state
Usually normal prior to the onset of seizures.
Etiology
Unknown. There is no family history. Brain neuropathology in 2 cases showed only severe hippocampal neuronal loss and gliosis.
Clinical manifestations
Nearly continuous multifocal seizures with variable and alternating localizations involving the whole cortex. Initially, seizures are motor (eye and head deviation, clonic jerks of eyelids or limbs, tonic components) with secondarily generalized tonic-clonic seizures and convulsive status epilepticus. Autonomic manifestations (apnea, cyanosis, sweating, hiccups) are prominent. After 1 to 10 months, the seizures become polymorphous, very frequent, or continuous. Epileptic spasms are exceptional.
Diagnostic procedures
All tests, including brain imaging, are normal.
Inter-ictal EEG
Exceptionally normal at onset. Diffuse slow activity is the rule with alternating side emphasis in serial EEGs. Multifocal spikes are prominent.
Ictal EEG
Focal discharges randomly involve multiple independent sites, moving from one cortical area to another in consecutive seizures. Duration is 1 to 4 min; subclinical discharges of 30 to 60 sec are common.
Prognosis
Devastating and often fatal. Rapid and relentless severe psychomotor regression with major axial hypotonia and quadriplegia.
Differential diagnosis
Focal symptomatic epilepsy.
Management options*
Conventional AEDs and steroids are ineffective. Treatment with stiripentol# and clonazepam or potassium bromide has been successful in a few otherwise intractable cases.
*Expert opinion, please check FDA-approved indications and prescribing information
#Not approved by the FDA
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
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