Epilepsy



Epilepsy





Seizures


I. Definitions



  • Seizure—a sudden temporary change in brain function caused by an abnormal rhythmic excessive electrical discharge


  • Epilepsy—a state of recurrent seizures


  • Epidemiology



    • Incidence of seizures: 80/100,000 per year


    • Incidence of epilepsy: 45/100,000 per year


    • Risk of epilepsy: 1% to 3%


  • Generalized status epilepticus—two or more generalized seizures without full recovery of consciousness or a single seizure lasting longer than 10 minutes


  • Aura—simple partial seizure producing sensory, autonomic, or psychic manifestations


  • Prodrome—the sensation or feeling that a seizure is about to occur


II. Classification



  • Revised International Classification of Epilepsies, Epileptic Syndromes and Related Seizure Disorders



    • Localization related



      • Idiopathic


      • Symptomatic or secondary


      • Cryptogenic


    • Generalized



      • Primary


      • Symptomatic


      • Cryptogenic


    • Undetermined



      • Both focal and generalized


      • Situation-related epilepsy


      • Febrile convulsions


      • Isolated seizure


      • Isolated status epilepticus


      • Toxic/metabolic



  • Generalized



    • Generalized tonic clonic seizures



      • Prodrome: apathy, fatigue, irritability


      • Aura: none



      • Tonic phase: 10 to 15 seconds; jaw snaps shut, tonic spasm, cyanosis


      • Clonic phase: 1 to 2 minutes; rhythmic generalized muscle contractions, apnea, increased blood pressure


      • Terminal phase: 5 minutes; coma, pupils react, breathing resumes


      • Postictal phase: minutes to hours; confusion, somnolence, agitation


      • Ictal electroencephalogram (EEG): generalized spike wave or polyspike


      • Drugs of choice: valproate, phenytoin, phenobarbital, lamotrigine


      • Epidemiology



        • Newborns—rare


        • Children—febrile, metabolic


        • Age <30 years—idiopathic epilepsy, metabolic


        • Age 30 to 60 years—idiopathic epilepsy, tumor, metabolic


        • Age >60 years—tumor or ischemia with secondary generalization, metabolic


    • Absence seizures



      • Prodrome: none


      • Aura: none


      • Seizure: seconds to minutes; sudden interruption of consciousness, staring, 3-Hz blinking, automatisms


      • Postictal phase: none


      • Ictal EEG: 3-Hz spike and wave


      • Drugs of choice: ethosuximide, valproate


      • Epidemiology: onset at age 4 to 10 years; usually resolves by age 20 years


    • Atypical absence seizures



      • Similar to absence seizures but often associated with other seizure types


      • Ictal EEG: spike and wave usually <3 Hz


      • Drugs of choice: valproate, lamotrigine


      • Epidemiology: usually occurs in patients who are neurologically or developmentally abnormal


    • Febrile seizures



      • Prodrome: fever


      • Seizure:



        • Simple—brief generalized tonic clonic seizure occurring after the onset of fever


        • Complicated—prolonged seizure activity or focal seizure activity


      • Drug of choice: no therapy indicated for isolated seizure; phenobarbital if frequent or severe


      • Epidemiology: 6 months to 5 years old with no other identifiable cause; occur in 2% to 5% of all children; only 10% have more than three febrile seizures.


    • Juvenile myoclonic epilepsy



      • Prodrome: morning myoclonus


      • Aura: none


      • Seizure: generalized tonic clonic +/- absence


      • EEG: polyspike and slow wave


      • Drugs of choice: valproate, lamotrigine


      • Epidemiology: Age of onset is typically 10 to 20 years. Patients are usually developmentally and neurologically normal.


    • Progressive myoclonic epilepsy



      • Unverricht-Lundborg disease (Baltic myoclonus)



        • Onset: age 6 to 16 years, mean age 11 years



        • Genetics: autosomal recessive (AR), chromosome 21q


        • Clinical features



          • Myoclonus > ataxia, dementia


          • IQ drops 10 points each decade.


          • Some develop absence or atonic seizures.


        • Pathologic finding: neuronal loss and gliosis of cerebellum medial thalamus and spinal cord


        • Epidemiology: most common in Finland


      • Myoclonic epilepsy and ragged red fibers



        • Onset: variable


        • Genetics: familial or sporadic; maternal inheritance in mitochondrial disorders


        • Clinical: myopathy, neuropathy, deafness, lipomas, optic atrophy, myoclonus


        • Pathologic finding: ragged red fibers on muscle biopsy; degenerative changes in dentate nucleus and inferior olive


      • Lafora disease



        • Onset: 10 to 18 years


        • Genetics: AR, chromosome 6


        • Clinical: dementia, ataxia > myoclonus; death by age 20 in most cases


        • EEG: shows occipital spikes in 50% of patients.


        • Pathologic finding: Lafora bodies (intracytoplasmic basophilic) in eccrine sweat glands or brain


        • Epidemiology: most common in southern Europe


      • Neuronal ceroid lipofuscinosis (also known as Batten disease)



        • Infantile (Santavori disease)



          • Onset: Age 1 to 2 years


          • Genetics: AR, chromosome 1


          • Clinical features: massive myoclonus, vanishing EEG, common in Finland


        • Late infantile (Jansky-Bielschowsky disease)



          • Onset: Age 2.5 to 4 years


          • Genetics: AR


          • Clinical features: seizures (myoclonic, generalized tonic-clonic, absence) followed by dementia, ataxia, and blindness; death usually occurs by age 5 years; is the most common neuronal ceroid lipofuscinosis outside Finland.


        • Juvenile (Spielmeyer-Vogt disease)



          • Onset: age 4 to 10 years


          • Genetics: AR, chromosome 16


          • Clinical features: starts with visual failure followed by ataxia, dementia, and seizures; is the most common neurodegenerative disorder of childhood


        • Adult (Kuf disease)



          • Onset: Age 30 years


          • Genetics: AR or autosomal dominant (AD)


          • Clinical features: seizures, dementia, ataxia; no visual failure


        • Pathologic finding: Diagnose with skin or brain biopsy. Accumulation of lipopigments in lysosomes. Electromicroscopy shows curvilinear or fingerprint inclusions.


      • Sialidosis



        • Type I



          • Onset: adolescence



          • Genetics: AR, chromosome 20


          • Clinical features: severe myoclonus, gradual visual failure, ataxia and cherry-red spots. No dementia.


          • Pathologic finding: decrease in neuraminidase


        • Type II



          • Onset: adolescence


          • Genetics: AR, chromosome 10


          • Clinical features: type I plus coarse facies and corneal clouding


          • Pathologic finding: decrease in neuraminidase and β-galactosidase


      • Noninfantile Gaucher disease



        • Genetics: AR, chromosome 1


        • Clinical features: supranuclear gaze palsy, splenomegaly, pancytopenia, myoclonus; no dementia.


        • Pathologic finding: Increased acid phosphatase. Decreased glucocerebrosidase.


      • Late infantile and juvenile GM2 gangliosidosis



        • Genetics: AR, chromosome 15


        • Clinical features: myoclonus, dementia; no cherry-red spots


        • Pathologic finding: decreased hexosaminidase


      • Juvenile neuroaxonal atrophy



        • Clinical features: Myoclonus, dementia, ataxia, neuropathy, choreoathetosis. Choreoathetosis appears when the myoclonus is suppressed, and myoclonus appears when the choreoathetosis is suppressed.


        • Pathologic finding: axonal spheroids in autonomic terminals


      • Dentatorubral-pallidoluysian atrophy



        • Genetics: AD


        • Clinical features: chorea, ataxia, dementia, myoclonus


        • Epidemiology: most common in Japan








      Genetics














      Autosomal Dominant

      Maternal Inheritance


      Dentatorubral-pallidoluysian atrophy

      MERRF


      Kuf disease


      MERRF, myoclonic epilepsy and ragged red fibers.









      Geography


















      Japan

      Finland


      Sialidosis type II

      Unverricht-Lundborg disease


      Dentatorubral pallidoluysian atrophy

      Santavori disease


      Sweden

      Canada


      Gaucher disease

      Myoclonus—renal failure










      Clinical Features














































      Severe Dementia

      Little or No Dementia


      Lafora disease

      Unverricht-Lundborg disease


      Late infantile NCL

      Sialidosis type I


      GM2 gangliosidosis

      Noninfantile Gaucher disease


      Juvenile neuroaxonal dystrophy

      Myoclonus-renal failure

      Biotin-responsive encephalopathy


      Severe Myoclonus

      Focal Occipital Spikes


      Lafora disease

      Unverricht-Lundborg disease


      MERRF

      MERRF


      Sialidosis


      Deafness

      Chorea


      MERRF

      Juvenile neuroaxonal dystrophy


      Sialidosis type II

      Dentorubral-pallidoluysian atrophy


      Biotin-responsive encephalopathy

      Juvenile Gaucher disease


      MERRF, myoclonic epilepsy and ragged red fibers; NCL, neuronal ceroid lipofuscinosis



    • Infantile spasms



      • West syndrome



        • Onset: 3 months to 3 years


        • Seizure: jack-knifing; myoclonus


        • EEG: hypsarrhythmia


        • Clinical features: infantile spasms, mental retardation; varies according to cause of spasms


        • Drug of choice: adrenocorticotropic hormone (ACTH) start at 150 U/m2 and taper


      • Aicardi syndrome



        • Onset: birth


        • Genetics: X-linked dominant


        • Seizure: infantile spasms, alternating hemiconvulsions


        • EEG: bursts of asynchronous slow waves, spikes and sharp waves alternating with suppressed EEG


        • Clinical features: coloboma, chorioretinal lacunae, agenesis of the corpus callosum, vertebral anomalies, and seizures


        • Drug of choice: ACTH


    • Lennox-Gastaut syndrome



      • Onset: age 1 to 10 years


      • Seizure: multiple seizure types


      • EEG: slow spike wave complex 1 to 2.5 Hz, multifocal spikes, generalized paroxysmal fast activity


      • Clinical features: multiple seizure types, retardation


      • Drugs of choice: felbamate (use restricted because of side effects), lamotrigine


  • Partial seizures—localization related epilepsy



    • Simple partial seizures




      • Definition: partial seizures with no alteration in consciousness


      • Origin: any part of the cortex


      • Jacksonian motor seizures



        • Clinical features: begins with tonic contractions of the face, fingers, or feet and transforms into clonic movements that march to other muscle groups on the ipsilateral hemibody. There is no alteration in consciousness, but postictal aphasia may occur if the primary epileptogenic zone is in the dominant hemisphere.


      • Autonomic: clinical features may include



        • Abdominal sensations


        • Apnea


        • Arrhythmia


        • Chest pain


        • Cyanosis


        • Erythema


        • Flushing


        • Genital sensations


        • Hyperventilation


        • Incontinence


        • Miosis


        • Perspiration


        • Vomiting


      • Sensory


      • Motor


      • Psychic


    • Complex partial seizures



      • Definition: partial seizure with alteration of consciousness


      • Benign Rolandic epilepsy



        • Epidemiology: incidence is 21/100,000 children <15 years old, usually 5 to 10 years old


        • Clinical features: Single nocturnal seizure with clonic movement of the mouth and gurgling. Secondary generalization is common. Alteration in consciousness, aura, and postictal confusion are rare. Resolves by age 16 years.


        • Interictal EEG: central and midtemporal high-amplitude spike and wave with a characteristic dipole


        • Genetics: AD with low penetrance


        • Drugs of choice: carbamazepine, phenobarbital


    • Temporal lobe epilepsy



      • Epidemiology: Accounts for ˜70% of partial seizures. Many patients have a history of febrile seizures or head trauma.


      • Prodrome: lethargy, and so forth


      • Aura: common


      • Seizure: may include the following



        • Oral or motor automatisms


        • Alteration of consciousness


        • Head and eye deviation



          • 90% of patients with versive head movements had a primary epileptogenic zone in the contralateral hemisphere.



          • Ipsiversive movements occurred most commonly with temporal foci.


          • Versive movements with retained consciousness arose from the contralateral hemisphere in 100% of cases and from the frontal lobe in 93% of cases.


        • Contralateral twitching or tonic-clonic movements


        • Some seizures are brief episodes of staring and behavior arrest.


        • Posturing


        • Right temporal lobe seizures are often hypermobile.


        • Left temporal lobe seizures often result in behavior arrest.


      • Postictal phase: typically minutes to hours of confusion and somnolence


    • Frontal lobe epilepsy

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Sep 8, 2016 | Posted by in NEUROLOGY | Comments Off on Epilepsy

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