SEIZURES

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SEIZURES
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SEIZURES

• Def Paroxysmal involuntary disturbance in
  brain function manifested as impairment or loss
  of consciousness , abnormal motor activity ,
  behavioral abnormalities , sensory disturbances ,
  or autonomic dysfunction .

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• Epilepsy is diagnosed when 2 or more unprovoked
  seizures occur at interval greater than 24 hours
  apart

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Types of epilepsy

• There are two basic types of seizures caused by
  epilepsy
  1-PARTIAL SEIZURES begin in a
  specific location in the brain. Partial seizures
  may affect awareness or only one side or part of
  the body, but they may also progress to affect
  the entire body.

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• 2-GENERALIZED SEIZURES begin over the entire
  surface of the brain and may affect the entire
  body. In people who have generalized seizures, it
  is impossible to pinpoint a specific location in
  the brain that is the source of the seizure.

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• The difference is important, because partial
  seizures and generalized seizures are often
  treated differently. The distinction is a key
  factor in guiding treatment.

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International classification of epileptic seizures

• PARTIAL SEIZURES
• SIMPLE PARTIAL
• Motor
• Sensory
• Autonomic
• Psychic'
• COMPLEX PARTIAL
• PARTIAL SEIZURES WITH 2ry GENERALIZATION

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• GENERALIZED SEIZURES
• ABSENCES
• Typical
• Atypical
• GENERALIZED TONIC CLONIC
• TONIC
• CLONIC
• MYOCLONIC
• ATONIC
• INFANTILE SPASMS
• UNCLASSIFIED SEIZURES

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PATHOPHYSIOLOGY

• Two sets of changes can determine the
  epileptogenic properties of neuronal tissues.
  Abnormal neuronal excitability is thought to
  occur as a result of disruption of the
  depolarization and repolarization mechanisms of
  the cell (this is termed the "excitability of
  neuronal tissue").

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• Aberrant neuronal networks that develop abnormal
  synchronization of a group of neurons can result
  in the development and propagation of an
  epileptic seizure (this is termed the
  "synchronization of neuronal tissue").

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• A hyperexcitability of neurons that results in
  random firing of cells, by itself, may not lead
  to propagation of an epileptic seizure. Indeed,
  both normal and abnormal patterns of behavior
  require a certain degree of synchronization of
  firing in a population of neurons.

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• Epileptic seizures originate in a setting of both
  altered excitability and altered synchronization
  of neurons.

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• The excitability of individual neurons is
  affected by
• cell membrane properties and the microenvironment
  of the neuron
• intracellular processes
• structural features of neuronal elements
• interneuronal connections

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Benign Rolandic Epilepsy

• Benign Rolandic epilepsy (also known as benign
  partial epilepsy of childhood) accounts for more
  than one-third of all cases of epilepsy that
  begin in middle childhood, accounting for 16
  percent of those beginning before age 15. There
  is a family history in 18 percent of cases and
  the condition is probably genetically determined.

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Rasmussen's Syndrome

• Rasmussen's syndrome, also known as Rasmussen's
  encephalitis, begins in childhood and produces a
  slow deterioration of one whole side (hemisphere)
  of the brain with loss of function on the
  opposite side of the body. An autoimmune response
  to a viral infection has been suggested as a
  possible cause.

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• Various types of treatment have been tried,
  including surgical removal of the affected side
  of the brain. In children, the remaining
  hemisphere may compensate for functions lost, but
  weakness on the affected side will remain.

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Childhood Absence Epilepsy

• Childhood Absence
• 40 outgrow seizures
• I.Q. scores 10 above normal
• Probably inherited
• Generalized tonic-clonic in 50

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• Children with this syndrome are otherwise normal
  40 percent outgrow the seizures, and as a group
  their I.Q. scores are 10 points above average.
  The syndrome is inherited (probably autosomal
  dominant trait with age-dependent expression).

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• Childhood absence epilepsy (also called petit mal
  epilepsy, pyknolepsy) accounts for 2 to 4 percent
  of all cases of epilepsy in children. Seizures
  are non-convulsive staring spells associated with
  a distinct 3 per second spike and wave EEG
  pattern. The seizures tend to occur in clusters
  (hence pyknolepsy -- derived from the Greek word
  for "cluster").

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• Despite its overall benign nature, approximately
  half of the children with absence epilepsy can
  expect to have a generalized tonic clonic
  seizure. The risk is higher if the EEG background
  readings are abnormal, or if the child has
  neurological deficits. The risk is reduced if
  seizures are quickly controlled with medication.

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• Remission of childhood absence epilepsy is most
  likely when the child is young at onset, the
  seizures are easily controlled with medication
  and there are no other neurological problems.

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MYOCLONIC EPILEPSIES OF CHILDHOOD

• Charcterized by repetitive seizures consisting
  of brief, often symmetric muscle
• contractions with losas of body tone and
  falling or slumping forward.

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• Myoclonic epilepsies include a heterogeneous
  group of conditions with multiple causes and
  variable outcomes
• Benign Myoclonus of Infancy.
• Typical Myoclonic Epilepsy of Early Childhood.
• Complex Myoclonic Epilepsies.
• Juvenile Myoclonic Epilepsy.
• Progressive Myoclonic Epilepsies.

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Benign Myoclonus of Infancy

• -     Benign myoclonus begins during infancy and
  consists of clusters of myoclonic movements
  confined to the neck, trunk, and extremities.
• -     The myoclonic activity may be confused with
  infantile spasms however, the EEG is normal in
  patients with benign myoclonus.

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• The prognosis is good, with normal development
  and the cessation of myoclonus by 2 yr of age.
• -     An anticonvulsant is not indicated.
• -     A familial autosomal dominant form is
  thought to be linked to a locus on chromosome 20

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Typical Myoclonic Epilepsy of Early Childhood

• - Pure form of myoclonic epilepsy in which
  genetic factors are important at least
  1/3 ? family Hx of epilepsy
• - Mean age of onset 2.5 yr
  Range 6 mo-4 yr

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• Children who develop typical myoclonic epilepsy
  are near normal prior to the onset of seizures
  with no previous evidence of brain damage and
  intact developmental milestones.

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• The frequency of myoclonic seizures varies they
  may occur several times daily or children may be
  seizure free for weeks.
• - Present as head nodding, more violent jerks
  of shoulder, flexion of the arms, trunk or legs.

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• - A few patients have febrile convulsions or
  generalized tonic-clonic afebrile seizures that
  precede the onset of myoclonic epilepsy.

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• Approximately one half of the patients
  occasionally have tonic-clonic seizures in
  addition to the myoclonic epilepsy. The EEG shows
  fast spike wave complexes of equal to or greater
  than 2.5 Hz and a normal background rhythm in
  most cases.

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•  The long-term outcome is relatively favorable.
• - Mental retardation develops in the minority
• - More than 50 are seizure free several years
  later.
• -  However, learning and language problems and
  emotional and behavioral disorders occur in a
  significant number of these children and require
  prolonged follow-up by a multidisciplinary team.
•  
• -    Attacks usually respond well to valproic
  acid

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Juvenile Myoclonic Epilepsy Janz syndrome (
Impulsive petit mal

• - Primary generalized epilepsy
• -     Juvenile myoclonic epilepsy usually begins
  between the ages of 12 and 16 yr ( early teens )
  
• -     accounts for approximately 5 of the
  epilepsies.

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• Genetic factors are important. Family history of
  epilepsy in up to 25
• -     A gene locus has been identified on
  chromosome 6p.
• -  The neurologic examination is normal

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• the distinctive features of JME
• -  Morning myoclonic jerks
• -  Generalized tonic-clonic convulsions just
  after awaking
• -  Normal intelligence
• -  Positive family history of similar seizures
• -  Myoclonic jerks occurs shortly after the
  patient awakes

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Lennox-Gastaut Syndrome

• Atypical absense
• Tonic seizures
• Drop attacks
• Mental retardation
• Slow spike wave
• Onset before age 5

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(West Syndrome)

• West syndrome is composed of the triad of
  infantile spasms, an interictal EEG pattern
  termed hypsarrhythmia, and mental retardation,
  although the diagnosis can be made even if one of
  the 3 elements is missing (according to the
  international classification). This severe
  epilepsy syndrome is an age-dependent expression
  of a damaged brain

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• Spasms can be flexor, extensor, or a mixture of
  flexion and extension. An arrest or regression
  in psychomotor development accompanies the onset
  of spasms in 70-95 of patients

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• Infantile spasms (West syndrome) can be
  classified according to its suspected etiology as
  symptomatic, cryptogenic, or idiopathic.
  Virtually any disorder that can produce brain
  damage can be associated with infantile spasms

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Landau-Kleffner Syndrome

• Begins between 3 to 7 years old
• Progressive loss of speech
• Seizures during sleep
• Loss of IQ

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• Language for many of these children will improve
  slowly over time, but may not return to a normal
  level for age. EEGs may continue to be abnormal,
  even when the speech has improved

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