Epilepsy

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					Epilepsy

  Eghan, BA
Epilepsy

 A group of disorders in which there
 are recurrent episodes of altered
 cerebral function associated with
 paroxysmal excessive and
 hypersynchronous discharge of
 cerebral neurones giving rise to
 seizures
Genetic, congenital, and
developmental conditions implicated
in young patients.
Tumours more likely after 40 years
Head trauma, CNS infections may
occur at any age.
Classification

 Organized according to whether the
 source in the brain is localize:
   Partial or focal/generalised onset of
   seizure
 Partial (focal)
   Paroxysmal neuronal activity is limited to
   one part of the cerebrum.
Partial seizures further divided
depending on the extent to which
consciousness is affected.
  If unaffected - simple partial
  Otherwise complex partial(psychomotor
Partial seizure may spread within the
brain by a process known as
secondary generalisation
If activity spreads to involve the
reticular activating system at the
thalamic level, awareness is lost and
a ‘complex partial seizure’ results.
May further lead to a secondary
generalized seizure.
It is sometimes possible to have
generalized seizure with no clear
focal onset.
Genaralised seizures

 Generalised seizures are also divided
 according to the effect on the body
 however all invove loss of
 consciouness. These include:
   Absence (petit mal)
   Myoclonic
   Clonic,
   Tonic
   tonic-clonic (grand mal)
   atonic
motor
 Seizure characterized by rhythmical jerking
 or sustained spasm of the affected parts.
 They may remain localized to one part or
 may spread to involve the whole side.
 Some attacks begin on one part e.g.
 mouth, thumb and great toe and spread
 gradually - Jacksonian epilepsy.
Attacks vary in duration from a few
seconds to several hours.
More prolong episode may leave
paresis of the involve limb for several
hours after seizure has ceased -
(Todd’s palsy)
Sensory

 Seizures arises from postcentral
 gyrus causing tingling or electric
 sensations in the contralateral face
 and limbs.
 May sometimes spread to become
 Jacksonian epilepsy
Versive

 A frontal epileptic focus.
 May involve the frontal eye field
 causing forced deviation of the eyes
 to the opposite side.
 May progress to generalized tonic-
 clonic seizures
Visual

 Occipital epileptic foci
 Visual hallucinations e.g.
   Balls of light
   Patterns of colour
 Temporal lobe (anterior portion)
   Formed visual hallucinations of faces or
   scenes
Generalized seizure

 Tonic-clonic seizure
 Common
Phases
 Prodromal
   Hours or days before attack, uneasy, irritability
 Aura
   Olfactory and jerking of one limb
 Tonic
   Rapid discharging of motor cortex cells causing
   tonic contraction of muscles; arms flexed and
   adducted, legs extended:
   respiratory muscle spasm causes ‘cry’ as air
   expelled; cyanosis; loss of consciousness. Last
   10-30 seconds
Clonic
  Slow discharge of cortical cells;
  jerking of face and limbs;
  tongue biting,
  incontinence.
  Last 1-5 minutes
Post-ictal
  Deep unconsciousness, flaccid limbs and jaw,
  loss of corneal reflexes, extensor plantar
  responses
What Triggers seizures
 Emotion stress
 Alcohol or alcohol withdrawal
 Infection
 Pyrexia
 Flickering light
 Noise
 Loud music
 Withdrawal of medication
Status epilepticus
 Generalized convulsive status
          epilepticus

Consist of sustained
unconsciousness and continuous or
intermittent generalized convulsive
seizure activity.
Definitions

Traditionally
  Status epilepticus can be defined as
  10-30 minutes of continuous seizure
  activity
                 or
  A series of seizures without return to
  full consciousness between the
  seizures.
Epidemilogy

 Sex: affects males and females
 equally.
 Age: Status epilepticus occurs in all
 age groups but more frequently at the
 extremes of age.
 In the elderly have an increased
 incidence of status epilepticus
 secondary to ischaemic CNS insults.
Mortality/Morbidity:

 Mortality rate could be as high as
 20%
 Death often is related to an underlying
 cause of brain injury.
 Mortality rate is highest in elderly
 patients with hypoxic or ischaemic
 central nervous system (CNS) insults.
Causes
 Exacerbation of an idiopathic seizure
 disorder.
 First onset of a seizure disorder (usually a
 diagnosis of exclusion).
 Toxic or metabolic causes
 Stroke
 Cerebral infarction
   embolic
 Subarachnoid hemorrhage
 Hypoxic injury
Tumours
Trauma
Drugs e.g.;
  alcohol withdrawal
  Cocaine
  Theophylline
  Isoniazid
Electrolyte abnormalities eg,
   Hyponatremia
   Hypernatremia
   Hypercalcemia
Hepatic encephalopathy
Uraemic encephalopathy
Infectious etiology eg
   Meningitis
   brain abscess
   Encephalitis
   HIV
   Schistosomiasis (metastatic)
CNS inflammatory processes
  CNS lupus
Medications
  Cyclosporine
  Imipenen
  Mepiridine
  Ciprofloxacin
History
 systemic or CNS neoplasms
 Infections
 Metabolic disorders
 Toxic ingestions
 Alcohol cessation
 As an initial presentation of a seizure
 disorder.
 Noncompliance with medications
 Injuries
   Fall
   involvement in a motor vehicle accident
physical

 rhythmic tonic-clonic activity is
 present.
 Consciousness is impaired.
 Sometimes, status epilepticus may
 present as a persistent tonic seizure.
Suspect subtle status epilepticus in
any patient who does not regain
consciousness within 20-30 minutes
of cessation of generalized seizure
activity.
At times all motor activity may be
absent.
Associated injuries that may be
present in patients with seizures
include
  tongue lacerations
  shoulder dislocations
  head trauma
  facial trauma.
Fractures
Defecation
Urination
Investigations

 Clinical information should guide the
 ordering of laboratory tests.
 low yield of multiple laboratory tests in
 evaluation of patients presenting with
 a single seizure.
 Status epilepticus should prompt a
 search for the etiology of status or
 potentially reversible conditions.
Laboratory studies
 RBS
 FBC
 Blood culture
 Electrolytes, BUN, Creatinine, Na and
 Calcium (especially in malignancy).
 Liver function test
 Serum levels of antiepileptic drugs
 Urine levels of drugs
 Arterial blood gas analysis
Treatment

 Goals
   Aggressive supportive care including
     A
     B
     C
   Prompt termination of electrical
   seizure activity.
Nasopharyngeal airway placement is
sufficient for some patients, particularly if
the seizures are stopped and the patient
is awakening.
For other patients, endotracheal
intubation is necessary.
At times, rapid sequence induction, with
neuromuscular paralysis, is necessary.
Employ short-acting paralytics so
that ongoing seizure activity is not
masked.
Employ EEG monitoring if long-
acting paralytics are used and if a
question exists about seizure
cessation.
Initiate rapid glucose determination and
correction.
Establish IV access, ideally in a large
vein.
  IV administration is the preferred route for
  anticonvulsant administration because it
  allows therapeutic tissue levels to be
  attained more rapidly.
Establish cardiac and other
haemodynamic monitoring.
Iv Thiamine 100mg followed by 50mls
of 50% dextrose
Medications
1. BENZODIAZEPINES
  Lorazepam (Ativan)
   0.1 mg/kg at 2mg/min not exceeding 4mg or
 Diazepam (Valium)
   0.2 mg/kg at 5mg/min up to 10mg
   Plus maintainance anticonvulsants
2. PHENYTOIN
   Phenytoin sodium
   Fosphenytoin (Cerebyx),
Phenytoin

 *Beware of the side effects of
 Phenytoin.
   Bradycardia
   Heart block
 Monitor BP, pulse rate and rhythm.
Refractory status epilepticus.

 Failure to respond to optimal
 benzodiazepine and phenytoin
 loading.
Third-line drugs

 Phenobarbital
 Midazolam (Dormicum)
 Propofol
 Pentobarbital
 Lidocaine
*Sometimes continuous infusion of
benzodiazepine (diazepam)
General principle is to maximize
the dosage of each drug before
adding an additional agent.
Special consideration of Isoniazid

 Isoniazid (INH) toxicity may present
 with
   profound acidosis
   Seizures
   Coma
 Give Pyridoxine (Vitamin B6)
 Specific antidote for managing INH-
 induced seizures.
Education

 Anticonvulsant therapy compliance
 Alcohol abstinence.
 Stress the importance of regular
 medical attention for medication
 adjustment.
 The importance of follow-up visits to
 adjust medications and for further
 medical workup and care.
Complications:

 Hyperthermia
 Acidosis
 Hypotension/hypertension
 Respiratory failure
 Rhabdomyolysis
 Aspiration
 Fractures
Prognosis:

 Prognosis is related strongly to the
 underlying process causing status
 epilepticus. E.g., if meningitis is the
 etiology, the course of that disease dictates
 outcome.
 Patients with status epilepticus from
 anticonvulsant irregularity or those with
 alcohol-related seizures generally have a
 favorable prognosis if treatment is
 commenced rapidly and complications are
 prevented.

				
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posted:2/22/2012
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