Seizures & Epilepsy

1. Seizures & Epilepsy MBBS IV Group C Tutor: Prof. V. Wong 16th Feb 2004

2. Outline • Definitions • Pathophysiology • Aetiology • Classification • Video demonstration • Diagnostic approach • Treatment • Quiz

3. Definition • Seizure (Convulsion) • Clinical manifestation of synchronised electrical discharges of neurons • Epilepsy • Present when 2 or more unprovoked seizures occur at an interval greater than 24 hours apart

4. Definition • Provoked seizures • Seizures induced by somatic disorders originating outside the brain • E.g. fever, infection, syncope, head trauma, hypoxia, toxins, cardiac arrhythmias

5. Definition • Status epilepticus (SE) • Continuous convulsion lasting longer than 30 minutes OR occurrence of serial convulsions between which there is no return of consciousness • Idiopathic SE • Seizure develops in the absence of an underlying CNS lesion/insult • Symptomatic SE • Seizure occurs as a result of an underlying neurological disorder or a metabolic abnormality

6. Aetiology of seizures • Epileptic • Idiopathic (70-80%) • Cerebral tumor • Neurodegenerative disorders • Neurocutaneous syndromes • Secondary to • Cerebral damage: e.g. congenital infections, HIE, intraventricular hemorrhage • Cerebral dysgenesis/malformation: e.g. hydrocephalus

7. Aetiology of seizures • Non-epileptic • Febrile convulsions • Metabolic • Hypoglycemia • HypoCa, HypoMg, HyperNa, HypoNa • Head trauma • Meningitis • Encephalitis • Poisons/toxins

8. Aetiology of Status Epilepticus • Prolonged febrile seizure • Most common cause • Idiopathic status epilepticus • Non-compliance to anti-convulsants • Sudden withdrawal of anticonvulsants • Sleep deprivation • Intercurrent infection • Symptomatic status epilepticus • Anoxic encephalopathy • Encephalitis, meningitis • Congenital malformations of the brain • Electrolyte disturbances, drug/lead intoxication, extreme hyperpyrexia, brain tumor

9. Pathophysiology • Still unknown • Some proposals: • Excitatory glutamatergic synapses • Excitatory amino acid neurotransmitter (glutamate, aspartate) • Abnormal tissues — tumor, AVM, dead area • Genetic factors • Role of substantia nigra and GABA

10. Pathophysiology • Abnormal tissues — tumor, AVM, dead area • These regions of the brain may promote development of novel hyperexcitable synapses that can cause seizures

11. Classification of seizures

12. Seizures • Partial • Electrical discharges in a relatively small group of dysfunctional neurones in one cerebral hemisphere • Aura may reflect site of origin • + / - LOC Generalized • Diffuse abnormal electrical discharges from both hemispheres • Symmetrically involved • No warning • Always LOC

13. Partial Seizures Simple Secondary generalized Complex 1. w/ motor signs 2. w/ somato-sensory symptoms 3. w/ autonomic symptoms 4. w/ psychic symptoms 1. simple partial --> loss of consciousness 2. w/ loss of consciousness at onset 1. simple partial --> generalized 2. complex partial --> generalized 3. simple partial --> complex partial --> generalized

14. Simple partial seizureswith motor signs • Focal motor w/o march • Focal motor w/ march • Versive • Postural • Phonatory

15. Simple partial seizures with motor signs • Sudden onset from sleep • Version of trunk • Postural • Left arm bent • Forcefully stretched fingers • Looks at watch • Note seizure

16. Simple partial seizures with sensory symptoms • Somato-sensory • Visual • Auditory • Olfactory • Gustatory • Vertiginous

17. Simple partial seizures with sensory symptoms • Vertiginous symptoms “Sudden sensation of falling forward as in empty space” • No LOC • Duration: 5 mins

18. Simple partial seizures with autonomic symptoms • Vomiting • Pallor • Flushing • Sweating • Pupil dilatation • Piloerection • Incontinence

19. Simple partial seizures with autonomic symptoms • Stiffness in L cheek • Difficulty in articulating • R side of mouth is dry • Salivating on the L side • Progresses to tongue and back of throat

20. Simple partial seizures with psychicsymptoms • Dysphasia • Dysmnesic • Cognitive • Affective • Illusions • Structured hallucinations

21. Simple partial seizure with pyschic symptoms • Dysmnesic symptoms • “déjà-vu” • Affective symptoms • fear and panic • Cognitive • Structured hallucination • living through a scene of her former life again

22. Complex Partial Seizures • Simple partial onset followed by impaired consciousness • with or without automatism • With impairment of consciousness at onset • with impairment of consciousness only • with automatisms

23. Simple Partial Seizures followed by Complex Partial Seizures • Seizure starts from awake state • Impairment of consciousness • Automatisms • lip-smacking • right leg

24. Complex Partial Seizures with impairment of consciousness at onset • Suddenly sit up • Roll about with vehement movement

25. Partial Seizures evolving to Secondarily Generalised Seizures • Simple Partial Seizures to Generalised Seizures • Complex Partial Seizures to Generalised Seizures • Simple Partial Seizures to Complex Partial Seizures to Generalised Seizures

26. Simple Partial Seizures to Generalised Seizures • Turns to his R with upper body and bends his L arm • Stretches body • LOC • Tonic-clonic seizure • Relaxation phase • Postictal sleep

27. Simple Partial Seizures to Complex Partial Seizures to Generalised Seizures • Initially unable to communicate but understands • Automatism • Smacking • Hand-rubbing • Abolished communication • Generalised tonic-clonic seizure

28. Generalized seizures • Absence • Myoclonic • Clonic • Tonic • Tonic-clonic • Atonic

29. Absence seizures • Sudden onset • Interruption of ongoing activities • Blank stare • Brief upward rotation of eyes • Duration: a few seconds to 1/2 minute • Evaporates as rapidly as it started

30. Absence seizures • Stops hyperventilating • Mild eyelid clonus • Slight loss of neck muscle tone • Oral automatisms

31. Myoclonic seizures • Sudden, brief, shock-like • Predominantly around the hours of going to or awakening from sleep • May be exacerbated by volitional movement (action myoclonus)

32. Myoclonic seizures • Symmetrical myoclonic jerks

33. Clonic seizures • Repetitive biphasic jerky movements • Repetitive vocalisation synchronous with clonic movements of the chest (mechanical) • Venous injection of diazepam • Passes urine

34. Tonic seizures • Rigid violent muscle contraction • Limbs are fixed in strained position • patient stands in one place • bends forward with abducted arms • deep red face • noises - pressing air through a closed mouth

35. Tonic seizures • Elevates both hands • Extreme forward bending posture • Keeps walking without faling • Passes urine

36. Tonic Phase Sudden sharp tonic contraction of respiratory muscle: stridor / moan Falls Respiratory inhibition cyanosis Tongue biting Urinary incontinence Clonic Phase Small gusts of grunting respiration Frothing of saliva Deep respiration Muscle relaxation Remains unconscious Goes into deep sleep Awakens feeling sore, headaches Tonic-clonic seizures(grand mal)

37. Tonic-clonic seizures • Tonic stretching of arms and legs • Twitches in his face and body • Purses his lips and growls • Clonic phase

38. Atonic seizures • Sudden reduction in muscle tone • Atonic head drop

39. Epilepsy syndrome • Epilepsy syndromes may be classified according to: • Whether the associated seizures are partial or generalized • Whether the etiology is idiopathic or symptomatic/ cryptogenic • Several important pediatric syndromes can further be grouped according to age of onset and prognosis • EEG is helpful in making the diagnosis • Children with particular syndromes show signs of slow development and learning difficulties from an early age

40. Table 1. Modified ILAE Classification of Epilepsy Syndromes

41. Table 1. Modified ILAE Classification of Epilepsy Syndromes (cond’)

42. Three most common epilepsy syndromes: • Benign childhood epilepsy • Childhood absence epilepsy • Juvenile myoclonic epilepsy Three devastating catastrophic epileptic syndromes: • West syndrome • Lennox-Gastaut syndrome • Landau Kleffner Syndrome

43. Benign childhood epilepsy with centrotemporal spike (Benign Rolandic Epilepsy) • Typical seizure affects mouth, face, +/- arm. Speech arrest if dominant hemisphere, consciousness often preserved, may generalize especially when nocturnal, infrequent and easily controlled • Onset is around 3-13 years old, good respond to medication, always remits by mid-adolescence

44. Childhood absence epilepsy • School age ( 4-10 years ) with a peak age of onset at 6-7 years • Brief seizures, lasting between 4 and 20 seconds • 3Hz Spike and wave complexes is the typical EEG abnormality • Sudden onset and interruption of ongoing activity, often with a blank stare. • Precipitated by a number of factors i.e. fear, embarrassment, anger and surprise. Hyperventilation will also bring on attacks. Juvenile myoclonic seizure • Around time of puberty • Myoclonic ( sudden spasm of muscles ) jerks → generalized tonic clonic seizure without loss of consciousness • Precipitated by sleep deprivation

45. West’s syndrome (infantile spasms) Triad: • infantile spasms • arrest of psychomotor development • hypsarrhythmia • Spasms may be flexor, extensor, lightning, nods, usually mixed. Peak onset 4-7 months, always before 1 year. Lennox-Gastaut syndrome Characterized by seizure, mental retardation and psychomotor slowing Three main type: • tonic • atonic • atypical absence Landau- Kleffner syndrome ( acquired aphasia )

46. Diagnosis in epilepsy • Aims: • Differentiate between events mimicking epileptic seizures • E.g. syncope, vertigo, migraine, psychogenic non-epileptic seizures (PNES) • Confirm the diagnosis of seizure (or possibly associated syndrome) and the underlying etiology

47. Diagnosis in epilepsy • Approach: • History (from patient and witness) • Physical examination • Investigations

48. History • Event • Localization • Temporal relationship • Factors • Nature • Associated features • Past medical history • Developmental history • Drug and immunization history • Family history • Social history

49. Physical Examination • General • esp. syndromal or non-syndromal dysmorphic features, neurocutaneous features • Neurological • Other system as indicated • E.g. Febrile convulsion, infantile spasm

50. Investigations • I. Exclusion of differentials: • Bedside: urinalysis • Haematological: CBP • Biochemical: U&Es, Calcium, glucose, ABGs • Radiological: CXR, CT head • Toxicological: screen • Microbiological: LP (Always used with justification)