west syndrome ppt hypsarrhythmia infantile.pptx

Infantile spasm

1. EEG IN WEST SYNDROME

2. The 2001 ILAE diagnostic scheme -‘epileptic encephalopathies ’ ‘epileptic spasms’ Over ‘infantile spasms’ unique type of seizure called epileptic spasms gross EEG abnormalities of hypsarrhythmia Developmental regression 2% of childhood epilepsies, 25% of epilepsy with onset in the first year of life.

3.  Dr W J West, gave the first detailed description of infantile spasms. Published in The Lancet in 1841 Generalized Flexion Epilepsy, Infantile Epileptic Encephalopathy, Infantile Myoclonic Encephalopathy, jackknife convulsions, Massive Myoclonia , Salaam spasms

4. Onset is between 3 and 12 months (peak at 5 months) in 90% of cases. Males (60–70%) predominate. The epileptic spasms -clusters of sudden, brief (0.2–2 s), bilateral tonic contractions of the axial and limb muscles. slower than myoclonic jerks and faster than tonic seizures spasms typically occurring in clusters of 1–30 per day, with each cluster having 20–150 attacks

5. Aetiologically classified into symptomatic (about 80% of all) due to discernible organic insults Cryptogenic idiopathic

6. Idiopathic West syndrome constitutes 5–30% of all cases. normal development before, during and after the active seizure period, with preservation of visual function normal functional and structural brain imaging or other symptomatic causes symmetrical epileptic spasms and EEG hypsarrhythmia a family history of other forms of idiopathic epilepsy or febrile seizures an EEG-identifiable basic activity and sleep spindles despite a hypsarrhythmic pattern

7. Only 14% of infants with symptomatic West syndrome have normal or borderline-normal cognitive development. 50-70% of patients develop other seizure types. 18-50% of patients will develop Lennox- Gastaut syndrome or some other form of symptomatic generalized epilepsy

8. hypsarrhythmia

9. Characteristic interictal EEG pattern occurs in two-thirds of patients Chaotic,high to extremely high voltage, polymorphic delta and theta rhythms with superimposed multifocal spike and wave discharges. Gibbs and Gibbs described hypsarrhythmia in 1952 Rarely persists beyond the age of 24 months .

10. Gibbs and gibbs description High voltage ( >200 microV ) Chaotic Asynchronous Random Independent Spike and Wave discharges Vary from moment to moment in duration & location Periods of electrodecrement lasting several seconds As a result of their high amplitude, individual components and localisation are impossible to detect at routine sensitivity There are no recognisable normal rhythms

11. Defining characteristics( Gibs and Gibs ): Essentially continuous Present in both awake and sleep Consist of random high voltage slow waves and spikes. Spikes vary in location and duration – focal or multifocal Occasionally generalized discharges but never in a rhythmic or highly organized pattern

12. In NREM sleep, hypsarrhythmia becomes fragmented and presents with discontinuous, repetitive, high amplitude discharges of spikes/ polyspikes and slow waves, which are more synchronous than in the awake-stage EEG. Either disappears or improves during a cluster of spasms and/or REM sleep

13. VARIANTS OF CLASSICAL HYPSARRHYTHMIA Hypsarrhythmia with increased interhemispheric synchronisation (35%) Symmetric and organised activity Longstanding evolution Evolving to LGS

14. Asymmetric hypsarrhythmia (12%) May be regional or hemispheric Focal or hemispheric structural brain lesion Hypsarrhythmia with consistent focus of abnormal discharge(26%) Persistant focus of spike/sharp wave or spike and wave activity

15. Hypsarrhythmia with episodes of voltage attenuation – electrodecrements Periods of voltage attenuation that persist for 2-10 seconds. Commonly occuring during NREM sleep Coincides with epileptic spasm- electrodecremental response

16. Hypsarrhythmia with little spike or sharp activity High amplitude bilaterally asynchronous slow waves Little or absent spike or sharp wave components

17. Drugs such as theophylline or anti-allergic agents of hista mine H1-receptor antagonists, particularly ketotifen may induce epileptic spasms and hypsarrhythmia that are entirely reversible upon drug withdrawal.

18. Correlation with etiology Symmetrical hypsarrhythmia is most likely to occur in idiopathic and cryptogenic cases. Asymmetrical and unilateral hypsarrhythmias almost always indicate ipsilateral brain structural lesions. Hemihypsarrhythmia -cerebral dysgenesis Consistently focal slow waves indicate localised lesions. These become more apparent with intravenous diazepam, which reduces the amount of hypsarrhythmia .

19. ICTAL EEG Kellaway et al. Described 11 different patterns. High amplitude fast activity is the most commonest. Asymmetry indicates possible symptomatic etiology.

20. Ictal EEG variable -at least 11 different types, lasting for 0.5 s to 2 min. The most common and more characteristic pattern in 72% of the attacks is a brief duration (1–5 s) consists of (1) a high-voltage, generalised slow wave, (2) episodic, low-amplitude fast activity and (3) marked diffuse attenuation of EEG electrical activity (electro decremental ictal EEG pattern ).

21. (1) a high-voltage, frontal-dominant, generalized slow wave transient followed by a period of attenuation; (2) a generalized sharp and slow wave complex; (3) a generalized sharp and slow wave complex followed by a period of voltage attenuation; (4) a period of voltage attenuation only; 5) a generalized slow transient only; (6) a period of attenuation with superimposed fast activity;

22. (7) a generalized slow wave transient followed by a period of voltage attenuation with superimposed fast activity (8) a period of attenuation with rhythmic slow activity; (9) fast activity only; (10) a sharp and slow wave complex followed by a period of voltage attenuation with superimposed fact activity; and (11) a period of voltage attenuation with superimposed fast activity followed by rhythmic slow activity

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