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Awake EEG showing hypsarrhythmia in a 4-month old girl with cryptogenic West syndrome. High amplitude waves and spikes are present, randomly appearing and with no topographical distribution identified; also, there is no frequency nor amplitude gradient, indicating a highly disorganized brain activity. Although having this seemingly chaotic EEG, the patient doesn't show any clinical seizures when recorded.

Hypsarrhythmia is an abnormal interictal pattern, consisting of high amplitude and irregular waves and spikes in a background of chaotic and disorganized activity seen on electroencephalogram (EEG), and frequently encountered in an infant diagnosed with infantile spasms, although it can be found in other conditions. In simpler terms, it is very chaotic and disorganized brain electrical activity with no recognizable pattern, whereas a normal EEG shows clear separation between each signal and visible pattern.

Gibbs and Gibbs described hypsarrhythmia in 1952 as "...random high voltage waves and spikes. These spikes vary from moment to moment, both in time and in location. At time they appear to be focal, and a few seconds later they seem to originate from multiple foci. Occasionally the spike discharge becomes generalized, but it never appears as a rhythmically repetitive and highly organized pattern that could be confused with a discharge of the petit mal or petit mal variant type".^[1]

In most cases of infantile spasms, hypsarrhythmia either disappears or improves during a cluster of spasms and/or REM sleep. Hypsarrhythmia rarely persists beyond the age of 24 months.

Classification

Through the use of video EEG and continuous monitoring, five variants of the "classical" hypsarrhythmic pattern have been identified:^[2]

Hypsarrhythmia with increased interhemispheric synchronization. Characterized by symmetric and synchronized activity, seen in patients with longstanding evolution, specially in those with West syndrome that changes to Lennox-Gastaut syndrome.
Asymmetric hypsarrhythmia. Associated with a brain structural abnormality, and does not necessarily predict the affected hemisphere.
Hypsarrhythmia with a consistent focus of abnormal discharge.
Hypsarrhythmia with episodes of voltage attenuation. Commonly seen during nonrapid eye movement (NREM) sleep. When the episodes of voltage attenuation appear at the same time as an epileptic spasm does, they are called electrodecrements.
Hypsarrhythmia with little spike or sharp activity.

It can be associated with mental retardation.^[3]

The "H" in PEHO syndrome stands for hypsarrhythmia.^[4]

Hypsarrhythmia is seen in patients with tuberous sclerosis. It is also frequently found in patients with West syndrome.^[5]

Opsoclonus myoclonus syndrome (in which the interictal EEG pattern is usually normal,^[6] rather than hypsarrhythmia) may be found in infants with neuroblastoma.^[7]

References

^ Gibbs, FA (1952). Atlas of electroencephalography. Cambridge, Mass.: Addison-Wesley.
^ Hrachovy, RA; Frost JD (2003). "Infantile epileptic encephalopathy with hypsarrhythmia". Journal of Clinical Neurophysiology 20 (6): 408–425. doi:10.1097/00004691-200311000-00004.
^ "Hypsarrhythmia" at Dorland's Medical Dictionary
^ Vanhatalo S, Somer M, Barth PG (April 2002). "Dutch patients with progressive encephalopathy with edema, hypsarrhythmia, and optic atrophy (PEHO) syndrome". Neuropediatrics 33 (2): 100–4. doi:10.1055/s-2002-32371. PMID 12075493.
^ "EEG in Common Epilepsy Syndromes: eMedicine Neurology".
^ Ronald, David. Clinical Pediatric Neurology, 3rd edition, 2009, page 205.
^ Fischer, Conrad. Master the Boards USMLE Step2CK. P.410. 2013.

UpToDate Contents

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1. 点頭てんかんの臨床的特徴および診断 clinical features and diagnosis of infantile spasms
2. 点頭てんかんのマネージメントおよび予後 management and prognosis of infantile spasms
3. 点頭てんかんの病因および発症機序 etiology and pathogenesis of infantile spasms
4. 新生児てんかん症候群 neonatal epileptic syndromes
5. 結節性硬化症：管理 tuberous sclerosis complex management

English Journal

Ketogenic diet for infantile spasms refractory to first-line treatments: An open prospective study.

Pires ME, Ilea A, Bourel E, Bellavoine V, Merdariu D, Berquin P, Auvin S.SourceAPHP, Hôpital Robert Debré, Service de Neurologie Pédiatrique, Paris, France.
Epilepsy research.Epilepsy Res.2013 Jul;105(1-2):189-94. doi: 10.1016/j.eplepsyres.2012.11.009. Epub 2013 Jan 26.
Ketogenic diet (KD) is an efficient treatment for refractory epilepsy including infantile spasms (IS). We evaluated the effect of a KD to treat IS as a third-line treatment, after vigabatrin (VGB) and steroids. We evaluated the efficacy and the tolerability of KD in IS using the rate of seizure-free
PMID 23357723

Prenatal corticosteroids modify glutamatergic and GABAergic synapse genomic fabric: Insights from a novel animal model of infantile spasms.

Iacobas DA, Iacobas S, Chachua T, Goletiani C, Sidyelyeva G, Velíšková J, Velíšek L.SourceDominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA.
Journal of neuroendocrinology.J Neuroendocrinol.2013 Jun 14. doi: 10.1111/jne.12061. [Epub ahead of print]
Prenatal exposure to corticosteroids has long-term postnatal somatic and neurodevelopmental consequences. Animal studies indicate that corticosteroid exposure-associated alterations in the nervous system include hypothalamic function. Infants with infantile spasms, a devastating epileptic syndrome o
PMID 23763471

Mutations in the C-terminus of CDKL5: proceed with caution.

Diebold B, Delépine C, Gataullina S, Delahaye A, Nectoux J, Bienvenu T.SourceLaboratoire de Biochimie et Génétique Moléculaire, Hôpital Cochin, Assistance Publique - Hôpitaux de Paris, Paris, France.
European journal of human genetics : EJHG.Eur J Hum Genet.2013 Jun 12. doi: 10.1038/ejhg.2013.133. [Epub ahead of print]
Mutations in the cyclin-dependent kinase-like 5 (CDKL5) gene have been described in girls with Rett-like features and early-onset epileptic encephalopathy including infantile spasms. Milder phenotypes have been associated with sequence variations in the 3'-end of the CDKL5 gene. Identification of no
PMID 23756444

Japanese Journal

周期性の失立を呈した epileptic spasms without hypsarrhythmia の女児例

日暮憲道,浜野晋一郎,吉成聡,田中学,南谷幹之,衞藤義勝
脳と発達 40(1), 49-53, 2008-01-01
NAID 10024134298

A case of Kabuki syndrome presenting West syndrome

ITO Hiromichi,MORI Kenji,INOUE Nami,KAGAMI Shoji
Brain & development 29(6), 380-382, 2007-07-01
NAID 10024136200

EEG abnormalities in West syndrome : Correlation with the emergence of autistic features

KAYAALP Levent,DERVENT Aysin,SALTIK Sema,ULUDUZ Derya,KAYAALP Inci Vural,DEMIRBILEK Veysi,GHAZIUDDIN Mohammad
Brain & development 29(6), 336-345, 2007-07-01
NAID 10024136015

Related Pictures

★リンクテーブル★

国試過去問	「100B054」「077B020」
リンク元	「ウエスト症候群」「ヒプスアリスミア」「hypsarhythmia」

「100B054」

Hypsarrhythmia
Classification and external resources
MeSH	D013036

　　[★]

Lennox-Gastaut症候群について正しいのはどれか。

a. 乳児期に好発する。
b. 知能低下はない。
c. 欠神発作が主体である。
d. けいれん重積発作を起こす。
e. 脳波でhypsarrhythmiaがみられる。

[正答]

※国試ナビ4※　［100B053］←［国試_100］→［100B055］

「077B020」

　　[★]

小児のてんかんについて正しいのはどれか。全て選べ

(1) 大発作では脳波上3サイクル棘徐波結合がみられる
(2) 純粋小発作の意識消失の持続時間は3-5分である
(3) 側頭葉てんかんは発作後Todd麻痺を生じることが多い
(4) 点頭てんかんの間欠期にはhypsarrhythmiaがみられる

「ウエスト症候群」

　　[★]

英: West syndrome
同: ウェスト症候群、(英)infantile spasm IS、(ラ)spasmus nutans; (国試)West症候群、点頭痙攣 salaam spasmus
関: てんかん、Lennox-Gastaut症候群、点頭発作、ヒプスアリスミア hypsarrhythmia

[show details]

ウェスト症候群 : 約 12,800 件
ウエスト症候群 : 約 42,500 件

概念

群発する短い筋収縮からなるスパズム、ヒプスアリスミアを特徴とするてんかん症候群
首をコックリするてんかん発作の一種
大部分の症例に精神発達遅滞がみられ、約半分の症例に先天性奇形、脳性小児麻痺などを重篤な基礎疾患を有する

疫学

生後4-6か月の間に発症、2歳までには発症。3-8ヶ月に発症(PED.1426)

症状

発作は群発する

3主徴

1. 点頭発作(腕と脚が両側性に外転伸展し首と体幹が突然屈曲する発作で、突然の首の屈曲が礼拝のお辞儀を連想させる)
2. ヒプスアリスミア(不規則で高振幅の多焦点性の棘徐波からなる脳波パターン)　←　発作間欠期に1-7Hzの高振幅徐波を背景に棘波、鋭波が多巣性に出現する(NHB.196)。
3. 精神発達遅滞