Epidémiologie

Le taux de mortalité par AVC varie de façon importante d'un pays à l'autre, allant de 40 à 250/100 000 habitants. On distingue des pays à taux élevé tels que le Japon et les pays de l'Europe de l'Est et d'autres à taux plus bas comprenant les pays de l'Europe de l'ouest et d'Amérique du Nord. En France, la mortalité par AVC était de 130/100 000 habitants (#62000 décès) en 1982.

L'incidence annuelle des AVC en France était de 145/100 000 habitants en 1985, soit la troisième cause de mortalité..

Un facteur de risque cérébro-vasculaire est associé statistiquement à une incidence accrue des manifestations cliniques cérébrales de l'athérosclérose à l'échelle d'une population. Ces facteurs n'impliquent pas forcément une relation de cause à effet, mais une simple relation statistique. Ces facteurs peuvent favoriser le développement des lésions athéroscléreuses des artères à destinée cérébrale ou leur complication (parfois les deux).

Le facteur de risque s'exprime à l'échelle d'une population. Sur le plan individuel, il faut le considérer avec circonspection car il peut exister des facteurs de protection (génétiques, environnementaux etc...).

Le critère de normalité du facteur de risque est souvent fixé de manière arbitraire. En réalité, dans de nombreux cas (HTA, cholestérol) le risque existe pour des valeurs inférieures aux normales recommandées.

Il existe une potentialisation des facteurs de risque ( 1+1 n'est pas égal à 2 mais à 3).

Les facteurs de risque n'ontpas la même puissance selon le territoire artériel. L'HTA semble plus néfaste aux artères cérébrales, le tabac aux artères des membres inférieurs et le cholestérol aux artères coronaires.

Voici des copies de quelques échelles d'évaluation en neurologie. C'est sur ces échelles que s'appuient beaucoup d'études thérapeutiques. Il faut savoir qu'il existe deux types d'échelles :

les échelles fonctionnelles (de vie quotidienne) qui mesurent des incapacités : index de Barthel,Rankin,Glasgow Outcome Scale

les échelles analytiques qui mesurent des défisciences neurologiques : échelle Orgogozo et Scandinavian stroke scale,NIH Stroke Scale

**Formulaire unifié pour les échelles neurologiques d'AVC**
Items	Items	Brut	Orgogozo	Scandinave
Vigilance - normale - somnolence - réaction à l'ordre verbal - stupeur - coma Communication verbale - normale - difficile - difficile - impossible Déviation tête et yeux - pas de paralysie du regard - parésie de la latéralité - paralysie de la latéralité Paralysie faciale - absente - paralysie ou parésie marquée Elévation - normale - possible contre résistance - ne dépasse pas l'horizontale - impossible - paralysie complète Force - normale - diminuée - très diminuée - paralysie Elévation - normale - possible contre résistance - possible contre pesanteur - impossible - paralysie complète Dorsiflexion du pied - possible contre résistance - possible contre pesanteur - ébauche Tonus du membre supérieur - normal - flaccidité ou spasticité nette Tonus du membre inférieur - normal - flaccidité ou spasticité nette Orientation - normale : temps-espace-personnes - normale pour 2 items - 1 seul item conservé - désorientation complète Marche - 5 m sans aide - avec aide d'un appareil - avec aide d'une personne - tient assis sans soutien - au lit ou fauteuil roulant	Vigilance - éveil spontané - obnubilation - éveil à l'ordre verbal - éveil à la douleur - aucune réaction adaptée Langage - pas d'aphasie - limité ou incohérent - pas de phrases longues - limité à oui ou non Regard - - négligence visuelle - déviation tonique Paralysie faciale - asymétrie minime - Force du membre supérieur - force normale - - - flexion du coude - Mouvements de la main - normaux - élaborés - préhension utile - pas préhension Force du membre inférieur - - - - flexion du genou - Dorsiflexion du pied - - - chute du pieds Tonus du membre supérieur - - Tonus du membre inférieur - - Confusion - - - - Statique - - - - -	4 3 2 1 0 3 2 1 0 2 1 0 1 0 4 3 2 1 0 3 2 1 0 4 3 2 1 0 2 1 0 1 0 1 0 3 2 1 0 4 3 2 1 0	15 10 10 5 0 10 5 5 0 10 5 0 5 0 10 10 5 0 0 15 10 5 0 15 10 5 0 0 10 5 0 5 0 5 0 - - - - - - - - -	6 4 2 0 0 10 6 3 0 4 2 0 2 0 6 5 4 2 0 6 4 2 0 6 5 4 2 0 - - - - - - - 6 4 2 0 12 9 6 3 0
Total		Brut / 32	/ 100	/ 58

**NIH Stroke Scale**
Instructions	Scale Definition	Score
1a. Level of Consciousness: The investigator must choose a response, even if a full evaluation is prevented by such obstacles as an endotracheal tube, language barrier, orotracheal trauma/bandages. A 3 is scored only if the patient makes no movement (other than reflexive posturing) in response to noxious stimulation.	0 = Alert; keenly responsive. 1 = Not alert, but arousable by minor stimulation to obey, answer, or respond. 2 = Not alert, requires repeated stimulation to attend, or is obtunded and requires strong or painful stimulation to make movements (not stereotyped). 3 = Responds only with reflex motor or autonomic effects or totally unresponsive, flaccid, areflexic.
1b. LOC Questions: The patient is asked the month and his/her age. The answer must be correct - there is no partial credit for being close. Aphasic and stuporous patients who do not comprehend the questions will score 2. Patients unable to speak because of endotracheal intubation, orotracheal trauma, severe dysarthria from any cause, language barrier or any other problem not secondary to aphasia are given a 1. It is important that only the initial answer be graded and that the examiner not "help" the patient with verbal or non-verbal cues.	0 = Answers both questions correctly. 1 = Answers one question correctly. 2 = Answers neither question correctly.
1c. LOC Commands: The patient is asked to open and close the eyes and then to grip and release the non-paretic hand. Substitute another one step command if the hands cannot be used. Credit is given if an unequivocal attempt is made but not completed due to weakness. If the patient does not respond to command, the task should be demonstrated to them (pantomime) and score the result (i.e., follows none, one or two commands). Patients with trauma, amputation, or other physical impediments should be given suitable one-step commands. Only the first attempt is scored.	0 = Performs both tasks correctly 1 = Performs one task correctly 2 = Performs neither task correctly
2. Best Gaze: Only horizontal eye movements will be tested. Voluntary or reflexive (oculocephalic) eye movements will be scored but caloric testing is not done. If the patient has a conjugate deviation of the eyes that can be overcome by voluntary or reflexive activity, the score will be 1. If a patient has an isolated peripheral nerve paresis (CN III, IV or VI) score a 1. Gaze is testable in all aphasic patients. Patients with ocular trauma, bandages, pre-existing blindness or other disorder of visual acuity or fields should be tested with reflexive movements and a choice made by the investigator. Establishing eye contact and then moving about the patient from side to side will occasionally clarify the presence of a partial gaze palsy.	0 = Normal 1 = Partial gaze palsy. This score is given when gaze is abnormal in one or both eyes, but where forced deviation or total gaze paresis are not present. 2 = Forced deviation, or total gaze paresis not overcome by the oculocephalic maneuver.

3. Visual: Visual fields (upper and lower quadrants) are tested by confrontation, using finger counting or visual threat as appropriate. Patient must be encouraged, but if they look at the side of the moving fingers appropriately, this can be scored as normal. If there is unilateral blindness or enucleation, visual fields in the remaining eye are scored. Score 1 only if a clear-cut asymmetry, including quadrantanopia is found. If patient is blind from any cause score 3. Double simultaneous stimulation is performed at this point. If there is extinction patient receives a 1 and the results are used to answer question 11.	0 = No visual loss 1 = Partial hemianopia 2 = Complete hemianopia 3 = Bilateral hemianopia (blind including cortical blindness)
4. Facial Palsy: Ask, or use pantomime to encourage the patient to show teeth or raise eyebrows and close eyes. Score symmetry of grimace in response to noxious stimuli in the poorly responsive or non-comprehending patient. If facial trauma/bandages, orotracheal tube, tape or other physical barrier obscures the face, these should be removed to the extent possible.	0 = Normal symmetrical movement 1 = Minor paralysis (flattened nasolabial fold, asymmetry on smiling) 2 = Partial paralysis (total or near total paralysis of lower face) 3 = Complete paralysis of one or both sides (absence of facial movement in the upper and lower face)
5 & 6. Motor Arm and Leg: The limb is placed in the appropriate position: extend the arms (palms down) 90 degrees (if sitting) or 45 degrees (if supine) and the leg 30 degrees (always tested supine). Drift is scored if the arm falls before 10 seconds or the leg before 5 seconds. The aphasic patient is encouraged using urgency in the voice and pantomime but not noxious stimulation. Each limb is tested in turn, beginning with the non-paretic arm. Only in the case of amputation or joint fusion at the shoulder or hip may the score be "9" and the examiner must clearly write the explanation for scoring as a "9".	0 = No drift, limb holds 90 (or 45) degrees for full 10 seconds. 1 = Drift, Limb holds 90 (or 45) degrees, but drifts down before full 10 seconds; does not hit bed or other support. 2 = Some effort against gravity, limb cannot get to or maintain (if cued) 90 (or 45) degrees, drifts down to bed, but has some effort against gravity. 3 = No effort against gravity, limb falls. 4 = No movement 9 = Amputation, joint fusion explain: ______________________ 5a. Left Arm 5b. Right Arm
	0 = No drift, leg holds 30 degrees position for full 5 seconds. 1 = Drift, leg falls by the end of the 5 second period but does not hit bed. 2 = Some effort against gravity; leg falls to bed by 5 seconds, but has some effort against gravity. 3 = No effort against gravity, leg falls to bed immediately. 4 = No movement 9 = Amputation, joint fusion explain:_________________ 6a. Left Leg 6b. Right Leg

7. Limb Ataxia: This item is aimed at finding evidence of a unilateral cerebellar lesion. Test with eyes open. In case of visual defect, insure testing is done in intact visual field. The finger-nose-finger and heel-shin tests are performed on both sides, and ataxia is scored only if present out of proportion to weakness. Ataxia is absent in the patient who cannot understand or is paralyzed. Only in the case of amputation or joint fusion may the item be scored "9", and the examiner must clearly write the explanation for not scoring. In case of blindness test by touching nose from extended arm position.	0 = Absent 1 = Present in one limb 2 = Present in two limbs If present, is ataxia in Right arm 1 = Yes 2 = No 9 = amputation or joint fusion, explain ___________________ Left arm 1 = Yes 2 = No 9 = amputation or joint fusion, explain ___________________ Right leg 1 = Yes 2 = No 9 = amputation or joint fusion, explain ___________________ Left leg 1 = Yes 2 = No 9 = amputation or joint fusion, explain ___________________
8. Sensory: Sensation or grimace to pin prick when tested, or withdrawal from noxious stimulus in the obtunded or aphasic patient. Only sensory loss attributed to stroke is scored as abnormal and the examiner should test as many body areas [arms (not hands), legs, trunk, face] as needed to accurately check for hemisensory loss. A score of 2, "severe or total," should only be given when a severe or total loss of sensation can be clearly demonstrated. Stuporous and aphasic patients will therefore probably score 1 or 0. The patient with brain stem stroke who has bilateral loss of sensation is scored 2. If the patient does not respond and is quadriplegic score 2. Patients in coma (item 1a=3) are arbitrarily given a 2 on this item.	0 = Normal; no sensory loss. 1 = Mild to moderate sensory loss; patient feels pinprick is less sharp or is dull on the affected side; or there is a loss of superficial pain with pinprick but patient is aware he/she is being touched. 2 = Severe to total sensory loss; patient is not aware of being touched in the face, arm, and leg.
9. Best Language: A great deal of information about comprehension will be obtained during the preceding sections of the examination. The patient is asked to describe what is happening in the attached picture, to name the items on the attached naming sheet, and to read from the attached list of sentences. Comprehension is judged from responses here as well as to all of the commands in the preceding general neurological exam. If visual loss interferes with the tests, ask the patient to identify objects placed in the hand, repeat, and produce speech. The intubated patient should be asked to write. The patient in coma (question 1a=3) will arbitrarily score 3 on this item. The examiner must choose a score in the patient with stupor or limited cooperation but a score of 3 should be used only if the patient is mute and follows no one step commands.	0 = No aphasia, normal 1 = Mild to moderate aphasia; some obvious loss of fluency or facility of comprehension, without significant limitation on ideas expressed or form of expression. Reduction of speech and/or comprehension, however, makes conversation about provided material difficult or impossible. For example in conversation about provided materials examiner can identify picture or naming card from patient's response. 2 = Severe aphasia; all communication is through fragmentary expression; great need for inference, questioning, and guessing by the listener. Range of information that can be exchanged is limited; listener carries burden of communication. Examiner cannot identify materials provided from patient response. 3 = Mute, global aphasia; no usable speech or auditory comprehension.
10. Dysarthria: If patient is thought to be normal an adequate sample of speech must be obtained by asking patient to read or repeat words from the attached list. If the patient has severe aphasia, the clarity of articulation of spontaneous speech can be rated. Only if the patient is intubated or has other physical barrier to producing speech, may the item be scored "9", and the examiner must clearly write an explanation for not scoring. Do not tell the patient why he/she is being tested.	0 = Normal 1 = Mild to moderate; patient slurs at least some words and, at worst, can be understood with some difficulty. 2 = Severe; patient's speech is so slurred as to be unintelligible in the absence of or out of proportion to any dysphasia, or is mute/anarthric. 9 = Intubated or other physical barrier, explain_____________________________

11. Extinction and Inattention (formerly Neglect): Sufficient information to identify neglect may be obtained during the prior testing. If the patient has a severe visual loss preventing visual double simultaneous stimulation, and the cutaneous stimuli are normal, the score is normal. If the patient has aphasia but does appear to attend to both sides, the score is normal. The presence of visual spatial neglect or anosagnosia may also be taken as evidence of abnormality. Since the abnormality is scored only if present, the item is never untestable.

0 = No abnormality.
1 = Visual, tactile, auditory, spatial, or personal inattention or extinction to bilateral simultaneous stimulation in one of the sensory modalities.
2 = Profound hemi-inattention or hemi-inattention to more than one modality. Does not recognize own hand or orients to only one side of space.

Additional item, not a part of the NIH Stroke Scale score.

A. Distal Motor Function: The patient's hand is held up at the forearm by the examiner and patient is asked to extend his/her fingers as much as possible. If the patient can't or doesn't extend the fingers the examiner places the fingers in full extension and observes for any flexion movement for 5 seconds. The patient's first attempts only are graded. Repetition of the instructions or of the testing is prohibited.

0 = Normal (No flexion after 5 seconds)
1 = At least some extension after 5 seconds, but not fully extended. Any movement of the fingers which is not command is not scored.
2 = No voluntary extension after 5 seconds. Movements of the fingers at another time are not scored.

a. Left Arm
b. Right Arm

**Index de Barthel**
Items	Avec aide	Indépendant
Alimentation (avec aide si nécessaire pour couper les aliments)	5	10
Transfert du fauteuil au lit et retour (peut s'asseoir dans son lit)	5-10	15
Toilette personelle (se laver le visage, se coiffer, se raser, se laver les dents)	0	5
Transfert aux et des toilettes (y compris déshabillage, s'essuyer, tirer la chasse)	5	10
Se baigner seul	0	15
Marche en terrain plat (ou si marche impossible, utilisation du fauteuil roulant)	0	5
Monter et descendre les escaliers	5	10
Habillage (y compris nouer les lacets, attacher les fermetures)	5	10
Contrôle intestinal	5	10
Contrôle vésical	5	10
Total

Indicateurs de retour à domicile à 2 mois : score > 20 les premiers jours
> 40 au moment du transfert en centre de rééducation, > 60 à 3 mois
Seuils de l'index de Barthel : > 60 contrôle sphinctérien, toilette et alimentation seul, déplacement sans aide
> 85 peut s'habiller, transfert lit fauteuil, > 100 indépendance complète

**Modified Rankin Scale**
0 = no symptoms at all 1 = no significant disability, despite symptoms; able to carry out all usual duties and activities 2 = slight disability; unable to carry out all previous activities but able to look after own affairs 3 = moderate disability; requiring some help, but able to walk without assistance 4 = moderately severe disbility; unable to walk without assistance and unable to attend to own bodily needs without assistance 5 = severe disability; bedridden, incontinent and requiring constant nursing care and attention

**Glasgow Outcome Scale**
1 = Good recovery - patient can lead a full and independent life with or without minimal neurological deficit 2 = Moderately disabled; patient has neurological or intellectual impairment but is independent 3 = Severely disabled. Patient conscious but totally dependent on others to get through daily activities 4 = Vegetative survival 5 = Dead

**Marqueurs de pronostic vital**
Age Sexe Troubles de la vigilance Déficit moteur touchant le membre inférieur Signe de Babinski Asymétrie pupillaire : signe d'engagement temporal Hémianopsie latérale homonyme Antécédents d'AVC Déficit neuropsychologique Type d'AVCI : hématome > occlusion gros tronc > lacune Topographie : vertébro-basilaire > carotidien Incontinence urinaire si présente à la fin de la première semaine TDM : hypodensité précoce

Quelques explications :

Age : principalement par complication du décubitus

Sexe : les femmes ont un plus mauvais pronostic vital. Il s'agit d'un biais, car cette variable est liée à l'âge. En effet, les femmes font des AVCI à un âge plus tardif que les hommes

Déficit moteur du membre inférieur : c'est l'indicateur d'un infarctus étendu dans le territoire sylvien (profond ou total)

Signe de Babinski : indicateur d'un infarctus étendu dans le territoire sylvien. Si il est bilatéral : il indique des lésions bilatérales ou une atteinte vertébro-basilaire ou un infarctus volumineux avec effet de masse

Hémianopsie latérale homonyme : lorsqu'elle est associée à un déficit sensitivo-moteur, à une aphasie ou à une héminégligence, elle signe un infarctus étendu dans le territoire sylvien

Déficit neuropsychologique (aphasie ou héminégligence) : lorsqu'il est associé à un déficit sensitivo-moteur, il signe un infarctus étendu dans le territoire sylvien

Topographie : les AVCI du territoire vertébro-basilaire ont un mauvais pronostic initial (vital). Par contre, à un mois d'évolution, ils ont un meilleur pronostic que les AVCI hémisphériques

La majorité des décès par AVCI surviennent dans les six mois. Après, la cause principale de décès est la récidive d'AVCI (25%) et l'infarctus du myocarde (40%). Le risque de récidive après AVCI reste constant dans le temps, il est évalué à 9% / an.

55 à 64 ans	1,7 à 3,6 / 1000 habitants
65 à 74 ans	4,9 à 8,9 / 1000 habitants
> 75 ans	13,5 à 17,9 / 1000 habitants