Intracerebral Hemorrhage Rupture of vessel wall due to hypertension

The blood supply to the brain is derived from two systems: Internal Carotid Vertebro-basilar The two systems anastamose in the great cerebral arterial circle of Willis at the base of the brain.

Arterial Distribution to the Brain: Basal View

Unilateral Anterior Cerebral Artery Syndrome Unilateral occlusion of the anterior cerebral artery is associated with the following clinical picture: Contralateral hemiplegia or hemiparesis affecting primarily the lower extremity and to a lesser extent the upper extremity Contralateral sensory deficit affecting primarily the lower extremity and to a lesser extent the upper extremity Transcortical motor aphasia when the left (dominant) hemisphere is affected

Bilateral Anterior Cerebral Artery Syndrome This syndrome occurs when both anterior cerebral arteries arise anomalously from a single trunk. In addition to the signs encountered in the unilateral syndrome, the following signs and symptoms occur in the bilateral syndrome due to involvement of orbitofrontal cortex, limbic structures, supplementary motor cortex, and cingulate gyrus: Loss of initiative and spontaneity Profound apathy Memory and emotional disturbances Akinetic mutism (complete unresponsiveness with open eyes only) Disturbance in gait and posture Grasp reflex Disorder of sphincter control

Arterial Distribution to the Brain: Basal View

Recurrent Artery of Heubner (Medial Striate Artery) Syndrome Infarction in the territory supplied by the recurrent artery of Heubner (medial striate artery), which is a branch of the anterior cerebral artery, results in the following signs: Contralateral face and arm weakness without sensory loss Behavioral and cognitive abnormalities, including abulia, agitation, neglect, and aphasia The clinical signs reflect involvement of the anterior limb of the internal capsule, rostral basal ganglia (caudate nucleus and putamen), and the basal frontal lobe.

Anterior Choroidal Artery Syndrome Occlusion of the anterior choroidal artery, a branch of the internal carotid artery, may be asymptomatic or may result in one or more of the following: Contralateral motor deficit (hemiplegia) involving the face, arm, and leg due to involvement of the posterior part of the posterior limb of the internal capsule and the cerebral peduncle. This is the most consistent and persistent deficit. Contralateral hemisensory deficit, usually transient, involving, in most cases, all sensory modalities (hemianesthesia) due to involvement of the sensory tracts within the posterior limb of the internal capsule. Contralateral visual field defect (hemianopia or quadrantanpoia) due to involvement of the retrolenticular part of the internal capsule (visual radiation) or the lateral genticulate nucleus. This is the most variable feature of the syndrome.

Arterial Distribution to the Brain: Basal View

Intracerebral Hemorrhage Rupture of vessel wall due to hypertension

Middle Cerebral Artery Syndrome This is the most frequently encountered stroke syndrome. The clinical picture varies according to the site of occlusion of the vessel and to the availability of collateral circulation. The conglomerate clinical signs and symptoms of this syndrome consist of: Contralateral hemiplegia or hemiparesis (complete or partial paralysis) affecting primarily the face and upper extremity and, to a lesser degree, the lower extremity. Weakness is greatest in the contralateral hand because more proximal limb and trunk muscles as well as facial muscles have greater representation in both hemispheres. Contralateral sensory deficit, also more prominent in the face and upper extremity than in the lower extremity. Position, vibration, deep touch, two-point discrimination, and stereognosis are more affected than pain and temperature because the latter two sensory modalities may be perceived at the thalamic level. Contralateral visual field deficit because of damage to the optic radiation, the tract that connects the lateral geniculate nucleus with the visual cortex. Depending on where the lesion in the optic tract is located, the visual field deficit may be a homonymous hemianopia (half-field deficit) or a quadrantanopia (quadrant-field deficit). Contralateral conjugate gaze paralysis because of the involvement of the frontal eye field (area 8 of Brodmann). The gaze paralysis is usually transient for 1 to 2 days. The reason for this transient duration is not clear.

Middle Cerebral Artery Syndrome (con’t) Aphasia (with impairment of repetition) if the dominant (left) hemisphere is involved. The aphasia may be of Broca’s, Wernicke’s, or global variety depending on the involved cortical region. Inattention and neglect of the contralateral half of body or space and denial of illness if the nondominant (right) hemisphere is involved. Spatial perception disorders if the right, nondominant hemisphere is involved. This includes such difficulties as copying simple pictures or diagrams (constructional apraxia), interpreting maps or finding one’s way out (topographagnosia), and putting on clothes properly (dressing apraxia). Gerstmann syndrome (finger agnosia, acalculia, right-left disorientation, and pure dysgraphia).

Cortical infarct involving the ventral (arm & head regions) of the precentral gyrus and Broca’s speech area (MCA)

Small caliber lenticulostriate arteries, branches of the middle cerebral artery, supply most of the internal capsule.

Capsular hemiplegia- involving genu (corticobulbars) and post Capsular hemiplegia- involving genu (corticobulbars) and post. limb (corticospinals) of the internal capsule (MCA)

Lenticulostriate Artery Syndrome Infarction in the territory of the lenticulostriate artery, a branch of the middle cerebral artery, is associated with pure motor hemiplegia because of involvement of the internal capsule.

Posterior Cerebral Artery Syndrome The clinical picture of posterior cerebral artery occlusion is variable depending on whether it is unilateral or bilateral, the site of occlusion, and the availability of collateral circulation. Unilateral Posterior Cerebral Artery Syndrome Unilateral occlusion of the posterior cerebral artery is associated with the following: Contralateral visual field deficit (hemianopia) due to involvement of the calcarine cortex. Macular (central) vision is usually spared because of macular representation in the occipital pole, which receives additional blood supply from the middle cerebral artery. Visual and color agnosia, the inability to name a color or point to a color named by the examiner because of involvement of the inferiomesial aspect of the occipitotemporal lobe in the dominant hemisphere. Contralateral sensory loss of all modalities with concomitant pain (thalamic syndrome) due to involvement of the ventral posterolateral and ventral posteromedial nuclei of the thalamus, which are supplied by deep penetrating branches of the posterior cerebral artery. Pure alexia (alexia without agraphia) with a left-sided lesion affecting the posterior corpus callosum and the left visual cortex. As a rule, the posterior cerebral artery syndrome is not associated with motor deficit. The hemiplegia reported occasionally in these patients is attributed to involvement of the midbrain by the infarct.

Branches of the posterior cerebral artery supply the basal midbrain.

Weber’s Syndrome (Alternating Oculomotor Hemiplegia) involving crus cerebri of the midbrain (corticospinals and corticobulbars) and oculomotor nerve (branches of PCA) Ipsilateral external strabismus (exotropia), ptosis, mydriasis (pupillary dilation) with contralateral spastic hemiplegia (positive Babinski).

Alternating abducent hemiplegia involving the basilar pons (corticospinals) and abducens nerve (br. of basilar artery) Ipsilateral internal strabismus (esotropia) with contralateral spastic hemiplegia.

The posterior inferior cerebellar artery, branch of the vertebral artery, supplies the dorsolateral medulla.

Wallenberg’s Syndrome- vascular lesion of dorsolateral medulla involving the spinal tract & nuc. of V, spinal lemniscus (spinothalamics), and nucleus ambiguus (PICA). Typically includes a Horner’s syndrome (slight ptosis).

Alternating hypoglossal hemiplegia involving the medullary pyramid (corticospinals) and hypoglossal nerve (anterior spinal artery). Medial lemniscus also involved. Ipsilateral tongue paralysis (tongue deviates to side of lesion) with contralateral hemiplegia. Contralateral loss of conscious proprioception, vibratory sense.

Symptom or Sign Internal Carotid Vertebrobasilar Motor deficit Contralateral Bilateral, crossed Sensory deficit Visual deficit Monocular blindness; contralateral field defect Bilateral, cortical blindness Speech deficit (aphasia) Present Absent Cranial nerve deficit

Vertebral-Basilar Arteries Syndrome Occlusion of the vertebral-basilar arterial system usually results in brain stem infarcts. The clinical picture varies according to the specific branch affected and the brain stem territory involved (e.g., lateral medullary syndrome, medial medullary syndrome, Benedikt syndrome, Weber’s syndrome, etc.). Common to all vertebral-basilar artery syndromes are the following: Bilateral long tract (motor and sensory) signs Crossed motor and sensory signs (e.g., facial weakness or numbness combined with contralateral extremity weakness or numbness) Cerebellar signs Cranial nerve signs Alteration in state of consciousness (stupor or coma) Disconjugate eye movements In general, the presence of “the four Ds with crossed findings” suggests a brain stem stroke from vertebrobasilar occlusion. The four Ds are diplopia, dysarthria, dysphagia, and dizziness.