Localization of stroke syndromes

Dr.M.Dhanaraj

Localization of stroke syndromes

Three steps

1.Clinical localization of the site of the lesion.

2.Identifying the vascular territory and the vessel involved.

3.Correlating with the imaging findings.

Clinical localization of stroke syndromes

Prerequisites

1.Functional anatomy of brain.

2.Blood supply to the different parts of brain.

Blood supply of brain-Carotid Arteries

Vertebral artery Circle of willis

Blood supply of brain – vertebral artery and circle of Willis

Blood supply of brain

ANTERIOR CIRCULATION STROKE SYNDROMES

Anterior circulation

Blood supply-Lateral view

Blood supply-Medial view

Blood supply-Coronal view

Blood supply-Axial view

Middle cerebral artery infarction - superior branch

Clinical features

1.Contralateral hemiplegia – face and

upper limb more involved than lower

limb.

2. Contralateral hemisensory loss.

3.Conjugate gaze paresis(patient looks

towards the side of lesion.

4.Broca’s dysphasia (if left sided)

Middle cerebral artery infarction - Inferior branch

Clinical features

1.Contralateral hemianopia.

2.Wernicke’s dysphasia ( if left sided )

3.Left spatial neglect ( if right sided )

Middle cerebral artery infarction - stem occlusion

Clinical features

1.Contralateral hemiplegia

2. Contralateral hemisensory loss

3. Contralateral gaze palsy

4. Contralateral hemianopia

5.Global dysphasia (Left sided lesion)

6.Anosognosia and amorphosynthesis

(Right sided lesion)

7.Altered sensorium (due to edema)

Middle cerebral artery infarction -

Clinical features

1.Contralateral hemiparesis

2.Contralateral sensory loss

3.Transcortical motor / sensory

aphasia ( left sided lesion)

Lenticular striate artery occlusion

Anterior cerebral artery infarctionClinical features

1.Contralateral

a.paralysis of leg and foot with paresis of arm

b.cortical sensory loss over leg and foot

c.presence of primitive reflexes

2.Urinary incontinence

3.Gait apraxia

4.Mutism, delay and lack of spontaneity of motor acts

5.Apraxia of left sided limbs(with left sided lesion and corpus callosum involvement)

Internal carotid artery infarction

Clinical features

Variable - based on the collaterals and mechanism of stroke (embolism, extension of thrombus , low flow)

1.Amaurosis fugax

2. Watershed infarctions

3.MCA/ACA- either alone or in combinations

Posterior circulation stroke syndromes

Posterior circulation

Lateral view

Posterior circulation

Medulla

Lateral medullary syndromeA. IPSILATERAL1.Xth cranial nerve palsy2.Cerebellar signs3.Horner’s syndrome4.Impaired pain, temperature

and touch on the upper half of face

B. CONTRA LATERAL1.Impaired pain and

temperature over the body

Medial medullary syndrome

A.IPSILATERAL

1.XIIth nerve palsy

B.CONTRALATERAL

1.Hemiplegia – sparing the

face

2.Hemianaesthesia sparing the

face.

Pons-Lower

Medial pontine syndrome – occlusion of paramedian branch of basilar artery

A.IPSILATERAL

1.Gaze paresis

2.Cerebellar signs

B.CONTRALATERAL

1.Hemiparesis

2.Hemianaesthesia

Lateral pontine syndrome-occlusion of anterior inferior cerebellar artery

A.IPSILATERAL

1.LMN VIIth nerve palsy

2.Gaze palsy

3.Deafness,tinnitus

4.Cerebellar signs

B.CONTRALATERAL

1.Impairment of pain and temperature on the body

MID BRAIN

Weber syndrome-occlusion of perforating branch of posterior cerebral

arteryClinical features

1.Ipsilateral

a.3rd nerve palsy

2.Contralateral

a.hemiplegia

Benedikt syndrome-occlusion of perforating branch of posterior cerebral

Clinical features

1.Ipsilateral

a.3rd nerve palsy

2.Contralateral

a.cerebellar ataxia

Thalamus-occlusion of thalamo geniculate branches of posterior

cerebral artery Contralateral

1.Sensory loss

2.Spontaneous pain

3.Choreo athetosis

4.Ataxic tremor

5.Mild hemiparesisTHALAMUS

Occipital lobe-optic pathway and visual reflexes

Occipital lobe-occlusion of left calcarine artery

Clinical features

1.Right Hemianopia

Occipital lobe-occlusion of both calcarine arteries

Clinical features

1.Bilateral hemianopia-

cortical blindness (light

reflex preserved)

Left occipital lobe with corpus callosum infarction

Left

Clinical features

1.Right hemianopia

2.Alexia without

agraphia

Basilar artery occlusionClinical features

1.Paralysis of all four limbs2.Bulbar paralysis3.Eye movements abnormalities4.Nystagmus5.Coma

Note: The neurological deficit is variable depending upon the ischemia – modifying factors.

Differentiating features between anterior and posterior circulation stroke

Clinical features Posterior circulation Anterior circulation

A.History

1.Vertigo Present Absent

2.Unsteadiness Present Absent

B.Physical findings

1.Crossed hemiplegia Present Absent

2.Bilateral deficits Present Absent

3.Cerebellar signs Present Absent

4.Ocular findings(LMN/INO/Gaze deviation to paralysed side) Present Absent

5.Dissociated sensory loss Present Absent

6.Sensory loss over V1 and V2 Present Absent

7.Horners syndrome Present Absent

Importance of clinical localisation of stroke

1. Careful clinical evaluation in combination with imaging

helps to find out the etiology of stroke and plan the

appropriate treatment.

2. Clinical observations in correlation with imaging helps to

understand neurology / neurophysiology better.

Note:Neurological examination must be tailored

according to the clinical scenario .

Limitations of clinical localisation of stroke syndromes

1. A single syndrome may occur due to lesion at different sites

Eg. Pure motor hemiplegia

2.A vascular occlusion at a specific site can produce varying clinical

manifestations.

3.Clinical examination may not detect very small or multiple

infarctions(as in SBE).

Note:Imaging is very useful in the above situations.