General
Internal carotid artery and its branches
- Risk and extent of stroke is influenced by
- Suddenness of occlusion
- Location of occlusion
- Presence of collateral circulation
Numbers
- Acute ICA occlusion (all comers)
- Results in 26–49% risk of stroke (18th century data)
- Not all of these strokes are severe
- 30-day risk of stroke recurrence after first stroke is
- 3% at 30 days
- 26% at 5 years.
- Annual stroke risk with symptomatic ICA occlusion
- 7% overall
- 5.9% ipsilateral to the occlusion (mean follow-up= 45.5 mos)
- Even with anticoagulation or antiplatelet drugs
- St. Louis Carotid Occlusion Study
- 2-year ipsilateral ischemic stroke rate in patients with symptomatic ICA occlusion is
- 5% in patients with normal O2 extraction fraction (OEF) by PET scan
- 26% in patients with increased OEF
- Stroke risk is less when one includes asymptomatic ICA occlusions
- (i.e., there are people walking around with ICA occlusion and no symptoms)
- In patients presenting with ICA territory stroke or TIA, complete ICA occlusion is found in 10 - 15%
Worst-case scenario of total ICA occlusion with no a-comm or p-comm flow and no collateral rescue
- Stroke in ACA and MCA territories
- ᵃ[CL]: contralateral; [IL]: ipsilateral; ᵇwith involvement on side of nondominant hemisphere; ᶜplus [CL]: upper quadrantanopsia; ᵈwith involvement on the side of the dominant hemisphere. An “X” indicates that the deficit is present
Deficitᵃ | Complete (M1 Occlusion) | Superior Division | Inferior Division |
[CL] Weakness UE > LE | X | X | ㅤ |
[CL] Weakness of Lower Face | X | X | ㅤ |
[CL] Hemisensory Loss (UE & LE) | X | X | ㅤ |
[CL] Hemisensory Loss of Face (all modalities) | X | X | ㅤ |
[CL] Neglectᵇ | X | X | ㅤ |
[IL] Gaze Preference | X | ㅤ | ㅤ |
[CL] Homonymous Hemianopsia | X | ㅤ | Xᶜ |
Receptive Aphasiaᵈ (Wernicke's area) | X | ㅤ | X |
Expressive Aphasiaᵈ (Broca's area) | X | X | ㅤ |
Gerstmann Syndrome: with dominant parietal lobe infarct | ㅤ | ㅤ | ㅤ |
- Risk of stroke after TIA: 5% during the first month. 25% are estimated to develop a stroke within 2 years.
- Diseases associated with Stroke
Disease | Presentation | Diagnostics | Other | Treatment |
Fibromuscular dysplasia (FMD) | - Transient ischemic attack (TIA) or stroke/headache/vertigo/pulsating tinnitus - Stenosis/aneurysm /dissection - Affects also renal artery (causing hypertension and bruits) | - "String of beads" appearance on angiogram - Irregularities in internal carotid artery (usually bilateral). Vertebral artery may also be affected | ㅤ | 1. Anticoagulation (usually aspirin) 2. Angioplasty |
CADASIL (Cerebral Autosomal Dominant Arteriopathy with Sub-cortical Infarcts and Leukoencephalopathy) | - Migraine headaches often with auras/TIA or stroke - Progressively: dementia/pseudobulbar palsy/ incontinence | - Binswanger's-like lacunae but at an early age (lesions around basal ganglia, pons, periventricular white matter) | - Familial. Chromosome 19 (Notch 3 gene) | - Anticoagulants (with slightly increased risk of microhemorrhages) |
MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes) | - Stroke (frequently occipital) - Multisystem disorder with childhood onset | - Elevated arterial lactate and pyruvate - Mitochondrial DNA analysis - MRI: high T2 signal and cerebral atrophy - Muscle biopsy | - Defective mitochondrial DNA (maternal inheritance) | - Coenzyme Q10/Idebenone has been tried - Avoid valproic acid (impacts mitochondria) Prognosis: Progressive with poor prognosis |
Location of occlusion
Oxford (Bamford) Stroke classification
Types | Vessels | Features |
Total Anterior Circulation Stroke (TAC) | Large cortical stroke in MCA/ACA territory | 1. Unilateral weakness (and/or sensory deficit) of face, arm, and leg 2. Homonymous hemianopia 3. Higher cerebral dysfunction (dysphasia, apraxia, astereognosis, reduced consciousness) |
Partial Anterior Circulation Stroke (PAC) | Cortical stroke in MCA/ACA territory | Any two of the following: 1. Unilateral weakness (and/or sensory deficit) of face, arm, and leg 2. Homonymous hemianopia 3. Higher cerebral dysfunction (dysphasia, apraxia, agraphia) |
Posterior Circulation Stroke | PCA and vertebrobasilar | Any one of the following: 1. Cerebellar or brainstem syndromes 2. Loss of consciousness 3. Isolated homonymous hemianopia |
Lacunar Syndrome (LACS) | Small-vessel subcortical stroke | Any one of the following (without higher cerebral dysfunction): 1. Pure motor stroke 2. Pure sensory stroke 3. Mixed sensorimotor stroke 4. Ataxic hemiparesis |
Carotid artery dissection
- Presentation
- Acute retro-orbital pain + Horner syndrome
- Reduced conscious level
- Contralateral homonymous hemianopia
- Contralateral hemiplegia
- Contralateral hemisensory disturbance
- Gaze palsy- eyes deviate towards lesion
- Partial Horner's syndrome
- Global aphasia if dominant
- Outcome depends on collateral blood supply
Anterior cerebral artery
- A1 syndrome
- Rare due to collateral supply
- Distal occlusion
- Contralateral leg weakness, sensory loss +incontinence
- Leg is in the medial surface of the cerebrum
- Proximal bilateral occlusion
- Paraplegia, sensory loss, incontinence, grasp and snout and palmomental reflex
- Bilateral frontal lobe infarction- akinetic mutism
Posterior cerebral artery
- Unilateral occipital lobe infarction → homonymous hemianopsia with macular sparing (visual cortex of the macula receives dual blood supply from MCA and PCA)
- Balint syndrome
- Cortical blindness (Anton syndrome)
- Weber syndrome
- Alexia without agraphia
- Thalamic pain syndrome (Dejerine-Roussy syndrome)
MCA strokes
- Complete MCA syndrome
- Contralateral hemiplegia
- Contralateral hemianaesthesia
- Contralateral homonymous hemianopia
- Gaze preference to ipsilateral side
- If dominant-global aphasia
- If non dominant- hemispatial neglect, anasognosia and constructional apraxia
- Partial MCA syndromes
- MI- occlusion lenticulostriate branches-
- If ischaemia of internal capsule pure contralateral motor or pure sensory motor stroke
- If ischaemia of putamen, pallidus predominantly parkinsonian features
- M2- occlusion
- If inferior division
- Dominant: Wernickes dysphasia without weakness and contralateral superior quadrantinopia
- Non- dominant: hemispatial neglect, spatial agnosia without weakness
- If superior division
- Brachial syndrome
- Frontal opercular syndrome- Broca's dysphasia with facial weakness or a combination of both
Recurrent medial striate artery (of Heubner)
- Supplies
- Head of caudate
- Anteroinferior internal capsule
- Causes
- Expressive aphasia AND
- Mild hemiparesis
- UE> LE
- Proximal muscles weaker than distal
Anterior choroidal artery (AChA) syndrome
- Supplies
- Visual system
- Inferior optic chiasm
- Posterior portion of optic tract
- Optic radiation
- Lateral geniculate body
- Temporal lobe
- Uncus
- Parahippocampal gyrus
- Amygdala
- Choroid plexus
- Temporal horn
- Atrium
- Basal ganglia
- Globus pallidus medial
- Tail of caudate
- Internal capsule (genu)
- Diencephalon
- Subthalamus
- Thalamus
- Lateral ventrolateral nucleus
- Lateral ventro-anterior nucleus
- Midbrain
- Middle 1/3 of cerebral peduncle
- Upper red nucleus
- Substantia nigra
- Complete form: Triad (mnemonic: 3 H’s)
- CL Hemiplegia
- Corticospinal tract
- CL hemisensory loss (to light touch and pinprick; usually transient)
- Spinothalamic tract
- CL Homonymous hemianopsia
- Optic tract
- Incomplete form: are more common.
- Aetiology
- Small vessel disease
- CT or MRI usually shows infarct in
- Posterior limb of IC (just above temporal horn of lateral vent), AND
- White matter posterior and lateral to it.
- Occlusion is usually tolerated fairly well, and ligation of this artery was actually utilized in treatment of Parkinsonism sometimes without ill effect but internal capsule infarct occurred in ≈ 15%.
Artery of Percheron
- Bilateral thalamic and mesencephalic infarctions
Posterior circulation (see brainstem)
- Vertebral artery
- Medial medullary syndrome (Dejerine syndrome)
- Lateral medullary syndrome (Wallenberg syndrome)
- Basilar artery
- AICA: lateral pontine syndrome (Marie-Foix syndrome)
- PICA: Sometimes lateral medullary (Wallenberg) syndrome
- SCA: infarction of superior cerebellar vermis and superior cerebellum
- Anterior spinal artery
Lacunar strokes
Definition
- Small infarcts in deep noncortical cerebrum or brainstem
Mechanism
- Due to
- Fibrinoid necrosis or Lipohyalinosis → thickening of the tunica media
- Atheroma plaques on the parent vessel occluding the origins of the penetrating small vessels
Location in decreasing frequency
- Putamen
- Caudate
- Thalamus
- Pons
- Internal capsule (IC)
- Convolutional white matter
Size of infarcts
- Ranges from 3–20mm (CT detects larger ones; better sensitivity in white matter).
- Small (3–7mm) multiple lacunes may be due to lipohyalinosis (vasculopathy due to HTN) of arteries < 200 microns (may also be cause of many ICHs);
- This vasculopathy is indicative of small vessel disease, unlikely to be prevented by carotid endarterectomy.
Lacunar strokes is virtually excluded by
- Aphasia
- Apractagnosia
- Sensorimotor stroke
- Monoplegia
- Homonymous hemianopsia (HH)
- Severe isolated memory impairment
- Stupor
- Coma
- LOC
- Seizures
L’etat lacunaire
- Multiple lacunes → chronic progressive neuro decline with one or more episodes of hemiparesis;
- Causes
- Invalidism
- Dysarthria
- Small-step gait (marche á petits pas),
- Imbalance,
- Incontinence,
- Pseudobulbar signs,
- Dementia.
- Can be mis-diagnosed as NPH (unrecognized originally).
Lacunar syndromes
Syndrome | Site | Vessel | Symptoms |
Pure motor | Post limb internal capsule | Lenticulostriate | Weakness contralateral face, arm, leg, dysarthria |
Pure sensory | VPL thalamus | Thalamogeniculate | Numbness contralateral face and limbs |
Dysarthria | Dorsal pons | Basilar perforator | Dysarthria, weakness of face and tongue, clumsy contralateral arm |
Ataxic hemiparesis | Ventral pons | Basilar perforator | Mild hemiparesis with marked ataxia |
Dysarthria + facial weakness | Anterior limb internal capsule | Lenticulostriate | Dysarthria, dysphagia, mutism with mild facial weakness |
- Pure sensory stroke or TIA
- Most common lacunar manifestation
- Isolated unilateral numbness of face, arm, and leg.
- Only 10% of TIA go on to stroke.
- Lacune in sensory (posteroventral) thalamus → CT detection is poor.
- Dejerine-Roussy= rare thalamic pain syndrome that may develop late
- Pure motor hemiparesis (PMH)
- 2nd most common lacunar manifestation
- Pure unilateral motor deficit of face, arm, and leg without sensory deficit, HH, etc.
- Lacune in
- Posterior limb of IC,
- Lower basilar pons where corticospinal (CS) tracts coalesce,
- Mid-cerebral peduncle (rare)
- Ataxic hemiparesis
- Contralateral PMH+ cerebellar ataxia of affected limbs (if they can move).
- Lacune in
- Basilar pons at junction of upper third and lower two–thirds
- Clinical features
- Dysarthria,
- Nystagmus
- Unidirectional toppling
- Differential severity in face, arm, and leg possible because Corticospinal fibers are dispersed by nuclei in the pons (unlike compact pyramids and peduncle)
- Variant: dysarthria-clumsy hand syndrome
- Lesion in same location or genu of IC.
- May be mimicked by a cortical infarct, but latter will have numb lips
- Pure Motor Hemiparesis sparing the face
- Lacune in
- Medullary pyramid;
- Clinical features
- At onset, there may be vertigo and nystagmus (approaching lateral medullary syndrome)
- Variant: thalamic dementia
- Central region of one thalamus + adjacent subthalamus
- Abulia, memory impairment+ partial Horner (miosis + anhydrosis)
- Mesencephalothalamic syndrome
- Aka
- “Top o’ the basilar syndrome.”
- Usually caused by embolus.
- Infarct typically butterfly shaped and bilateral
- Involving rostral brainstem and cerebral hemisphere regions fed by the distal basilar artery.
- Clinical
- III palsy,
- Parinaud’s syndrome & abulia,
- May have amnesia, hallucinations and somnolence, usually without significant motor dysfunction
- Weber’s syndrome
- Clinical features
- CN3 palsy AND
- Contralateral Pure Motor Hemiparesis (no sensory loss).
- Due to
- Occlusion of interpeduncular branches of basilar artery
- Aneurysm of
- Basilar bifurcation or
- BA-SCA junction
- Central midbrain infarction → disrupting cerebral peduncle and CN3 fascicles.
- Pure Motor Hemiparesis with crossed VI palsy
- Lacune in paramedian inferior pons
- Cerebellar ataxia with crossed III palsy (Claude syndrome)
- Lacune in dentatorubral tract (superior cerebellar peduncle)
- Hemiballism
- Due to
- Infarct OR
- Hemorrhage
- Located in subthalamic semilunar nucleus of Luys
- Lateral medullary syndrome
- Locked-in syndrome
- Bilateral PMH from infarct at IC, pons, pyramid or (rarely) cerebral peduncles
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