Posterior cerebral artery syndrome

Symptoms of Posterior cerebral artery infarct
Structures affected in PCA syndromes
Posterior cerebral artery syndromes
Clinical presentation of Posterior Cerebral Artery (PCA) occlusion

Middle Cerebral Artery (MCA) Syndrome

The clinical picture vary depends on the site of occlusion and availability of collaterals.It is characterized by:

• Contralateral hemiplegia affecting the face and arm more than the leg.
• Contralateral hemianesthesia affecting the face and arm more then leg. There is also loss of cortical sense like stereognosis, discrimination and tactile extinction.
• Contralateral homonymous hemianopia or inferior quadrantanopia.
• Aphasia when dominant lobe is involved
• Inattention, neglect, denial of illness and apractic syndromes mainly with nondominant hemispheric lesions.
• Paresis and apraxia of conjugate gaze to the opposite side.
• Alexia and agraphia (Left angular gyrus lesion)
• Gerstmann'ssyndrome (Fingeragnosia, acalculia dysgraphia and right-left disorientation).Infarction in the nondominant hemisphere result in it

Perioral and distal upper limb sensory dysfunction is called as cheiro-oral syndrome,may occur . 

Ataxic hemiparesis with cheiro-oral syndrome is sometime seen contralateral posterior capsular infarction 

Rarely, nondominant infarction may result in  an acute confusional state and acute agitated delirium with affective and autonomic excitement, delusions, and hallucinations .

Lesions of either hemisphere may result in  contralateral homonymous hemianopia or contralateral homonymous inferior quadrantanopia.

Cataleptic posturing in isolation from other manifestations of the catatonic syndrome is also mentioned in association with MCA territory infarction 

Symptoms of main artery occlusion:

• Coma at the  onset.
• Contralateral hemiplegia affecting  face and arm more than leg
• Contarlateral hemihyposthesia with cortical sensory loss in upperlimb. There is also loss of cortical sense like stereognosis, discrimination and tactile extinction.
• Contralateral homonymous hemianopia.
• Aphasia and agraphia in left sided lesions.

Capsular Branch Occlusion: (Lenticulo striate artery)

• Contralateral complete hemiplegia affecting the upper and lower limbs to the same extent
• Contralateral hemihyposlhesia of subcortical type.
• Contralateral hemianopia may occur.
• No loss of consciousness or aphasia.

Cortical branch occlusion

Frontal Branches occlusion:

• Facio-brachial monoplegia.
• Motor aphasia and agraphia in left-sided lesions.

Parietal vessel occlusion:

• Cortical sensory loss in the upper limb.
• Lower.quadrantic homonymous hemianopia
• Sensory aphasia (alexia) and apraxia in left sided lesions.

Temporal  vessel occlusion

• Upper quadrantic homonymous hemianopia.
• Sensory aphasia (auditory agnosia).

Structures affected in PCA syndromes

Symptoms and signs of stroke depends on the areas of brain affected and the stuctures involved .The various structures involved in central and peripheral territory stroke is given below

Peripheral territory infarction

• Homonymous hemianopia (often upper quadrantic): Calcarine cortex or optic radiation nearby.
• Bilateral homonymous hemianopia, cortical blindness, awareness or denial of blindness; tactile naming, achromatopia (color blindness), failure to see to-and-fro movements, inability to perceive objects not centrally located, apraxia of ocular movements, inability to count or enumerate objects, tendency to run into things that the patient sees and tries to avoid-Bilateral occipital lobe with possibly the parietal lobe involved. 
• Verbal dyslexia without agraphia, color anomia: Dominant calcarine lesion and posterior part of corpus callosum.
• Memory defect: Hippocampal lesion bilaterally or on the dominant side only.
• Topographic disorientation and prosopagnosia: Usually with lesions of nondominant, calcarine, and lingual gyrus.
• Simultanagnosia, hemivisual neglect: Dominant visual cortex, contralateral hemisphere. 
• Unformed visual hallucinations, peduncular hallucinosis, metamorphopsia, teleopsia, illusory visual pread, palinopsia, distortion of outlines, central photophobia: Calcarine cortex.
• Complex hallucinations: Usually nondominant hemisphere.

Central territory infarction

• Thalamic syndrome: sensory loss (all modalities), spontaneous pain and dysesthesias, choreoathetosis, intention tremor, spasms of hand, mild hemiparesis: Posteroventral nucleus of thalamus; involvement of the adjacent subthalamic body or its afferent tracts. 
• Thalamoperforate syndrome: crossed cerebellar ataxia with ipsilateral third nerve palsy (Claude’s syndrome): Dentatothalamic tract and issuing third nerve. 
• Weber’s syndrome: third nerve palsy and contralateral hemiplegia: Third nerve and cerebral peduncle.
• Contralateral hemiplegia:  Cerebral peduncle. 
• Paralysis or paresis of vertical eye movement, skew deviation, sluggish pupillary responses to light, slight miosis and ptosis (retraction nystagmus and “tucking” of the eyelids may be associated):Supranuclear fibers to third nerve,interstitial nucleus of Cajal, nucleus of Darkschewitsch, and posterior commissure.
• Contralateral rhythmic, ataxic action tremor; rhythmic postural or “holding” tremor (rubral tremor): Dentatothalamic tract.