1. Stroke syndromes of posterior circulations
Done By: Dana Marafie

2. Posterior Circulation

3. Posterior circulation

4. Arteries & structures they supply
PCA: temopral & occipital lobes, parts of thalamus & midbrain
SCA: midbrain &superior cerebellum
AICA: pons & cerebellum
PICA: medulla & cerebellum
Basilar: pons , other braches
Vertebral:
Anterior spinal : upper 2/3 of ant. Surface of spinal cord

5. Specific supply Occipital lobe: PCA
Temporal lobe: MCA (suerpior lateral ) &PCA ( rest)
Midbrain: PCA( ant surface), SCA ( post surface)
Pons: Basilar ( mainly), AICA
Medulla: ant. Spinal , Vertebral & PICA . Small region by ( post spinal)
Thalamus: branches from PCA
Cerebellum : SCA, AICA & PICA

6. Posterior circulation strokes
Form 20% of all ischemic strokes
Mortalility is around 4% except for basilar artery occlusion where it can be up to 90% !
However, outcome is not very good
Usually cause bilateral involvement
severe headache, vomiting & Nausea are more common in posterior circulation strokes
Vertigo, Nystagmus , hemiplagia or quadriplegia, ocular eye movements, ataxia & change in level of consciousness are also seem
When to expect Post circulation stroke in a patient?
1- different symptoms & different functions or str. Affected in a way that can not be explained by a cortical region (many tracts or cranial nerves involved)????
2- when patient is presented with vomiting ,Nystagmus, Nausea, ocular movement disorders or vertigo along with the other symptoms

7. Arteries & Syndromes! From SUPERIOR TO INFERIOR : PCA Occlusion :
Basilar Artery Occlusion: Locked-in Syndrome
Branches;
AICA Occlusion :
PICA Occlusion : Wallenberg’s Syndrome
Vertebral Occlusion :
Anterior Spinal Artery Occlusion:
These Syndrome can be produced by occlusion of not just mentioned artery but the other arteries as ,long as the same str involved: However, there are commonly seen in case of occlusion of the mentioned artery

8. PCA occlusion
Lateral surface
Medial surface

9. PCA Occlusion contralateral hemianopia ( with macular sparing)
memory deficit : damage in hippocampal formation
(disconnection syndrome )
Bilateral PCA occlusion = Blindness + inability to form new memories

10. Left homonymous hemianopia ( with macular sparing)
Picture as seen in
Left homonymous hemianopia ( with macular sparing)

11. PCA occlusion
T1 MRI of PCA infart

12. PCA ( al level of branches to midbrain) (Weber’s syndrome)
at level of midbrain ,
specifically the BASE X

13. PCA ( al level of branches to midbrain) (Weber’s syndrome)
Manifestations: : at level of midbrain
Motor Weakness – contralateral hemiplegia (upper and lower extremity) : Corticospinal tract
corticobulbar fibers in the cerebral peduncle
Ipsilateral Lateral gaze weakness & diplopia :CN 3 fibers (LMN)
PE eye movements: patient is inable to move eye up,down, or medially in the epsilateral side
pupillary dilitation: if Edinger-Westphal nucleus are involved

14. CASE!
A 55 year old African woman had abdominal surgery 2 weeks before suddenly remarking to her husband that she was seeing double. She also felt a weakness in her left arm and leg. Her husband noticed that her right eyelid was drooping.
PE: Her general physical condition was good.
EYES: : right eyelid does not open fully.
right eye was deviated to the right (laterally).
When asked to converge the eyes only the left eye adducted showed pupillary constriction ( right is dilated).
MOTOR SYSTEM: Motor strength was normal on the right but was reduced on the left, especially in the arm where there was an increased biceps reflex and resistance to passive stretch.

15. Basilar artery occlusion (Locked-in Syndrome)

16. Basilar artery occlusion (Locked-in Syndrome)
Manifestation :at the Level of the Pons
Weakness of both upper and lower extremity (Quadriplegia): bilateral cortical spinal tracts
Weakness of face - entire side :Bilateral corticobulbar tracts
If lesion is big,Horizonal gaze weakness: Bilateral fascicles of CN VI ( ONLY vertical gaze is possible!)
Dysarthria: Bilateral corticobulbar tracts
Death from respiratory failure is common
PATEINT are alert, conscoius with normal cognitive fuction
IF VERY SEVERE, the only way to communication may be blinking 
Patient is LOCKED-IN their bodies : Quadriplegic, with dysarthria& facial weekness!

17. MRI after 19 days in hospital MRA after 19 days in hospital
Locked-in Syndome
A 62-year old woman with a history of hypertension for 35 years developed left-sided hemiparesis. One week later she became tetraplegic and unable to speak. However, she was able to communicate by blinking. She died three months after the onset of her neurological symptoms.
MRI after 19 days in hospital MRA after 19 days in hospital
After autopsy

18. locked-in syndrome
A quadriplegic patient with locked-in syndrome who managed to survive ( less severe case)

19. Labyrinthine Artery Syndrome
labyrinthine or internal auditory artery usually takes its origin from AICA, but it can also take origin from PICA or the basilar artery.
It supplies the inner ear
Occlusion of this artery can lead to sudden tinnitus, vertigo or even unilateral ipsilateral deafness !!!
Labrinthine Artery

20. PICA Occlusion (Lateral Medullary syndrome Of Wallenberg )
At the level of dorso-lateral part of medulla
& Cerebellum

21. PICA Occlusion (Lateral Medullary syndrome Of Wallenberg )
The commonest of brainstem strokes!
Manifestation: At the level of dorso-lateral
medulla & Cerebellum
Ipsilateral Sensory loss of face - pain and
Temperature CN 5 spinal N
Ipsilateral Facial pain CN 5 spinal N
Ipsilateral Ataxia - arm and l Restiform body, Ipsilateral cerebellum
Ipsilateral Gait ataxia Restiform body, cerebellum
Ipsilateral Nystagmus Vestibular nucleus
Ipsilateral Nausea / vomiting Vestibular nucleus
Ipsilateral Vertigo Vestibular nucleus
Ipsilateral Horseness Nucleus ambiguus
Ipsilateral Dysphagia Nucleus ambiguus
Ipsilateral Horner syndrome-Descending sympathetics
Contralateral Hemisensory loss - pain and
Temperature Spinothalamic tract
Hiccups  ( whatever you do, it does not go !!!)
Prognosis is generally quite good with full or near full recovery expected at 6 months.

23. CTscan showing lesion in Medulla & Cerebellum in Wallenberg Syndrome

24. Vertebral artery occlusion
Can also give Wallenberg’s syndrome

25. Thalamic infarction (Dejerine-Roussy syndrome or central pain synrome)
PCA Pentrating branches to thalamus
Very sad syndrome
Manifestation : pure sensory loss without weakness : due to lesion of (CONTRLATERAL: WHY? Crossing below thalamus)
- Hemilateral sensory loss of all modalities
- Hemilateral pain
( hypersensitivity) :
if you touch their affected side, they will shout !
PCA

26. MRI of the patient I day after MRI of the patient I day after
After death, autopsy

27. Anterior Spinal Artery Occlusion ( Anterior Spinal Artery syndrome)
Complete sensory & motor loss below the level of occlusion except for proprioception

28. Anterior Spinal Artery syndrome
Manifestations:
Loss of motor function below level of damage : due to damage of corticospinal tracts ( ant & post)
Bilateral anesthesia ( loss of sensation below the level of damage )
: damage of spinothalamic
Loss of bladder & bowel control : damage of descending autonomic tracts;
Proprioception is intact due to sparing of dorsal system
motor & sensory function in face can be intact

29. Note
Keep in mind that these are not the only syndromes we see in posterior circulation
There are many other syndrome that are seen in infartions affecting other regions of brain stem
EG of other syndromes of :
Midbain :Claude, Benedict ,Nothnagel,Parinaud Syndromes
Pons: Millard-Gubler and Raymond-Foville
Medulla: Medial medullary syndrome

30. Quiz ! 
Alia :Overall mortality for posterior circulation strokes is:
a.       5% b.      20% c.       40% d.      70% e.       90%

31. Wadha :
1- Locked-in Syndrome consists of:
 a. Coma with quadriplegia
b. Bilateral upper extremity weakness greater than lower extremity weakness
c. Quadriplegia, bilateral facial and oropharyngeal palsy but preservation of cortical function and vertical gaze
d. Cranial nerve findings contralateral to motor and sensory findings

32. Lastly, Sulaiman  :In Weber Syndome:
a .Ipsilatral 3rd nerve palsy & hemiplgia
b. Ipsilateral hearing loss
c. vertigo, vomiting , ipsilateral ataxia & facial sensory loss & contralateral sensery loss of limbs
d.Ipsilatral 3rd nerve palsy & crossed hemiplgia