Posterior circulation stroke


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Posterior circulation stroke

  2. 2.  Stroke or CVA is defined as abrupt onset of neurologic deficit that is attributable to a focal vascular cause. Stroke has occured if the neurologic signs and symptoms last for >24 hours
  3. 3.  It is composed of the paired vertebral artery,basilar artery&paired PCA’s These major arteries give rise to short&long circumferential branches that supply the cerebellum,medulla,pons,midbrain,thalamus,hipp ocampus and medial temporal&occipital lobes PCA syndromes usually result from atheroma or emboli at the top of basilar artery,fibromuscular dysplasia or vertebral artery dissection
  4. 4.  P1 SYNDROME:infarction usually occurs in the I/L subthalamus&medial thalamus and in I/L cerebral peduncle&midbrain P2 SYNDROME:Cortical temporal and occipital lobe signs
  5. 5.  The VERTEBRAL artery has 4 segments V1,V2,V3&V4 The fourth segment courses upward to join the other vertebral artery to form the basilar artery Only V4 gives rise to branches that supply the brainstem&cerebellum The PICA,in its proximal segment supplies the lateral medulla and in its distal branches the inferior surface of cerebellum
  6. 6.  ON SIDE OF LESION:1) Pain,numbness,impaired sensation over one-half of face:5th nerve nucleus2) Ataxia:restiform body,cerebellar hemisphere,spinocerebellar tract3) Nystagmus,diplopia,vertigo,nausea,vomting :vestibular nucleus4) Horner’s syndrome:descending sympathetic tract5) Dysphagia,paralysis of palate,vocal cord,diminished gag reflex:fibres of 9th&10th nerves
  7. 7. 6)Loss of taste:nucleus&tractus solitarius7)Numbness of I/L arm,trunk&leg: cuneate&gracile nucleus8)Weakness of lower face:UMN fibres to I/L facial nucleus ON SIDE OPPOSITE LESION:1) Impaired pain&thermal sense over half the body,sometimes face:Spinothalamic tract
  8. 8.  On the side of lesion:1) Paralysis with atrophy of half the tongue: I/L 12th nerve On the side opposite lesion:1) Paralysis of arm&leg sparing face;impaired tactile&proprioceptive sense over one half of the body:C/L pyramidal tract&medial leminiscus
  9. 9.  Branches of basilar artery supply the base of the pons&superior cerebellum and fall into 3 groups:1) Paramedian,7-10 in number supply a wedge of pons on either side of midline2) Short circumferential,5-7 that supply lateral two-thirds of pons&middle,superior cerebellar peduncle3) B/L long circumferential(SCA&AICA) course around pons to supply the cerebellar hemispheres
  10. 10.  MEDIAL INFERIOR PONTINE SYNDROME: ON THE SAME SIDE:1) Paralysis of conjugate gaze to the side of lesion2) Nystagmus:vestibular nucleus3) Ataxia:middle cerebellar peduncle4) Diplopia on lateral gaze:abducens nerve ON THE OPPOSITE SIDE:1) Paralysis of face,arm&leg:CB&CS tracts2) Impaired tactile&proproiceptive sense over one-half of body:medial leminiscus
  11. 11.  LATERAL INFERIOR PONTINE (AICA) SYNDROME: ON THE SIDE OF LESION:1) Horizontal&vertical gaze nystagmus,vertigo,nausea,vomting:vestibula r nerve or nucleus2) Facial paralysis:7th nerve3) Ataxia:middle cerebellar peduncle&cerebellar hemisphere4) Impaired sensation over face:descending tract&5th nucleus ON THE SIDE OPPOSITE LESION:1) Impaired pain and thermal sense over one- half of body
  12. 12.  ON THE SIDE OF LESION:1) Ataxia of limbs and gait-pontine nucleii ON THE SIDE OPPOSITE LESION:1) Paralysis of face,arm&leg:corticobulbar and corticospinal tracts2) Variable impaired touch and proprioception:medial leminiscus
  13. 13.  ON THE SIDE OF LESION:1) Ataxia:middle cerebellar peduncle Paralysis of muscles of mastication:motor fibres or nucleus of 5th nerve ON THE SIDE OPPOSITE LESION:1) Impaired pain and thermal sense on limbs and trunk:spinothalamic tract
  14. 14.  MEDIAL SUPERIOR PONTINE SYNDROME: ON THE SIDE OF LESION:1) Cerebellar ataxia:superior/middle cerebellar peduncle2) Internuclear ophthalmoplegia:MLF3) Myoclonic syndrome,palate,pharynx,vocal cords-dentate projection,inferior olivary nucleus ON THE SIDE OPPOSITE LESION:1) Paralysis of face,arm&leg:CB&CS tract2) Rarely touch,vibration&position:medial leminiscus
  15. 15.  LATERAL SUPERIOR PONTINE SYNDROME OR SCA OR MILLS’ SYNDROME: ON SIDE OF LESION:1) Ataxia:middle&superior cerebellar peduncles,dentate nucleus2) Dizziness,nausea,horizontal nystagmus:Vestibular nucleus3) Horner’s syndrome:descending sympathetic tract4) Tremor:red nucleus,superior cerebellar peduncle
  16. 16.  ON SIDE OPPOSITE LESION:1) Impaired pain&thermal sense on face,limbs&trunk:spinothalamic tract2) Impaired touch,vibration&position sense:medial leminiscus
  17. 17.  MILLARD-GUBLER SYNDROME:I/L LMN type facial nerve palsy&C/L hemiparesis due to involvement of 7th nerve nucleus&CST FOVILLE’S SYNDROME:I/L LMN type facial nerve palsy&horizontal gaze palsy with C/L hemiparesis due to involvement of horizontal gaze centre,7th nerve nucleus&CST RAYMOND’S SYNDROME:I/L abducens palsy C/L hemiparesis due to involvement of 6th cranial nerve&CST
  18. 18.  MEDIAL MIDBRAIN SYNDROME:1) ON THE SIDE OF LESION:Eye”down&out” secondary to unopposed action of 4th&6th cranial nerves,with dilated&unresponsive pupil(3rd cranial nerve)2) ON SIDE OPPOSITE LESION:paralysis of face,arm,leg(CB&CS tracts in crus cerebri) LATERAL MIDBRAIN SYNDROME:1) ON THE SIDE OF LESION:eye down&out2) ON THE OPP. SIDE: hemiataxia,hyperkinesias,tremor:Red nucleus,dentatorubrothalamic pathway
  19. 19.  WEBER’S syndrome:third nerve palsy on the I/L side due to involvement of occulomotor nerve fascicles,Hemiplegia on C/L side due to superior cerebral peduncle involvement CLAUDE’S syndrome:I/L 3rd nerve palsy,C/L ataxia&tremor due superior cerebellar peduncle involvement BENEDIKT’S syndrome:3rd nerve palsy on I/L side&C/L side hemiparesis&ataxia due involvement of red nucleus,SCP
  20. 20.  Lesion is dorsal midbrain Structures involved are quadrigeminal plate region,periaqeuductal gray matter Clinical findings: impaired upgaze; convergence&retraction nystagmus NOTHNAGEL’S SYNDROME:it is more a variant of parinaud’s with U/L or B/L 3rd nerve palsy.lesion is in midbrain tectum
  21. 21.  C/L homonymous hemianopia with visual sparing is the usual manifestation ACUTE MEMORY DISTURBANCES:due to medial temporal lobe&hippocampus involvement on the dominant side ALEXIA without agraphia:due to dominant hemisphere plus splenium of corpus callosum involvement PEDUNCULAR HALLUCINOSIS:due to occlusion of PCA
  22. 22.  ANTON’S syndrome:B/L infarction in distal PCA produces cortical blindness If the visual association areas are spared and only calcarine cortex is involved,patient may be aware of his blindness BALINT’S syndrome:disorder of orderly visual scanning of the environment due to bilateral visual association area lesions,resulting from infarctions secondary to low flow in the watershed areas between the distal PCA&MCA territories Pallinopsia&asimultognosia may also be seen
  23. 23. THANK YOU