Brain stem syndromes

NEUROLOGY

1. BRAINSTEM SYNDROMES DR. JITHIN GEORGE

2. POSTERIOR CEREBRAL ARTERY BASILAR ARTERY VERTEBRAL ARTERY Occlusion of PCA– P1 syndromes P2 syndromes POSTERIOR CIRCULATION STROKE

3. POSTERIOR CEREBRAL ARTERY P1 Syndromes : Central/perforating branch occlusion Dejerine-Roussy Synd : Thalamic Synd Sensory loss Spontaneous pain & dysesthesias Choreoathetosis Intention tremor Spasm of hand Mild hemiparesis

4. Claude’s Synd : Ipsilateral lll CN palsy Contralateral cerebellar ataxia Weber’s Synd Ipsilateral lll CN palsy Contralateral hemiplegia Contralateral Hemiballismus : lesion in the Subthalamic nucleus POSTERIOR CEREBRAL ARTERY

5. P2 Syndromes : Peripheral artery occlusion Homonymous hemianopia with macular sparing Anomic aphasia Alexia without agraphia /Visual agnosia Cortical blindness Memory defect Prosapagnosia Anton’s Syndrome Balint’s Syndrome POSTERIOR CEREBRAL ARTERY

6. Ventral Pontine Syndromes

7. A unilateral lesion of the ventral medial pons , affects the ipsilateral abducens nerve fascicles and the corticospinal tract but spares cranial nerve VII also called alternating abducens hemiplegia ) Ipsilateral lateral rectus paresis (cranial nerve VI) Contralateral hemiplegia , sparing the face, due to pyramidal tract involvement Raymond Syndrome

8. Lesions (especially lacunar infarction) involving the corticospinal tracts in the basis pontis may produce a pure motor hemiplegia with or without facial involvement Patients often have severe dysarthria and dysphagia . Bouts of uncontrollable laughter may also occur A combination of dysarthria and a history of previous transient gait abnormality or vertigo favor a pontine lesion as the cause of pure motor hemiparesis rather than a more common capsular lesion Pure Motor Hemiparesis

9. Vascular lesions in the basis pontis (especially lacunar infarction) at the junction of the upper one-third and lower two-thirds of the pons may result in dysarthria clumsy hand syndrome. In this syndrome facial weakness and severe dysarthria and dysphagia occur along with clumsiness, and paresis of the hand. Hyperreflexia and a Babinski's sign may occur on the same side as the arm paresis, but sensation is spared. Dysarthria Clumsy Hand Syndrome

10. A lesion (usually a lacunar infarction) the basis pontis at the junction of the upper one-third and the lower two-thirds of the pons may result in the ataxic hemiparesis ( homolateral ataxia and crural paresis) syndrome. In this syndrome hemiparesis that is more severe in the lower extremity , is associated with ipsilateral hemiataxia and occasionally dysarthria , nystagmus , and paresthesias . The lesion is located in the contralateral pons . The ataxia is unilateral , probably because transverse fibers originating from the contralateral pontine nuclei (and projecting to the contralateral cerebellum) are spared Ataxic Hemiparesis

11. Bilateral ventral pontine lesions This syndrome consists of the following signs: Quadriplegia due to bilateral corticospinal tract involvement in the basis pontis Aphonia due to involvement of the corticobulbar fibers innervating the lower cranial nerve nuclei Occasional impairment of horizontal eye movements due to bilateral involvement of the fascicles of cranial nerve VI Because the reticular formation is not injured, the patient is fully awake . The supranuclear ocular motor pathways lie dorsally and are therefore spared; therefore, vertical eye movements and blinking are intact Locked-in Syndrome

12. Foville Syndrome lesions involving the dorsal pontine tegmentum in the caudal third of the pons . Contralateral hemiplegia (with facial sparing) which is due to interruption of the corticospinal tract. Ipsilateral peripheral-type facial palsy which is due to involvement of the nucleus and fascicle (or both) of cranial nerve VII. Inability to move the eyes conjugately to the ipsilateral side due to involvement of the PPRF or abducens nucleus, or both DORSAL PONTINE SYNDROMES

13. rostral lesions of the dorsal pons . Cerebellar signs (ataxia) with a coarse tremor which is due to the involvement of the cerebellum. Contralateral hypesthesia with reduction of all sensory modalities (face and extremities) which is due to the involvement of the medial lemniscus and the spinothalamic tract. With ventral extension, there may be contralateral hemiparesis (due to corticospinal tract involvement) or paralysis of conjugate gaze toward the side of the lesion (due to involvement of the PPRF). Raymond- Cestan Syndrome

14. Unilateral mediobasal infarcts. severe facio-brachio-crural hemiparesis , dysarthria , and homolateral or bilateral ataxia. Presentations include dysarthria Clumsy hand syndrome, ataxic hemiparesis with prominent sensory or eye movement disorders, and hemiparesis with contralateral facial or abducens palsy. Paramedian Pontine Syndromes

15. Unilateral mediobasal infarcts. These patients have pseudobulbar palsy and bilateral sensorimotor disturbances. The most common etiology for paramedian pontine infarcts is small vessel disease; vertebrobasilar large vessel disease and cardiac embolism are less common causes.

16. Marie- Foix Syndrome lateral pontine lesions affecting the brachium pontis Ipsilateral cerebellar ataxia due to involvement of cerebellar connections Contralateral hemiparesis due to involvement of the corticospinal tract Variable contralateral hemihypesthesia for pain and temperature due to involvement of the spinothalamic tract LATERAL PONTINE SYNDROME

17. combined right superior cerebellar artery occlusion resulting in lateral superior pontine infarction and left posterior inferior cerebellar artery occlusion , resulting in a left Wallenberg lateral medullary syndrome loss of pain and temperature sensation, whereas light touch, vibration, position, and deep pain sensation were preserved (dissociated sensory loss). This interesting lesson in localization was due to bilateral discrete interruption of spinothalamic fibers and the spinal nucleus and tract of the trigeminal nerve. The Syndrome of Universal Dissociative Anesthesia

18. Medulla oblongata A- ant view B- post view

19. Medulla Oblongata Gross appearnse : - Connect the pons sup to spinal cord inf - About 2.5 cm in length - The junction of the medulla and spinal cord is at the origin of the anterior and posterior roots of the first cervical spinal nerve at level of foramen magnum - It is conical in shape - central canal - cavity of fourth ventricle Anteriorly : - ant median fissure - pyramid - decussation of the pyramids - Posterolateral to the pyramids are the olives Posteriorly : - sup is the floor 4 th ventricle - inf the median sulcus - gracile tubercle and lat to it the cuneate tubercle

20. The internal structure of the medulla oblongata is considered at four levels: level of decussation of pyramids level of decussation of lemnisci level of the olives level just inferior to the pons .

21. Transverse section of the medulla oblongata at the level of decussation of the pyramids

22. Transverse section of the medulla oblongata at the level of decussation of the medial lemnisci

23. Transverse section of the medulla oblongata at the level of the middle of the olivary nuclei

24. Blood supply of Medulla oblongata: 1) ventrally: branches from vertebral and basilar arteries, Also branches from ant spinal artery artery 2) dorsolaterally : by post inf cerebellar artery Venous drainage: 1)ventrally: basilar venous plexus and inf petrosal sinus 2) Dorsally and dorsolaterally to occipital sinus 3) Medullary veins communicate with sinuses and spinal veins

25. Lateral Medullary Synd : Wallenberg’s synd On the side of lesion V, VII, VIII, IX, X CN & desc . sympathetic tract On the opp side Impaired pain &thermal sense over half of the body MEDULLARY SYNDROMES

26. Medial Medullary Synd On the side of lesion Paralysis with atrophy of half of the tongue On the opp side Paralysis of arm and leg sparing face Impaired tactile & proprioceptive sense over half of the body

27. Midbrain

28. Transverse section of the midbrain through the inferior colliculi shows the division of the midbrain into the tectum and the cerebral peduncles. Note that the cerebral peduncles are subdivided by the substantia nigra into the tegmentum and the crus cerebri

29. Transverse sections of the midbrain. A: At the level of the inferior colliculus . B: At the level of the superior colliculus . Note that trochlear nerves completely decussate within the superior medullary velum

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