brain stem pathology.pptx-hem
DESCRIPTION
leasion of brainstemHEMANT RAJ SINGHMPT(NEURO)TRANSCRIPT
The medulla oblongata not only contains many cranial nerve nuclei that are concerned with vital functions (regulation of heart rate and respiration),but it also serves as a conduit for the passage of ascending and descending tracts connecting the spinal cord to the higher centers of the nervous system.
These tracts may become involved in demyelinatingdiseases, neoplasms, and vascular disorders.
(1) Medial medullary syndrome
occlusion of vertebral artery medullary branch .
Ipsilateral to lesion
Structures involved Signs and symptoms
CN XII,hypoglossal,or nucleus Paralysis with atrophy of half the tongue with deviation to the paralyzed side when tongue is protruded
Contralateral to lesion
Structures involved Signs and symptoms
Corticospinal tract Paralysis of UE and LE
Medial lemniscus Impaired tactile and proprioceptive sense
(2) Lateral medullary syndrome (wallenburg’s syndrome)
occlusion of any of five vessels may be responsible—vertebral, posterior inferior cerebellar, or superior, middle, or inferior lateral medullary arteriesIpsilateral to lesion
Structures involved Signs and symptoms
Descending tract and decreased pain and nucleus of CN V,Trigeminal temperature sensation in
face
Ceraballum or cerebellar ataxia: gait andinferior cerebellar peduncle limbs ataxia
Structures involved Signs and symptoms
Vestibular nuclei and connections vertigo, nausea, vomiting, nystagmus
Descending sympathetic tract Horner’s syndrome( miosis, ptosis, decreased sweating)
CN IX, Glossopharyngeal, and Dysphagia and dysphonia:CN X,vagus, or nuclei paralysis of palatal and laryngeal
muscles, diminished gag reflex
Cuneate and gracile nuclei sensory impairment of Ipsilateral UE,trunk,or LE
Contralateral to lesion
Structures involved Signs and symptoms
Spinal lemniscus-spinothalamic impaired pain and thermal tract sense over 50% of body,
sometimes face
The Pons situated in the posterior cranial fossa lying beneath the tentorium cerebelli. It is related anteriorly to the basilar artery, the dorsum sellae of the sphenoid bone, and the basilar part of the occipital bone.
In addition to forming the upper half of the floor of the fourth ventricle, it possesses several important cranial nerve nuclei(Trigeminal, Abducent , Facial and Vestibulocochlear )and serves as a conduit for important ascending and descending tracts ( Corticonuclear, Corticopontine , Corticospinal , Medial longitudinal fasciculus , and Medial , Spinaland lateral Lemnisci )therefore, that tumors, hemorrhage,or infarcts in this area of the brainstem produce a veriety of symptoms and signs.
(1)-MEDIAL INFERIOR PONTINE SYNDROME
Occlision of paramedian branch of basilar artery
Ipsilateral to lesion
Structures involved Signs and symptoms
Pontine center for lateral Paralysis of conjugate gaze togaze paramedian pentine side of lesion(preservation ofreticular formation(PPRF) convergence)
Vestibular nuclei and Nystagmusconnections
Structures involved Signs and symptoms
Middle cerebellar peduncle Ataxia of limbs and gait
CN VI(Abducens) or nucleus Diplopia on lateral gaze
Contralateral to lesion
Structures involved Signs and symptoms
Corticobulbar and corticospinal Paresis of face ,UE andtract in lower pons LE
Medial lemniscus Impaired tactile and proprioceptive sense over 50% of the body
(2)-LATERAL INFERIOR PONTINE SYNDROME
Occlusion of anterior inferior cerebellar artery, a branch of
the basilar artery.
Ipsilateral to lesion
Structures involved Signs and symptoms
CN VIII(Vestibular) or nucleus Horizontal and vertical nystagmus,vertigo,nausea, vomiting
CN VII(Facial )or nucleus Facial paralysis
Structures involved Signs and symptoms
Pontine center for lataral Paralysis of conjugategaze(PPRF) gaze to side of lesion
CN VIII(Cochlear )or nucleus Deafness,tinnitus
Middle cerebellar peduncle Ataxiaand cerebellar hemisphere
Main sensory nucleus and impaired sensation overdescending tract of fifth nerve face
Contralateral to lesion
Structures involved Signs and symptoms
Spinothalamic tract impaired pain and thermal sense over half the body
(3)-MEDIAL MIDPONTINE SYNDROME
Occlusion of paramedian branch of the mid-basilar artery
Ipsilateral to lesion
Structures involved Signs and symptoms
Middle cerebellar peduncle Ataxia of limbs and gait
Contralateral to lesion
Structures involved Signs and symptoms
Corticobulbar and corticospinal tract Paralysis of face,UE and LE
Pontine center of lateral gaze Deviation of eyes
(4)-LATERAL MIDPONTINE SYNDROME
Occlusion of short circumferential artery
Ipsilateral to lesion
Structures involved Signs and symptoms
Middle cerebellar peduncle Ataxia of limbs
Motor fibers or nucleus of Paralysis of muscles ofCN V(trigeminal) mastication
Sensory fibers or nucleus of Impaired sensation overCN V (trigeminal) side of face
(5)-MEDIAL SUPERIOR PONTINE SYNDROME
Occlusion of paramedian branches of upper basilar artery
Ipsilateral to lesion
Structures involved Signs and symptoms
Superior or middle Cerebellar ataxiacerebellar peduncle
Medial longitudinal fasciculus Internuclear ophthalmoplegia
Contralateral to lesion
Structures involved Signs and symptoms
Corticobulbar and corticospinal tract Paralysis of face,UE and LE
(6)-LATERAL SUPERIOR PONTINE SYNDROME
Occlusion of superior cerebellar artery,a branch of the basilar artery.
Ipsilateral to lesion
Structures involved Signs and symptoms
Middle and superior cerebellar Cerebellar ataxia of limbspeduncles,superior surface of and gait, falling to side ofcerebellum,dentate nucleus lesion
Vestibular nuclei Dizziness,nausea,vomitingHorizontal nystagmus
Structures involved Signs and symptoms
Descending sympathetic fibers Horner’s syndrome: miosis,ptosis,decreasedsweating on opposite side face
Uncertain Paresis of conjugate gaze(ipsilatereal),Loss of optokinetic nystagmus
Contralateral to lesion
Structures involved Signs and symptoms
Spinothalamic tract Impaired pain and thermal sense of face,limbs and trunk
Medial lemniscus(lateral portion) Impaired touch, Vibration,and position sense,more in LE than UE (tendency to incongruity of pain and touch deficits)
The midbrain forms the upper end of the narrow stalk ofbrainstem.
As it ascends out of the posterior cranial fossa through therelatively small rigid opening in the tentorium cerebelli,it isvulnerable to traumatic injury.
It possesses two important cranial nerve nuclei(Oculomotor and trochlear), reflex centers(the colliculi),and theRed nucleus and substantia nigra, which greatly influence motorfunction and the midbrain serves as a conduit for many importantascending and descending tracts.
As in other parts of the brainstem,it is a site fortumors,hemorrhage,or infercts that will produce a wide variety ofsymptoms and signs.
1)-PARINAUD’S SYNDROME
Lesion location Midbrain dorsum
Structures involved Quadrigeminal plate region; pretectum;periaqueductal gray matter
Clinical findings Impaired upgaze;convergenceretraction nystagmus;dilated pupils with light near dissociation
Comment Usually due to mass lesion in the region of the posterior third ventricle,most often pinealoma, or due to midbrain infarction
2)-WEBER’S SYNDROME
Lesion location Midbrain base
Structures involved CN III ,fibers’cerebral peduncle
Clinical findings Ipsilateral CN III palsy’ contralateral hemiparesis
Comment Usually vascular
3)-BENEDIKT’S SYNDROME
Lesion location Midbrain tegmentum
Structures involved CN III fibers,Red nucleus,CST,SCP
Clinical findings Ipsilateral CN III palsy’contralateralhemiparesis with ataxia,hyperkinesisand tremor “rubral tremor”
Comment Usually vascular
4)-CLAUDE’S SYNDROME
Lesion location Midbrain tegmentum
Structures involved CN III fibers; Red nucleus; SCP
Clinical findings Ipsilateral CN III palsy; contralateralataxia and tremor(rubral tremor)
Comment Usually vascular