Brain Stem Lesions A59 Brain Stem lesions



Download 2.36 Mb.
Date08.02.2017
Size2.36 Mb.

Brain Stem Lesions A59 ()banner_for_pages


Brain Stem LESIONS

Last updated: April 3, 2016




Medial syndromes of medulla and pons 4

Lateral syndromes of medulla and pons 5

Midbrain syndromes 6




  • brain stem sandara labai sudėtinga – kompaktiškai susiglaudę guli įvairiausios struktūros.

  • neįmanoma aprašyti visų galimų sindromų.

  • patogiausia nagrinėti kraujagyslinius sindromus – geriausiai koreliuoja su topografija.


Clinical features depend on:

  1. Longitudinal site (midbrain, pons, medulla)

  2. Cross-sectional site (tegmentum vs. basis; medial vs. lateral)


Unilateral brain stem syndromesalternating signs:

  1. Ipsilaterally – lesion of cranial nerves (LMN paralysis or loss of sensation) – specifies longitudinal site.

  2. Contralaterally – lesion of long tracts, which will decussate (descending) or has decussated (ascending) – specifies cross-sectional site;

    • alternating hemiplegia – tr. pyramidalis (dažnai kartu pažeidžiami somitiniai nervai CN3, CN6, CN12 – jie išeina ventraliai paramedianinėje plokštumoje, šalia tr. pyramidalis).

    • alternating hemianesthesiamedial lemniscus, tr. spinothalamicus.

    • alternating hemihyperkinesia – subst. nigra (tremor), red nucleus (hemichorea).






Lateral

Medial




Long tracts

Cranial nerves

Long tracts

Cranial nerves

Pons

TrSpinthal TrRetspin

VestConn


LatLem

Hiccup

CN5 (touch)

CN7 (motor)

CN8


TrPyr

MedLem CerebellConn



Palatal myoclonus, etc

CN6 + pontine gaze center,

MLF


Medulla

TrSpinthal TrRetspin VestConn CerebellConn

CN5 (pain + t-re)

CN7 (taste)

CN9

CN10


TrPyr

MedLem


CN12


Bulbar Palsyperipheral paralysis of CN9, CN10, CN12. see Mov3 p.

Pseudobulbar Palsycentral paralysis of CN9, CN10, CN12. see Mov3 p.

Bilateral lesion of tegmentum above midpontine level (rostral RF – ARAS) → coma. see S30 p.



Respiratory drive disturbance – kuo kaudalesnis pažeidimas, tuo labiau trinka kvėpavimo dažnis ir ritmas; medulocervikalinis pažeidimas → apnea. see 2115 (4-5) p. (respiratory)

d:\viktoro\neuroscience\a. neuroscience basics\a55-59. brain stem\00. pictures\medullary syndromes (medial, lateral).jpgd:\viktoro\neuroscience\a. neuroscience basics\a55-59. brain stem\00. pictures\inferior pontine syndomes (lateral, medial).jpg
d:\viktoro\neuroscience\a. neuroscience basics\a55-59. brain stem\00. pictures\midpontine syndomes (lateral, medial).jpgd:\viktoro\neuroscience\a. neuroscience basics\a55-59. brain stem\00. pictures\superior pontine syndromes (lateral, medial).jpg
d:\viktoro\neuroscience\a. neuroscience basics\a55-59. brain stem\00. pictures\brainstem syndromes - general scheme.jpg

Medial syndromes of medulla and pons

- paramedian branches of a. vertebralis / a. basilaris.


Long tracts:

  1. Tr. pyramidalis → (contralateral) hemiplegia

  2. Medial lemniscus → (contralateral) loss of tactile (?), position and vibratory sensation.

  3. Cerebellar connections (superior / middle cerebellar peduncle; in pons only) → (ipsilateral) limb ataxia or nystagmus.


Pažeidimo aukštį nurodo įtraukti nervai:

Medial medullary (s. Dejerine) syndrome:

CN12 → (ipsilateral) tongue hemiparalysis.
Medial pontine syndrome:

  1. CN6 nucleus, pontine gaze center → paralysis of horizontal gaze to side of lesion.

  2. MLF → internuclear ophthalmoplegia (failure of adduction in horizontal gaze but preservation of convergence). see Eye64 p.

  3. Central tegmental tract → palatal myoclonus accompanied by rhythmic movements of pharynx, larynx, face, eyes, or respiratory muscles.

  • gaze-evoked nystagmus – due to vestibular connections, cerebellar connections, MLF.


Foville syndrome (variant of alternating hemiplegia) – ipsilateral CN6, contralateral hemiplegia.

Millard-Gubler syndrome (variant of alternating hemiplegia) – ipsilateral CN7, contralateral hemiplegia.

Locked-in Syndrome – complete lesion of basis pontis. see Mov3 p.

Drop Attacks – TIA in bilateral pontine / medullary pyramidal tract. see Mov3 p.

Lateral syndromes of medulla and pons

- specific clinical features due to lateral structures:



  1. Tr. spinothalamicus → (contralateral)* loss of pain-temperature sensation in trunk and extremities.

  2. Nucl. sensorii of CN5 (descend from midpons to C3) → (ipsilateral)* loss of cutaneous sensation in face: *i.e. crossed sensory loss

nucl. pontinus (pons) – touch;

nucl. spinalis (medulla) – pain and temperature (hypalgesia, thermoanesthesia, corneal hypesthesia).



  1. Tr. reticulospinalis (descending sympathetic fibers from hypothalamus) → (ipsilateral) Horner’s syndrome.

  2. Vestibular connections → vertigo, nystagmus, nausea, vomiting.

  3. Cerebellar connections (inferior / middle / superior cerebellar peduncles) → (ipsilateral) limb ataxia, asynergia, intention tremor.

  4. Hiccup – unclear cause.

No plegia, no loss of touch-proprioception!

The only contralateral sign - loss of pain-temperature sensation in trunk and extremities.



Pažeidimo aukštį nurodo įtraukti nervai:

Lateral superior pontine syndromesuperior cerebellar artery (SCA):

Lateral lemniscus → partial hearing loss.

  • vertigo is less common.

  • in lesions at and above superior pons (lesion of trigeminal lemniscus) – sensory loss in face becomes contralateral (as in rest of body), i.e. sensory loss is no longer crossed.



Lateral inferior pontine (s. Marie-Foix) syndromeanterior inferior cerebellar artery (AICA):

  1. Pontine gaze center → paralysis of horizontal gaze to side of lesion.

  2. CN7 → (ipsilateral) facial paralysis

  3. CN8 → (ipsilateral) tinnitus, deafness

+ crossed hypesthesia (ipsilateral face loss of touch / contralateral body hypalgesia-thermoanesthesia)

Lateral medullary (s. Wallenberg) syndromeposterior inferior cerebellar artery (PICA) (in 80-85% cases also vertebral artery – exclude VA dissection):

  1. Nucl. tractus solitarii (CN7) → (ipsilateral) loss of taste.

  2. CN9, CN10 → dysphagia, dysarthria, etc.

+ crossed* hypalgesia-thermoanesthesia (ipsilateral face / contralateral body)

*this is essentially the only location where lesion will produce crossed sensory loss

Absence of pyramidal tract findings + no change in mental status




Midbrain syndromes

Išskiriami trys pagrindiniai sindromai:

d:\viktoro\neuroscience\a. neuroscience basics\a55-59. brain stem\00. pictures\midbrain syndromes.jpg
Dorsal midbrain (s. midbrain pretectal, collicular, Parinaud) syndrome – lesion of pretectal area, superior colliculi (e.g. compression from above by pineal mass; PCA infarct) → supranuclear paralysis of conjugate upward gaze → downward eye deviation (rarely, if unilateral → skew deviation);

+ Collier sign (pathological lid retraction) with Bell phenomenon (bandant užsimerkti, akys pakyla į viršų), mydriasis, anisocoria, light-near dissociated pupils, defective convergence, convergence-retraction nystagmus. smulkiau žr. Eye64 p.


Ventral midbrain (s. Weber) syndrome - paramedian PCA branches to midbrain - variant of alternating hemiplegia:

  1. Tr. pyramidalis → (contralateral) hemiplegia, incl. supranuclear CN7 palsy.

  2. Ipsilateral emerging CN3 fibers.


Central (s. tegmental) midbrain syndrome:

  1. CN3 nucleus

  2. Medial lemniscus, tr. spinothalamicus → (contralateral) hemianesthesia

  3. Nucl. ruber, subst. nigra → (contralateral) hemichorea, hemiparkinsonism.

  • if bilateral (rostral RF – ARAS) → coma.



Eilė papildomų sindromų: smulkiau žr. Eye64 p.

  1. Claude syndrome

  2. Benedikt syndrome

  3. Nothnagel syndrome


Bibliography for ch. “Brain Stem” → follow this link >>

NMS Surgery 2000, Medicine 2000, Pediatrics 2000, Emergency Medicine 1997, Neuroanatomy 1998, Radiographic Anatomy 1990, Physiology 2001


Viktor’s Notes℠ for the Neurosurgery Resident



Please visit website at www.NeurosurgeryResident.net


Directory: A.%20Neuroscience%20Basics -> A55-59.%20Brain%20Stem
A.%20Neuroscience%20Basics -> Embryogenesis of cns blood vessels A201 Embryogenesis of cns blood vessels
A.%20Neuroscience%20Basics -> Bbb a8 Blood-brain barrier (bbb)
A.%20Neuroscience%20Basics -> Diencephalon A110 Diencephalon
A.%20Neuroscience%20Basics -> Vestibulospinal Tract
A.%20Neuroscience%20Basics -> Facial Nerve A73 Facial Nerve
A55-59.%20Brain%20Stem -> Corticonuclear (corticobulbar) fibers A55 (8) Corticonuclear (corticobulbar) fibers
A.%20Neuroscience%20Basics -> Autonomic ns pharmacology A35 Autonomic Nervous System Pharmacology
A.%20Neuroscience%20Basics -> Smell functions Warning spoiled foods, leaking natural gas, polluted air, smoke. Basic communication
A55-59.%20Brain%20Stem -> Brain Stem Lesions A59 Brain Stem lesions


Share with your friends:


The database is protected by copyright ©dentisty.org 2019
send message

    Main page