Download

BRAIN STEM, CEREBELLUM and NEURO-OPTHALMOLOGY






Advertisement
/ 61 []
Download Presentation
Comments
limei
From:
|  
(935) |   (0) |   (0)
Views: 241 | Added: 16-02-2012
Rate Presentation: 1 0
Description:
BRAIN STEM, CEREBELLUM and NEURO-OPTHALMOLOGY. Submitted to AskTheNeurologist.Com in 2007. GROSS ANATOMY . LATERAL VIEW. LOCATION OF CRANIAL NERVE NUCLEI WITHIN BRAINSTEM. CRANIAL NERVE 5.
BRAIN STEM, CEREBELLUM and NEURO-OPTHALMOLOGY

An Image/Link below is provided (as is) to

Download Policy: Content on the Website is provided to you AS IS for your information and personal use only and may not be sold or licensed nor shared on other sites. SlideServe reserves the right to change this policy at anytime. While downloading, If for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.











- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -




Slide 1

BRAIN STEM, CEREBELLUM and NEURO-OPTHALMOLOGY

Submitted to AskTheNeurologist.Com

in 2007

AskTheNeurologist.Com

Slide 2

GROSS ANATOMY

AskTheNeurologist.Com

Slide 3

LATERAL VIEW

AskTheNeurologist.Com

Slide 4

LOCATION OF CRANIAL NERVE NUCLEI WITHIN BRAINSTEM

AskTheNeurologist.Com

Slide 5

CRANIAL NERVE 5

Note that although all fibres enter the brainstem at the level of the pons, those concerned with pain and temperature descend as low as C3

AskTheNeurologist.Com

Slide 6

PATHWAYS INVOLVED IN HORIZONTAL GAZE

LEFT FRONTAL

EYE FIELD

AskTheNeurologist.Com

Slide 7

INTERNUCLEAR OPTHALMOPLEGIA ( INO)

AskTheNeurologist.Com

Slide 8

THE FACIAL NERVE

Therefore a lesion at or distal to the facial nucleus will result in weakness of the upper as well as the lower part of the face:- this is what is know as a “ peripheral facial palsy ”

AskTheNeurologist.Com

Slide 9

The Long Tracts

Note sites of decussation of major tracts :

Spinothalamic

Cuneate / Gracile

Corticospinal

AskTheNeurologist.Com

Slide 10

LONG TRACT DECUSSATION

  • Spinothalamic

Spinal cord

  • Gracile / Cuneate

Medulla

Medulla

  • Corticospinal

Therefore: - Lesions at medulla and below can result in dissociated sensory syndromes

- Lesions above the medulla will result in a contralateral upper motor neuron syndrome

AskTheNeurologist.Com

Slide 11

The Corticobulbar Tract

  • Accompanies the corticospinal tract: can assume decussation occurs at level of nucleus

  • Connects with the brain-stem motor nuclei

  • Each tract connects bilaterally with most cranial nerve motor nuclei

EXCEPT:

Part of VII dealing with lower face is innervated unilaterally

Sometimes XII innervated unilaterally

AskTheNeurologist.Com

Slide 12

Lower motor neuron therefore signs of denervation present

Tongue wasting and fasciculation

Upper motor neuron therefore bilateral damage necessary

Inappropriate spells of crying / laughing

Jaw jerk and gag reflex increased

Bulbar Palsy

Pseudobulbar Palsy

Dysarthria, dysphagia, weight loss, risk of aspiration pneumonia present in both cases

AskTheNeurologist.Com

Slide 13

LATERAL MEDULLARY (WALLENBERG’S) SYNDROME

LESION SITE IN

LATERAL MEDULLARY

SYNDROME

( BLUE)

AskTheNeurologist.Com

Slide 14

VERTIGO, NYSTAGMUS

VESTIBULAR NUCLEI

CLINICAL FEATURES OF LMS I

  • IPSILATERAL HORNER’S SYNDROME

  • DESCENDING SYMPATHETIC TRACT

  • IPSILATERAL CEREBELLAR SIGNS

  • INFERIOR CEREBELLAR PEDUNCLE

  • DYSPHONIA AND DYSPHAGIA

  • NUCLEUS AMBIGUUS

AskTheNeurologist.Com

Slide 15

CLINICAL FEATURES OF LMS II

  • LOSS OF IPSILATERAL FACIAL PAIN AND TEMPERATURE SENSATION

  • SPINAL TRACT AND NUCLEUS OF TRIGEMINAL NERVE

  • LOSS OF IPSILATERAL VIBRATION AND PROPRIOCEPTION IN LIMBS AND TRUNK

  • GRACILE AND

    CUNEATE NUCLEI

AskTheNeurologist.Com

Slide 16

CLINICAL FEATURES OF LMS III

  • LOSS OF CONTRALATERAL PAIN AND TEMPERATURE SENSATION IN LIMBS AND TRUNK

  • SPINOTHALAMIC TRACT

  • HICCUPS

  • UNKNOWN

  • NUCLEUS AND

    TRACTUS

    SOLITARIUS

  • LOSS OF TASTE

AskTheNeurologist.Com

Slide 17

Blood supply of Brainstem and Cerebellum

  • Ant. cerebral

  • Internal carotid

  • Middle cerebral

  • Post. communicating

  • Sup. cerebellar

  • Basilar

  • Ant. Inf. cerebellar

  • Vertebral

  • Ant. Spinal

  • Post. Spinal

  • Post. Inf. Cerebellar

  • Post cerebral

  • Mesencephalic

AskTheNeurologist.Com

Slide 18

Somatotopy of cerebellum

  • Midline lesions:

    • nystagmus

    • Titubation

    • Trunk / gait ataxia

  • Hemispheric lesions:

    • nystagmus

    • ipsilateral limb signs

posterior

AskTheNeurologist.Com

Slide 19

Basic Plan of Cerebellar connections

DN= Dentate nucleus

T = Thalamus

RN = Red nucleus

Each cerebellar cortex controls ipsilateral side of body

Efferents to cortex leave cerebellum via superior cerebellar peduncle

Note: red nucleus is present in midbrain and ultimately controls contralateral half of body

AskTheNeurologist.Com

Slide 20

DSCT= dorsal spinocerebellar tract

VSCT= ventral spinocerebellar tract

VSCT is crossed in the cord but crosses back within cerebellum

AskTheNeurologist.Com

Slide 21

Fronto-ponto Cerebellar tract

Right Cerebral cortex

Note that right side of cortex ultimately controls left cerebellar hemisphere

Fronto-ponto-cerebellar fibres enter cerebellum via middle cerebellar peduncle

AskTheNeurologist.Com

Slide 22

Symptoms and signs of cerebellar disease (VANISH’D)

  • Vertigo

  • Ataxia - usually falls towards lesion

  • Nystagmus – increased with gaze towards lesion

  • Intention Tremor

  • Scanning speech

  • Hypotonia

  • Dysdiadochokinesia + Dysmetria

AskTheNeurologist.Com

Slide 23

Approach to differential diagnosis of cerebellar dysfunction

AskTheNeurologist.Com

Slide 24

Approach to localisation within brainstem

A combination of long-tract and brainstem signs may allow accurate location of a brainstem lesion

AskTheNeurologist.Com

Slide 25

Case 1*

  • Right facial paralysis affecting upper and lower face + diplopia + left hemiparesis ( arm and leg)

  • What is the likely cause of the diplopia and where is the lesion?

AskTheNeurologist.Com

Slide 26

Answer 1

  • Diplopia likely to be due to a right VIth nerve lesion – the VIIth nerve passes around the nucleus of VI just below the 4th ventricle in the pons

  • Right pons

AskTheNeurologist.Com

Slide 27

Case2

  • A 72 year old man with a right hemiplegia. On examination in addition to the hemiplegia with pyramidal signs his tongue deviates to the left and is atrophic and fasciculating on the left side

AskTheNeurologist.Com

Slide 28

Answer 2

  • Left medulla

  • Combination of XII LMN lesion on left, and

    right UMN hemiplegia places lesion in the

    left medulla above the decussation of the

    pyramidal tract

AskTheNeurologist.Com

Slide 29

Case 3*

  • A 26 year old woman with horizontal diplopia on looking to left and right. On examination impaired adduction of both eyes on attempted lateral gaze with relative preservation of convergence. In addition dysmetria and intention tremor of right hand.

AskTheNeurologist.Com

Slide 30

Answer 3

The patient has features of

- a lesion of the medial longitudinal

fasciculus bilaterally

- a lesion of the right cerebellum ( or its connections)

  • A bilateral MLF lesion is almost pathognomonic of MS and the addition of cerebellar signs strengthens the diagnosis

AskTheNeurologist.Com

Slide 31

Case 4 *

  • A 24 year old woman with vertical diplopia maximal on looking up and horizontal diplopia maximal on looking right, difficulty swallowing, ptosis more pronounced on left, facial weakness more pronounced on right. Sensation in tact.

AskTheNeurologist.Com

Slide 32

Answer 4

  • No single brainstem lesion can account for all these features.

  • Myaesthenia gravis may present in this way with a combination of pure motor signs attributable to NMJ dysfunction of muscles innervated by various brainstem nuclei.

AskTheNeurologist.Com

Slide 33

Case 5*

  • A 65 year old lady with a right sided ptosis, right pupil dilatation, diplopia, left sided cerebellar and pyramidal signs

AskTheNeurologist.Com

Slide 34

Answer 5

  • Right Midbrain

  • Eye signs are due to right III palsy.

  • Contralateral cerebellar signs due to damage to right Red Nucleus

  • Contralateral pyramidal signs due to damage to corticospinal tract

AskTheNeurologist.Com

Slide 35

Case 6*

  • A 84 year old lady with sudden onset of a left hemiparesis and deviation of both eyes to the left side

AskTheNeurologist.Com

Slide 36

Answer 6

  • Right pons

  • The combination of gaze deviation and hemiparesis usually occurs with large hemispheric CVA’s; in such a case the eyes deviate to the side of the lesion ( due to destruction of the frontal gaze centre)

  • In case 8 the eyes deviate away from the lesion (left) due to the destruction of the right pontine paramedian reticular formation (PPRF)

AskTheNeurologist.Com

Slide 37

What is Nystagmus?

  • Rhythmic oscillation of the eyes

  • Fast phase ( saccade)

  • Slow phase ( smooth-pursuit – like)

AskTheNeurologist.Com

Slide 38

Describing nystagmus

  • Position of gaze in which occurs or is most prominent

  • Direction ( of FAST phase)

  • Precipitating / exacerbating factors

  • Fatiguing / persistent

  • Associated symptoms

    - Vertigo

    - Oscillopsia – feeling that vision is jerky

AskTheNeurologist.Com

Slide 39

Example: - Vestibular neuronitis left side

  • Most prominent on gaze towards right

  • Horizontal right – sided nystagmus with a rotatory component

  • Exacerbated by quick head movements

  • Associated with severe vertigo + / - vomiting

  • Persistent / may fatigue

Illustrates following rule:

Nystagmus is always most prominent on gaze towards the direction of the fast phase

AskTheNeurologist.Com

Slide 40

Nystagmus may be………

  • Physiological

  • Pathological

Central

Peripheral

this is THE most important distinction to be made in assessing nystagmus!

AskTheNeurologist.Com

Slide 41

IS IT NORMAL??

AskTheNeurologist.Com

Slide 42

Central vs Peripheral ( guidelines)

AskTheNeurologist.Com

Slide 43

Diplopia

“ The subjective feeling of seeing double”

May be:

  • Monocular ( present even when one eye open)

  • Binocular ( present only when 2 eyes open)

Monocular diplopia is either due to a local (ocular) process, “non-organic” in origin or very rarely from visual cortical dysfunction

Therefore almost all neurological causes of diplopia are “ binocular ”

AskTheNeurologist.Com

Slide 44

Binocular diplopia…questions

  • Horizontal vs Vertical ?

  • Worse on looking in which direction?

  • Worse on focussing near or far ?

  • RULES

  • Diplopia is maximal on gaze in the direction of action of the weak muscle.

  • The false image is projected towards the direction of action of the weak muscle

AskTheNeurologist.Com

Slide 45

Anatomical sites which may cause diplopia

  • Internuclear ( INO )

  • Nucleus

  • Fascicle

  • Cranial nerve

  • Neuromuscular junction (NMJ)***

  • Muscle

  • Local distortion of orbit

*** ANY type of diplopia or gaze disturbance may be due to a problem at the NMJ….usually Myaesthenia Gravis …and often with ptosis

AskTheNeurologist.Com

Slide 46

Example of a patient with Myaesthenia Gravis

The examiner is lifting the patient’s eyelids for 2 reasons:

- Good examination technique!

- In this case the patient has bilateral ptosis

AskTheNeurologist.Com

Slide 47

Which of the following patients cannot have MG?

  • Right eye totally paralysed, left eye moves freely but with ptosis

  • Inability of both eyes to move to left with no diplopia

  • Bilateral inability to look up with bilateral ptosis

  • Left eye deviated down and laterally with ptosis on left and left pupil larger than right

Myaesthenia Gravis NEVER causes pupil asymmetry ( anisocoria)

…..which brings us onto the next subject…..

AskTheNeurologist.Com

Slide 48

Anisocoria

“ Inequality between the 2 pupils”

Pupils may be :

- equal ( to within 1mm)

- unequal due to surgery / trauma usually irregular)

- unequal due to a neurological condition

AskTheNeurologist.Com

Slide 49

The 2 neurological causes of anisocoria

  • One pupil too big

  • One pupil too small

Parasympathetic---------------------------------------Sympathetic

Constricts (Ach)

Travels in III

Dilates (Nad)

Symp fibres

AskTheNeurologist.Com

Slide 50

Anisocoria rules

  • Darkness exaggerates failure of dilation

  • Bright light exaggerates failure of constriction

  • If unilateral ptosis is present assume that the eye with the ptosis is sick!

AskTheNeurologist.Com

Slide 51

Patient with a left IIIrd nerve palsy:

- Left sided ptosis

- Left pupil > Right

- Medial rectus weakness seen on attempted gaze to right

AskTheNeurologist.Com

Slide 52

Right – sided Horner’s Syndrome

AskTheNeurologist.Com

Slide 53

Horner’s syndrome

  • Due to interruption of sympathetic input to eye

    - Ptosis

    • Miosis ( constriction )

    • Anhidrosis ( lack of sweating on side of face)

Lesion sites - hypothalamus, brainstem, cervical cord

- cervical sympathetic chain and ganglion

- fibres running next to carotid artery

AskTheNeurologist.Com

Slide 54

Sphincter pupillae muscle

Pathways involved in the pupillary light reflex

AskTheNeurologist.Com

Slide 55

Left RAPD ( relative afferent pupillary defect)

AKA Marcus-Gunn pupil

For example a patient with multiple sclerosis who is suffering from acute left sided optic neuritis

Step 1

small reaction of BOTH pupils to light on L

Step 2

Normal (large) reaction of BOTH pupils to light on R

Step 3

Dilatation of BOTH pupils with light on L when compared to Step 2

AskTheNeurologist.Com

Slide 56

A lesion here would cause RAPD

A lesion beyond the chiasm would NOT cause RAPD

AskTheNeurologist.Com

Slide 57

Case 7*

  • Right facial paralysis with sparing of the forehead, right hemiparesis affecting arm>leg, diplopia maximal on looking right, left ptosis, left pupil larger than right, tongue deviation to right side

AskTheNeurologist.Com

Slide 58

Answer 7

  • Left midbrain

  • The UMN facial weakness places lesion above pons; remember that supra-nuclear innervation of each XIIth nerve nucleus is often unilateral therefore tongue deviation may occur

  • The IIIrd nerve palsy places lesion in midbrain

AskTheNeurologist.Com

Slide 59

Question 8*

  • A 23 year old obese woman with acne with a 3 month history of headaches vomiting and transient visual symptoms. Over last 3 days horizontal diplopia maximal on looking left and into distance; except for the diplopia and one other abnormality the neurological examination is normal.

AskTheNeurologist.Com

Slide 60

Answer 8

  • The “other abnormality” is papilloedema

  • This woman is exhibiting classical features of raised intracranial pressure (likely in this case to be due to pseudotumour cerebri). A VIth nerve palsy may occur as a false localising sign in any case of raised intracranial pressure.

AskTheNeurologist.Com

Slide 61

THE END

For presentation requests and downloads please visit

AskTheNeurologist.Com

AskTheNeurologist.Com


Copyright © 2014 SlideServe. All rights reserved | Powered By DigitalOfficePro