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1. AskTheNeurologist.Com BRAIN STEM, CEREBELLUM and NEURO-OPTHALMOLOGY Submitted to AskTheNeurologist.Com
2. AskTheNeurologist.Com GROSS ANATOMY
3. AskTheNeurologist.Com LATERAL VIEW
4. AskTheNeurologist.Com LOCATION OF CRANIAL NERVE NUCLEI WITHIN BRAINSTEM
5. AskTheNeurologist.Com CRANIAL NERVE 5
6. AskTheNeurologist.Com PATHWAYS INVOLVED IN HORIZONTAL GAZE
7. AskTheNeurologist.Com INTERNUCLEAR OPTHALMOPLEGIA ( INO)
8. AskTheNeurologist.Com THE FACIAL NERVE
10. AskTheNeurologist.Com LONG TRACT DECUSSATION
11. AskTheNeurologist.Com The Corticobulbar Tract Accompanies the corticospinal tract: can assume decussation occurs at level of nucleus
12. AskTheNeurologist.Com Bulbar Palsy 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
13. AskTheNeurologist.Com LATERAL MEDULLARY (WALLENBERG’S) SYNDROME
14. AskTheNeurologist.Com CLINICAL FEATURES OF LMS I VERTIGO, NYSTAGMUS VESTIBULAR NUCLEI
18. AskTheNeurologist.Com Somatotopy of cerebellum
22. AskTheNeurologist.Com Symptoms and signs of cerebellar disease (VANISH’D) Vertigo
Ataxia - usually falls towards lesion
Nystagmus – increased with gaze towards lesion
Dysdiadochokinesia + Dysmetria
23. AskTheNeurologist.Com Approach to differential diagnosis of cerebellar dysfunction
24. AskTheNeurologist.Com Approach to localisation within brainstem
25. AskTheNeurologist.Com 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?
26. AskTheNeurologist.Com 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
27. AskTheNeurologist.Com 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
28. AskTheNeurologist.Com Answer 2 Left medulla
29. AskTheNeurologist.Com 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.
30. AskTheNeurologist.Com Answer 3 The patient has features of
- a lesion of the medial longitudinal
- 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
31. AskTheNeurologist.Com 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.
32. AskTheNeurologist.Com 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.
33. AskTheNeurologist.Com Case 5* A 65 year old lady with a right sided ptosis, right pupil dilatation, diplopia, left sided cerebellar and pyramidal signs
34. AskTheNeurologist.Com 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
35. AskTheNeurologist.Com Case 6* A 84 year old lady with sudden onset of a left hemiparesis and deviation of both eyes to the left side
36. AskTheNeurologist.Com 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)
37. AskTheNeurologist.Com What is Nystagmus? Rhythmic oscillation of the eyes
Fast phase ( saccade)
Slow phase ( smooth-pursuit – like)
38. AskTheNeurologist.Com Describing nystagmus Position of gaze in which occurs or is most prominent
Direction ( of FAST phase)
Precipitating / exacerbating factors
Fatiguing / persistent
- Oscillopsia – feeling that vision is jerky
39. AskTheNeurologist.Com 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
40. AskTheNeurologist.Com Nystagmus may be……… Physiological
41. AskTheNeurologist.Com IS IT NORMAL??
42. AskTheNeurologist.Com Central vs Peripheral ( guidelines)
43. AskTheNeurologist.Com Diplopia “ The subjective feeling of seeing double”
Monocular ( present even when one eye open)
Binocular ( present only when 2 eyes open)
44. AskTheNeurologist.Com Binocular diplopia…questions Horizontal vs Vertical ?
Worse on looking in which direction?
Worse on focussing near or far ?
45. AskTheNeurologist.Com Anatomical sites which may cause diplopia Internuclear ( INO )
Neuromuscular junction (NMJ)***
Local distortion of orbit
46. AskTheNeurologist.Com Example of a patient with Myaesthenia Gravis
47. AskTheNeurologist.Com 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
48. AskTheNeurologist.Com 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
49. AskTheNeurologist.Com The 2 neurological causes of anisocoria One pupil too big
One pupil too small
50. AskTheNeurologist.Com 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!
52. AskTheNeurologist.Com Right – sided Horner’s Syndrome
53. AskTheNeurologist.Com Horner’s syndrome Due to interruption of sympathetic input to eye
Miosis ( constriction )
Anhidrosis ( lack of sweating on side of face)
57. AskTheNeurologist.Com 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
58. AskTheNeurologist.Com 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
59. AskTheNeurologist.Com 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.
60. AskTheNeurologist.Com 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.
61. AskTheNeurologist.Com THE END