BRAIN STEM, CEREBELLUM and NEURO-OPTHALMOLOGY

1. AskTheNeurologist.Com BRAIN STEM, CEREBELLUM and NEURO-OPTHALMOLOGY Submitted to AskTheNeurologist.Com in 2007

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

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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

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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 Intention Tremor Scanning speech Hypotonia 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 Right 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 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

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 Associated symptoms - Vertigo - 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 Pathological

41. AskTheNeurologist.Com IS IT NORMAL??

42. AskTheNeurologist.Com Central vs Peripheral ( guidelines)

43. AskTheNeurologist.Com Diplopia � The subjective feeling of seeing double� May be: 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 ) Nucleus Fascicle Cranial nerve Neuromuscular junction (NMJ)*** Muscle 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 - Ptosis 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