MS

Question 1

24 y.o. shop assistant presents w 3 day hx of pain around right eye, associated with reduced vision in that eye

unable to see small objects or distinguish colours

visual acuity 6/36 in right eye, 6/6 in left

right optic disc swollen, right RAPD

one year previously she had experienced an episode of numbness affecting both legs and associated with urgency of micturition and temporary urinary incontinence. this had all resolved spontaneously and had been attributed to a “trapped nerve”. you suspect MS.

(a)(i) what is an afferent pupillary defect?

Answer 1

lesion anterior to optic chiasm

light shone into the affected eye will cause reduced/no constriction of both pupils

light shone into the normal eye will cause constriction of both pupils

Question 2

(a)(ii) what is the immediate cause of the visual loss?

Answer 2

optic neuritis

Question 3

(b) suggest 2 investigations that should be undertaken and what results you will expect from them.

Answer 3

1. MRI brain and SC - demyelinating plaques in the white matter of right optic tract. Gadolinium will enhance recent plaques. Old plaques may be found on the corticospinal tract (urinary sx)
2. LP - antibodies with oligoclonal banding and protein
3. VEP - delayed

Question 4

(c) the further ix confirm the dx. she is now well but comes to see you to “talk things over”.

what points will you make with regard to px and mx? suggest 4.

Answer 4

1. disease is not curable
2. disease course is relapsing and incompletely remitting. it eventually becomes progressive declination without remission (over 5-25 years). reduced life expectancy.
3. you can remain active and not grossly disabled for much of the time
4. IV steroids are used for acute attacks. they decrease the severity and duration of the attack but have no effect on the long term outcome.

Question 5

(d) what aetiological factors are associated with this condition?

Answer 5

1. viral infection and inappropriate autoimmune reaction
2. genetics