Neuro week 1

1. Neuro week 1 Case 1

2.   Q1 Describe/demonstrate a clinical examination of the eyes that you would perform in your general practice rooms. Katherine, aged 28 years, is a previously healthy woman who presents to you because of blurred vision of the right eye. She noticed this upon awakening three days earlier.  Over the next 2 days, her vision gradually deteriorated, and she developed right ocular pain when she moved her eyes. There is no prior history of neurologic symptoms and she has had no recent infection or immunisation.  

3.   Q1 Describe/demonstrate a clinical examination of the eyes that you would perform in your general practice rooms. • Inspection • Look for ptosis • Inspect colour of slcerae: • Yellow (jaundice) • Blue (osteogenesisimperfecta) • Blue/grey (ochronosis) • Red (iritis/scleritis/conjuctavitis/subconjunctivalhaemorrhage) • Look for exopthalmos (prominence of eyes) and proptosis (protrusion of eyes from orbits) • Look for corneal ulceration (fluorescein will stain corneal ulcers)

4.   Q1 Describe/demonstrate a clinical examination of the eyes that you would perform in your general practice rooms. • Cranial nerve examination (2,3,4,6): • Visual acuity • Test each eye with Snellen chart with other eye covered • Glasses can be used • Visual fields • Without glasses, eyes of patient and examiner should be level, patient should be at arms length • Patient covers one eye, mirrors the examiner and both stare straight ahead • Hat pin is brought in gradually from outstreched arm in diagonal direction • Patient reports when pin is first sighted in peripheral vision and if it disappears while travelling to centre of vision • Enquire about diplopia • Pupillary responses to light • Shine focused light in one eye at a time • Assess direct and consensual response • Repeat these tests on other eye • Move torch in arc from pupil to pupil to test for afferent pupillary defect

5.   Q1 Describe/demonstrate a clinical examination of the eyes that you would perform in your general practice rooms. • Cranial nerve examination (2,3,4,6): • Accommodation • Ask patient to look into distance and then at the hat pin placed 30cm from nose • Normally both pupils constrict and eyes converge • Eye movements • Patient to follow hat pin with eyes only • Use modified H pattern • Look for failure of movement and for nystagmus • Corneal reflex • Fundoscopy • Refer to ophthalmic notes

6. Q2 Describe the pathophysiological mechanism behind this presentation.  Describe the nerve fibres involved in the pupillary reflex.  Explain the finding of an afferent pupillary defect. Her visual acuity is 6/24 in her right eye and 6/6 in her left eye.  A right afferent pupillary defect and a central scotoma are present.  Fundoscopic  examination is normal.  The rest of her neurological examination is normal.  You involve your local ophthalmologist who finds no intrinsic eye pathology and agrees with your diagnosis of optic neuritis.

7. Q2 Describe the pathophysiological mechanism behind this presentation.  Describe the nerve fibres involved in the pupillary reflex.  Explain the finding of an afferent pupillary defect. • Right eye visual acuity poor • Right eye afferent pupillary defect • Right eye central scotoma • These findings are most commonly due to optic nerve pathology eg: • Optic neuritis • Sarcoidosis • Tumour • Leber’s hereditary optic neuropathy • Nerve fibres involved in pupillary reflex: • Afferent – optic nerve • Efferent – occulomotor nerve

8. Left afferent pupillary defect

9. Q3 Briefly discuss the clinical course and outcome.  What information can you give Katherine about the recovery of her vision? Her visual acuity is 6/24 in her right eye and 6/6 in her left eye.  A right afferent pupillary defect and a central scotoma are present.  Fundoscopic  examination is normal.  The rest of her neurological examination is normal.  You involve your local ophthalmologist who finds no intrinsic eye pathology and agrees with your diagnosis of optic neuritis.

10. Q3 Briefly discuss the clinical course and outcome.  What information can you give Katherine about the recovery of her vision? • Recovery of vision  • Without treatment, vision begins to improve after a few weeks. Improvement can continue over many months; • 90 percent have 20/40 or better vision at one year • Some chronic features: • Persistent visual loss. Most patients with optic neuritis recover functional vision within one year. However, on testing, deficits in color vision, contrast sensitivity, stereo acuity, and light brightness are detectable in most patients at up to two years • A relative afferent pupillary defect remains in approximately one-fourth of patients two years after presentation • Colour desaturation • Temporary exacerbations of visual problems during increases of body temperature eg. hot showes, exercise • Optic atrophy (despite return of visual acuity) occurs to some degree in most cases of optic neuritis

11. Q4 What can you tell Katherine about the risk of developing multiple sclerosis? • ~50% of people with optic neuritis go on to develop MS • ~15-20% of people with MS had optic neuritis as their first symptom

12. Q5 What features, if any, predict a patient's likelihood of developing MS following a single episode of optic neuritis? • MRI • white matter brain lesions increase risk of developing MS by 3x (but ~1/2 of patients with lesions on MRI will not have developed MS 10 years later) • Lumbar puncture • oligoclonalbands increase risk • Papillitis, peripapillary haemorrhage and retinal exudates with a normal MRI brain decreases risk of MS

13. Q6 What can you tell Katherine now about her diagnosis? One year after the episode of optic neuritis, Katherine develops painless numbness under her left foot, which gradually ascend to involve the entire leg and eventually moves up to her ribcage, with less severe numbness on the other leg.  She also complains of leg weakness and urinary urgency, and takes time off work.

14. Q6 What can you tell Katherine now about her diagnosis? • Can now be defined as MS • Two or more episodes of symptoms • Two or more signs that reflect pathology in anatomically non-contiguous white matter tracts of the CNS • -> symptoms must last for > 24 hr and occur as distinct episodes that are separated by a month or more • There is no specific investigation, but MRI/evoked potentials/CSF abnormalities

15. Q7 What additional information can you provide about the course of her illness? Katherine understandably expresses concern about what the future hold for her with a diagnosis of Multiple Sclerosis.

16. Q7 What additional information can you provide about the course of her illness? • Average number of years to death from onset of MS is 30, with life expectancy of people with MS 5 – 10 years lower than those unaffected. MS doesn’t always cause paralysis – Most people living with MS do not become severely disabled. 90% of those living with MS are still walking at 10 years from onset, and 75% at 15 years. Two thirds never get severely disabled although they are using walking aids etc in later years. Those with MS are encouraged to keep working. “I have MS, MS doesn’t have me”. • Not curable, not contagious, not fatal, not heritable (only 1% chance that offspring have MS too) pregnancy is actually associated with lower frequency of relapse. There is no special diet but increasing vigilance over good diet and exercise will help combat some symptoms of MS like fatigue; reduced mobility can lead to increased weight – which is not good if balance is not the best. Keeping a healthy lifestyle will also reduce infective illness which can lead to increased weakness. Keep cool wherever possible – don’t overdo exercise – workout hard and fast and then have a cool down period. • Drug treatment aims at reducing the frequency and severity of attacks and slowing the progress of disability.

17. Q8 Are there any prognostic features that might give Katherine further information? • Better prognosis is associated with: • Female gender • Relapsing – remitting subtype of MS • Optic neuritis of sensory symptoms at onset • Few attacks in the initial years • Early age at onset