unilateral optic neuropathy? - the value of visual fields

Unilateral optic neuropathy? - the value of the visual fields

Dr Clare Fraser

History

46 yo man, Fijian-Indian heritage

6 Feb: family doctor with 2 week history myalgia nausea and loss of appetite blurred vision

Diagnosed as viral illness Told to increase his thyroxine dose

8 Feb

Presents to Eye Emergency Department

blurred vision when reading vision “fading in and out” in his left

eye

denies recent viral illness denies current systemic symptoms no headache no pain on eye movement

Background

Past ocular history myopic colour blind

Past medical history Hashimotos thyroiditis thalassaemia trait low Vit D

Medications thyroxine

Background

Family history thalassaemia trait no vision loss

Social history works in office, lots of computer work no cigarettes or alcohol normal balanced diet

8 Feb

RIGHT

6/6

full eye movements

Anterior segment normal

Dilated fundus exam normal

LEFT

6/18 50% red desaturation

no RAPD



HR 69 reg, BP 100/68, temp 36.8C

8 Feb

Resident review no obvious ocular cause ? bitemporal inferior quadrant field

defect CT scan

normal

Referred for routine clinic follow-up “left optic neuritis”

19 Feb (+11 days)

returns to Eye Emergency no longer feels safe to drive

myalgia, arthralgia and nausea returned

no neurological symptoms no headache no pain on eye movement

19 Feb

RIGHT

6/21

full eye movements



LEFT

6/120 no red desaturation

no RAPD



HR 72 reg, BP 105/70, temp 36.7C

19 Feb

Patient didn’t want to wait in emergency for repeat work-up very busy at work

Advised not to drive!

Booked for neuro-ophthalmology clinic 2 days later

21 Feb

Failed to attend neuro-ophthalmology clinic patient contacted really very busy at work

22 Feb (+ 14 days)

Comes back to Eye Emergency vision is so blurred he can’t work

anymore

gradual progression of vision loss

intermittent mild headache loss of appetite difficulty sleeping

22 Feb

RIGHT

6/120

no RAPD



LEFT

Count Fingers at 30cm

no red desaturation

full EOMS, pain in left


Dilated fundus exam ? slight disc hyperaemia

HR 70 reg, BP 100/70, temp 36.7C

22 Feb

22 Feb

Call for a neuro-ophthalmology consult Admit

Blood tests – inflammatory, infective work-up

Chest X-ray Lumbar puncture 1g IV methyprednisolone daily

MRI brain/orbits with gadolinium ordered - outside institution

22 Feb: Neuro-op review (+14 days)

Vision 1/60 right, count fingers left Fields to confrontation

left central scotoma right hemi-field red desaturation

Poor pupil response to light OU 0.3 log-unit left RAPD

Cranial nerves normal Upper and lower limb exam – normal Anterior and posterior segments -

normal

Early results

full blood count – normal renal function – normal liver function – normal ESR 2, CRP 0.5

chest X-ray – no evidence of TB or sarcoid

Lumbar puncture - normal opening pressure and basic constituents

Diagnosis

“Atypical optic neuritis” 46 year old man Fijian-Indian nausea, sleep disturbance

Long lesion suspected left optic nerve intra-cranially extending to left optic tract (right hemifield)

neuromyelitis optica until proven otherwise Ddx: sarcoid

Dilemma

anti-AQP4 (NMO) results = 2 weeks MRI scan can only be done next week

Do you: continue IVMP? move rapidly to plasma exchange? ▪ based on clinical diagnosis of NMO▪ PLEX started within 15-20 days = best outcome

Magana S et al. Beneficial plasma exchange response in central nervous system inflammatory demyelination. Arch Neurol 2011; 68(7): 870-8

24 Feb (+16 days)

2 days IVMP – no change in vision

Transferred to general hospital 5 days plasma exchange 1g IV methylprednisolone continued 5

days

MRI – left optic nerve enhances

MRI – long optic nerve lesion

MRI – chiasm involved also

MRI – left optic tract

MRI – hypothalmic involvement

MRI – cervical spine = normal

2 March (discharge)

RIGHT

6/60

full EOMs



LEFT

6/90

0.3 log-unit RAPD



Oral prednisolone 60mg taper, azathoprine increasing to 150mg

Follow-up

1 week after discharge

repeat MRI brain – reduction in lesion size and intensity

NMO antibody positive

Longer term follow-up

21 March: (+ 6 weeks) VAR 6/18 VAL 6/18

2 May: (+ 3 months) VAR 6/9 VAL 6/9

14 Nov: (+ 9 months) VAR 6/7.5 VAL 6/7.5

Follow-up visual fields

Now

18 months with no relapses Back at work full-time Able to return to driving

Final medication: mycophenolate 500mg BD thyroxine Vit D supplement

Teaching pointsNeuromyelitis optica

Atypical optic neuritis

Patient subgroups MS is rare: African, Asian

30s+ Bilateral – simultaneous or sequential loss Progresses for > 2 weeks Severe pain > 2 weeks since onset Require steroids to induce recovery

Cannot apply the findings of the Optic Neuritis Treatment Trial

NMO- IgG antibody

Useful after first episode of transverse myelitis, severe or recurrent ON

Serum autoantibody Aquaporin-4 (AQP4) One of the major water channel proteins Sensitivity 50-80% (cell-based higher than ELISA)

Specificity 90-100%

Trebst C et al. Update on the diagnosis and treatment of neuromyelitis optica: recommendations of the meuromyelitis optica study group (NEMOS). J Neurol 2013; 261: 1-16.

Neuromyelitis optica

Optic neuritis Transverse myelitis

Within 2 years of each other Plus 2 of:

Brain MRI non diagnostic for MS Spinal cord lesion > 3 vertebral segments Seropositive for NMO-ab (anti-AQP4)

Wingerchuk D et al. Revised diagnostic criteria for neuromyelitis optica. Neurology 2006; 66(10): 1485-9

NMO spectrum

AQP4-IgG positive longitudinally extensive transverse myelitis

AQP4-IgG positive recurrent or bilateral optic neuritis

Wingerchuk D et al. The spectrum of neuromyelitis optica. Lancet Neurol 2007; 6(9):805-15

Management

Poor prognosis without treatment = medical emergency

5 days IV methylprednisolone Plasmapheresis

immediate improvement 50% improvement in 6 months in 78%

1mg/kg oral prednisolone – slow taper Immunosuppression (azathioprine)

Kim S et al. Clinical efficacy of plasmapheresis in patients with neuromyelitis optica spectrum disorder and effects on circulating anti-aquaporin 4 antibody levels. J Clin Neurol 2013;9(1): 36-42

Comparison

Multiple sclerosis ON

Neuromyelitis optica ON

Race Caucasians Asians, Africans

Eye Unilateral Bilateral or sequential

Recovery Spontaneous Poor without steroids

Course of optic neuritis

Less severe Profound vision loss

Neurological Varied CNS signs Transverse myelitis

Overall prognosis Good recovery Poor recovery without Rx

Thank you

unilateral optic neuropathy? - the value of visual fields

Health & Medicine