Neuromyelitis optica

Clinical:

• A 28 years old lady
• First 2 presentations were optic neuritis
• Third presentation with lower limbs weakness
• Current presentation with bilateral lower limb weakness and urgency.
• Clinical examination shows bilateral lower limb power 4/5.
• Sensory level reduction at T2-T11 and L5-S1.

MRI findings:

• Initial MRI shows diffuse long segment high signal intensity within the cord (yellow arrows) with superior most margin at C4/C5 level and inferior margin at T8/T9 level. Faint abnormality also seen at C2-C3 level. There is  no enhancing lesion on post Gado.
• Repeat MRI during current admission shows lesion at C2-C3 level, more conspicuous and almost of CSF density as compared to previous MRI. It is already hypointense on T1. No cord expansion.
• Hyperintense signal is also seen at C5 to T8 level, similar extension of involvement as compared to previous findings.
• However, there are multiple foci of enhancement seen at level of C7 to T2 on post contrast (red arrows). These enhancing lesion are peripherally and mostly posterolateral in location.
• There is cord expansion with the largest AP diameter of the spinal cord measures 0.7cm at T2 level
• MRI brain is normal (images not shown).

Diagnosis: Correlating with clinical presentations, features are in consistent with neuromyelitis optica.

Discussion: Neuromyelitis optica (NMO)

• NMO is an idiopathic, autoimmune, inflammatory, demyelinating condition
• It is characterised by bilateral optic neuritis and myelitis resulting in blindness and paraplegia
• Involvement of optic nerve and spinal cord is common
• The brain and brainstem are generally spared (10%)
• 23% mortality rate
• Women in their 30s and 40s

Comparison Neuromyelitis optica and multiple sclerosis: