Neuromyelitis optica (NMO) (Devic disease), demyelinating disorder

1. NEUROMYELITIS OPTICA (NMO) (DEVIC
DISEASE)
Dr. Pawan Kumar Barolia MBBS MD
Fellowship in intensive care Pediatrics

2. Neuromyelitis optica (NMO) (Devic
disease)
 It is a demyelinating disorder characterized by monophasic or
polyphasic episodes of optic neuritis and/or transverse myelitis
 It was once thought that NMO was a variant of MS
 Most authorities believe that NMO is a distinct disorder.
Epidemiology
 Nmo has an age of onset of 11 yr.
 In 1 study, in monophasic patients, the range of age of onset was 1-
54 yr;
 In polyphasic patients, the range was 6-72 yr
 NMO is more common in women and girls than in men and boys;
 65% of monophasic and 80-85% of polyphasic NMO patients are
female.
 It is also more common in asians than in blacks or whites
 Appears to have a higher mortality rate in individuals of african
descent than in others

3. Pathogenesis
 NMO is associated with IgG antibodies to the
aquaporin-4 water channel
 It is not clear why the attack on and depletion of spinal
cord and optic nerve aquaporin-4 results in disruption
of the myelin sheath in these parts of the CNS,
 Pathologic examination of autopsy specimens reveals
both anti–aquaporin-4 IgG deposits and B cells in the
spinal cord and optic nerves of NMO patients
 Although most cases of NMO are idiopathic
 only occasional familial cases have been reported
 there have been reports of postinfectious NMO
 HIV, syphilis, chlamydia, varicella, cytomegalovirus,
and Epstein-Barr virus have been associated with
subsequent development of NMO.

4. Clinical Manifestations
 Either optic neuritis or transverse myelitis or both
 Visual field defects and color desaturation are
common.
 The symptoms and signs of transverse myelitis
depend on the spinal level and completeness of the
inflammatory changes
 NMO differs from MS in that other parts of the
nervous system are generally not involved
 Recovery of visual and spinal cord function is
generally not as complete after each episode
 Optic neuritis is more frequently bilateral in NMO
than in MS
 NMO is more frequently fatal than MS.

5. Laboratory Findings
 CSF in patients with NMO often has 50 or more WBC/mL
 Unlike MS, it is devoid of oligoclonal bands
 Serum positivity for anti–aquaporin-4 antibodies (so-called
NMO antibodies) has a sensitivity of 73% and a specificity of
91% for NMO
 Neuroimaging studies may show small, asymptomatic lesions
in the white matter of the brainstem or hemispheres, but not
the large (>3 mm), oval lesions in the periventricular white
matter seen in MS.
 MRI lesions are most commonly demonstrated in the optic
nerves and spinal cord, and in the diencephalons

6. Diagnosis
 Clinical criteria for the diagnosis of NMO include
finding at least 2 of the following
 normal brain MRI, spinal cord widening and
cavitation involving at least 3 spinal segments,
 decreased serum/CSF albumin ratio with normal
IgG synthesis rate
 the absence of oligoclonal bands,
 acute episode(s) of spinal cord and/or optic nerve
involvement separated by months or years without
any other systemic or neurologic features

7. Differential Diagnosis
 MS; ADEM
 rheumatologic etiologies of transverse myelitis and/or
optic neuritis including SLE, Behcet disease, and
neurosarcoidosis (usually accompanied by other
nonneurologic manifestations);
 idiopathic transverse myelitis, tropical spastic
paraparesis,
 viral encephalomyelitis (none of which have NMO
antibodies in the serum or CSF);
 metabolic and idiopathic causes of isolated optic
neuritis or other acute monocular or binocular visual

8. Complications
 left with fixed neurologic deficits
 affecting visual acuity, visual fields, color vision
 motor and sensory function, balance, and
bowel/bladder function.

9. Treatment
 Initial episodes and relapses may be treated acutely with
methylprednisolone, 20-30 mg/kg/day (maximum
1,000 mg/day) for 3-5 days,
 followed by a slow prednisone taper
 It is not yet known whether injectable DMT (interferon-
beta1α or interferon-beta1β; glatiramer acetate) reduces
relapse frequency in NMO.
 However, agents like rituximab that reduce B cell number
and function have shown promise in this regard in early
studies.

10. Prognosis
 The prognosis in NMO is generally poor for
patients with NMO
 In 1 study, approximately 20% remained
functionally blind (i.e., 20/200 vision or worse) in
at least 1 eye
 31% had permanent monoplegia or paraplegia.
 Five-year survival of the patients with paraplegia
is approximately 90%.