Neuromyelitis optica (NMO), also known as Devic disease or the optic-spinal variant of multiple sclerosis (MS), is an inflammatory condition of the central nervous system marked by simultaneous or sequential acute or subacute bilateral optic neuritis and transverse myelitis. Initially felt to be a variant of MS, evidence now supports NMO as a unique disease entity demonstrating an aggressive clinical course with poor response to standard MS immunomodulatory therapies; characteristic features include 1) T2-hyperintense spinal cord lesions extending for greater than 3 vertebral segments, 2) the presence of NMO-IgG serum antibodies, and 3) a brain MRI not meeting the diagnostic criteria for MS (1). The presence of 2 of the 3 latter characteristics in the setting of optic neuritis and acute myelitis is diagnostic of NMO (Table 1) with an estimated 99% sensitivity and 90% specificity (2). Limited reports have suggested a possible link between NMO and autoimmune disorders, such as systemic lupus erythematosus, Hashimoto thyroiditis, and Sjogren syndrome, although the strength of this association remains unclear (3,4).
Leber hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disease marked by acute or subacute onset optic neuropathy in 1 eye with frequent simultaneous or sequential involvement of the contralateral eye (5). More than 90% of European families demonstrate 1 of 3 mitochondrial DNA (mtDNA) point mutations named for the position of the nucleotide mutation (11778, 14484, and 3460) (6). While LHON is classically isolated to pathology of the optic nerves, rarely patients with LHON have an associated MS-like disease (7-10). We present a case of LHON masquerading as NMO.
A 65-year-old African American woman was referred to our clinic after sequential subacute onset of simultaneous painless vision loss 3 months prior. One year before the onset of visual symptoms, the patient first noted bilateral lower extremity pain, weakness, and gait imbalance. The diagnosis of idiopathic cervical myelopathy was established following an extensive workup by several neurologists. The evaluation included the following unremarkable studies: complete blood count, comprehensive metabolic profile, B-12/folate, vasculitis panel, syphilis serology, infectious hepatitis panel, thyroid function tests, serum angiotensin-converting enzyme, and paraneoplastic panel (including CRMP-5 antibody). A lumbar puncture revealed normal cerebrospinal fluid (CSF) composition, normal CSF IgG index/synthesis, and a negative CSF-VDRL. NMO IgG antibody was sent and was negative. Electromyography (EMG) and nerve conduction studies demonstrated mild axonal sensory polyneuropathy. A subsequent sural nerve biopsy showed axonal degeneration without inflammation, vasculitis, or amyloid. CT of the chest was unremarkable. A spinal MRI study revealed a longitudinal nonenhancing T2 hyperintensity of the posterior columns throughout the entire cervical spine (Fig. 1).
The patient's myelopathy-related deficits remained stable for more than 1 year. She then developed subacute onset of simultaneous painless vision loss in both eyes, and the visual acuity was 20/300, right eye, and 20/200, left eye. The optic discs were noted to be “hyperemic” with no comment regarding telangiectasias. Two months later, vision was 6/200 in both eyes. Visual fields showed cecocentral scotomas in each eye. Pupils were minimally reactive to light without an afferent pupillary defect. The patient was unable to recognize any color plates. Tonometry, external and anterior segment examinations, and cranial nerve testing were all unremarkable. The optic discs were pale temporally (Fig. 2). Contrast-enhanced MRI of the brain and orbits was normal (Fig. 3).
Review of the patient's medical history revealed well-controlled hypertension and mild chronic obstructive pulmonary disease presumably due to a history of smoking. She quit smoking 1 year ago and denied current or past alcohol abuse. Her family history was negative for autoimmune disease, neurologic degeneration, and serious vision problems. Genetic testing for LHON revealed the pathologic mtDNA 14484 point mutation.
In 1970, Wallace (7) published a report highlighting an association between LHON and other neurological signs, including encephalopathy, spasticity, and increased deep tendon reflexes. In 1992, Harding further described a rare subset of LHON patients with MS-like features (LHON-MSL), which has led some to refer to LHON-MSL as “Harding syndrome” (8,9). Since that time, there have been less than 30 reported cases of LHON-MSL. All 3 of the most common causative LHON mtDNA point mutations have been reported in LHON-MSL, with the 11778 mutation being the most frequent (10). Perez compiled 17 cases of LHON-MSL from the literature and found a surprising 1.8:1 female to male ratio (F:M) in contrast to the previously published F:M of 1:3—1:8 in LHON without MSL (ratios depending on specific mutation) (10,11). The neurologic manifestations of LHON-MSL are highly variable and often result in severe disability, with 75% (8 of 12) of patients demonstrating difficulty walking due to nonvisual neurologic disease over a mean 13-year follow-up period (10). Visual decline consistent with LHON precedes other neurologic sequelae in 70% of cases by an average of 4.3 years. Central nervous system white matter changes on MRI often have an appearance similar to inflammatory demyelinating plaques of MS, and 87% of LHON-MSL patients demonstrate CSF oligoclonal bands during the disease course. Histologic examination of CNS tissue in LHON-MSL has demonstrated findings consistent with inflammatory demyelinating MS-like plaques (12). The postmortem histology of an LHON-MSL patient with T2 hyperintensity of the dorsal spinal tracts reported by Jaros et al (13) demonstrated changes consistent with a primary spinal cord neurodegeneration plausibly from mitochondrial dysfunction rather than inflammatory demyelination. In our case, the spinal cord changes detected on MRI involved predominately the posterior columns, in contrast to typical NMO lesions, which involve the entire spinal cord with expansion. While the underlying pathophysiology for LHON-MSL remains elusive, the volume of case reports in the literature seems to support an association between LHON and white matter CNS disease, not explainable by chance alone.
An NMO-like presentation of LHON has only rarely been described (13). Key features distinguishing NMO from LHON-MSL include the location and characteristics of spinal cord lesions, the presence of a known pathogenic LHON mtDNA mutation, the absence of NMO-IgG serum antibodies, and the clinical differences between NMO associated optic neuritis and LHON-MSL associated optic neuropathy.
Demyelinating optic neuritis was also a diagnostic consideration in our patient. This optic neuropathy is characterized by an acute onset of eye pain (92.2%) with vision loss, good visual recovery with 92% of affected eyes demonstrating better than or equal to 20/40 vision at 15 years of follow-up, and enhancement of the affected optic nerve on MRI (14,15). In contrast, LHON typically is associated with painless vision loss, tends to be familial (50%) and only rarely demonstrates enhancement on MRI (5). Spontaneous recovery of vision is unusual in LHON and primarily associated with the 14484 mtDNA mutation (16). Optic neuritis associated with NMO produces more severe long-term visual impairment than demyelinating optic neuritis. Papais-Alvarenga et al (17) reported that 63% of affected eyes with NMO optic neuritis were left with severe visual loss (<20/200) over a median follow-up period of 8 years.
We acknowledge the possibility that our patient might have co-occurrence of seronegative NMO and LHON. However, we consider this highly unlikely for the following reasons: 1) the lack of pain at the onset of visual loss, 2) slow progression of visual loss over months rather than weeks, and 3) lack of enhancement or high T2 signal within either optic nerve on MRI.
In conclusion, LHON is occasionally associated with MS-like features, which can confound the diagnosis. We present a case of LHON-MSL masquerading as NMO. Establishing the correct diagnosis is critical, since the prognosis and management options for the 2 conditions are very different. While NMO may respond to potent immunosuppressive agents, no treatment to date has been shown to be effective for LHON. The diagnosis of LHON should be considered in all cases of acute or subacute bilateral optic neuropathy, including presumed seronegative NMO.
1. Argyriou AA,
Makris N. Neuromyelitis optica: a distinct demyelinating disease of the central nervous system. Acta Neurol Scand. 2008;118:209-217.
2. Wingerchuk DM,
Lennon VA, Pittock SJ, Lucchinetti CF, Weinshenker BG. Revised diagnostic criteria for neuromyelitis optica. Neurology. 2006;66:1485-1489.
3. Karim S,
Majithia V. Devic's syndrome as initial presentation of systemic lupus erythematosus. Am J Med Sci. 2009;338:245-247.
4. Sergio P,
Mariana B, Alberto O, Claudia U, Oscar R, Pablo M, Alberto A. Association of neuromyelitis optic (NMO) with autoimmune disorders: report of two cases and review of the literature. Clin Rheumatol. 2010;29:1335-1338.
5. Yen M,
Wang A, Wei Y. Leber's hereditary optic neuropathy: a multifactorial disease. Prog Retin Eye Res. 2006;25:381-396.
6. Mackey DA,
Oostra RJ, Rosenberg T, Nikoskelainen E, Bronte-Stewart J, Poulton J, Harding AE, Govan G, Bolhuis PA, Norby S. Primary pathogenic mtDNA mutations in multigeneration pedigrees with Leber hereditary optic neuropathy. Am J Hum Gen. 1996;59:481-485.
7. Wallace DC.
A new manifestation of Leber's disease and a new explanation for the agency responsible for its unusual pattern of inheritance. Brain. 1970;242:121-132.
8. Harding AE,
Sweeney MG, Miller DH, et al. Occurrence of a multiple sclerosis-like illness in women who have a Leber's hereditary optic neuropathy mitochondrial DNA mutation. Brain. 1992;115:979-989.
9. Parry-Jones AR,
Mitchell JD, Gunarwardena WJ, Shaunak S. Leber's hereditary optic neuropathy associated with multiple sclerosis: Harding's syndrome. Pract Neurol. 2008;8:118-121.
10. Perez F,
Anne O, Debruxelles S, Menegon P, Lambrecq V, Lacombe D, Martin-Negrier ML, Brochet B, Goizet C. Leber's optic neuropathy associated with disseminated white matter disease: A case report and review. Clin Neurol Neurosurg. 2009;111:83-86.
11. Carelli V,
Ross-Cisneros FN, Sadun AA. Mitochondrial dysfunction as a cause of optic neuropathies. Prog Retin Eye Res. 2004;23:53-89.
12. Kovacs GG,
Hoftberger R, Majtenyi K, Horvath R, Barsi P, Komoly S, Lassmann H, Budka H, Jakab G. Neuropathology of white matter disease in Leber's hereditary optic neuropathy. Brain. 2005;128:35-41.
13. Jaros E,
Mahad DJ, Hudson G, Birchall D, Sawcer SJ, Griffiths PG, Sunter J, Perry RH, Chinnery PF. Primary spinal cord degeneration in Leber hereditary optic neuropathy. Neurology. 2007;69:214-216.
14. Optic Neuritis Study Group.
The clinical profile of optic neuritis: experience of the optic neuritis treatment trial. Arch Ophthalmol. 1991;109:1673-1678.
15. Optic Neuritis Study Group.
Visual function 15 years after optic neuritis: a final follow-up report from the optic neuritis treatment trial. Ophthalmology. 2008;115:1079-1082.
16. Riordan-Eva P,
Sander MD, Govan GC, Sweeney MG, DaCosta J, Harding AE. The clinical features of Leber's hereditary optic neuropathy defined by the presence of pathogenic mitochondrial DNA mutation. Brain. 1995;118:319-337.
© 2011 Lippincott Williams & Wilkins, Inc.
17. Papais-Alvarenga RM,
Carellos SC, Alvarenga MP, Holander C, Bichara RP, Thuler LC. Clinical course of optic neuritis in patients with relapsing neuromyelitis optica. Arch Ophthalmol. 2008;126:12-16.