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Ophthalmology – Devic’s Disease (Neuromyelitis Optica)
Neuromyelitis optica (NMO), also known as Devic’s disease, is a rare autoimmune demyelinating disorder of the central nervous system characterized primarily by severe optic neuritis and transverse myelitis. Although it was previously considered a variant of multiple sclerosis (MS), it is now recognized as a distinct disease entity, especially after the discovery of the aquaporin-4 (AQP4) antibody (NMO-IgG). This antibody targets water channels in the CNS, leading to inflammation, demyelination, and tissue necrosis.
The disease is more common in women, who are affected 4–9 times more often than men, and typically presents in the third to fourth decade of life. It is relatively rare in Western populations but more prevalent in regions such as Japan. The exact cause remains unclear, though some cases have been associated with prior infections, suggesting a possible immune-triggering event.
Pathophysiologically, NMO is driven by autoantibodies against aquaporin-4 channels, which activate the complement system and lead to severe inflammation and destruction of myelin and neural tissue. Unlike MS, which primarily affects white matter, NMO can involve both gray and white matter and often causes more extensive damage, particularly in the spinal cord.
Clinically, patients often present with sudden, painful vision loss, frequently affecting both eyes either simultaneously or sequentially. Visual loss can be severe and includes both central and peripheral deficits, often accompanied by loss of color vision (achromatopsia). In addition, patients develop transverse myelitis, which leads to motor weakness (paraparesis or quadriparesis), sensory deficits, and bowel or bladder dysfunction. Severe muscle spasms and systemic symptoms such as fever, headache, and malaise may also occur.
Diagnosis is based on a combination of clinical findings, laboratory testing, and imaging. The presence of aquaporin-4 IgG antibodies supports the diagnosis in approximately 80% of cases. MRI of the brain, optic nerves, and spinal cord is essential. A key feature is longitudinally extensive spinal cord lesions spanning more than three vertebral segments. Brain MRI findings are typically atypical for MS. Lumbar puncture may show elevated white blood cells, often with neutrophils, and typically lacks oligoclonal bands, helping differentiate NMO from MS.
Management focuses on both acute treatment and prevention of relapses. Acute attacks are treated with high-dose intravenous corticosteroids, such as methylprednisolone. If there is inadequate response, plasmapheresis is often effective. Long-term management aims to prevent relapses using immunosuppressive therapy, commonly with agents such as azathioprine combined with oral prednisone. Other therapies, including rituximab and mycophenolate mofetil, are also used based on the autoimmune nature of the disease.
Patients with spinal cord involvement often require rehabilitation, including physical and occupational therapy, due to persistent neurologic deficits. Regular follow-up with neurology and ophthalmology is essential, as the disease is often relapsing and progressive.
The prognosis of NMO is generally worse than multiple sclerosis, with significant risk of permanent disability. Many patients experience incomplete recovery after each attack, and cumulative damage leads to progressive neurologic impairment. The mortality rate can reach 20–25%, often due to complications of severe myelitis, such as respiratory failure. Early diagnosis and aggressive immunosuppressive treatment are critical in improving outcomes and reducing relapse frequency.
Neuromyelitis optica (NMO), also known as Devic’s disease, is a rare autoimmune demyelinating disorder of the central nervous system characterized primarily by severe optic neuritis and transverse myelitis. Although it was previously considered a variant of multiple sclerosis (MS), it is now recognized as a distinct disease entity, especially after the discovery of the aquaporin-4 (AQP4) antibody (NMO-IgG). This antibody targets water channels in the CNS, leading to inflammation, demyelination, and tissue necrosis.
The disease is more common in women, who are affected 4–9 times more often than men, and typically presents in the third to fourth decade of life. It is relatively rare in Western populations but more prevalent in regions such as Japan. The exact cause remains unclear, though some cases have been associated with prior infections, suggesting a possible immune-triggering event.
Pathophysiologically, NMO is driven by autoantibodies against aquaporin-4 channels, which activate the complement system and lead to severe inflammation and destruction of myelin and neural tissue. Unlike MS, which primarily affects white matter, NMO can involve both gray and white matter and often causes more extensive damage, particularly in the spinal cord.
Clinically, patients often present with sudden, painful vision loss, frequently affecting both eyes either simultaneously or sequentially. Visual loss can be severe and includes both central and peripheral deficits, often accompanied by loss of color vision (achromatopsia). In addition, patients develop transverse myelitis, which leads to motor weakness (paraparesis or quadriparesis), sensory deficits, and bowel or bladder dysfunction. Severe muscle spasms and systemic symptoms such as fever, headache, and malaise may also occur.
Diagnosis is based on a combination of clinical findings, laboratory testing, and imaging. The presence of aquaporin-4 IgG antibodies supports the diagnosis in approximately 80% of cases. MRI of the brain, optic nerves, and spinal cord is essential. A key feature is longitudinally extensive spinal cord lesions spanning more than three vertebral segments. Brain MRI findings are typically atypical for MS. Lumbar puncture may show elevated white blood cells, often with neutrophils, and typically lacks oligoclonal bands, helping differentiate NMO from MS.
Management focuses on both acute treatment and prevention of relapses. Acute attacks are treated with high-dose intravenous corticosteroids, such as methylprednisolone. If there is inadequate response, plasmapheresis is often effective. Long-term management aims to prevent relapses using immunosuppressive therapy, commonly with agents such as azathioprine combined with oral prednisone. Other therapies, including rituximab and mycophenolate mofetil, are also used based on the autoimmune nature of the disease.
Patients with spinal cord involvement often require rehabilitation, including physical and occupational therapy, due to persistent neurologic deficits. Regular follow-up with neurology and ophthalmology is essential, as the disease is often relapsing and progressive.
The prognosis of NMO is generally worse than multiple sclerosis, with significant risk of permanent disability. Many patients experience incomplete recovery after each attack, and cumulative damage leads to progressive neurologic impairment. The mortality rate can reach 20–25%, often due to complications of severe myelitis, such as respiratory failure. Early diagnosis and aggressive immunosuppressive treatment are critical in improving outcomes and reducing relapse frequency.
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