Neuromyelitis optica is an immunologic inflammatory disorder of the central nervous system that is associated with severe demyelination and axonal damage most of the optic nerves and spinal cord. Neuromyelitis optica is now known as neuromyelitis optica spectrum disorders (NMOSD). In the past, neuromyelitis optica was considered a variety of multiple sclerosis, but now it is clinically a distinct entity based on its immunologic characteristics. The prevalence of neuromyelitis optica is around 0.5-10 cases per 100,000 populations. It is 10 times more prevalent in women than in men. The median age group for neuromyelitis optica is 32-41 years.(1)
How To Stop Neuromyelitis Optica From Spreading?
The aquaporin-4 (AQP4) autoantibody (neuromyelitis optica (NMO)-immunoglobulin G (IgG)) may be considered a marker for disease course and prognosis. If neuromyelitis optica is not stopped then it will lead to higher relapses, poorer prognosis, and higher mortality. Therefore, it is important to prevent and treat the attacks of neuromyelitis optica. The initial treatment for patients suspected for neuromyelitis optica should be managed with high dose intravenous methylprednisolone (1 gm daily x 3-5 consecutive days). Patients with severe symptoms and who do not respond to glucocorticoids can be managed with therapeutic plasma exchange that is carried out at alternate days totaling 5-7 cycles.(1)
Since neuromyelitis optica causes progressive disability following each relapse, it is important to prevent these attacks from occurring and this involves long term treatment with immunosuppressive drugs and the treatment should be initiated as soon as the disease is diagnosed. The best treatment option for patients who are AQP4-IgG antibody seropositive is eculizumab. Other immunosuppressive agents used for the management of neuromyelitis optica relapses include azathioprine, rituximab, mycophenolate mofetil, methotrexate, mitoxantrone, and oral glucocorticoids. Management with tocilizumab has been noted to stabilize or improve the symptoms in a few patients who do not respond to standard treatment. Looking at the severity and high-risk relapse rate of the disease, immunosuppression should be carried out for at least 5 years for AQP4 seropositive patients.(1)
Signs And Symptoms Of Neuromyelitis Optica
The classical features of neuromyelitis optica include acute flares of rapid optic neuritis that leads to severe visual loss. It is also associated with transverse myelitis that leads to limb weakness, sensory loss, and bladder dysfunction. The course of acute flares occurs over days and remits over weeks to months. The course of neuromyelitis optica is usually relapsing in more than 90% of the cases and the residual effects of the attacks may lead to permanent disability leading to blindness and paralysis within 5 years of the disease progression. Patients with brain manifestations can have recurrent brain attacks without the involvement of optic nerve or spinal cord. Other symptoms include nausea and vomiting, hiccups, daytime sleepiness, seizures (in children), posterior reversible leukoencephalopathy syndrome, neuroendocrine disorders, autonomic manifestations, such as hypotension, hypothermia, bradycardia, fulminant vasogenic edema, brain herniation, and even death.(1)
Optic neuritis is the inflammation of the optic nerve that is associated with vision. It is associated with vision loss and eye pain that worsens with eye movement. The optic neuritis associated with neuromyelitis optica cannot be differentiated with optic neuritis associated with other causes, such as multiple sclerosis, although the vision loss is more severe in neuromyelitis optica. Most of the flares of optic neuritis in neuromyelitis optica are unilateral; however, successive flares affecting both the eyes simultaneous have also been observed.(1)
Transverse myelitis is the involvement of the spinal cord that develops in hours or days without any structural spinal cord pathology. It can lead to weakness or paralysis of either both or all four extremities, sensory loss below the level of spinal cord lesion and bladder dysfunction. Other symptoms include attacks of spasms and pain of the trunk or extremities, Lhermitte sign or radicular pain. The extent of spinal cord demyelination and symptoms last longer than that of multiple sclerosis, although the shorter extent of spinal cord involvement is seen in some patients.(1)