Causes and Symptoms of Retrobulbar Neuritis
Symptoms of Retrobulbar Neuritis vary and depend on the cause of the illness. The causes include Multiple sclerosis, GFAP astrocytopathy, COVID-19, and other conditions.
Multiple sclerosis
During an attack of demyelinating retrobulbar optic neuritis (ON), the optic nerve is damaged and inflammation occurs, resulting in pain with eye movement and reduced vision. The condition is commonly associated with multiple sclerosis. The pathogenesis of ON has not been fully understood. However, an autoimmune mechanism is proposed.
The inflammatory process damages the myelin in the retina and ganglion cell axons begin to degenerate. When myelin is destroyed, astrocytes and macrophages proliferate. During this phase, glial (sclerotic) areas may appear multiple throughout the brain and spinal cord.
Clinical examination includes fundus oculi, magnetic resonance, and visual field tests. A fluorescein angiogram is performed to rule out true edema of the optic nerve. This test can be negative for true edema but should be done if neuroretinitis is suspected. A lumbar puncture is not necessary for diagnosis but can be used to rule out elevated intracranial pressure or bilateral anterior disc edema. The most common scans are MRIs of the brain, spinal cord, and peripheral scotomas.
The risk of developing MS after an episode of ON is 38%. The risk is lowest for patients with severe optic disc swelling and is higher for patients who do not have lesions on their baseline MRI. Male sex is associated with a lower risk of MS, as are certain atypical features of optic neuritis. In addition, there is a low incidence of MS in patients who have a history of migraines.
The cumulative probability of developing MS by 15 years after the onset of optic neuritis is 50%. The onset of the disease is usually in the early to mid-adult years, and the average age of onset is approximately 35. The median time to diagnosis is about three years.
The incidence of MS is also lower in patients without a history of pain or psychiatric disorders. In addition, patients with an MRI of the brain are less likely to develop MS than patients who do not have a baseline MRI. In addition, atypical clinical features of optic neuritis, including optic disc swelling, are associated with a lower risk of MS.
The onset of an MS attack is usually preceded by an acute, unilateral loss of vision. In addition, the periorbital pain is often worse with eye movement. The onset of periorbital pain can occur days or weeks before the loss of vision. If this is the first sign of an upcoming MS attack, further testing may be necessary.
GFAP astrocytopathy
GFAP astrocytopathy is an autoimmune CNS disease that is most commonly associated with myelitis and meningoencephalomyelitis. It is also characterized by relapsing-remitting patterns. Some patients show a poor response to treatment. The disease is treatable with immunosuppressants and high-dose corticosteroids.
In addition to meningoencephalomyelitis and myelitis, the disease can present with other symptoms such as encephalopathy, delirium, loss of vision, delirium, convulsions, fever, and inflammatory lesions. These symptoms can occur with the acute or subacute onset and can be accompanied by flu-like symptoms. However, the majority of patients are asymptomatic.
In addition to the clinical manifestations, MRI findings of GFAP astrocytopathy are usually limited to a linear enhancement oriented radially to the ventricles. In a small number of patients, the phenotype was mixed with typical meningoencephalomyelitis. Several factors can trigger GFAP-dependent autoimmunity, including infection, tumors, and T-cell dysfunction. Other components of the immune system might also contribute to the pathogenesis.
A 13-year-old girl with acute-onset meningoencephalitis was diagnosed with GFAP astrocytopathy by detecting anti-GFAP antibodies in her cerebrospinal fluid. Her CSF analysis showed an elevated protein level, adenosine deaminase levels, and monocytic pleocytosis. Her neurological features included a cervical abnormality and cervical stenosis. The sagittal section of her brain showed abnormally large pia and pons, as well as extensive abnormalities in the white matter around the ventricle. She also had incidental findings of ovarian teratoma.
A retrospective analysis of clinical data from 35 children was performed. Of these, 19 cases had GFAP astrocytopathy. The clinical and morphological characteristics of GFAP astrocytopathy were studied in seven of these patients. The clinical course of these patients was studied in a follow-up study. The majority of patients had a good prognosis. There were six cases of bad prognosis and one case of death.
Patients with GFAP astrocytopathy are treated with high-dose corticosteroids, plasma exchange, intravenous immunoglobulin, and oral steroids. These treatments are generally effective. However, some patients may experience relapses or develop atypical manifestations. Some patients may also have coexisting diseases such as rheumatoid arthritis, type 1 diabetes mellitus, and autoimmune thyroid disease. In addition, some of these patients have dysautonomia.
The most common triggers for GFAP astrocytopathy are tumors, infections, and T-cell dysfunction. However, it is unclear why infection is a common trigger for GFAP-dependent autoimmunity in humans.
COVID-19
Several studies have shown that optic neuritis is associated with SARS-CoV-2, a severe acute respiratory syndrome coronavirus. However, the mechanisms underlying optic neuropathy remain unclear. Molecular mimicry or inflammatory cytokines have been proposed as the cause. In addition, lymphopenia is suggested to be a factor.
Here we report three cases of neuro-ophthalmic manifestations of COVID-19. We investigated a 16-year-old boy, a 38-year-old male, and a 67-year-old man. All three patients were positive for the virus. They presented with sudden gross diminution of vision in one eye, a week or less after infection. They did not require steroids. They underwent systemic examination and imaging. They showed bilateral optic disc swelling on funduscopic examination and a grade 2 relative afferent pupillary defect.
The 16-year-old boy had an unremarkable past history. He was tested for COVID-19 two weeks prior to the onset of symptoms. Upon presentation, he had a sudden gross diminution of vision in his left eye. He was advised to stay at home, without steroids. A month later, he had a similar episode. He was treated with intravenous methylprednisolone. The headache improved. MRI was negative for the virus but did show bilateral optic nerve sheath enhancement. He was diagnosed with optic neuritis. He was advised to remain at home, avoiding oxygen and supplemental steroid. He was prescribed oral prednisolone.
The 38-year-old male had an onset of pain in extraocular movements in his LE. He had a prior COVID-19 infection. He had a negative MOG-IgG test. His neurological exam was normal. He was treated with oral prednisolone and intravenous methylprednisolone. His visual acuity returned to normal after the course of treatment. He did not have an onset of blindness. MRI did not detect the virus in his CSF.
The 63-year-old male had temporal pain and blurred vision in his left eye. He had an initial COVID-19 mRNA vaccination 11 days before symptom onset. He also had a history of severe granulomatous disease. The patient recovered well, without needing steroids. He was diagnosed with ischemic optic neuritis.
A 38-year-old male had a similar complaint one month earlier. He was treated with steroid pulse therapy. His visual acuity returned to 20/20. He had no occurrence of recurrent symptoms. He was found to have MOG antibody-associated optic neuritis.
Other causes
Depending on the cause, retrobulbar neuritis can cause a wide range of symptoms. A person suffering from the disorder may experience loss of vision, side vision, impaired color perception, and ataxia. It can also lead to peripheral neuropathy. In addition, some people never fully recover from the condition. It can occur either anteriorly or posteriorly and can be due to infection, toxins, or autoimmune diseases.
The most common cause of optic neuritis is inflammation. Inflammation occurs when the immune system mistakenly attacks the optic nerve and its covering, the myelin sheath. This process causes the loss of myelin, which provides the protective layer that helps electrical impulses travel from the eye to the brain. When myelin is lost, the retinal ganglion cell axons begin to degenerate. Papillitis, a swelling of the optic disk, is also a common symptom. The condition can result in blurring of the disk margins, distended veins, and hyperemia.
Another cause of optic neuritis is a disorder known as neuromyelitis optica. In this condition, the patient experiences pain in ocular movement and may experience a reduced response to light. It is possible to diagnose this condition using an MRI of the orbits. It can also be diagnosed by looking at the optic disc with special equipment. The optic disc is the area where the optic nerve fibers emerge from the eye. It is normal for this area to be normal, but it is not always the case.
Other causes of optic neuritis include multiple sclerosis, a disorder that affects the brain, spinal cord, and nerves. In this condition, the brain is attacked by antibodies, and the disease is thought to be an autoimmune disorder.
A diagnosis of optic neuritis can be made by a physician, and the symptoms can be treated by corticosteroid medication. In addition, a lumbar puncture, or spinal tap, can be performed to test fluid around the brain and spinal cord.
If you have optic neuritis, you should tell your doctor right away if you have any new symptoms. If the condition does not improve, it may be a sign of MS, and you should be tested for the autoimmune disorder. If you have symptoms of MS, you should talk to your doctor about whether you should start on interferon. It may help reduce the chances of future attacks of neuritis.
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