Non-infectious Orbital Vasculitides
Non-infectious Orbital Vasculitides
Dermatomyositis (DM) is an inflammatory myopathy of children and adults; the pathogenesis of this disease is related to a complement mediated microangiopathy. It is an autoimmune disease in which antibodies are directed toward the vascular endothelium, leading to activation of the complement system. The classic laboratory study that helps to diagnose a patient with DM is an elevated creatine kinase level. Electromyography demonstrates increased spontaneous activity and short duration, low amplitude units on voluntary activity.
The main symptom is proximal muscle weakness, which has a subacute course and develops over weeks to months. Patients with DM also develop a rash on the hands, eyelids ('heliotrope'), back, and/or chest. There have been two case reports of extraocular muscle involvement, which may be associated with DM. Kokotis et al reported a case in which a patient with a history of muscle weakness developed bilateral exophthalmos. Laboratory studies were normal except for a mild leukocytosis and CRP. MRI of the orbits revealed enlargement of the lateral and inferior rectus of both eyes and the superior rectus of the left eye. Electromyography demonstrated changes consistent with a myopathy in the frontalis and orbicularis muscles. In a reply to the article by Kokotis et al, Marasini et al reported a similar case in which a patient developed orbital myositis years after a presentation of DM. The definitive method for diagnosing DM is biopsy of the affected muscle, although this was not done in either case reported.
Treatment of DM mainly consists of glucocorticoids, although IVIG has been used in some cases as a first-line agent. Other immunosuppressants such as methotrexate and azathioprine have been used as well. The two patients reported to have orbital involvement improved with the combination of methotrexate and prednisone. The two cases reported in the literature demonstrate possible orbital involvement, although there was no definitive evidence of the association between DM and orbital myositis. Results of infliximab treatment for DM have not been promising, although rituximab may be a better option. New anti-interferon alpha antibodies may be another option, although studies are ongoing. The efficacy in orbital disease is unknown thus far.
Dermatomyositis
Dermatomyositis (DM) is an inflammatory myopathy of children and adults; the pathogenesis of this disease is related to a complement mediated microangiopathy. It is an autoimmune disease in which antibodies are directed toward the vascular endothelium, leading to activation of the complement system. The classic laboratory study that helps to diagnose a patient with DM is an elevated creatine kinase level. Electromyography demonstrates increased spontaneous activity and short duration, low amplitude units on voluntary activity.
The main symptom is proximal muscle weakness, which has a subacute course and develops over weeks to months. Patients with DM also develop a rash on the hands, eyelids ('heliotrope'), back, and/or chest. There have been two case reports of extraocular muscle involvement, which may be associated with DM. Kokotis et al reported a case in which a patient with a history of muscle weakness developed bilateral exophthalmos. Laboratory studies were normal except for a mild leukocytosis and CRP. MRI of the orbits revealed enlargement of the lateral and inferior rectus of both eyes and the superior rectus of the left eye. Electromyography demonstrated changes consistent with a myopathy in the frontalis and orbicularis muscles. In a reply to the article by Kokotis et al, Marasini et al reported a similar case in which a patient developed orbital myositis years after a presentation of DM. The definitive method for diagnosing DM is biopsy of the affected muscle, although this was not done in either case reported.
Treatment of DM mainly consists of glucocorticoids, although IVIG has been used in some cases as a first-line agent. Other immunosuppressants such as methotrexate and azathioprine have been used as well. The two patients reported to have orbital involvement improved with the combination of methotrexate and prednisone. The two cases reported in the literature demonstrate possible orbital involvement, although there was no definitive evidence of the association between DM and orbital myositis. Results of infliximab treatment for DM have not been promising, although rituximab may be a better option. New anti-interferon alpha antibodies may be another option, although studies are ongoing. The efficacy in orbital disease is unknown thus far.
