Idiopathic orbital inflammatory disease

Idiopathic Orbital Inflammatory Disease

Inflammatory pseudotumor - Plasma cell granuloma

Idiopathic Orbital Inflammatory Disease (IOID), also known as orbital pseudotumor, is a non-specific inflammation of the orbit without an identifiable local or systemic cause. It is a diagnosis of exclusion, meaning that other potential causes of orbital inflammation, such as infection, neoplasm, or systemic inflammatory diseases, must be ruled out before diagnosing IOID.

Clinical Presentation

Patients with IOID typically present with acute onset of orbital pain, proptosis (protrusion of the eye), diplopia (double vision), and periorbital swelling. The condition can affect any age group but is most commonly seen in adults. The inflammation can involve any of the orbital structures, including the extraocular muscles, lacrimal gland, and optic nerve.

Pathophysiology

The exact cause of IOID is unknown, which is why it is termed "idiopathic." The inflammation is characterized by a polymorphic infiltrate of lymphocytes, plasma cells, and macrophages. In some cases, fibrosis may occur, leading to chronic symptoms and potential vision loss if not treated appropriately.

Diagnosis

Diagnosis of IOID is primarily clinical, supported by imaging studies such as CT scan or MRI of the orbit. These imaging modalities can help differentiate IOID from other causes of orbital inflammation by showing characteristic features such as diffuse or localized mass-like lesions without bone destruction. A biopsy may be performed in atypical cases to rule out malignancy or specific infections.

Treatment

The mainstay of treatment for IOID is corticosteroids, which are highly effective in reducing inflammation and symptoms. In cases where corticosteroids are contraindicated or ineffective, other immunosuppressive agents such as methotrexate or rituximab may be used. Radiation therapy is another option for refractory cases.

Prognosis

The prognosis for IOID is generally good with appropriate treatment. Most patients respond well to corticosteroids, with resolution of symptoms. However, some patients may experience recurrent episodes or develop chronic inflammation, requiring long-term management.

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