What is orbital inflammatory disease and its treatment?

Orbital Inflammatory Disease and Treatment

Orbital inflammatory disease (OID) is a collection of inflammatory conditions affecting the orbit that presents with eyelid or periocular swelling, lacrimal gland enlargement, extraocular muscle involvement, intra-orbital mass, proptosis, and cranial nerve V involvement, requiring prompt diagnosis and treatment to prevent vision loss and other complications. 1

Definition and Classification

OID broadly encompasses:

• Idiopathic orbital inflammatory syndrome (IOIS) - previously known as orbital pseudotumor, a diagnosis of exclusion that may present with signs and symptoms mimicking infection 1
• IgG4-related orbital disease - a relatively recently described inflammatory condition that may account for a significant percentage of patients previously described as having idiopathic disease 1
• Specific structure involvement - can preferentially affect particular orbital structures:
  • Dacryoadenitis (lacrimal gland)
  • Myositis (extraocular muscles)
  • Cellulitis
  • Optic perineuritis
  • Periscleritis
  • Orbital apicitis
  • Focal mass 2
• Sclerosing orbital inflammation - a rare condition with a chronic, indolent course involving dense fibrosis and lymphocytic infiltrate, now considered a distinct pathologic entity 2

Diagnostic Approach

Imaging

• CT of the orbits with contrast - often the initial imaging modality in emergent settings, superior for:

  • Foreign body assessment
  • Calcification detection
  • Osseous evaluation 1

• MRI of the orbits without and with contrast - complementary to CT, particularly valuable for:

  • Detailed assessment of intra-orbital spread of inflammation
  • Evaluation of suspected intracranial extension
  • Soft-tissue characterization
  • Detecting fibrosis (hallmark of chronic IOIS) which results in decreased signal on T2-weighted MRI sequences 1

• CTA or MRA - may be added if vascular invasion or cavernous sinus thrombosis is suspected 1

Clinical Evaluation

• Multidisciplinary approach involving:

  • Endocrinologic evaluation
  • Neurologic evaluation
  • Ophthalmologic evaluation 1

• Biopsy may be necessary for definitive diagnosis, especially to rule out neoplastic processes like lymphoma 1, 3

Treatment Approaches

Medical Management

Corticosteroids are the first-line treatment for non-infectious orbital inflammatory disease, with immunosuppressive agents reserved for steroid-resistant or recurrent cases. 1

• Systemic corticosteroids - primary initial therapy for most forms of OID

  • Typically high-dose oral prednisone (1 mg/kg/day) with gradual taper 3, 4
  • Rapid response to steroids is characteristic of IOIS and can be diagnostic 4

• Immunosuppressive agents - for steroid-resistant cases or to reduce steroid dependence:

  • Methotrexate
  • Azathioprine
  • Mycophenolate mofetil
  • Cyclosporine 4

• Biological agents - for refractory cases:

  • Rituximab (particularly effective for IgG4-related disease)
  • TNF-α inhibitors 1, 4

Surgical Management

• Biopsy - often necessary for definitive diagnosis to rule out malignancy 1

• Surgical decompression - reserved for cases with:

  • Optic nerve compression
  • Severe proptosis
  • Failure of medical management 5

Special Considerations

IgG4-Related Orbital Disease

• Requires specific diagnostic criteria:

  • Elevated serum IgG4 levels
  • Tissue biopsy showing IgG4-positive plasma cell infiltration
  • Characteristic fibrosis pattern 2, 4

• May respond particularly well to rituximab therapy 4

Sclerosing Orbital Inflammation

• More resistant to conventional therapy
• Often requires more aggressive immunosuppression
• May need surgical intervention more frequently 2

Monitoring and Follow-up

• Regular ophthalmologic examinations to monitor:

  • Visual acuity
  • Intraocular pressure
  • Extraocular muscle function 4

• Repeat imaging to assess treatment response and disease progression 1

• Monitoring for medication side effects, particularly with long-term steroid or immunosuppressive therapy 4

Pitfalls and Caveats

• Misdiagnosis - OID can mimic infection, neoplasm, or other systemic inflammatory conditions; thorough workup is essential 3, 2

• Delayed treatment - can lead to permanent vision loss, particularly in cases involving the optic nerve 4, 5

• Inadequate treatment duration - premature discontinuation of therapy can lead to relapse; treatment often needs to be continued for months 4

• Overlooking systemic associations - OID can be associated with systemic inflammatory or autoimmune conditions that require separate management 3, 4