Orbital Inflammatory Diseases




Acknowledgment


The authors recognize Madhura Tamhankar, MD, for her contributions to the previous edition of this chapter.




  • 1.

    What is inflammation?


    The concept of inflammation is ancient and was used to describe a combination of rubor (redness), dolor (pain), tumor (swelling), calor (heat), and functio laesa (loss of function). We now recognize inflammation as a tissue response governed by multiple cellular processes.


  • 2.

    How does inflammation affect the orbit?


    Inflammation is the most common problem that affects the adult orbit, leading to a spectrum of clinical presentations with variable onset and variable orbital tissues affected, causing mass effect, inflammation, and/or infiltration resulting in variable deficits in function or vision.


  • 3.

    What are the best terms to describe orbital inflammation?


    For purposes of better understanding and better management, orbital inflammation should be classified based on pathology, anatomic location, and/or associated systemic disease as either specific or nonspecific in nature.


  • 4.

    What is specific orbital inflammation?


    The diagnosis of specific orbital inflammation is based on the identification of a specific etiology causing the disorder, such as a specific pathogen (infection, as in orbital cellulitis), specific histopathology (granulomatous disease, as in sarcoidosis), or specific local and/or systemic constellation of findings that define a distinct entity (vasculitis, as in granulomatosis with polyangiitis) ( Box 36-1 ).



    Box 36-1





    • Nonspecific Orbital Inflammation (NSOI)



    • Diagnosis after exclusion of specific inflammations



    • Specific Orbital Inflammation



    • Thyroid-associated orbitopathy



    • Infection/infestation



    • Bacterial




      • Contiguous spread from sinusitis



      • Retained orbital foreign body




    • Fungal




      • Rhino-orbital mucormycosis



      • Aspergillosis



      • Endogenous spread from septic emboli




    • Parasitic




      • Echinococcosis



      • Cysticercosis




    • Tuberculosis and syphilis



    • Vasculitis



    • Granulomatosis with polyangiitis



    • Polyarteritis nodosa



    • Hypersensitivity angiitis




      • Orbital vasculitis secondary to systemic lupus erythematosus




    • Giant cell arteritis



    • Granulomatous inflammation



    • Sarcoidosis/sarcoidal reactions



    • Xanthogranulomatous disorders of orbit



    • Foreign-body granuloma



    • Erdheim-Chester disease



    • Sjögren’s syndrome



    • IgG4-related disease of the orbit



    • Sclerosing inflammation of the orbit



    • Idiopathic granulomatous inflammation



    • Nonspecific Orbital Inflammation (NSOI)



    • Noninflammatory Diseases of the Orbit that Mimic Inflammation



    • Vascular disorders



    • Dural–cavernous sinus arteriovenous fistula



    • Neoplasia



    • Lymphoproliferative disorders



    Differential Diagnosis of Orbital Inflammation


  • 5.

    How is nonspecific orbital inflammation different?


    Orbital inflammation that has no identifiable cause is considered nonspecific. It is a diagnosis of exclusion.


  • 6.

    What is orbital pseudotumor?


    “Nonspecific orbital inflammation” and “idiopathic orbital inflammatory syndrome” are more accurate terms that replace orbital pseudotumor.


  • 7.

    What, then, is the etiology of nonspecific orbital inflammation?


    The exact etiology is unknown but it is generally believed to be an immune-mediated process, possibly related to previous bacterial or viral infection, previous trauma, or other autoimmune conditions, such as Crohn’s disease, rheumatoid arthritis, and systemic lupus erythematosis.


  • 8.

    Describe a typical clinical presentation of nonspecific orbital inflammation.


    Anterior orbital nonspecific orbital inflammation (NSOI) commonly presents as painful periorbital swelling and erythema, S-shaped eyelid deformity, and chemosis that may be unilateral or bilateral. Onset is typically acute (hours to days) or subacute (days to weeks) but can also be insidious or chronic (weeks to months). The symptoms and physical findings will vary based on the degree and anatomic location of the inflammation. Disease affecting the posterior orbit may present with proptosis and motility disturbances, and disease affecting the orbital apex may present with functional deficits and/or vision loss.


  • 9.

    Is the symptom of pain necessary to make the diagnosis?


    Although pain or discomfort is a typical symptom, absence of pain may occur less commonly.


  • 10.

    How is nonspecific orbital inflammation in children different?


    In the pediatric population, bilateral manifestation is much more common, as well as concurrent uveitis, elevated erythrocyte sedimentation rate, and eosinophilia. When present, uveitis in particular appears to portend a poor outcome in children. Overall, NSOI in children is rare and cases should be monitored closely for future development of autoimmune disease.


  • 11.

    Name the five most common anatomic patterns of nonspecific orbital inflammation.




    • 1.

      Extraocular muscle (myositis)


    • 2.

      Lacrimal gland (dacryoadenitis)


    • 3.

      Anterior orbit including scleritis


    • 4.

      Orbital apex


    • 5.

      Diffuse



  • 12.

    How is the diagnosis of nonspecific orbital inflammation made?


    Because NSOI is a diagnosis of exclusion, all known specific triggers of inflammation should be ruled out first. Ultimate diagnosis and treatment rely on complete history and detailed clinical examination followed by judicious use of ancillary diagnostic testing. Diagnostic testing includes neuroimaging, laboratory testing, and biopsy when appropriate.


  • 13.

    What is the best imaging technique for nonspecific orbital inflammation?


    Orbital computed tomography (CT), gadolinium-enhanced magnetic resonance imaging (MRI), or ultrasound can all provide useful information, but orbital MRI with fat saturation is the imaging study with the highest yield. Subtle edema of the retrobulbar fat is often one of the earliest changes seen in NSOI. The use of diffusion weighted imaging is helpful in differentiating NSOI from lymphoid lesions and orbital cellulitis.


  • 14.

    What blood tests can be ordered to evaluate nonspecific orbital inflammation?


    Complete blood count, electrolytes, erythrocyte sedimentation rate, C-reactive protein, antinuclear antibody, anti-double-stranded DNA, anti-neutrophil cytoplasmic antibody (ANCA), angiotensin-converting enzyme level, rapid plasma reagin, and thyroid function tests.


  • 15.

    When should an orbital biopsy be performed?


    Although the role of orbital biopsy has previously been an area of controversy, the only way to obtain an accurate and definitive diagnosis of an infiltrative lesion is through pathologic examination. Most orbital surgeons advocate biopsy, except for two clinical scenarios—that of orbital myositis, in which the clinical and radiographic findings are classic, and that of an orbital apex syndrome—in which the risk of biopsy must be weighed against the risk of a missed diagnosis. Empiric steroid treatment may be employed in such cases. However, recurrent or nonresponsive orbital myositis and orbital apex syndrome warrant orbital biopsy.


  • 16.

    What is the histopathology of nonspecific orbital inflammation?


    In the acute phase, pathology reveals a diffuse polymorphous infiltrate composed of mature lymphocytes, plasma cells, macrophages, eosinophils, and polymorphonuclear leukocytes. In the subacute and chronic phases, an increasing amount of fibrovascular stroma is seen.


  • 17.

    Name two histological subtypes of orbital inflammation.


    A distinct sclerosing form of orbital inflammation exists, which is characterized by dense fibrous replacement. Clinically, the sclerosing subtype typically produces limited inflammatory signs and atypical pain.


    Another distinct form displays granulomatous inflammation similar to sarcoidosis but is not associated with systemic sarcoidosis.


  • 18.

    What is IgG4-related disease?


    IgG4-related disease is a systemic fibroinflammatory condition that should be considered in patients with NSOI, particularly in cases with bilateral lacrimal gland involvement. Histology reveals IgG4-positive plasma cells and fibrosis, with or without obliterative phlebitis. Serum IgG4 is often elevated. Systemic manifestations of IgG4-related disease include sclerosing pancreatitis, retroperitoneal fibrosis, sclerosing cholangitis, Reidel’s thyroiditis, and interstitial lung disease. IgG4-related orbital inflammation is typically exquisitely and rapidly responsive to steroid treatment.


  • 19.

    How is nonspecific orbital inflammation treated?


    High-dose oral corticosteroids are the mainstay of treatment. The recommended starting dose for prednisone is 1.0 to 1.5 mg/kg/day with a maximum adult dose of 60 to 80 mg/day for 1 to 2 weeks, then tapering off over the course of 6 to 12 weeks. For patients with vision loss or apical involvement, intravenous methylprednisone 1.0 g/day can be administered for 1 to 3 days. The response is usually quick with resolution of pain and proptosis within 24 to 48 hours of onset of the treatment.


  • 20.

    What if a patient fails to respond to or is intolerant of steroids?


    Alternative therapies include antimetabolites (azathioprine, methotrexate), T-cell inhibitors (cyclosporine), and alkylating agents (cyclophosphamide). Low-dose external beam radiation has also been shown to be effective.


    Local injection of betamethasone can also be effective in treating acute idiopathic dacryoadenitis, myositis, and anterior diffuse orbital inflammation.


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Jul 8, 2019 | Posted by in OPHTHALMOLOGY | Comments Off on Orbital Inflammatory Diseases

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