JERARQUÍA, TAMAÑO Y ROL DE CENTROS POBLADOS

Despite patient age, duration of symptoms, or tissue type involved, one of the most consistent fi ndings in patients with IOIS is an exquisite sensitivity to corticosteroids. It is common to observe near-complete resolution of a patient’s signs and symptoms aft er the fi rst dose or two of oral or intravenous steroids (Fig. 3.10). Some have advocated that such a rapid and signifi cant response to corticoster- oids be considered diagnostic of IOIS [29]. Others coun- ter that any type of reactive infl ammation, be it due to tumor, infection, systemic vasculitis, or hematological malignancy, will demonstrate clinical improvement with systemic steroids, and that therefore a “steroid response” cannot be used as a diagnostic test for IOIS [34, 49]. Th ere are also numerous examples in the literature of patients with IOIS who “fail” corticosteroid therapy. Care must be taken in interpreting these steroid failures, however, as steroid resistance may be multifactorial. For example, inadequate dosage may result in incomplete resolution of

a patient’s symptoms and thus may be interpreted as treat- ment failure. Th e standard oral dose for suspected IOIS is between 1.0 and 1.5 mg/kg/day or approximately 80 mg of prednisone a day for a 70-kg adult. In addition, corticos- teroids that are tapered too rapidly may predispose a patient to signifi cant symptomatic fl ares, which may also be misconstrued as “steroid failures.”

Th e literature addressing the use of corticosteroids in the diagnosis of IOIS is limited. Mombaerts et al exam- ined the effi cacy of systemic corticosteroids in a group

Summary for the Clinician

IOIS is a diagnosis of exclusion. ■

Patients with TED may present with periorbital ■

pain, proptosis, and diplopia that is slow in onset and accompanied by characteristic eyelid fi nd- ings, such as upper eyelid retraction and lateral fl are.

Acute bacterial cellulitis has an abrupt onset, is ■

painful, and is oft en associated with a prior his- tory of sinusitis, dental disease, or trauma. Patients are oft en febrile with an elevated white blood cell count. Orbital imaging usually distin- guishes infection from IOIS.

Sarcoidosis is a chronic systemic disease charac- ■

terized by noncaseating granulomatous infl am- mation involving at least two organ systems. Within the orbit, sarcoidosis can involve the lac- rimal gland, the EOMs and other soft tissues, and the optic nerve. On occasion, isolated orbital sar- coid may occur with no serologic or chest abnormality.

WG is a chronic systemic disease characterized by ■

necrotizing granulomatous infl ammation of the upper or lower respiratory tract; necrotizing gran- ulomatous vasculitis, usually aff ecting small ves- sels; and focal segmental glomerulonephritis. Cases involving the orbit may be part of a more limited form of the disease and may present with sinusitis, proptosis, nasolacrimal duct obstruction, conjunc- tival granulomas, or dacryoadenitis. cANCA may be negative in the limited form of WG.

Primary orbital tumors oft en present with the ■

insidious onset of proptosis, orbital congestion, or diplopia.

Tumors metastatic to the orbit are rare but may pres- ■

ent in a manner similar to IOIS. Orbital biopsy should be strongly considered in any patient with a known history of cancer who presents with suspected IOIS.

of patients with IOIS that excluded all patients with infl ammatory myositis or dacryoadenitis [34]. Of the 27 patients in this study who were initially treated with corticosteroids, only 78% of patients demonstrated an initial response to a single course of oral corticosteroids. With this relatively low sensitivity rate and the low spec- ifi city of corticosteroids, they concluded that the response to corticosteroids should not be used as a diag- nostic test of IOIS. However, when the same group examined patients with the myositis variant of IOIS, all patients responded to oral corticosteroids. However, 50% of initial responders experienced symptomatic recurrence, and all of these cases were defi ned as a ste- roid failure [33].

Certainly, in a patient who presents in a manner classic for IOIS, an immediate and near-complete response to systemic corticosteroids may allow the cli- nician to feel more comfortable with the presumptive diagnosis. Th is adequate response to empiric therapy does not mean that continued vigilance is not neces- sary, however. In addition, one cannot conclude that an initially successful corticosteroid regimen is diagnostic of IOIS if the patient cannot be easily tapered off of the steroids, or if he or she experienced a recurrence of symptoms. Such a case would be considered “atypical,” and alternative diagnoses should be sought, be it through a biopsy of the involved tissue or through fur- ther systemic workup.

Fig. 3.9 Metastatic breast carcinoma. A T1-weighted postcontrast MRI with fat suppression of a patient who presented with an indolent progressive external ophthalmoplegia. Despite the presence of bilateral orbital infi ltrates (arrows) and a history of breast cancer, the patient was treated with an 18-month course of oral corticosteroids for presumed IOIS. Subsequent referral diagnosed bilateral metastatic breast carcinoma to the orbits, which responded to chemotherapy

Fig. 3.10 A patient with suspected IOIS based on clinical exam and imaging (see Fig. 3.6b) on presentation (left ) and aft er 2 days of oral corticosteroid therapy. Note the dramatic improvement in external signs

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