Dear editor,

I read with great interest the manuscript by Colon M. and El Khoury L. about “Orbital compartment syndrome as the first manifestation of SLE” [1], very well structured, extremely rare report, drawing the attention of the orbital compartment syndrome (OCS) to be the initial manifestation of systemic lupus erythematosus (SLE).

Orbital myositis (OM) is classified as an orbital inflammatory disease and is defined by inflammation of the extraocular muscles. OM was considered a subgroup of the orbital pseudotumor syndrome in which one or more of the extraocular muscles are primarily infiltrated by an inflammatory process [2]. The major differential diagnosis is thyroid ophthalmopathy. However, dysthyroid myopathy is usually painless in onset, symmetrical, slowly progressive, and associated with systemic manifestations of Graves’ disease. [3]

In a recent review, McNah [4] presents the 10 reported cases of OM occurring in patients with SLE (8 cases) or discoid lupus erythematosus (2 cases); clinical details have been reported in 8 (6 SLE, 2 discoid lupus erythematosus). Six of 8 (75%) have been bilateral, and 75% were acute in onset. Half were on treatment for SLE when presenting with OM, and one was known to have discoid lupus erythematosus. One patient’s OM was their first presentation of SLE. [5] In this report, myositis with OCS was the initial manifestation of SLE. Would the authors have any explanation for the clinical manifestation being unilateral, would they have information on the patient’s evolution, and did it have a recurrence?

The role of the image is fundamental for the diagnosis of OM [2]. I would like to know the criteria of the authors to choose the orbital CT and not the MRI.

I congratulate the authors for the report of a case of myositis secondary to SLE complicated by OCS and the opportunity to delve into a topic so interesting.