a 49yearold woman suspected of having a right optic neuritis was referred to the neurology department .
she had been diagnosed with systemic lupus erythematosus ( sle ) 10 years earlier , and , at the time of presentation , she was receiving azathioprine 50 mg three times a day , prednisone 5 mg daily , and belimumab 640 milligrams intravenously every 4 weeks .
four months earlier , during an ophthalmologist screening test for retinal toxicity , an optic coherence tomography ( oct ) had shown a reduction in the thickness of the macular and retinal nerve fiber layer in the right eye .
she was recommended to stop treatment with hydroxychloroquine , which the patient had been receiving since the initial diagnosis of sle 10 years before ( 200 mg orally per day ) .
an mri showed a highintensity signal in her right optic nerve at that moment ( fig .
, followup showed an inferior nasal scotoma in her right eye , not present in previous examinations , and she was referred to the neurology department .
a perineural contrast enhancement can be seen on the right optic nerve , suggesting inflammation of the nerve sheath . during the first visit to the neurologist , physical examination
did not reveal other pathological findings , so ancillary tests ( visual evoked potentials and both orbital and cerebral mri ) were requested .
before the tests could be carried out , the patient developed vertical diplopia on the primary gaze position that was accentuated when looking up .
a paralysis of the right eye in upgaze position was found on physical examination then .
mri showed signs of inflammation in the right orbit with affected the orbital fat and conditioned a slight proptosis of the eyeball , not visible to the naked eye on physical examination .
a mild posterior perineural signal could still be seen in the optic nerve , but also , both the right superior rectus and superior oblique muscles were thickened ( fig .
, we found that these alterations in the muscles were already but subtly present in the first mri , long before the diplopia appeared ( fig .
visual evoked potentials demonstrated prolonged latencies after visual stimulus , consistent with a moderate demyelinating neuropathy of the right eye .
extensive laboratory tests , including blood cell count , renal function , liver function , thyroid function , antiaquaporin4 antibodies , angiotensinconverting enzyme levels , and serologic tests for syphilis , hiv , herpesvirus , and borrelia burgdoferi , were negative or normal .
antidsdna levels were 167 ui / ml , and serum complement levels were low , with c3 0.76 g / l and c4 0.07
g / l ; these results were similar to the results of previous blood tests . t2weighted brain and orbital mri .
( a ) coronal view of the mri performed nine months before the patient developed the symptoms .
a slight thickening of the superior rectus , which appears hyperintense compared to the contralateral muscle , is patent , as well as mild infiltration of the surrounding fat .
( c ) axial cuts of the same mri showing also slight proptosis of the right eye .
hydroxychloroquinerelated toxicity was ruled out due to both clinical and radiologic progression after suspension of the treatment .
the patient was diagnosed with orbital inflammatory pseudotumor secondary to sle , and highdose corticosteroid therapy was initiated ( oral metilpredinsolone one gram daily for 5 days ) , followed by slowly decreasing doses of prednisone to 10 mg daily .
this therapy achieved to improve the symptoms and diplopia resolved , without permanent damage to the visual field . afterward , immunosuppressive treatment with rituximab was started .
the patient has remained asymptomatic ever since , and both antidsdna and complement levels have returned to normal values .
neuroophthalmic manifestations , however , are less frequent , with a prevalence of 3.6% in adults ; among these , optic neuritis is the most common form of presentation and also one of the most visually compromising complications of sle 1 .
the implication of orbital structures in sle and , specifically , inflammatory pseudotumor is very rare and therefore may go unnoticed 1 , 2 , 3 .
it usually presents with proptosis , pain , and diplopia , due to infiltration of the ocular muscles .
although increases in the titers of antidsdna antibodies and decreases in the complement levels may accompany disease relapses , this is not true for all sle patients 4 , 5 . in our case , although high levels of antidsdna and low levels of c3 and c4 were found , these results were similar to the results of previous blood tests .
visual loss due to inflammatory infiltration of the optic nerve is uncommon ; however , it may be a preceding sign , as in this case . 2 , 6 .
response to corticosteroid therapy is excellent in most patients , but sometimes progression of the disease could lead to major damage 2 .
although sleassociated retinopathy has been associated with elevated levels of antiphospholipid antibodies 2 , this does not seem to be the case in inflammatory pseudotumor , and due to its low incidence , no risk factors that could help early diagnosis have been identified .
retinopathy and maculopathy are widely known complications of hydroxychloroquine treatment , although inflammatory pseudotumor has never been described in this setting .
although visual loss may be irreversible and even worsen after suspending treatment with hydroxychloroquine , this is more likely if high doses of hydroxychloroquine are used for more than 5 years or if there is impaired renal or liver function 7 , 8 .
although our patient had been treated with hydroxychloroquine for 10 years , the daily doses were below 6 , 5 mg / kg , which are associated with very low risk of retinopathy . besides , she never presented impaired renal or liver function in successive blood tests . taking all this into account
suspecting inflammatory pseudotumor and its relation to the sle is imperative to avoid further complications . in this case , the slow progression of the disorder , probably due to simultaneous immunosuppressive therapy and chronic treatment with low doses of oral corticosteroids , as well as the interference of confounding factors ( treatment with hydroxychloroquine ) delayed the diagnosis .
however , when the patient developed diplopia a review of the previous mri showed that mild signs had been already present months before the symptoms appeared .
therefore , after a new finding appears , going back to previous studies may help to put things into perspective .
 key clinical messageorbital inflammatory pseudotumor is a rare complication of systemic lupus erythematosus . 
 it may present a challenge for differential diagnosis , especially in the context of treatment with hydroxychloroquine , although dosage and duration of the treatment may guide us . 
 although high antibody titers can be found , this is not specific . 
Case
Discussion
Conflict of Interest