Orbital Myositis (Om): Insights From Our Case Series
Main Author: Maisam Musgrave
Dubai, United Arab Emirates
Mediclinic City Hospital
Background(s):
OM is a rare inflammatory condition of unclear aetiology affecting extraocular eye muscles, causing pain, swelling & diplopia. It can be associated with various autoimmune diseases (AID), infections & rarely can be familial (1,2).
We are reporting our experience of OM in patients referred to our department between June and December 2023.
Methods(s);:
Case 1
A 57-year-old Caucasian male had seronegative rheumatoid arthritis (RA) for 12 yrs. His RA was well controlled on Upadacitinib having previously failed 2 DMARDS & 3 biological therapies. He presented to the ER in June 2023 with a 4-day history of bilateral eye pain, periorbital swelling but no active arthritis. Intravenous antibiotics was given for presumed orbital cellulitis pending investigations. He had negative cultures, raised inflammatory markers, normal IgG subclasses & thyroid function tests. MRI orbits with contrast showed enhancement of the right medial rectus & left lateral rectus. OM was diagnosed & he was commenced on systemic steroids, with full resolution of symptoms & signs. Upadacitinib was resumed 1 week later.
Case 2
44-year-old Arab male with seronegative RA for 14 years, was admitted in Nov 2023 with arthritis of left ankle & shoulder for 3 months & a 2-week history of right eye pain, diplopia & periorbital swelling. He was previously on Salazopyrin & Adalimumab which were discontinued when he was in remission 4 years ago. MRI brain revealed inflammatory changes in the retro-orbital region on the right side & thickened medial & superior rectus muscles. He was treated empirically with antibiotics pending investigations which were eventually unremarkable. Systemic steroids were given with notable improvement in his arthritis & OM. Methotrexate was given as long-term therapy of his RA .
Case 3
A 30-year-old normally fit & well Arab lady was referred in Dec 2023 with 2 weeks history of diplopia to the right & no constitutional or joint symptoms. Investigations excluded any underlying infection or Connective tissue diseases. MRI revealed orbital myositis. Idiopathic OM was diagnosed, and she was started on steroids with full resolution of symptoms.
Results:
OM can be idiopathic or have an association with an underlying pathology. To date, there have been 6 cases of OM associated with RA reported in the literature, showing a male to female ratio of 1:5 (1). In our series both cases of RA-associated OM were in males. Like published data, our patients’ clinical symptoms & signs were diplopia, periorbital swelling & headaches(1) . Our 3rd case reflects a classic case of idiopathic OM which is more common in young adult females in the absence of underlying secondary associations (3). All 3 cases responded favourably to systemic steroids.
Conclusion(s):
Early diagnosis of OM is paramount for appropriate management and preservation of vision. Clinical features and characteristic MRI findings are diagnostic. Rheumatologists are often involved in OM given it’s known coexistence with AID. How orbital myositis develop in rheumatic diseases remains poorly understood & does not necessarily correlate with disease activity, as seen with case 1. This suggests a potential immune related effect, thus more research is warranted to better understand this relationship.
