Abstract ID: 26-348
Unilateral Orbital Myositis in a Patient with Graves’ Disease: Diagnostic Reasoning in an Atypical Case
Author: Carolina Mota Base Hospital / Institution: Unidade Local de Saúde da região de Leiria
Presentation Type: ePoster Presentation
Purpose
To describe the clinical reasoning for an atypical unilateral orbital myositis in a patient with Graves’ disease following vaccination.
Methods
A 68-year-old male with a history of Graves’ disease presented with sudden vertical diplopia one week after Nimenrix vaccination. The study included MRI, serial TRAb titers, myositis panels, PET/CT, and orbital biopsy.
Results
Examination revealed right hypotropia and restricted abduction and elevation without eyelid retraction. MRI showed isolated infiltrative enlargement of the right inferior and medial rectus muscles. Due to the unilateral pattern and family history, malignancy was a priority, but PET/CT and biopsy excluded neoplasia and IgG4-RD. Biopsy showed marked muscular fibrosis. Laboratory tests revealed anti-PL-7 positivity and TRAb levels that nearly doubled post-vaccination (3,58 to 6,17 IU/L). The condition was refractory to steroids, which motivated surgery for severe mechanical restriction.
Conclusion
Orbital myositis typically manifests as acute, painful ophthalmoplegia. Differential diagnosis includes inflammatory pathology, infectious causes, or neoplastic disease. Accurate differentiation is crucial for therapeutic guidance.
This case likely represents an atypical presentation of thyroid orbitopathy, a vaccine-induced inflammatory reaction, or a combination of both in a predisposed patient. The temporal association with vaccination and rising TRAb titers suggest a flare or reactivation of Graves’ disease. Alternatively, the anti-PL-7 positivity suggests a complex polyclonal B-cell activation, which may have independently accelerated the observed fibrotic transformation. In such atypical scenarios, systemic investigation and biopsy remain mandatory to exclude malignancy and guide functional rehabilitation.
Additional Authors
| First name | Last name | Base Hospital / Institution |
|---|---|---|
| Alexandra | Campos da Silva | Centro Hospitalar Universitário de São João |
| Ricardo | Roleiro | Centro Hospitalar Universitário de São João |
| Vítor | Leal | Centro Hospitalar Universitário de São João |
| Cristina Maria | Sousa | Centro Hospitalar Universitário de São João |