Mixed Response to IV Methylprednisolone in restrictive myopathy due to Thyroid Eye Disease

In a recent prospective study, researchers delved into the therapeutic potential of intravenous methylprednisolone (IVMP) for patients grappling with restrictive myopathy due to thyroid eye disease (TED). The findings showed that despite successful inflammation control with IVMP, strabismus angle worsening can occur in a subset of patients, potentially due to uncontrolled fibrosis.

The study was published in the journal Graefe's Archive for Clinical and Experimental Ophthalmology on 21st February 2023. 

For patients with restrictive myopathy caused by TED, the struggle with diplopia (double vision) can be both frustrating and debilitating. In a bid to alleviate these symptoms, researchers from the Republic of Korea embarked on a prospective uncontrolled study to report the therapeutic efficacy of intravenous methylprednisolone (IVMP) in patients with restrictive myopathy caused by thyroid eye disease (TED). 

The study involved 28 patients, all experiencing diplopia within the six months leading up to the study, on a chosen treatment path involving a 12-week course of IVMP. To evaluate its efficacy, a range of clinical parameters were closely examined, including the deviation angle (the angle at which the eyes deviate from their normal alignment), the extent of extraocular muscle (EOM) movement limitation, binocular single vision score, Hess score, clinical activity score (CAS), modified NOSPECS score, exophthalmometry values, and the size of EOMs as determined by computed tomography.

Mixed results: 

• The results yielded a mix of encouraging and challenging outcomes.
• Notably, the mean CAS for the entire group significantly decreased at both one month and three months after initiating IVMP treatment. 
• Despite the promising inflammation control, the mean deviation angle showed an increase at one, three, and six months when compared to baseline.
• This unsettling finding revealed that some patients experienced strabismus angle worsening during the course of the study.
• Alarmingly, no single variable was identified as the cause of this deterioration.

In essence, this study serves as a reminder that while IVMP therapy can effectively manage inflammation in TED patients with restrictive myopathy, it does not guarantee the resolution of all symptoms. The deterioration in strabismus angles highlights the persistent challenge of uncontrolled fibrosis, which can lead to motility impairment.

Further reading: ang, J.H., Park, J.W., Park, KA. et al. Early response to intravenous methylprednisolone therapy for restrictive myopathy in patients with thyroid eye disease. Graefes Arch Clin Exp Ophthalmol 261, 2375–2382 (2023). https://doi.org/10.1007/s00417-023-06013-4