Yield of screening blood work and MRI of the brain and orbits in the work-up of unilateral chronic optic neuropathy.

Background/objectives: No guidelines exist for the investigation of treatable causes of chronic optic neuropathy, including sarcoidosis, lupus, and syphilis. The purpose of this study was to determine the diagnostic yield of screening blood work (ACE (Angiotensin Converting Enzyme) for sarcoidosis, Antinuclear Antibodies (ANA) for lupus, CMIA (chemiluminescence microparticle enzyme immunoassay) for syphilis) and contrast-enhanced MRI brain and orbits in atypical unilateral chronic optic neuropathy.

Subjects/methods: Retrospective review from February 2012 to June 2018 at a neuro-ophthalmology practice. Six hundred and eighty-three consecutive charts with optic neuropathy were reviewed. Inclusion criteria were unilateral chronic optic neuropathy and a work-up including contrast-enhanced MRI brain and orbits, CBC, ESR, CRP, ANA, CMIA, and ACE. Exclusion criteria were optic nerve swelling in either eye on initial assessment or an established cause of optic neuropathy. The main outcome measure was diagnostic yield.

Results: Fifty-seven patients were included. One patient had elevated ACE, seven had positive ANA titers, and three had positive CMIA. Zero patients were diagnosed with sarcoidosis, one patient was diagnosed with lupus-related optic neuropathy, and one patient was diagnosed with syphilitic optic neuropathy. The diagnostic yield of ACE was 0%, ANA was 1.75%, and CMIA was 1.75%. MRI revealed planum sphenoidale meningioma causing compressive optic neuropathy in one patient, giving it a diagnostic yield of 1.82%.

Conclusion: Routine screening blood work (ACE, ANA, CMIA) and MRI brain and orbits for chronic idiopathic unilateral optic neuropathy has low diagnostic yield, especially if clinical suspicion for syphilis, lupus, and sarcoidosis is low. MRI should still be performed in all cases in order to rule out compressive lesions.