#2461 A rare cause of orbital apex syndrome

Abstract Background and Aims Orbital apex syndrome is a symptom complex of ophthalmoplegia and optic neuropathy due to multiple cranial nerve pathology resulting from involvement of the bony orbital apex. The causes of this rare neurological condition can be infectious, inflammatory, neoplastic or traumatic. A multi-systemic approach is required to identify the underlying etiology and provide appropriate treatment, as the visual prognosis is dependent on accurate diagnosis and timely management. We describe a rare cause of this neurological syndrome in a patient on hemodialysis. Method A 35 yr old lady on hemodialysis for 5 years, awaiting a deceased donor renal transplant, presented acutely with proptosis, ophthalmoplegia, pain and visual loss in right eye. She was clinically diagnosed with orbital apex syndrome involving 2nd, 3rd, 4th, 6th cranial nerve palsies. MRI of orbit confirmed a right orbital apex process causing optic perineuritis and multiple orbital neuropathies. She underwent systemic evaluation to rule out infection, inflammatory etiologies and malignancy. Results Her autoimmune screen including ANA and ANCA were negative. Anti-acetyl choline receptor and anti-MUSK antibodies—negative. MRI of cervicothoracic spine was normal. The cerebrospinal fluid was negative for oligoclonal band, aquaporin 4 antibody and anti-MOG antibody. ACE level—normal. Plasma IgG4 level—normal. No paraprotein in serum protein electrophoresis. Syphilis serology—negative. The initial contrast enhanced CT imaging of her chest and abdomen showed evidence of nodal calcification but no evidence of active granulomatous disease or significant lymphadenopathy. The PET-CT revealed small FDG avid nodes in the supraclavicular fossae, metabolically active mediastinal and ileocolic nodes and intense tracer uptake in the proximal half of the stomach. Small calcified nodes as well as minor left apical lung scarring and calcified granulomata. She underwent left supraclavicular lymph node biopsy that showed granulomatous reaction with multi nucleated giant cells and necrosis and negative for AFB stain and TB PCR. She had no previous history or family history of tuberculosis or leprosy. Interestingly, her original kidney biopsy done 5 years ago had shown tubulointerstitial nephritis, before she ended up in end stage kidney disease. An endobronchial ultrasound guided mediastinal lymph node biopsy was done that showed granulomatous inflammation with positive AFB culture for mycobacterium tuberculosis that was resistant to isoniazid. In the meantime, her ocular symptoms worsened and a repeat MRI orbit showed non-specific inflammatory process of the right orbital apex, with subsequent crowding and mass effect on structures passing through it (CN II, III, IV, VI and superior opthalmic vein). Conclusion She was initiated on anti-tuberculous treatment with rifampicin, pyrazinamide and moxifloxacin. But she developed QT prolongation with the fluoroquinolone, hence given an extended treatment for 12 months with rifampicin and pyrazinamide, with which her ocular symptoms fully subsided and she regained normal vision. This case is reported to highlight the need for prompt recognition and treatment of this rare but sight-threatening manifestation of tuberculosis in immunosuppressed and vulnerable patients on haemodialysis.