Demyelinating Optic Chiasmopathy Due to Mycobacterium Haemophilum in a Patient with AIDS (P6.298)

Objective: We report the first case of Mycobacterium haemophilum causing a demyelinating optic chiasmopathy in a patient with AIDS. Background: Optic chiasmopathy may be due to inflammatory, neoplastic, or infectious processes. Mycobacterium tuberculosis can cause infectious optic chiasmopathy, but M. haemophilum has never been reported to affect the central visual pathway. M. haemophilum can cause ulcerating subcutaneous skin lesions in immunocompromised individuals and cervicofacial lymphadenitis in immunocompetent children. To our knowledge, M. haemophilum affecting the CNS has only once been reported in an immunocompromised patient who developed a brainstem spindle cell pseudotumor. Design/Methods: A 43-year-old man with AIDS and a CD4 count of 4 off HAART presented with four days of headache and vision loss OS. On examination, he had diffuse visual field and acuity loss OS and a temporal hemianopsia OD, suggestive of a junctional scotoma. Results: MRI revealed a T2 hyperintense, avidly enhancing lesion of the optic chiasm and left optic tract. CSF analysis revealed: WBC 9, RBC 0, protein 54, glucose 47, bacterial culture negative. CSF was negative for ACE, VDRL, CMV, EBV, HSV, VZV, JCV, and Toxoplasma. Body imaging was negative for malignancy and infection. Histopathology of the optic chiasm biopsy revealed numerous acid-fast bacilli, inflammatory cells and demyelination with axonal sparing. DNA sequencing on the biopsy revealed M. haemophilum and was negative for M. tuberculosis. The patient was started on HAART, antibiotics and steroids with significant improvement in visual acuity (VA). He later re-presented with decreased VA OS and new enhancement of the left optic nerve, likely from medication non-compliance. Conclusions: We describe the first case of demyelinating optic chiasmopathy associated with M. haemophilum,and the second report of the organism affecting the brain. This case highlights the wide differential of optic chiasmopathy, especially in immunocompromised individuals and the challenges in diagnosing atypical mycobacterial infections. Disclosure: Dr. Merkler has nothing to disclose. Dr. Parlitsis has nothing to disclose. Dr. May has nothing to disclose. Dr. Bier has nothing to disclose. Dr. Simpson has nothing to disclose. Dr. Patel has nothing to disclose. Dr. Lavi has nothing to disclose. Dr. Shuetz has nothing to disclose. Dr. Dinkin has nothing to disclose.