Chiasmal Syndromes

This 39-year-old HIV-positive man presented in 1982 with 1 month of bilateral vision loss. His prior evaluation had included 2 CT scans, which suggested a fullness to the chiasm, and a spinal tap that showed 6 monocytes, 14 red cells, a protein of 81 mg/dl, and a glucose of 56 mg/dl, with a negative VDRL and India ink preparation. His acuity at neuro-ophthalmologic assessment was 20/40 OD and NLP OS . He had an absolute temporal field defect OD. and NLP OS. There were no retinal lesions, but he had marked pallor to both disks. Metrizamide cisternography showed intrinsic expansion of the anterolateral chiasm. A subsequent lumbar puncture showed a positive cryptococcal antigen and a protein elevated to 185 mg/dl, with 15 white cells. The toxoplasmosis titers were negative. A subsequent CT scan showed numerous enhancing lesions, and therapy with pyrimethamine, amphotericin B, clindamycin, and flucytosine was ineffective, with blindness developing OD. The man expired 1 month later. Autopsy demonstrated findings that included toxoplasmosis of the chiasm.