Visual loss in immunocompetent patients with Cryptococcus neoformans var. gattii meningitis

In Papua New Guinea cryptococcal meningitis occurs predominantly in immunocompetent patients in whom Cryptococcus neoformans var, gattii is implicated in 95% of cases. Ocular complications are common. We have reviewed ophthalmic findings in 82 immunocompetent patients and have attempted to identify those features of the disease that predict an unfavourable visual outcome. Visual loss occurred in 52.6% of survivors and was associated with optic atrophy following optic disc swelling in 60.9%. Progression of disc swelling to optic atrophy was predicted by the presence of an abducens palsy (P = 0.049) and cerebrospinal fluid (CSF) cryptococcal antigen titres > 1:1024 (P = 0.036). Raised intracranial pressure (defined as opening CSF pressure > or = 300 mm on admission) was not associated with visual loss. Vision deteriorated in 17.3% of patients despite anticryptococcal therapy and in 3.7% it followed curative therapy. The high rate of visual loss in immunocompetent patients with C. neoformans var. gattii infection contrasts with others' experience of immunosuppressed patients with C. neoformans var. neoformans infection, in whom visual loss was rare. This difference may reflect immune mediated optic nerve dysfunction in C. neoformans var. gattii meningitis caused by either compression due to arachnoid adhesions or oedema and inflammatory cell-mediated damage.