Decoding a cryptic brain

Abstract

Background

Cryptococcosis is a deadly infection caused by Cryptococcus which majorly affects immunosuppressed individuals but may also be seen in immunocompetent hosts. It may present as meningitis, meningoencephalitis and CNS cryptococcomas. We report a unique presentation of CNS cryptococcosis.

Results

We report a case of a 48 year old lady with a background of diabetes mellitus and hypothyroidism, who presented with apathy and aphasia. Her routine blood investigations were normal and her MRI Brain revealed T2 fluid attenuated inversion recovery (FLAIR) hyperintensities with post contrast enhancement and diffusion restriction seen in cortical and deep white matter.

CSF showed mild pleocytosis and all infective panels and routine auto-antibody panels were negative. Considering a possible etiology of demyelination, she was pulsed with steroids during the course of disease yet worsened clinico-radiologically. Her brain biopsy was indicative of demyelination, and Cryptococcus PCR in CSF and biopsy specimen were positive. Repeat India ink and fungal culture persisted to be negative. The patient was treated with amphotericin and fluconazole.

Conclusions

The immunopathogenesis in cryptococcal infection is complex and the fungus-host interaction determines the outcome. Our case showed extensive demyelination due to the excess inflammation mounted by the host, but the process was ineffective in clearing the fungus as evidenced by PCR positivity on CSF and biopsy specimens. Worsening on steroids and positive response to anticryptococcal regime gives the evidence of a fungus mediated disease. This case shows that any demyelination should be extensively investigated for secondary causes before labelling it resistant.