A retrospective study of contributing factors for prognosis and survival length of cryptococcal meningoencephalitis in Southern part of China (1998–2013)

BACKGROUND: Cryptococcal meningoencephalitis (CM) is the most common opportunistic infection of the central nervous system (CNS). Despite this observation, there have only been a few studies analyzing clinical characteristics as well as cerebrospinal fluid (CSF), electroencephalograph (EEG), and magnetic resonance imaging (MRI) features in CM patients of all ages. METHODS: We reviewed the medical records of all patients diagnosed with cryptococcal meningoencephalitis from 1998 to 2013 in the Nanfang Hospital in China and gathered data on the underlying diseases, bird exposure history, and clinical features, including those from CSF, EEG and MRI. RESULTS: CM is more likely to infect adults younger than 60 years old. 71.3% of CM patients were male. Unlike data from other countries, we found that chronic use of corticosteroids or other immunosuppressants (17.59%) was the most frequent risk factor in CM patients rather than HIV infection (1.85%). Clear exposure with bird/ bird droppings before CM onset is obvious in a previous study in CM children. However, our study found that 4.63% CM patients had such an exposure. More importantly, patients with brain tissue damage (p = 0.021) and decreased CSF/blood glucose ratio (p = 0.008) were significantly associated with death, but only the decreased CSF/blood glucose ratio was the contributing factor of prognosis (odds ratio, 0.047; p = 0.025). Decreased CSF/blood glucose ratio was significantly related to the survival length of CM (odds ratio, 0.134; p = 0.033). CONCLUSIONS: Our study shows that CM has predilection for young male adults. The chronic use of corticosteroids or other immunosuppressants, rather than HIV infection or bird/bird droppings exposure, was the most frequent risk factor in CM patients in our study. Decreased CSF/blood glucose ratio was both an independent contributing factor to death and was significantly related to the survival length of CM patients. The more decreased the CSF/blood glucose ratio was, the worse prognosis and shorter survival length CM patients had. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12879-015-0826-y) contains supplementary material, which is available to authorized users.