17 Feb - cryptococcal meningitis in an immunocompetent patient

     Todays case was a young otherwise healthy male with chronic meningitis.  Cerebrospinal fluid analysis revealed abundant mononuclear cells, high protein, and low glucose.  In the developing world this strongly suggests TB.  In the US, most likely it is cryptococcus or histoplasmosis.  There are several other causes of the chronic meningitis syndrome, nicely summarized in this Nov 1999 Neurological Clinics article available here at MD Consult.  Though often associated with HIV/AIDS, cryptococcal disease occurs in immunocompetent patients.  There is an emerging outbreak of a novel pathogen, Cryptococcus gattii, in the Pacific Northwest, especially Vancouver Island - so watch for it in travelers returning from the Olympics.  This has caused significant morbidity and mortality in both immunosuppressed and immunocompetent patients.  Recently updated treatment guidelines for cryptococcal disease can be found here.  Traditional teaching is that all patients with cryptococcus isolated from sputum require lumbar puncture to exclude cryptococcal meningitis.  The recent guidelines indicate that select immunocompetent patients with negative serum cryptococcal antigen titers and no signs of meningitis can be managed without lumbar puncture.  All immunosuppressed patients require LP, whether they have meningitis symptoms or not.
     On an related note, this recent JAMA article on performance and interpretation of lumbar puncture lists the "normal" opening pressure as 6 - 14 mm Hg or 6 - 18 cm H2O.