Cryptococcus neoformans is the most common cause of meningitis in patients with HIV/AIDS. Cryptococcal meningoencephalitis typically manifests itself in patients whose CD4 cell counts are less than 50/mm3. The onset tends to be insidious with fairly nonspecific symptoms such as fever, nausea, and headache. Symptoms may be present for several weeks, and diagnostic delay is common. Seizures or focal neurologic presentations are rare, and neck stiffness and/or photophobia are usually absent. Diagnosis is usually made on examination of cerebrospinal fluid (CSF). Opening pressures may be quite elevated on LP, and CSF values usually reveal a normal CSF glucose concentration, a mildly elevated CSF protein concentration, and a CSF leukocyte count of less than 20/mL. India ink staining shows the organisms directly with an approximate sensitivity of 70%, whereas CSF cryptococcal latex antigen testing has a sensitivity approaching 90%. Fungal CSF cultures should also be sent. Cutaneous manifestations are seen in disseminated disease.
Management and Disposition
Treatment should begin for presumptive meningitis pending completion of CSF studies. Most often, the decision to treat for cryptococcal meningitis will be based on the results of CSF studies, along with consultation with infectious disease specialists. Cryptococcus can also cause pneumonia and skin lesions. Treatment regimens are usually based on amphotericin preparations plus flucytosine, followed by fluconazole.
Perform the LP only after CT with contrast rules out space-occupying lesions, and do so with the patient in a lateral decubitus position so as to obtain an accurate opening pressure.
CSF antigen testing is most often used to obtain diagnosis, and repeat LPs may be needed to manage elevated intracranial pressures. India ink stains may also be positive with other encapsulated organisms such as Klebsiella pneumoniae, Rhodotorula, Candida, and Proteus species.
Cryptococcal Infection. Cryptococcal skin lesions in disseminated form. Note that the umbilicated centers give a similar appearance to that of molluscum contagiosum. (Photo contributor: Briana Hill, MD.)
Cryptococcal Infection. Cutaneous cryptococcal lesions are often clinically difficult to distinguish from other cutaneous eruptions. (Photo contributors: Seth W. Wright, MD, and Universidad Peruana Cayetano Heredia, Lima, Peru.)
Cryptococcal Infection. This patient had extensive cutaneous involvement with disseminated cryptococcal infection. (Photo contributors: Seth W. Wright, MD, and Universidad Peruana Cayetano Heredia, Lima, Peru.)
India Ink Preparation. Cryptococcus neoformans seen as encapsulated yeast on India ink preparation of the CSF from an HIV patient with cryptococcal meningitis. (Photo contributor: Seth W. Wright, MD.)