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4. 1 and 3
Our patient’s CSF demonstrated a neutrophilic pleocytosis with glucose value of <1 and elevated CSF protein. This can be seen in bacterial meningitis such as meningitis due to Streptococcus pneumoniae or other bacterial causes including Mycobacterium tuberculosis. Amoebic meningitis from endemic species such as Naegleria fowleri is a possibility if the patient has fresh water exposure, particularly lake water. Malignancy also is in the differential however the patient is fairly young. Within Arizona, fungal meningitis due to Coccidioides spp. is not infrequent and may present with diminished CSF glucose and elevated CSF protein. Lymphocytic pleocytosis is generally more common however neutrophilic pleocytosis may occur. Herpes encephalitis may also cause an initial neutrophilic pleocytosis prior to shift to predominantly lymphocytes and is known to cause behavioral disturbances, however, is not usually associated with a low CSF glucose.
Although bacterial meningitis is typically the most common diagnosis with low CSF glucose, other causes can be common. In study done by Chow (4) “one third of hypoglycorrhachia episodes were associated with noninfectious causes such as strokes, bleeds, carcinomatosis, lymphomatosis, leukemia, and neurosarcoidosis.” Also, in the same study most of the HIV-infected patients had fungal meningitis and not bacterial (4).
Gram stain of patient’s CSF is shown in Figure 1. It is catalase negative and optochin sensitive.
Figure 1. Gran stain of patient’s CSF.
What organism is suggested by the Gram stain? (Click on the correct answer to be directed to the fifth of seven pages)