12-02-2008, 07:56 PM
Q1 AAAA.
This patient has transfusion-related West Nile virus encephalitis. Most cases of West Nile virus infection are subclinical, and the virus remains in the circulation for as long as 28 days. Blood products occasionally become infected, and cases have been documented in which West Nile virus was transmitted via donated blood. Although donated blood is tested using nucleic acid amplification techniques, this study is not 100% sensitive.
Bacterial infection should always be considered early in the course of a patient with a suspected central nervous system infection, but this patient's clinical course and cerebrospinal fluid findings more strongly support a diagnosis of West Nile virus infection. Both pneumococcal and meningococcal meningitis are unlikely because of the absence of leukocytosis and the lack of characteristic findings associated with bacterial meningitis in the cerebrospinal fluid. Staphylococcal sepsis is also unlikely because the patient has no signs of a localized bacterial infection and does not have leukocytosis. Although aseptic meningitis should also be included in the differential diagnosis, this patient's muscle symptoms and findings suggestive of encephalitis (e.g., severe headache, mental status changes) are more consistent with West Nile virus infection.
This patient has transfusion-related West Nile virus encephalitis. Most cases of West Nile virus infection are subclinical, and the virus remains in the circulation for as long as 28 days. Blood products occasionally become infected, and cases have been documented in which West Nile virus was transmitted via donated blood. Although donated blood is tested using nucleic acid amplification techniques, this study is not 100% sensitive.
Bacterial infection should always be considered early in the course of a patient with a suspected central nervous system infection, but this patient's clinical course and cerebrospinal fluid findings more strongly support a diagnosis of West Nile virus infection. Both pneumococcal and meningococcal meningitis are unlikely because of the absence of leukocytosis and the lack of characteristic findings associated with bacterial meningitis in the cerebrospinal fluid. Staphylococcal sepsis is also unlikely because the patient has no signs of a localized bacterial infection and does not have leukocytosis. Although aseptic meningitis should also be included in the differential diagnosis, this patient's muscle symptoms and findings suggestive of encephalitis (e.g., severe headache, mental status changes) are more consistent with West Nile virus infection.