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Factitious meningitis: a recurring problem
R L Penn1, R Normand, S A Klotz
1Department of Medicine, Veterans Administration Medical Center, Shreveport, LA 71101-4295.
Abstract:
Although gram-negative meningitis is rare in our hospital, between July, 1982 and July, 1983 clusters of cerebrospinal fluid (CSF) smears were reported positive for gram-negative bacilli. Fourteen specimens were obtained by diagnostic lumbar punctures, and one was obtained during a myelogram. No CSF cultures were positive, and a diagnosis of factitious meningitis was eventually established for each patient. Nonviable gram-negative bacilli were found in 6.7% of manometers, and 23.3% to 90% of the specimen tubes tested from the same lots of commercial lumbar puncture trays. It was estimated that there were between 44 and 333 organisms per specimen tube. Two lots of the commercial myelogram trays yielded nonviable gram-negative bacilli from 50% of the specimen tubes and 33.3% of the manometers tested. Retrospective review of laboratory records for 1982 and 1983 revealed 23 total CSF smears positive for gram-negative bacilli. No CSF grew gram-negative bacilli, and chart reviews confirmed a diagnosis of factitious meningitis in each case. In addition to the clusters of false-positive smears, this had occurred sporadically in both years. The problem did not recur after separate sterile tubes were provided for CSF collection. Physicians and laboratories should be aware that nonviable contaminants in commercial products may be a source of false-positive CSF gram-stained smears.
Insights
Contaminated lumbar puncture trays led to false-positive gram-negative bacilli results in cerebrospinal fluid (CSF) smears, mimicking meningitis. This contamination issue was resolved by using separate sterile collection tubes for CSF specimens.
Area of Science:
- Microbiology
- Clinical Diagnostics
- Infectious Diseases
Background:
- Gram-negative meningitis is a rare but serious infection.
- Clusters of positive cerebrospinal fluid (CSF) smears for gram-negative bacilli were observed.
- No CSF cultures confirmed bacterial growth, suggesting an alternative explanation.
Purpose of the Study:
- To investigate the cause of recurrent false-positive CSF smears for gram-negative bacilli.
- To identify the source of contamination in diagnostic procedures.
- To prevent future occurrences of factitious meningitis diagnoses.
Main Methods:
- Analysis of cerebrospinal fluid (CSF) smears and cultures from patients.
- Testing of commercial lumbar puncture and myelogram trays for microbial contamination.
- Retrospective review of laboratory records and patient charts.
Main Results:
- Nonviable gram-negative bacilli were detected in commercial specimen tubes and manometers.
- Contamination levels varied significantly between lots and types of medical devices.
- Diagnosis of factitious meningitis was confirmed in all affected patients.
- The issue ceased after implementing the use of separate sterile tubes for CSF collection.
Conclusions:
- Nonviable contaminants in commercial diagnostic products can cause false-positive CSF gram-stained smears.
- Healthcare professionals and laboratories must be aware of potential contamination sources.
- Implementing procedural changes, such as using sterile collection tubes, can effectively resolve contamination issues.