Blood stained cerebrospinal fluid responsible for false positive reactions of latex particle agglutination tests

Usefulness of Pneumotest-latex for direct serotyping of Streptococcus pneumoniae isolates in clinical samples

This study evaluated the usefulness of the Pneumotest-Latex assay for serotyping Streptococcus pneumoniae isolates directly in clinical samples. With an agreement of 88.1% with a PCR-based reference method, this test can be a useful tool for this study purpose, especially in clinical laboratories that do not have access to nucleic acid amplification technologies.

Diagnostic value of latex agglutination test in diagnosis of acute bacterial meningitis

Objectives:

To know the incidence of bacterial meningitis in children below five years of age. To compare conventional culture and antigen detection methods (Latex agglutination test).

Materials and Methods:

100 CSF samples of clinically suspected meningitis cases in children below 5 years of age were included. The samples were subjected to cell count, Gram stain, culture and LAT. The organisms isolated in the study were characterized according to standard procedures.

Results:

Of the 100 cases studied, 31 cases were diagnosed as ABM by Gram stain, culture and latex agglutination test as per WHO criteria. The hospital frequency of ABM was 1.7%. 15 (48.38) cases were culture positive. Gram stain was positive in 22(70.96) cases and LAT in 17(54.83) cases. Haemophilus influenzae was the most common causative agent of acute bacterial meningitis followed by S.pneumoniae. Case fatality rate was 45.16%. The sensitivity and specificity of LAT was 66.66% and 87.91% respectively.

Conclusion:

Bacterial meningitis is a medical emergency and early diagnosis and treatment is life saving and reduces chronic morbidity. LAT was more sensitive compared to conventional Gram stain and Culture technique in identifying the fastidious organisms like H.influenzae, S.pneumoniae and Group B Streptococcus. However, the combination of Gram stain, Culture and LAT proved to be more productive than any of the single tests alone.

Lumbar punctures: use and diagnostic efficiency in emergency medical departments

Background

Lumbar punctures (LP) are regularly and effortlessly used in the emergency medical departments (EMD). LP use and efficiency have not been fully explored in the published literature.

Aims

The goal of this study was to assess in a French EMD, the frequency of use and the diagnostic efficiency of LP, the final diagnoses, and related medical practices.

Methods

We retrospectively studied all patients who underwent an LP after admission to our adult EMD in 2004 and 2005. Patients’ medical files were reviewed to collect clinical and paraclinical features. We defined efficient LP as abnormal LP, which confirmed a suspected diagnosis in an emergency setting.

Results

A total of 247 patients, representing 0.5% of all admissions, underwent an LP. LP were efficient in fewer than 15% of cases and confirmed aseptic meningitis (8.5%), bacterial meningitis (2.4%), Guillain-Barré syndromes (1.6%), subarachnoid hemorrhages (SAH, 0.4%), and carcinomatous meningitis (0.4%). The principal differential diagnoses were infections outside the central nervous system (CNS, 30%), noninfectious neurological disorders (28.7%), and benign headaches (14.2%). The main assumed LP indications were to search for CNS infection (62%) and for SAH (25%). LP efficiency decreased dramatically according to patients’ age. Brain imaging was performed in 90% of patients prior to LP. Excessive use of polymerase chain reaction to detect herpes simplex in cerebrospinal fluid was observed. The only LP complications found were postdural puncture headaches (6.1% of cases). The rate of traumatic LP was 17%.

Conclusions

Our results are in accordance with the few published surveys on this topic. LP efficiency is modest but must be considered in light of the seriousness of suspected diagnoses. However, the search for differential diagnoses should not be neglected.

Probable acute disseminated encephalomyelitis due to Haemophilus influenzae meningitis

We report the case of a 17-year-old male on long-term steroid therapy for minimal lesion glomerulopathy who, after an upper respiratory infection, presented with Haemophilus influenzae type b meningitis. Twenty-four hours later he developed depression of consciousness which progressed to coma and left hemiparesis. Brain magnetic resonance imaging (MRI) revealed multiple lesions (hyperintense on T2 and slightly hypointense on Tl) involving mainly white matter suggestive of inflammation. MRI features were compatible with acute disseminated encephalomyelitis (ADEM), although a differential diagnosis included cerebritis or vasculitis, secondary to bacterial meningitis. The patient was treated with high-dose steroids which resulted in a gradual improvement followed by complete clinical recovery. We propose a diagnosis of ADEM was the best diagnosis because of the radiological features and response to steroids. The occurrence of ADEM associated with acute meningitis, however rare, represents an important diagnostic challenge for the clinician.