Value of cerebrospinal fluid lactate for the diagnosis of bacterial meningitis in postoperative neurosurgical patients.

OBJECTIVE: To evaluate the diagnostic value of CSF lactate (L(CSF)) for the diagnosis of bacterial meningitis (BM) following neurosurgery, and compare it with other CSF markers. METHODS: Prospective study of consecutive neurosurgical postoperative patients admitted to the Intensive Care Unit (ICU) at Maciel Hospital. Patients with clinical suspicion of BM were categorised, according to preset criteria, into 3 groups: (1) proven BM; (2) probable BM, and (3) excluded BM. CSF markers were plotted in a receiver operating curve (ROC) to evaluate their diagnostic accuracy. RESULTS: The study included 158 patients. We obtained 46 CSF samples from patients with clinical suspicion of BM by lumbar puncture (LP): 10 corresponded to proven BM, 4 to probable BM and 32 to excluded BM. Mean lactate in CSF (L(CSF)) was: 10.72±4.68mM for proven BM, 6.07±0.66mM for probable BM and 3.06±1.11mM for excluded BM (P<.001 for proven BM and probable BM vs excluded BM; P=NS for proven BM vs probable BM). L(CSF) displayed a better diagnostic accuracy for BM in the 2 scenarios studied: (1) positive bacterial CSF culture or Gram stain as positive control (gold standard) (sensitivity: 87%, specificity: 94%, cut-off value: 5.9mM), and (2) combination of proven BM and probable BM as positive control (sensitivity: 92%, specificity: 100%, cut-off value: 5.2mM). CONCLUSIONS: According to our results, determination of L(CSF) is a quick, sensitive and specific test to identify the need for antimicrobial therapy in neurosurgical postoperative patients with clinical suspicion of BM.

Molecular alterations of parotid saliva in infantile chronic recurrent parotitis.

Infantile chronic recurrent parotitis (ICRP) is an insidious disease whose etiopathogenesis remains an enigma. Alterations in the physical appearance of parotid saliva from ICRP patients have been frequently reported. However, sialochemical studies in regard to ICRP are very rare. The aim of this study was to determine whether saliva of ICRP patients presents major physicochemical and biochemical alterations compared with saliva from paired healthy controls. Parotid, whole, and submandibular/sublingual saliva was collected at an asymptomatic stage from 33 ICRP patients (5-16 y old, both sexes) and from 33 sex- and age-matched healthy controls. Saliva was analyzed for protein concentration, mode of protein diffusion on cellulose membranes, unidimensional sodium dodecylsulfate (SDS)-polyacrylamide gel electrophoresis protein profiles and zymographic profiles of metalloproteinase 2 (MMP-2) and metalloproteinase 9 (MMP-9). Parotid saliva of ICRP patients showed an increased protein concentration, altered mode of protein diffusion, a higher frequency of polypeptide bands of 43, 37, 33, 29, 26, 16, and 10 kD, higher asymmetry in the polypeptide profiles of both contralateral parotid saliva, and an increase in the frequency of MMP-2 and MMP-9. Parotid saliva of patients with ICRP is molecularly altered with respect to normal saliva. Some of the molecular differences could be related to the etiopathogenesis of the disease.