Childs Nerv Syst (2015) 31:1335–1340 DOI 10.1007/s00381-015-2745-z

ORIGINAL PAPER

The diagnostic value of cerebrospinal fluid chemistry results in childhood tuberculous meningitis R. S. Solomons 1 & D. H. Visser 2 & P. R. Donald 1 & B. J. Marais 3 & J. F. Schoeman 1 & A. M. van Furth 2

Received: 29 October 2014 / Accepted: 5 May 2015 / Published online: 15 May 2015 # Springer-Verlag Berlin Heidelberg 2015

Abstract Purpose Cerebrospinal fluid (CSF) hypoglycorrhachia and elevated protein is well-described in bacterial meningitis, but evidence for its differential diagnostic value in tuberculous meningitis (TBM) is lacking. We aimed to assess the diagnostic utility of CSF glucose, CSF to serum glucose ratio and CSF protein in children with suspected TBM. Methods We describe CSF glucose and protein values as well as CSF to serum glucose ratios in a prospective evaluation of TBM suspects seen at Tygerberg Children’s Hospital, Cape Town, South Africa, from January 1985 to January 2014. Results Of 615 TBM suspects, 88 (14 %) had microbiologically confirmed TBM, 381 (62 %) ‘probable’ TBM and 146 (24 %) ‘non-TBM’. Mean absolute CSF glucose concentration was significantly lower in the microbiologically confirmed (1.87±1.15 mmol/L) and ‘probable’ TBM (1.82± 1.19 mmol/L) groups compared to non-TBM (3.66 ± 0.88 mmol/L). A CSF glucose concentration of 1 g/L (100 mg/dL) differentiated between cases of TBM and bacterial meningitis [10], as well as viral meningitis [18]. A uniform research case definition, categorizing patients as definite, probable or possible TBM, was proposed by an international panel of experts [19]. Scoring criteria to aid in the diagnosis of TBM include CSF to serum glucose ratio less than 0.5 or an absolute CSF glucose concentration less than 2.2 mmol/L and elevated CSF protein >1 g/L. We aimed to describe CSF glucose, CSF to serum glucose ratio and CSF protein in children with suspected meningitis and assess their diagnostic utility in the diagnosis of TBM. Methodology This study was conducted at Tygerberg Children’s Hospital, Cape Town, a major referral centre for Cape Town and surrounding areas. Between January 1985 and April 2005 and between January 2010 and January 2014, children were prospectively enrolled in several TBM research studies and CSF and serum glucose prospectively determined. Inclusion criteria were (1) age 3 months to 13 years, (2) clinical suspicion of TBM, (3) CSF glucose and/or CSF glucose to serum glucose ratio and (4) a written consent from the caregiver and assent if the child was older than 7 years and competent to do so. Patients with bacterial meningitis were excluded. Clinical procedures All patients had comprehensive clinical assessment and routine investigations, including full blood count, basic biochemistry, tuberculin skin test (TST), mycobacterial analysis of sputum, gastric washings and CSF, bacterial blood culture, HIV screening, chest radiography and neuroimaging, when clinically indicated. CSF was evaluated in all patients including macroscopic appearance, total and differential cell count, protein, glucose, chloride, Gram stain, India ink examination,

Childs Nerv Syst (2015) 31:1335–1340

auramine BO^ fluorescence microscopy and culture for Mycobacterium tuberculosis (M. tuberculosis). CSF glucose was determined by the glucose oxidase method, and CSF protein by the biuret method (currently both Beckman Synchron CX7 Clinical Systems, Beckman, Miami, FL, USA). CSF lactate was not routinely performed in meningitis suspects. Descriptive case definitions A diagnosis of TBM was based on the uniform research case definition by Marais et al. [19]. TBM was classified as ‘definite’ when CSF demonstrated acid-fast bacilli and/or positive M. tuberculosis culture and/or positive commercial nucleic acid amplification test for M. tuberculosis in a patient with symptoms or signs suggestive of the disease. Probable and possible TBM cases were identified according to the uniform research case definition criteria, with points allocated for (1) clinical presentation, (2) CSF findings, (3) neuroimaging, (4) evidence of extraneural TB and (5) additional laboratory criteria. For this study, only ‘definite’ and ‘probable’ TBM were included, as ‘possible’ TBM criteria had low sensitivity in the identification of TBM [20]. TBM was staged according to revised British MRC criteria as: stage I, Glasgow Coma Scale (GCS) of 15 and no focal neurology; stage IIa, GCS of 15 plus focal neurology; stage IIb, GCS of 11–14 with focal neurology and stage III, GCS

The diagnostic value of cerebrospinal fluid chemistry results in childhood tuberculous meningitis.

Cerebrospinal fluid (CSF) hypoglycorrhachia and elevated protein is well-described in bacterial meningitis, but evidence for its differential diagnost...
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