Tuberculous meningitis (TM) is a common intracranial infection with high misdiagnosis rate due to slow onset, atypical symptoms and difficult etiological diagnosis. There are few available effective diagnostic tools for TM. Developing a diagnostic scoring system based on the common symptoms and examination findings of TM may help to improve the diagnostic accuracy and reduce the misdiagnosis rate regarding TM.

To establish a clinical diagnostic scoring system for TM and to evaluate its application value.

One hundred and eighty-seven inpatients with a diagnosis of meningitis were selected from Department of Infectious Diseases, Liuzhou People's Hospital from November 2011 to September 2021, and randomly divided into a model group (n=147, including 71 with TM, and 76 with non-TM) and a validation group (n=40) by a SPSS (version 21.0) algorithm. General data of all cases were collected, mainly including sex, age, clinical symptoms (fever, headache, disturbance of consciousness, cervical resistance) , laboratory and imaging examination results〔including prevalence of HIV infection, CD₄⁺ T lymphocyte count, C-reactive protein, intracranial pressure and routine cerebrospinal fluid (CSF) biochemical markers (glucose, chlorine, protein and cell number) 〕. The influencing factors of TM in the model group were identified using Multivariate Logistic regression, and were used to develop a diagnostic scoring system for TM with each factor rated according to its β coefficient. Then its predictive value for TM was tested using the receiver operating characteristic (ROC) curve.

TM and non-TM patients in the model group had statistically significant differences in the prevalence of headache and HIV infection, CD₄⁺ T lymphocyte count less than 200/μl, elevated C-reactive protein, intracranial pressure greater than 200 mm H₂O, decreased glucose and chlorine in CSF, elevated protein and monocytes in CSF (P<0.05) . Multivariate Logistic regression analysis revealed that headache, CD₄⁺ T lymphocyte cell count less than 200/ μl, elevated C-reactive protein, decreased CSF glucose, and elevated CSF protein were associated with TM (P<0.05) . Based on our clinical practical experience, CSF chlorine and monocytes were added in the multivariate Logistic regression, and further analysis found that headache, CD₄⁺ T lymphocyte count less than 200/μl, elevated C-reactive protein, decreased CSF glucose, and elevated CSF protein were still the associated factors of TM (P<0.05) . The clinical diagnostic scoring system for TM was developed using the aforementioned 7 factors with their values assigned based on the β coefficient value for scoring, among which the assigned value for decreased CSF was 1 point, and the assigned value for each of the other six factors was calculated using that of decreased CSF multiplying the corresponding multiples. For the ease of clinical use, the assigned values for both headache and CD₄⁺ T lymphocyte count less than 200/μl were increased by 2.5 points since the original assigned values of them were negative. The area under the curve (AUC) of the clinical diagnostic scoring system for TM in predicting TM in model group was 0.807〔95%CI (0.735, 0.879) , standard error=0.037, P<0.001〕with 21.50 points as the optimal cut-off value. And that of the system in predicting TM in the validation group was 0.766〔95%CI (0.610, 0.921) , standard error=0.079, P=0.004〕, with sensitivity of 0.789 and specificity of 0.667.

The clinical diagnostic scoring system for TM developed using seven factors is simple and easy-to-use, which has proven to be effective in early diagnosis of TM.