How is tuberculous meningitis diagnosed?

Generally, confirming a diagnosis of tuberculous meningitis requires a comprehensive evaluation of clinical manifestations, cerebrospinal fluid (CSF) analysis, imaging studies, tuberculosis-related pathogen testing, and tuberculin skin tests. Through systematic elimination and analysis, the presence of Mycobacterium tuberculosis侵犯 meningeal involvement can be determined. Detailed analyses are as follows:

1. Clinical Evaluation: Doctors will thoroughly review the patient's medical history, including any history of tuberculosis exposure or previous tuberculosis, and observe symptoms such as persistent headache, fever, vomiting, altered consciousness, and neck stiffness.

2. Cerebrospinal Fluid Analysis: Cerebrospinal fluid samples are collected via lumbar puncture to measure CSF pressure, appearance, white blood cell count and classification, protein levels, and glucose and chloride concentrations. In patients with tuberculous meningitis, CSF typically shows increased pressure, a cloudy or "frosted glass" appearance, lymphocyte-predominant pleocytosis, elevated protein levels, and reduced glucose and chloride levels.

3. Imaging Studies: Cranial magnetic resonance imaging (MRI) or computed tomography (CT) scans are commonly used. MRI provides clearer visualization of meningeal enhancement, cerebral inflammation, or edema, while CT helps identify hydrocephalus or parenchymal brain lesions. Imaging findings help visualize structural brain changes and support the diagnosis of tuberculous meningitis.

4. Tuberculosis-related Pathogen Testing: Samples such as cerebrospinal fluid, blood, or sputum are tested for Mycobacterium tuberculosis using methods including acid-fast staining, culture, and nucleic acid amplification tests. Detection of Mycobacterium tuberculosis in the cerebrospinal fluid provides direct evidence for diagnosing tuberculous meningitis.

5. Tuberculin Skin Test: A tuberculin skin test involves injecting tuberculin into the forearm and observing the reaction at the injection site after 48–72 hours. If redness and induration develop, and the induration reaches a certain diameter, it suggests possible Mycobacterium tuberculosis infection.

Patients suspected of having tuberculous meningitis are advised to actively cooperate with their doctors in completing all necessary examinations, following medical instructions during preparation—for example, avoiding strenuous activity and maintaining a stable position before lumbar puncture. After the examination, adequate rest is important, and any discomfort should be promptly reported to healthcare providers for timely management, ensuring the smooth completion of tests and accurate diagnosis.