Diagnostic Accuracy of Imaging Findings in TBM/Spinal Tubercular Arachnoiditis and Correlation With Outcomes

Methodology of the study Study design:Ambispective cohort study; Observational study; Diagnostic accuracy study

Sample size: All consecutive patients in the database will be included in the retrospective study and all new patients registered in the neurology OPD and admitted in the Neurology or General Medicine or Geriatric medicine or Medical oncology wards will be included in the prospective arm

Expecting a sensitivity of 70% of sulcal tuberculomas in tubercular meningitis with a range of 60 to 80, the investigators expect (4*70*30) /10*10=84 patients Expecting sulcal tuberculomas to have a specificity of 80%, with a range of 70 to 90%, the investigators expect (4*80*20)/10*10=64 patients Expecting a 70% prevalence of tubercular meningitis amongst patients with chronic meningitis, sample size of atleast 120 patients (70% of 120=84).

Subjects:

• Study Population: Patients with chronic meningitis as per criteria described
• Inclusion criteria
• Patients attending Neurology OPD or are admitted in General Medicine or Geriatric medicine or Medical oncology wards with chronic meningitis diagnosed on the basis of composite clinical criteria, imaging criteria as well as natural history of the illness
• Atleast 14 years of age of all sexes
• Chronic meningitis : Case definition above
• Willing to undergo periodic assessment clinically and with MRI as per clinical condition demands.
• Diagnostic criteria for Tuberculous meningitis ▪ Described in the diagnostic test section ahead
• Diagnostic criteria for clinical spinal tubercular arachnoiditis ▪ Developed paraparesis/quadriparesis/sphincter dysfunction due to spinal radiculomyelitis OR areflexia OR hyperreflexia with no obvious brain parenchymal lesions (suggestive of spinal meningitis-myelitis) or vision loss due to optico-chiasmatic arachnoiditis with imaging evidence of arachnoiditis
• Sample Size: All consecutive patients presenting with chronic meningitis as described above will be included

Exclusion criteria for prospective arm

● Not willing to provide consent

Conduct of the study

• Study protocol
• Consent: Participants or their legally authorized representatives will be explained about the study and informed written consent will be taken in the language they understand for the prospective study
• Participants will undergo magnetic resonance imaging of the brain and spine with contrast using the standardized protocol for chronic meningitis used at AIIMS as the standard of care in the workup of chronic meningitis.
• The final diagnosis of Tubercular meningitis will be made based on the criteria described above and the sensitivity and specificity of sulcal tuberculomas in the diagnosis of TBM will be determined
• Other imaging findings of spinal tubercular arachnoiditis will be collected on a structured proforma by the radiologist who will be blinded to the clinical information on the presence or absence of clinical features.
• Participants will follow treatment for tuberculosis as per the treating physician's discretion in terms of anti-tubercular therapy, anti-seizure medication therapy, duration and dose of corticosteroids and steroid sparing agents.
• Data collection and analysis will be done as per protocol Follow up and outcomes assessed > Participants of the prospective arm will be carefully assessed with detailed history, clinical examination, necessary laboratory investigations and imaging > Detailed history and clinical and neurologic examination, lab parameters and imaging data will be documented into a database as per protocol > Participants will follow treatment for his/her primary condition as per the treating physician's discretion > Outcomes will be assessed at 3 months, 6 months and at end of therapy > The outcome parameters of interest will be modified Rankin scale, visual acuity at 3 months and end of therapy.

Diagnostic accuracy of imaging parameters in the diagnosis of tubercular meningitis will be assessed by sensitivity and specificity.

The investigators aim to do a descriptive study of the clinical, laboratory and imaging parameters of patients tubercular meningitis and spinal tubercular arachnoiditis and compare with patients with other forms of chronic meningitis.

The treatment strategy, usage of anti-tubercular therapy, usage of corticosteroids, steroid sparing therapy, and surgical interventions offered will be studied.

Outcomes will be assessed and compared those who have sulcal tuberculumas and those who don't. The patients with and without spinal arachnoiditis on imaging also will be compared, and their outcomes assessed. Factors affecting outcomes will be studied and exploratory analysis will be done. Statistical analysis will be performed on the available information. Qualitative data will be presented as the number and the percentage of patients in each treatment group. Quantitative data will be presented as mean and standard deviation, range, median and inter-quartile range by treatment group. The absence of imbalance between groups will be checked on baseline variables. Comparisons of qualitative variables between groups will be performed by a Fisher exact test; comparison of quantitative data will be performed by a t test or a comparison of median when they will not follow a Normal distribution. All statistical tests will be performed with the use of a two-sided type I error rate of 5%.