Tuberculous central nervous system (CNS) infection is rare in the developed world, requiring a high index of suspicion to avoid delay in diagnosis and reduce morbidity and mortality when such cases are encountered.

A 25-year-old Micronesian patient who presented to the emergency department after an episode of unresponsiveness. Six weeks prior to presentation, they developed a cough and generalized weakness, was treated as a case of pneumonia. Following discharge, they experienced a persistent headache, intermittent fevers, and worsening weakness, and eventually a seizure leading to readmission.

Initial labs were significant for hyponatremia (116 mEq/L) and leukocytosis (16,000/µL). CT scan of the head showed mild ventriculomegaly, and scans of the chest, abdomen and pelvis revealed extensive lymphadenopathy and bilateral ground-glass opacities.

MRI of the brain demonstrated multiple areas of restricted diffusion in the brainstem, thalamus, and basal ganglia, consistent with acute infarcts. Contrast-enhanced images showed basilar leptomeningeal enhancement. Intracranial MR angiography was suggestive of widespread vasculitis.

Cerebrospinal fluid studies included elevated protein (391 mg/dL), low glucose (17 mg/dL), and Lymphocyte predominate pleocytosis 80% (122 WBCs/µL), 11 RBCs/µL, negative meningitis/encephalitis panel by PCR and negative parasitological and fungal tests.

Further investigations with an axillary lymph node biopsy indicated granulomatous inflammation with moderate acid-fast bacilli, CSF and bronchoalveolar lavage PCR confirmed Mycobacterium tuberculosis infection. The patient was treated with Rifampin, Isoniazid, Pyrazinamide, and Ethambutol, along with Dexamethasone.

Interestingly, Cancer Antigen 125 (CA-125), which is a well-known non-specific marker in peritoneal tuberculosis, was elevated in our patient. Elevation of CA-125 has not been previously reported in cases with primarily CNS tuberculosis.  

This case illustrates that infectious causes as basilar meningitis can be complicated by CNS vasculitis causing strokes in the young, underscoring the importance of timely diagnosis and treatment in similar presentations.