Diagnostic Pitfalls in Tuberculous Meningitis

Introduction: Tuberculous meningitis is a severe infection of the central nervous system by Mycobacterium tuberculosis associated with a high morbidity and mortality rate. Early recognition of tuberculous meningitis is crucial as the clinical outcome strongly depends on the stage of the disease when therapy is initiated. However, establishing a definitive diagnosis remains difficult, as the sensitivity of acid-fast bacilli smear and nucleic acid amplification is low.

Case Report: Here, we report a 2-year-old girl of Bulgarian ancestry, who was admitted with diffuse abdominal pain, recurrent vomiting, and fever. Because of a progressive reduction of vigilance a MRI scan was performed, which showed unspecific meningeal enhancement with multiple small infarctions and signs of acute CSF circulatory dysfunction, necessitating immediate decompressive neurosurgery. CSF examination showed lymphocytic pleocytosis with moderate protein and lactate elevation. There was no evidence of acid-fast bacilli in gastric aspirate, liquor, and bronchial lavage specimen. Repeated CSF investigations for M. tuberculosis DNA remained negative. Several chest X-ray and abdominal sonography were inconspicuous. Bacterial infection or infections by neurotropic viruses could be excluded. Empiric tuberculostatic therapy combined with dexamethasone led to significant clinical improvement. In the course of disease, tuberculin skin test became positive. The diagnosis of tuberculous meningitis was confirmed by CSF culture positive for M. tuberculosis 8 weeks after the start of first symptoms. Despite a mild fluctuant hemiparesis no residual symptoms were noted.

Conclusion: Tuberculous meningitis is a life-threatening disease, which should be taken into consideration in any patient presenting with meningitis syndrome and CSF findings of lymphocytic pleocytosis, protein elevation and low glucose if prompt investigations fail to establish an alternative diagnosis.

Keywords: tuberculous meningitis, reduction of vigilance, lymphocytic pleocytosis.