Minimally Invasive Tissue Sampling for Postmortem Diagnosis of Tuberculous Meningitis in Zambian Adults

The true burden of tuberculous meningitis (TBM), particularly in low and middle-income countries, is unknown due to imperfect diagnostics. Complete diagnostic autopsy (CDA) to confirm TBM in deceased meningitis patients is uncommon. Minimally invasive tissue sampling (MITS) has been shown to be a viable alternative to CDA to establish infectious etiologies of meningitis. We used MITS to determine the burden of TBM among deceased adult Zambians who presented with meningitis.

We performed a prospective cohort study of Zambian adults who presented with symptoms suggestive of TBM, recording whether they had a complete cerebrospinal fluid (CSF) diagnostic assessments during their admission. We followed patients for the outcome of discharge or death. Among those who died, after obtaining consent from the family, we performed MITS, collecting CSF, brain, lung, and liver tissue looking for evidence of Mycobacterium tuberculosis infection.

We completed MITS on 50 deceased Zambian adults who presented with meningitis symptoms. Twenty-two cases had a complete antemortem CSF evaluation. Among these cases, 4/22 (18%) were diagnosed with TBM before death and an additional 2/22 (9%) were diagnosed with TBM via MITS after death. Twenty-eight deaths occurred in patients with an incomplete or no CSF evaluation. Among these cases, 4/28 (14%) were diagnosed with TBM via MITS.

MITS can confirm the diagnosis of TBM in deceased meningitis patients. It can be a valuable tool in meningitis surveillance to establish an infectious etiology.