Tuberculous Meningitis and Hemophagocytic Lymphohistiocytosis in a Patient on Adalimumab: Diagnostic Challenges in the Setting of Suspected Non-Tuberculous Mycobacteria Co-Infection.

BACKGROUND

Tumour necrosis factor-alpha (TNF-alpha) inhibitors increase susceptibility to granulomatous infections, including both (MTB) and nontuberculous mycobacteria. We describe a complex case of sequential disseminated (MAC) and central nervous system MTB infection in a patient treated with adalimumab, complicated by hemophagocytic lymphohistiocytosis (HLH).

CASE REPORT

A 65-year-old man on long-term adalimumab for psoriasis presented with prolonged fever, hepatosplenomegaly, cytopenia and elevated inflammatory markers. Bone marrow aspiration revealed hemophagocytosis and liver and bone marrow biopsy revealed granulomatous inflammation. Polymerase chain reaction (PCR) testing of bronchoalveolar lavage (BAL) fluid identified MAC, supporting a diagnosis of disseminated MAC-associated HLH. The patient responded to triple MAC therapy (azithromycin, ethambutol, rifampicin), intravenous immunoglobulin and low-dose corticosteroids, with rapid clinical improvement. Three months later, he was readmitted with fever and altered mental status. Brain magnetic resonance imaging showed meningeal thickening. Lumbar puncture revealed cerebrospinal fluid pleocytosis, hypoglycorrhachia and elevated protein. PCR detected MTB complex deoxyribonucleic acid and a rifampicin resistance gene, prompting the initiation of a four-drug antituberculosis regimen (isoniazid, pyrazinamide, levofloxacin, ethambutol) and high-dose dexamethasone. The patient improved and was discharged after a month of hospitalization, remaining clinically stable at 1-year follow-up.

CONCLUSION

This case highlights the risk of sequential or overlapping MAC and MTB infections in patients receiving TNF-alpha inhibitors, the potential for HLH as a serious complication, and the diagnostic value and limitations of BAL PCR testing. Vigilant screening and multidisciplinary management are essential in such high-risk populations.

LEARNING POINTS

The increased risk of opportunistic infections associated with long-term tumour necrosis factor-alpha inhibitor use necessitates ongoing infection screening.Hemophagocytic lymphohistiocytosis triggered by mycobacterial infections requires prompt recognition and targeted treatment.Polymerase chain reaction results should be interpreted with caution in complex clinical scenarios, as deoxyribonucleic acid detection may indicate colonization rather than active infection.