Miliary-Pattern Pulmonary Tuberculosis During Infliximab Therapy Despite Negative Tuberculosis Screening

Tumour necrosis factor-alpha (TNF-α) inhibition increases the risk of tuberculosis (TB), including disseminated and miliary disease.Although screening for latent TB is recommended before anti-TNF therapy, negative or indeterminate interferon-gamma release assay (IGRA) results do not exclude active TB, particularly in immunosuppressed patients.We report a 32-year-old man with ulcerative colitis who developed progressive respiratory and constitutional symptoms while receiving infliximab.He developed severe hypoxaemic respiratory failure requiring high-flow nasal oxygen.Chest imaging demonstrated diffuse miliary nodularity with bilateral ground-glass changes, consolidation, and mediastinal lymphadenopathy.Despite previous negative and subsequent indeterminate QuantiFERON-TB results, the clinical and radiological findings prompted empirical anti-tuberculous treatment while respiratory samples were obtained.Sputum culture subsequently grew Mycobacterium tuberculosis, while a Hain molecular assay and bronchial washing confirmed the M. tuberculosis complex.Infliximab was withheld, and the patient improved clinically, with respiratory support reduced from high-flow nasal oxygen to conventional oxygen.He subsequently reported symptomatic improvement during respiratory follow-up.This case highlights the limitations of TB screening tests in patients receiving anti-TNF therapy and demonstrates that a negative or indeterminate interferon-gamma release assay (IGRA) should not delay investigation for active TB when clinical and radiological features are strongly suggestive.