Abstract / Summary
Extrapulmonary tuberculosis is increasingly reported in low-incidence settings, but its clinical spectrum, microbiological profile, and relationship with concurrent pulmonary tuberculosis remain incompletely defined. We aimed to characterize its epidemiology, clinical presentation, diagnostic yield, drug resistance patterns, and outcomes in a large tertiary referral centre in Italy. We performed a retrospective observational study of all adults hospitalized with tuberculosis at the National Institute for Infectious Diseases L. Spallanzani, Rome, between 2018 and 2024. Patients were classified as isolated extrapulmonary tuberculosis or concurrent pulmonary and extrapulmonary tuberculosis. We analyzed demographic, clinical, microbiological, radiological and outcome data, and used multivariable logistic regression to assess associations between disease sites and clinical features. Among 2085 patients, 632 (30.3%) had extrapulmonary tuberculosis. Concurrent pulmonary involvement was present in the overwhelming majority of cases (91.8%), whereas isolated EPTB accounted for 8.2% of cases. The most frequent sites were lymph nodes (42.7%), pleura (38.6%), abdomen (20.1%), and musculoskeletal system (15.2%). Compared with isolated extrapulmonary disease, concurrent pulmonary and extrapulmonary tuberculosis was more often associated with cough, dyspnea, fever, and fatigue (all p < 0.05), while other constitutional symptoms did not differ. Malignancy and mental disorders were associated with isolated extrapulmonary tuberculosis. HIV co-infection was associated with abdominal and central nervous system involvement. Overall, 79.3% cases were microbiologically confirmed. Diagnostic yield varied substantially by specimen type, with highest positivity in respiratory, genitourinary, lymph node, and osteoarticular samples. Most isolates were drug susceptible; multidrug resistance occurred in 2.4% of cases. Treatment success at 12 months was 85.0%, with no between-group differences. In-hospital mortality was 2.1%. In a large low-incidence cohort, extrapulmonary tuberculosis rarely occurred as isolated but it was usually accompanied by concurrent pulmonary disease, supporting the concept of tuberculosis as a multisystemic infection. Overall, microbiological confirmation was high but diagnostic yield varied substantially by specimen type. These findings have important clinical and public health implications, underscoring the need for systematic bidirectional assessment of pulmonary and extrapulmonary sites and for maximal diagnostic efforts to identify all sites of infection, to improve diagnosis, clinical management and public health interventions. Not applicable.