Clinical Characteristics, Diagnostic Performance, and Treatment Outcomes of Extrapulmonary Tuberculosis at a Tertiary Care Center in Oman: A 10-year Retrospective Cohort
Omar Al-Busaidi, Akram Al-Subhi, Ibrahim Al-BusaidiBackground:
Extrapulmonary tuberculosis (EPTB) accounts for a substantial proportion of the global tuberculosis (TB) burden and continues to pose major diagnostic and therapeutic challenges, particularly in low-incidence settings. Comprehensive descriptions of the clinical spectrum, diagnostic yield of available laboratory modalities, and treatment-related toxicity of EPTB in the Arabian Gulf are limited. We aimed to describe the clinical characteristics, diagnostic performance of microbiological and histopathological tests, and safety profile of first-line anti-TB therapy in adult patients with EPTB managed at a tertiary care hospital in Oman.
Methods:
This was a single-center, retrospective cohort study conducted at Sultan Qaboos University Hospital (SQUH), University Medical City, Muscat, Sultanate of Oman, and reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology statement. All adults (≥18 years) with a confirmed diagnosis of EPTB between January 2010 and January 2020 and at least 12 months of follow-up were enrolled by consecutive purposive sampling. Demographic, clinical, microbiological (acid-fast bacilli [AFB] smear, GeneXpert
Results:
Of 225 patients with confirmed TB during the study period, 46 (20.4%) had EPTB and were included. The mean age was 41.5 ± 16.5 years, and 30 (65.2%) were male. Tuberculous (TB) lymphadenitis and disseminated TB were the most common forms (13/46, or 28.3%), followed by musculoskeletal (7, or 15.2%), pleural, abdominal, and meningeal TB (4 each, or 8.7%), and genitourinary TB (1, or 2.2%). Five patients (10.9%) were co-infected with human immunodeficiency virus (HIV), and 3 (6.5%) were on systemic immunosuppression. Constitutional symptoms were uncommon: fever, 39%; night sweats and weight loss, 13% each. AFB smear and mycobacterial culture had the highest yield in TB lymphadenitis (85% and 77%), Xpert MTB/RIF in tuberculous meningitis (75% of cerebrospinal fluid [CSF] samples), and histopathology in gastrointestinal TB (75%). All 46 patients received standard four-drug therapy; drug-induced liver injury (DILI) occurred in 19.6%, gastrointestinal intolerance in 9%, peripheral neuropathy in 7%, and cytopenia in 2%.
Conclusions:
EPTB represents one-fifth of the TB caseload at a tertiary center in Oman, with TB lymphadenitis and disseminated disease as the leading forms. The diagnostic yield of individual tests varies markedly by anatomical site, supporting a multimodal approach combining AFB smear, Xpert MTB/RIF, mycobacterial culture, and histopathology on every available specimen. Hepatotoxicity remains the dominant treatment-limiting adverse event and warrants systematic monitoring.