Haematogenous dissemination of tuberculous lymphadenitis

Abstract

Objective: To determine whether Mycobacterium tuberculosis infection spreads through the blood to different lymph-node groups in patients with tuberculous lymphadenitis. Design: Prospective analytical study. Setting: The patients were recruited, managed and followed at the lymphodenopathy clinic, Central Police Hospital, Burr, Khartoum, Sudan. Subjects: Fifty two sequential patients were enrolled. Thirty patients with FNAC diagnosis of tuberculous lymphadenitis and positive PCR for M. tuberculosis complex had a mean age of 26.9±11.2 years and similar male, female affection. Nine patients with FNAC tuberculous lymphadenitis, but negative PCR had a slightly higher mean age (32.6±18.2 years) with similar male : female proportions. Patients with reactive lymphadenopathy (9/52) were older than patients with tuberculous lymphadenitis with a mean age of 45±24.6 years. Results: None of the patients were positive for HIV or had clinical or radiological evidence of pulmonary tuberculosis. M.tuberculosis DNA was detected in the blood samples of 30/39 (77%) patients with tuberculous lymphadenitis, but in none of the cases with reactive or malignant lymphadenopathy. The presence of M.tuberculosis DNA correlated strongly to multiple lymphnode involvement [OR (odds ratio) = 96.7,95% confidence interval (CI) 9.0-1,039] and to caseatinggranulomatous and predominantly necrotic cytbmorphological categories [OR = 70,95% confidence interval (CI) 7.0 - 703]. Conclusion: M.tuberculosis most probably disseminates through the blood from one node group to the other in patients with tuberculous lymphadenitis.