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 lymph-node involvement [OR (odds ratio) = 96.7, 95% confidence interval (CI) 9.0 - 1,039] and to caseating-granulomatous and predominantly necrotic cytomorphological 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.