Rare Extrapulmonary Tuberculosis: Covert symptoms and Diagnostic Dilemma

Area of Science:

• Medical Microbiology
• Pathology
• Infectious Diseases

Background:

• Pulmonary tuberculosis can spread to other organs (extrapulmonary tuberculosis) if not detected early or in immunocompromised individuals.
• Rare sites include the gastrointestinal tract, musculoskeletal system, genital tract, middle ear, and pericardium.
• Diagnosis relies on histopathology showing granulomas, Ziehl-Neelsen staining for acid-fast bacilli (AFB), and GeneXpert for Mycobacterium tuberculosis DNA.

Purpose of the Study:

• To evaluate the diagnostic utility of histopathology, Ziehl-Neelsen staining, and GeneXpert in extrapulmonary tuberculosis.
• To assess the accuracy of these methods in identifying Mycobacterium tuberculosis in biopsy specimens.

Main Methods:

• Histopathological examination of biopsy specimens for granuloma and necrosis.
• Ziehl-Neelsen (ZN) staining for acid-fast bacilli (AFB).
• GeneXpert MTB assay for Mycobacterium tuberculosis DNA detection in biopsy samples.

Main Results:

• Out of 10 cases, 8 showed caseous necrosis, and 7 were positive for AFB on ZN staining.
• GeneXpert detected Mycobacterium tuberculosis DNA in 9 out of 10 cases.
• Histopathology and ZN staining identified granulomas and AFB in most cases, while GeneXpert showed higher sensitivity.

Conclusions:

• Extrapulmonary tuberculosis is often secondary to pulmonary TB, spreading hematogenously.
• It presents diagnostic challenges and should be considered in chronic, non-responsive cases.
• Biopsy with ZN staining is cost-effective for initial diagnosis; GeneXpert is valuable for confirmation, especially with negative ZN staining or absent necrosis.