In genital tuberculosis causing primary amenorrhea, which investigation would most accurately diagnose endometrial TB when gold standard culture is negative and histology is non-contributory?

• A Serum CA-125 levels
• B Hysterosalpingography showing 'lead pipe' pattern
• C Laparoscopy with peritoneal biopsy
• D Nucleic acid amplification test (NAAT/PCR) on menstrual blood or endometrial samples ✓

Explanation

Genital TB diagnosis is challenging because culture (LJ medium) has low sensitivity (~50%) and takes 6–8 weeks. When histology (caseating granulomas) is non-contributory, NAAT/PCR on endometrial aspirate or menstrual blood provides rapid, sensitive diagnosis and can detect non-viable or paucibacillary organisms. PCR using IS6110 insertion sequence has sensitivity of ~80–90% in endometrial samples. Hysterosalpingography may show characteristic pipe-stem fallopian tubes or a shrunken Asherman-type uterus, but these are late features; HSG also carries risk of hematogenous spread in active disease.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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