What is the next step for an infertile female with a positive Mantoux (tuberculin skin test)?

Management of Positive Mantoux Test in an Infertile Female

For an infertile female with a positive Mantoux tuberculin skin test, the next step is to perform a chest radiograph and clinical evaluation to rule out active tuberculosis, followed by evaluation for genital tuberculosis through endometrial sampling if latent TB is confirmed.

Initial Assessment After Positive Mantoux Test

1. Chest Radiography and Clinical Evaluation

   • All individuals with a positive tuberculin skin test (≥5 mm induration) should undergo chest radiography and clinical evaluation to rule out active pulmonary tuberculosis 1
   • Assess for symptoms of active TB: cough lasting >2-3 weeks, fever, night sweats, weight loss, and hemoptysis 2

2. Interpretation of Positive Mantoux Test

   • For infertile women, a tuberculin skin test induration of ≥5 mm is considered positive if there are risk factors such as:
     • HIV infection
     • Recent contact with TB cases
     • Fibrotic changes on chest X-ray consistent with prior TB 1, 2
   • For those without specific risk factors but from high-prevalence countries, ≥10 mm is considered positive 2

Evaluation for Genital Tuberculosis

Genital tuberculosis is a significant cause of infertility, particularly in women from TB-endemic regions 3, 4.

1. Endometrial Sampling

   • If latent TB is confirmed (positive Mantoux with normal chest X-ray), obtain endometrial biopsy for:
     • Histopathologic examination for granulomatous endometritis
     • PCR testing for Mycobacterium tuberculosis
     • Acid-fast bacilli (AFB) smear
     • Culture for Mycobacterium tuberculosis 3, 5

2. Additional Diagnostic Tests

   • Hysterosalpingography to evaluate tubal patency and detect characteristic findings of TB (such as blocked, dilated, or irregular fallopian tubes) 4
   • Laparoscopy and hysteroscopy if clinical suspicion is high, to evaluate for:
     • Peritubal and periovarian adhesions
     • Tubal abnormalities
     • Intrauterine adhesions 4, 5

Treatment Approach

1. For Latent TB Infection (LTBI)

   • If active TB is ruled out but Mantoux test is positive, treatment for LTBI is indicated:
     • Isoniazid 300mg daily for 9 months (standard regimen) 2, 6
     • Alternative regimens: rifampin 600mg daily for 4 months, or isoniazid plus rifampin for 3-4 months 2
   • Monitor for hepatotoxicity with liver function tests every 2-4 weeks 2

2. For Genital Tuberculosis

   • If genital TB is confirmed, standard anti-tubercular therapy should be initiated:
     • Initial phase (2 months): isoniazid, rifampin, pyrazinamide, and ethambutol
     • Continuation phase (4 months): isoniazid and rifampin 2
   • Total treatment duration of at least 6 months

Follow-up and Fertility Management

• After completion of TB treatment, reassess fertility status and consider appropriate assisted reproductive techniques if needed 3, 7
• Women with a history of genital TB may require in vitro fertilization (IVF) due to tubal damage 4
• Important: Thorough TB testing should be conducted in infertile women before IVF to prevent congenital tuberculosis 7

Common Pitfalls and Caveats

• Relying solely on Mantoux test without further evaluation may miss genital TB, as it requires multiple diagnostic modalities 3, 5
• Genital TB can be present even with a normal chest X-ray 4, 8
• In high TB prevalence regions, genital TB should be suspected in all cases of unexplained infertility, even without other TB symptoms 8
• Failure to diagnose genital TB before fertility treatment may lead to congenital tuberculosis if pregnancy occurs 7

Remember that genital tuberculosis is a significant but often overlooked cause of female infertility, particularly in regions with high TB prevalence. A comprehensive approach to diagnosis is essential for appropriate management and to prevent complications.