What is the management for a patient exposed to a spouse with active Tuberculosis (TB) who is asymptomatic?

Management of Asymptomatic Patient Exposed to Spouse with Active TB

After excluding active TB disease, immediately initiate treatment for latent tuberculosis infection (LTBI) in this household contact, regardless of tuberculin skin test (TST) or interferon-gamma release assay (IGRA) results. 1

Immediate Assessment Steps

Exclude Active TB Disease First

• Obtain a chest radiograph (posterior-anterior view) to rule out active pulmonary TB before starting any LTBI treatment 1
• Assess for TB symptoms including persistent cough (≥3 weeks), weight loss, night sweats, bloody sputum, fever, or anorexia 2, 1
• If any symptoms are present or chest radiograph shows abnormalities, perform full diagnostic workup including sputum cultures before proceeding with LTBI treatment 2

Testing for LTBI

• Perform either TST or IGRA testing to document infection status, though treatment should not be delayed for test results in high-risk household contacts 2, 1
• Either test is acceptable; IGRA may be preferred if the patient received BCG vaccination 2, 3
• A TST reaction ≥5 mm is considered positive in recent TB contacts 2, 3

LTBI Treatment Regimens

Preferred Options (Choose One)

• 9 months of daily isoniazid (5 mg/kg, maximum 300 mg daily) - this is the most extensively studied regimen 2, 1
• 3-4 months of daily isoniazid plus rifampin (isoniazid 5 mg/kg max 300 mg + rifampin 10 mg/kg max 600 mg) - shorter duration with similar efficacy 2, 1
• 6 months of daily isoniazid - acceptable alternative with slightly lower completion rates 2, 1

Essential Adjunct Therapy

• Add pyridoxine (vitamin B6, 25-50 mg daily) to prevent peripheral neuropathy when using isoniazid 1

Baseline Laboratory Testing

Who Needs Baseline Testing

• Obtain baseline AST/ALT and bilirubin if the patient has: 2
  • HIV infection
  • History of chronic liver disease (hepatitis B or C, alcoholic hepatitis, cirrhosis)
  • Regular alcohol use
  • Pregnancy or within 3 months postpartum
  • Concurrent use of other hepatotoxic medications
• Baseline testing is not routinely required for otherwise healthy adults 2

Contraindications to Treatment

• Active hepatitis and end-stage liver disease are relative contraindications to isoniazid or pyrazinamide 2

Monitoring During Treatment

Clinical Monitoring

• Schedule monthly visits to assess adherence and monitor for adverse effects 1, 3
• Educate the patient about hepatotoxicity symptoms: nausea, vomiting, abdominal pain, dark urine, jaundice 1
• Instruct the patient to stop medication immediately and seek medical evaluation if these symptoms occur 2

Laboratory Monitoring

• Routine monthly laboratory monitoring is not required for patients with normal baseline tests and no risk factors 2
• Perform liver function tests if symptoms of hepatotoxicity develop 2
• Consider withholding isoniazid if AST/ALT exceeds 3 times upper limit of normal with symptoms, or 5 times upper limit without symptoms 2

Public Health Coordination

Mandatory Reporting and Follow-up

• Report this exposure to local public health authorities immediately 1, 3
• Public health will conduct contact investigation to identify other exposed individuals 1, 3
• Ensure the spouse with active TB is started on appropriate multidrug treatment as soon as possible to reduce ongoing transmission 1, 3

Special Considerations

If Patient is HIV-Positive

• Treatment for LTBI is even more critical, as HIV infection increases TB reactivation risk to 7-10% per year 2
• A TST reaction ≥5 mm is considered positive in HIV-infected persons 3
• Baseline and ongoing laboratory monitoring is mandatory 2
• Consider drug interactions if patient is on antiretroviral therapy, particularly with rifampin-containing regimens 2

Common Pitfalls to Avoid

• Do not delay LTBI treatment while waiting for TST/IGRA results in household contacts of active TB cases 1
• Do not skip the chest radiograph - active TB must be excluded before starting LTBI treatment to avoid inadequate treatment and resistance development 1
• Do not assume the patient will complete 9 months of therapy - consider shorter regimens (3-4 months) to improve adherence 1
• Do not forget pyridoxine supplementation with isoniazid to prevent neuropathy 1