Is Tuberculous (TB) Lymphadenitis spreadable to other family members living in the same house?

Tuberculous Lymphadenitis Transmission Risk to Household Members

Tuberculous (TB) lymphadenitis can spread to family members living in the same household, though the risk is significantly lower than with pulmonary TB and becomes negligible once the patient has started effective treatment.

Understanding TB Lymphadenitis and Transmission Risk

TB lymphadenitis is a form of extrapulmonary tuberculosis that primarily affects the lymph nodes. The transmission dynamics differ from pulmonary TB in important ways:

• Transmission mechanism: Unlike pulmonary TB which spreads through airborne droplets when coughing, TB lymphadenitis is generally considered less infectious because:

  • The bacteria are contained within the lymph nodes
  • There is no direct airborne spread unless there is a draining sinus
  • The bacterial load is typically lower than in pulmonary cases

• Risk factors for household transmission:

  • Duration of exposure (≥5 hours/day significantly increases risk) 1
  • Bedroom density (less than 8m²/2 people increases risk) 1
  • Occupation type of household members 1

Household Contact Management

The CDC and National TB Controllers Association recommend the following approach for household contacts of TB patients 2:

1. Initial assessment of all household members:

   • Tuberculin skin testing (Mantoux technique)
   • Symptom screening
   • Chest radiographs for those with symptoms or positive skin tests

2. Priority classification for contacts:

   • High priority: Children <5 years, immunocompromised individuals (HIV-infected, those on immunosuppressive medications like prednisone >15mg/day, TNF-α antagonists) 2
   • Medium priority: Household members with regular exposure
   • Low priority: Occasional visitors with minimal exposure

3. Infection control measures at home:

   • Precautions may be discontinued when the patient is no longer infectious 2
   • Generally, TB lymphadenitis patients become non-infectious quickly after starting effective therapy
   • Well-ventilated living spaces reduce transmission risk

When to Consider Household Members Safe

Family members can generally be considered safe from infection when:

1. The TB lymphadenitis patient has started effective anti-TB therapy
2. Clinical improvement is observed (reduction in lymph node size)
3. No evidence of concurrent pulmonary TB exists

Special Considerations

• Definition of "household": Use a broader definition that includes all dwellings on the same plot of land sharing the same address, not just those sharing eating arrangements, to avoid missing at-risk contacts 3

• Social interactions: In high-incidence areas, transmission may also occur through social gatherings outside the home 4

• Immunocompromised household members: Require special attention as they have higher risk of developing active TB if infected 2, 5

Preventive Measures

1. Patient education: Instruct patients to:

   • Cover any draining sinuses with clean dressings
   • Maintain good personal hygiene
   • Take medications as prescribed to quickly reduce infectivity 2

2. Contact investigation: Should begin as soon as TB is suspected 2

3. Preventive therapy: Consider for close contacts, especially:

   • Children under 5 years
   • Immunocompromised individuals
   • Those with newly positive tuberculin tests 2

Important Caveats

• Always rule out concurrent pulmonary TB, which would significantly increase transmission risk
• Drug-resistant TB lymphadenitis, though rare (1.3% MDR-TB rate in one study), requires more aggressive contact management 6
• The definition of "household" should be broad enough to capture all individuals at risk 3

Remember that while TB lymphadenitis is less infectious than pulmonary TB, proper evaluation of household contacts remains essential for preventing TB disease in family members.