Tuberculosis Flashcards
Subtypes of tuberculosis
Multi-drug resistant TB (MDR-TB) & extensively drug resistant TB (XDR-TB).
Predisposing factors of TB
- Extended periods in TB-endemic areas
- Close proximity to personnel with active Mycobacterium Tuberculosis (Mtb)
- Recirculated air
- Immunocompromise
Transmission of TB
Transmission occurs when a contagious patient
coughs, spreading bacilli through the air.
Incubation period of TB
3-12 weeks (TST/PPD); Transition from latent to
active can be 10-60 years.
Leading infectious cause of death worldwide.
Tuberculosis
- High-endemic areas, primary infection occurs usually in childhood, but in less-endemic areas can occur in adults.
- Characterized by local granulomatous inflammation in periphery of the lung (GHON focus) may be accompanied by ipsilateral lymph node involvement (GHON complex).
- Infection is usually asymptomatic but can present as an acute lower respiratory tract infection.
Tuberculosis
Routinely given to children in countries with a high
prevalence of TB to prevent childhood TB, however, not used in the U.S. because of low risk of TB infection.
Bacille Calmette-Guerin (BCG)
How does BCG affect TST
may cause a false positive reaction to a TB skin
test.
What is the preferred method of testing for people who have received BCG
*QuantiFERON® – TB Gold In-Tube test (QFT–GIT); *
SPOT® TB test (T–Spot).
TB Navy Instruction
BUMEDINST 6224.8C
LTBI is defined as a positive result on the following labs:
(a) Tuberculin skin test (TST)
(b) Purified protein derivative (PPD)
(c) Positive QuantiFERON Gold blood test
(d) Positive IGRA-TB blood test
Labs & Rads Status for LTBI:
(1) Positive TST/PPD or blood test
(2) Normal CXR
(3) Negative acid-fast sputum test
(4) Has Mtb bacteria in their body (typically the lungs) that are alive, but inactive.
Initial TB Exposure Risk assessment form
NAVMED 6224/7
Evaluation of Positive TB tests
- Chest Radiograph
- Sputum Examination
- LFTs
What must the provider r/o prior to dx of LTBI
Active TB
Treatment of LTBI
(a) Isoniazid & rifapentine (3HP) PO once a week x 12 weeks.
(b) Rifampin (4R) 1 PO QD x 16 weeks (4 months)
(c) Isoniazid & Rifampin (3HR) 1 PO daily x 12wks (3 months).
Why are shorter duration regiments for LTBI treatment preferred?
Poor compliance with longer treatment regiments
How often is the follow up for LTBI treatment?
- Monthly
What form is used for LTBI monthly evaluations
NAVMED 6224/9
Patient education for LTBI
(a) Implications of positive IGRA or TST results, benefits/risks of LTBI treatment, and potential signs of an adverse drug effect.
(b) Necessity for strict adherence to treatment in the absence of side effects.
Where should successful completion of LTBI treatment be documented
Medical record
What percentage of TB infections occur in the lungs
70-80%
What three terms are denoted for Active TB
- Post primary TB
- Reactivation TB
- Active TB
- Most common in adults (60%–80%). Can occur years to decades after primary infection after immunological impairment.
- Frequent symptoms of active disease are fever, anorexia or reduced appetite, weight loss, night sweats, anemia, and persistent cough (>14 days) with purulent and/or bloodstained sputum.
- Hemoptysis is usually the result of cavitating lung disease causing erosion of pulmonary blood vessels.
- Patients may complain of localized thoracic pain secondary to accompanying pleural inflammation
Post-primary Re-Activation TB
Lab/Imaging Findings for Active TB
- IGRA-TB – Measures immune response to TB antigens.
- Tuberculin Skin Test (TST)
- Sputum Test - Acid-Fast Bacillus (AFB) with NAAT
- Gold standard for confirmatory diagnosis; can
differentiate between LTBI & ATB. - CXR
Procedures for suspected or confirmed Active TB
- Patients with suspected/known active TB immediately get surgical masks to minimize aerosolization of respiratory secretions and spread.
- Medical department personnel must wear particulate respirators (N95 minimum) when working in spaces containing a person with known or
suspected active TB. - Immediate isolation from non-infected personnel & other crewmembers, and transfer to an MTF as soon as practicable.
When must a MER be submitted for known or suspected cases of active TB
24 hours
Who should be notified of suspected or active TB
cognizant NEPMU
Who will conduct/facilitate TB contact investigation with SMDER
Cognizant NAVENPVNTMEDU assisted by ISIC/TYCOM
TB prevention
- Follow routine testing & screening guidelines in BUMEDINST 6224.8C
- Exercise extreme caution when dealing with suspected cases or confirmed cases.
- Crew education in endemic areas and thorough port-briefs.
- Ensure pre-deployment and post-deployment TST/PPD is conducted.
