Flashcards in TB Deck (26):
What is the pathogen that causes TB?
What is the leading killer of HIV pts?
What is a major characteristic about m. tuberculosis?
Acid-fast bacilli (AFB)
How is TB spread and acquired?
1. Spread from infected person to susceptible host
2. Infection with M. tuberculosis with inadequate containment by immune system
How are TB infections presented in the lungs?
1. Initial infection may be contained and walled off leading to the formation of granulomatous inflammation
2. Initial infections that are not contained
A. May cause either local disease (primary progressive pulmonary tuberculosis)
B. May disseminate hematogenously to seed other organs such as kidney, CNS, or bones
What is the pathophys of TB?
1. Person inhales airborne droplet nuclei containing viable organism
2. Tubercle bacilli that reach alveoli are ingested by alevolar macrophages
If not contained, replicate
Attract inflammatory cells
Seed other parts of body (eye, skin, kidney)
Most become suppressed by immune system at this point
No symptoms develop
Form caseating granulomas
Bacilli can survive in granulomas for years to decades (primary TB)
What is primary TB?
Initial infection, (+) tuberculin skin test (PPD test)
Usually self limiting
5-10% develop TB over lifetime
What is Progressive Primary or Active TB?
Early progression of infection
What is Latent TB?
No active disease
TB bacteria in lungs but body prevents infection from developing- not contagious or infectious
(+) PPD, asymptomatic, (-) CXR, (-) sputum Cx
Can have reactivation of disease if host immune system is compromised- latent TB active TB
What are the sxs of TB?
Cough (chronic) > 3 weeks
Dry to productive
Anorexia, wt loss
Patient appears chronically ill & malnourished
(Sx’s progress slowly)
What are the dx studies for TB?
1. Sputum culture for AFB
A.May take up to 12 weeks to grow
B. AFB smear takes several hours
2. Nucleic acid amplification (NAA) test for M tuberculosis
C. Apical segment involvement
4. Needle biopsy of pleura
A. Caseating granulomas hallmark
What is the criteria for a PPD reaction for ppl with HIV or repeated contact with active TB?
When is a PPD reaction os >10mm with evidence of TB on CXR considered a positive reaction?
Recent immigrants from TB prevalent country
Mycobacteria lab personnel
Diabetics or others with immunocompromised health status
When is a PPD reaction >15mm considered positive?
Patients with no risk for TB
How latent TB treated?
1. INH x 9 months daily (Vit B 6 to ↓ neuropathy) OR
2. Rifampin x 4 months daily
How is active TB treated?
1. INH/Rif/PZA/EMB x 2 months
2. INH/Rif x 4 months
What 4 drugs are used to treat TB?
Rifampin (RIF), Pyrazinamide (PZA),
What are common SE of isoniazid (INH)?
Hepatitis, Peripheral neuropathy
What are common SE of Rifampin?
Saliva, tears and urine orange-red color
What are common SE of EMB?
True/false: TB needs to be reported in NYS.
True. NYSDOH reportable-call
TB skin testing
When do sputum cultures need to be repeated?
Repeat sputum cultures after 2 months of therapy
Lengthen therapy if still (+)
TB infection warrants testing for what other disease?
TB is AIDS defining illness
HIV testing indicated
When and why would a TB pt be isolated?
Isolation X first 5-14d of treatment
If high suspicion or confirmed cases
Where are TB pts treated?
1. Airborne infection isolation rooms
A. Neg pressure rooms