Chapter 67: Tuberculosis Flashcards
The 2nd leading infectious cause of death
Tuberculosis
Who is the most high risk with PTB infection
1st immigrants from high-prevalence countries 2nd HIV 3rd prisons or shelters for the homeless 4th alcoholism and drug user 5th elderly
How many percent develops TB after exposure to TB droplets?
30%
This is a sign of primary infection and may progress to caseation necrosis and calcification
Tubercles
When is the skin test becomes positive after initial exposure to TB
1-2 months
What dose of corticosteroids is at high risk of reactivation of latent TB
≥15 milligrams/d for ≥4 weeks of prednisone or its equivalent
The most common extrapulmonary site of tuberculosis is the ____
Lymphatic system
The most common method for screening for exposure to M. tuberculosis is
Skin test or Mantoux test (purified protein derivative)
When is the best time to read the skin test?
48-72 hours
Can give false-negative skin test
- MMR vaccine
- Improper administration
- Improper test reading
- Very early in the disease
- Profound immmunocompromised
In immunocompromised patients with a negative test but recent close contact to infectious tuberculosis, retest in ____
In immunocompromised patients with a negative test but recent close contact to infectious tuberculosis, retest in 8 weeks and consider treatment.
This is indirect assess for TB. it trigger the release of interferon-y by the infected host
Interferon-y release assays (IGRAs)
The most common findings in chest radiograph with TB patient
Normal chest radiograph, especially in immunocompromised patient
True or False
During primary infection of TB, younger patients are more likely to have enlarged hilar lymph nodes, whereas adults more frequently have parenchymal abnormalities and effusions
True
During primary infection of TB, younger patients are more likely to have enlarged hilar lymph nodes, whereas adults more frequently have parenchymal abnormalities and effusions.
Amount of phlegm need s to improve yield of TB
5-10ml
True or False
Negative smears are found in approximately 60% of culture-positive cases of tuberculosis, with higher false-negative smear results in children and HIV patients (approaching 80%)
False
Negative smears are found in approximately 60% of culture-positive cases of tuberculosis, with higher false-negative smear results in children and HIV patients (approaching 80%)
The World Health Organization endorses this for diagnosis of pulmonary and extrapulmonary tuberculosis
Nucleic acid amplification test (NAAT) - can detect within 1 day
It is best used for the diagnosis of Tuberculosis
NAAT
The recommended Centers for Disease Control and Prevention regimens for Tuberculosis
- Daily four-drug (INH, RIF, pyrazinamide, and ethambutol) therapy for 8 weeks, followed by either INH/RIF or INH/rifapentine for 18 weeks
- Daily four-drug therapy for 2 weeks, followed by two times per week for 6 weeks, with subsequent INH/RIF or INH/rifapentine for 18 weeks or
- Three times weekly four-drug therapy for 8 weeks, followed by INH/ RIF three times weekly for 18 weeks or
- Daily three-drug therapy (INH, RIF, and ethambutol) for 8 weeks fol- lowed by INH/RIF for 31 weeks
Major adverse effect of Isoniazid?
Hepatotoxicity
When to stop INH in patient who has TB?
If serum transaminases are greater than five times the upper limit of normal or if serum bilirubin is >3 milligrams/dL
Paradoxical reaction or immune reconstitution syndrome
A portion of patients treated for tuberculosis worsen after the initia- tion of antituberculous medications. Seen in CD4<50
Unique findings in paradoxical reactions
Hypercalcemia
Treatment for latent TB
Isoniazid for 9 months
Rifampicin and pyrazinamide for 9 months
