____ epidemic is considered a major risk factor for opening the door for active TB infection
AIDS
Factors that contribute to the emergence of TB?
Epidemic proportions of TB among HIV patients, emergence of multi-drug resistant strains of M. Tuberculosis
Tuberculosis is an infectious disease transmitted by
Mycobacterium tuberculosis
Tuberculosis is spread by
coughing, sneezing, laughing or __? (Airborne)
TB usually involves the lungs but also occurs in
kidneys, bones, lymph nodes, and meninges
3 strains of Mycobacterium tuberculosis that affect man
human, Avian (bird), Bovine (cows)
MDR-TB strains developed due to
poor vigilance in treating TB clients, poor compliance w/ drug therapy, patients lost in FU tx, drug regimens that infections are not susceptible to anymore
Who are at risk for TB?
poor, underserved and minorities; homeless, socio-economically disadvantaged, residents of inner city neighborhoods, foreign-born persons, older adults in LTC, injection drug users, medically underserved in all races
M. Tuberculosis is a gram _____ acid-fast bacilli
negative
TB transmission requires
close (w/in 6 inchest of person's mouth), frequent, and/or prolonged exposure
TB cannot be spread by
hands, books, glasses or dishes
TB infection
small droplet remains airborne for minutes to hours until inhaled, deposits in alveoli, replicates slowly and spreads to lymphatic system, cellular immunity limits further multiplication and spreads to infection, after cellular immune system is activated
Favorable environment for TB
upper lobes of lungs, kidneys, epiphyses of bones, cerebral cortex, and adrenal glands
____ can be seen on x-ray
Pockets of infection
Will have a positive skin test ___ post exposure
2-10 weeks
Durimg the 2-10 weeks post exposure can you spread to others?
no
Reactivation of latent TB can occur with
impaired host defense mechanisms, elderly, concomitant disease, immunosuppresant therapy (long-term corticosteroid use, diabetics)
Classification of TB
Class 0 - No TB exposure
Class 1 - TB exposure, no infection
Class 2 - Latent TB infection, no disease
Class 3 - TB clinically active
Class 4 - TB, but no clinically active
Class 5 - TB suspect
S/S of early stages of TB
usually no symptoms
S/S of latent TB
positive skin test but no symptoms
S/S of active TB
fatigue, malaise, anorexia, unexplained weight loss, low-grade fever, night sweats, cough that becomes frequent and produces white frothy sputum
Active TB with acute sx
high fever, chills, generalized flu-like sx, pleuritic pain, productive cough
HIV-infected w/ TB symptoms
atypical exam and cxray findings, weight loss, fever and cough
Complications of TB
military TB - either acute or chronic systemic problems, pleural effusion, empyema, TB pneumonia, CNS problems (confusion, HA, back pain, disorientation
What is the TB skin test called
Mantoux test
Positive TB reaction occurs
2-12 weeks after exposure
A positive TB reaction indicates
the individual has been infected and has developed sensitivity to the protein of the Tubercle Bacillus--does not confirm presence of actual disease-only few with positive TB will ever develop active TB
Guidelines for PPDs
Must be checked after 48-72 hours (2-3 days) ***need to look up, can't read the slide ;-) be back soon
Other diagnostic tests for TB
Chest x-ray - upper lobe infiltrates and lymph nodes
Bacteriologic studies - sputum smear, sputum culture, QuantiFERON-TB (QFT)
Sputum smear as diagnostic test for TB
microscopic exam for acid-fast bacilli (AFB tests) --need >10,000 bacteria/mL to produce a positive smear
Sputum culture as a diagnostic test for TB
most accurate means of dx, BUT takes up to 8 weeks for culture to grow
QuantiFERON-TB as a diagnostic test for TB
Serum placed in chambers in mycobacterial antigens - if positive takes only a few hours
Drug therapy for TB
Long-term tx with antimicrobials, FU bacteriologic studies and chest x-rays
Drug therapy for active TB
isoniazid (INH) - but many are resistant to this; rifampin (Rifadin)
pyrazinamide (PZA); ethambutol *
combo therapy best
*
Others: fluroquinolones, levofloxacin, moxifloxacin, gatifloxacin, steptomycin, kanamycin
Problems w/ TB drug therapy
Length of time meds must be taken, short course 6-9 months, Dev of severe liver disease, FU evals, compliance, side effects,
Latent TB infection
infection is present but not active, drug therapy administered to prevent TB infection dev into clinical disease in some cases
Drug of choice for latent TB infection
INH (isoniazid) - short course is 6-9 months; 9-month course more effective but lower compliance
What is the vaccine to prevent TB?
bacille Calmette0Guerin (BCG)
Precautions for patients with TB who are hospitalized
Place in respiratory isolation (HEPA masks), give appropriate drug therapy, immediate medical workup of sputum smear, culture and chest x-ray
How long are they isolated?
Isolated in negative pressure airflow room with 6-12 exchanges per hour. Must be there until 3 negative AFB smears