TB

what are 2 blood tests and 1 skin test for diagnosis. what interferon release assay test measure 1 what is it s advantage 2 and disadvantages 2 when to use assay 2 what is special consideration to skin test 4 how to interpret skin test and what risk factors to determine how progressive is tb (4, *chronic condition*

.2 blood tests available for M. tuberculosis infection detection *T-Spot and Interferon-gamma r*elease assay (Quantiferon Gold) 1. A negative reaction does NOT exclude diagnosis of LTBI or active TB disease Interferon-gamma release assay (IGRA) QuantiFERON® TB Gold Blood test that measures immunity to M. tuberculosis 2.Doesn't cross-react with BCG vaccine (vaccine for TB), non-tuberculous mycobacteria 1.Differentiate between infected vs. uninfected 1. Doesn't distinguish between active and latent TB Preferred in groups that historically have poor rates of return for TST reading and who have received BCG vaccinatio Tuberculin skin test (TST) Inject 0.1 mL purified protein derivative (PPD) intradermally A delayed-type hypersensitivity reaction is produced if the person has been infected with M. tuberculosis Not sensitive or specific Read after 48 - 72 hours Diameter of induration (swelling) measured, not erythema TST special considerations Anergy (might not have response evenough you have postive for the infection) , false negative/positive, BCG vaccine, booster effect if >5mm Highest risk HIV positive Recent TB contacts + CXR Organ transplants Immunosuppressed if >10mm Recent immigrants (5 years) IVDU Residents/employees of crowded settings Mycobacteriology lab personnel Chronic conditions Children exposed to high risk adults (i am an immigrant, i start working as a lab tech, i (exposuse) to many) crowded bac so i have (chronic) disease so i need to take (med) if >15mm no risk factors

Pointer Questions - Exam 3 1) What are the three main groups of functional groups responsible for the action of rifamycin antibiotics? How do they act? What happens if each one of them is oxidized or somehow modified? 2) What are mycolic acids? What is their importance? How does isoniazid interfere with their synthesis? 3) What is squalene epoxidase? How can it be inhibited? What happens when it is inhibited? Is it also present in human cells? Why? 4) What are the main representatives of polyene antifungals? How do they act? What is the main source of their side effects? 5) What is the mechanism of action of Azoles? What is the importance of the HEME group for the functionality of the enzyme 14-α-demethylase? What is the functional group responsible for the activity of the azoles?

1. p - p Bonding between naphthalene and aromatic amino acids of DDRP 2. Chelation to zinc present in metalloenzyme DDRP 3. Hydrogen bonding to enzyme (DNA-dependent RNA polymerase) through C21 and C23 OH (required) 2. Purpose is destroy the ability of the bacteria to make the cell wall. Make stop growing of mycolic acid

*besides blood test and skin test, what else to use for dignosis of tb 5* advantage 1 and dis 1 of smearing method 1 *how many bac needed in smrearing stest * what test is gold standard of lab confirmation of tb advantage of culture 1 *how many bca neened to grow*

1. x ray for abnormality on chest 2. smear sputum from coughing 5Acid-fast bacillus (AFB) stain Quick and easy (results available within 24 hours) Negative smears do NOT exclude TB disease There must be 5,000 to 10,000 bacilli/mL of specimen to allow for detection of bacteria in stained smear 3 Culture Gold standard for laboratory confirmation of active TB disease Slow growing, hard to culture, doubling time 20 hours Can be "smear negative" but culture positive Only 10 to 100 bacilli are needed for a positive culture 4. . Drug-susceptibility testing should be conducted for resistance to the first-line anti-TB drugs Isoniazid, rifampin, ethambutol, and pyrazinamide Culture and susceptibility testing takes 4 to 14 days

how significant tb affects people in world ? what countries has most affected people?

1/3 world's population infected by Mycobacterium tuberculosis Highest incidence in 2010 were in India, China, South Africa, Indonesia, and Pakistan

how tb develop in body describe Latent TB

A small number of tubercle bacilli enter bloodstream and spread throughout body from oveoli Within 2 to 8 weeks T lymphocytes are activated, producing interferon-γ and other cytokines, stimulating macrophages to surround the tubercle bacilli These cells form a barrier shell (granuloma) that keeps the bacilli contained and under control (LTBI)

how disease is transmitted specifically? what environment bac grow best? how fast bac grow if exposing to bac, what can haapen? 3

An airborne disease caused by the bacterium Infectious droplet nuclei are generated when persons who have pulmonary TB disease cough, sneeze, shout, or sing Each droplet contains 1-3 organisms Droplet particles can remain suspended in air for several hours Mycobacterium tuberculosis Bacillus with waxy outer layer Acid-fast bacillus (AFB) stain Slow growing, hard to culture Doubling time 20 hours Exposure to M. tuberculosis can cause Latent TB Active TB disease No infection

what are 3 main goals of treating tb what are goals of non pharm of tb

Goals Cure the individual patient Minimize risk of death and disability Reduce transmission of M. tuberculosis to other persons b.c of public health pb Non-pharmacologic Prevent spread of TB (isolation, negative pressure rooms) Contact local health department Identify contacts (the person who infected with TB) Return patient to normal weight and well-being (the goal: i should identify and contact person with destructive health and tell them not to spread disease

describe active tb

If the immune system CANNOT keep tubercle bacilli under control, bacilli begin to multiply rapidly and cause active TB disease Liquefaction of granulomas by immune system -> pulmonary cavity -> bacterial spread This process can occur in different places in the body

how long is initial phase, 4 main agents in this phase purpose of this phase 2 how long is continuation phase 3 agents purpose 1

Initial Phase 2 months Four agents form the core treatment regimen INH, RIF, PZA, and EMB Purpose 1. Kill most of the tubercle bacilli during first 8 weeks of treatment 2. Prevents emergence of drug resistance Continuation Phase 4 to 7 months INH and RIF/RFB Purpose Kill remaining tubercle bacilli (after initial phase) If treatment not continued long enough, surviving bacilli may cause TB disease in patient at a later time (recurrent if you don't continue for the whole tx course)

*.Risk Factors for Infection (pneumonic)*

Location and birthplace 3 Urban areas, crowding, immigration, low socioeconomic status Race, ethnicity 3 Hispanic/Latino (29%), Asian (28%), African-American (25%) Age 3 25- 44 year olds (34%), 45 - 64 year olds (30%), > 65 years old (19%) Gender 1 More common in males with each decade of life Co-infection with HIV 1 10% of TB patients ages 25 - 44 are co-infected with HIV LEO dap GA LO,eht, age, gen, co,

what to monitor when treating lalent tb 3

Monitoring Baseline laboratory testing is not routinely indicated Consider baseline serum AST, ALT, and bilirubin in at risk populations HIV infection, pregnant women, persons with history of chronic liver disease (alcoholic hepatitis, HCV, HBV)

can tb carriers transmit disease how fast tb develop in person who also have hiv

Patients who have M. tuberculosis in their bodies, but do not have TB disease and cannot spread the infection to other people 10% of persons with normal immune function will develop active TB at some point in their lives 5% will develop active TB disease in the first 2 years after infection In persons co-infected with HIV, risk of developing TB is 7-10% each year

2 purposes of lalent treatment *what types of people should receive treatment for latent tb*

Purpose of treatment 1. Reduces the risk of person infected with M. tuberculosis will progress to active TB disease 2. Make sure to rule out active TB disease before treatment 1. Targeted to certain groups who are at high risk of developing active TB disease 2. Positive reaction to the tuberculin skin test is ≥ 5 mm HIV infected persons , recent contacts of persons with infectious TB disease, chest radiograph consistent with prior TB disease, organ transplants, and immunosuppressed patients (prednisone equivalent of 15 mg/day for > 1 month)

treament monitor 3 in term of hepatotoxicity if use ethambutol , what to monitor 2 *what else tomonitor 3*

Renal function and AST, ALT, and bilirubin at baseline b.c all of these drug at risk of hepatoxicity Visual acuity and color vision monthly if EMB used > 2 months or doses > 15-20 mg/kg 1. *Serial sputum smears every 2 weeks until 2 consecutive negative smears to assess early response 2 Remove from isolation (meaning they are no longer at risk for transmitting the disease) 3 Monthly sputum for culture (until 2 consecutive cultures negative) 4. Additional drug-susceptibility tests if culture-positive after 2 months of treatment (TB is continueously resistant envought the patient on tx, therefore, you need to have the culture tests)* 5 Periodic (minimum monthly) evaluation to assess adherence and identify 6. adverse reactions

what are risk factors of having this disease (what types of people) 3 what are sites of tb on body , including most comon site

Risk factors Age: children and elderly Immunocompromised 100 times increased risk in patients with HIV Progressive primary disease in 5% of patients Persons who have TB disease may spread the bacteria to other people Sites of TB disease Pulmonary Most common site for development of TB disease Extrapulmonary Larynx, lymph nodes, brain, kidneys, bones and joints May coexist with pulmonary reactivation

compare latent and active tb*, TST TEST*

latent:have bac, not infectious, no symtomp, *TBT TEST AND blood test is positive,* normal chest exray, neg culture, not a acase active: hava multipling bac , infectious, cough, fever, positive blood test, not normal, culture pos, is a case of tb

Factors that determine probability of transmission: 4

suseptibility: immune status of exposed person Infectiousnes: the sicker is the person, the more bac they spit them out into air eviroment: smaller room, higher is the contact. the lower is ventilation or lower positive air pressure, more contact exposure: longer duration, frequency, contact proximity.