Tuberculosis Flashcards
0
Q
A person is considered to be exposed if there is…
> shared breathing space with someone who has pulmonary or laryngeal TB at a time when infectious person in not wearing a mask and the other person in not wearing N95 respirator.
A
A person has to be in CLOSE CONTACT with someone with infectious TB for LONG PERIOD OF TIME to become infected.
But some people do become infected in short period of time if the contact is in a closed or poorly ventilated space.
1
Q
LTBI vs TB disease : >tubercle bacilli > mantoux skin test > chest X-ray > sputum smear and culture > symptoms > infectiousness > case of TB
A
LTBI vs TB disease : >tubercle bacilli (inactive; active) > mantoux skin test (+;+) > chest X-ray (normal; abnormal) > sputum smear and culture (- ;+) > symptoms (- ; +) > infectiousness (no; yes) > case of TB (no; yes)
2
Q
Mode of action of isoniazid
A
Inhibits Mycolic acid synthesis in bacterial cell wall (bactericidal)
3
Q
Mode of action of pyrazinamide.
A
Exact target unclear.
Disrupts plasma membrane and energy metabolism
4
Q
TB that is resistant to one TB treatment drug
A
Mono-resistant TB
5
Q
TB class and type:
Positive result to TST
Negative smears and cultures
No clinical or X-ray evidence of active TB disease
A
Class 2 - TB infection / No TB disease
6
Q
Mode of action of rifampin
A
Inhibits beta unit of bacterial RNA polymerase thus inhibits RNA synthesis
7
Q
Is likely responsible for the resistance and a key virulence factor.
A
Mycolic acid (rich in lipids)
8
Q
The risk may be about ___ times higher (as with diabetes) to more than ____ times higher (as with HIV infection) for people who have these condition than for those who do not.
A
3x higher : diabetes
100x higher : HIV infection
9
Q
TB that is resistant to at least the drugs isoniazid and rifampin; it is more difficult to treat that drug-susceptible TB.
A
Multidrug-resistant TB (MDR TB)
10
Q
Droplet nuclei are very small droplets containing M.tuberculosis. What is its diameter?
A
1-5 um
11
Q
People with prolonged, frequent, or close contact with people with TB are at high risk of becoming infected. Infection rate?
A
22%
12
Q
Drug resistant TB can be caused by two different ways:
Caused by person to person transmission of drug-resistant organism
A
Primary resistance
13
Q
Patient with drug resistant TB must be closely monitored to see if they are responding to treatment, they should remain in isolation until it is shown that they are no longer infectious.
A
Truelala
14
Q
TB class and type: Medical history of TB disease Abnormal but stable X-ray findings Positive TST Negative smear and culture No clinical or X-ray evidence
A
Class 4 - Previous TB disease (not clinically active)
15
Q
T or F: M.tuberculosis can withstand weak disinfectants and can survive in a dry state for weeks
A
True.
16
Q
Each droplet may transmit the disease, since the infectious dose of TB is very low. The inhalation of ___ bacteria may cause an infection.
A
At least 10 bacteria
17
Q
From infection to development of a positive TB skin test reaction (incubation period) is approximately…
A
2-12 weeks
18
Q
Refers to the condition when a person us infected with tubercle bacilli but has not developed TB disease
A
Latent TB infection LTBI
19
Q
Not everyone who is exposed to an infectious TB patient become infected with M.tuberculosis. The probability that TB will be transmitted depends on 4 factors:
A
- How Infectious or contagious
- Kind of environment when exposure occurs
- Duration of exposure
- Virulence of the tubercle bacilli
20
Q
Doubling time of TB
A
15-20 hrs
18-24 hrs
21
Q
Global TB has begun to fall since…
A
2004
22
Q
TB is an infectious disease that usually attacks the lungs but also attack any part of the body. TB is historically known as…
A
Consumption
White plague
Wasting disease
23
Q
Means that the tubercle bacilli are in the body, but the body’s immune system is keeping it under control and inactive.
A
LTBI
24
A single sneeze can release up to...
40,000 droplets
25
TB that is resistant to at least two TB treatment drugs (but not isoniazid and rifampin) but is not MDR TB
Poly-resistant TB
26
```
TB class and type:
Signs and symptoms of TB disease but evaluation not complete.
```
Class 5 - TB suspected
27
Drug resistant TB can be caused by two different ways:
Develops during TB treatment, either because the patient was not treated with appropriate treatment regimen or the patient did not follow as prescribed.
Secondary resistance
28
TB of the lungs may also occur via infection from the blood stream
Simon focus
| Hematogenous transmission
29
Flow chart of TB suspect
Do it!!!
30
Type of blood test that measures a person's immune reactivity to M.tuberculosis.
Interferon gamma release assay (IGRA)
31
The best way to stop transmission is to...
Isolate infectious persons and give standard TB treatment ASAP.
32
TB class and type:
No history of TB exposure
Negative result to TST or to QFT-G
Class 0 - No exposure / Not infected
33
Refers to ability of an organism to produce a disease
Virulence.
| It is associated with the severity of the disease.
34
The risk for developing active disease is the highest in the _____ after infection and development of positive TB skin test reaction.
The first two years
35
Blood test used to determine TB infection. It measures the response to TB proteins when they are mixed with a small amt of blood.
Quantiferon TB-gold test (QFT-G)
36
Develops during TB treatment. Also referred to As acquired drug-resistant TB
Secondary drug-resistant TB
37
T caused by organism that are able to grow in the presence of particular drug; TB that is resistant to at least one 1st line anti-TB drug.
Drug resistant TB
38
Tuberculous mycobacteria
```
M.tuberculosis
M.bovis
M.africanum
M.canetti
M.microti
```
39
The granuloma prevents dissemination of the mycobacteria and provides a local environment for interaction of cells of the immune system
Another feature if granuloma is the development of abnormal cell death (necrosis) in the center of tubercles.
40
TB disease that occurs in the lungs typically causing cough and an abnormal chest X-ray
Pulmonary TB
| Infectious
41
Simon focus can spread infection to more distant sites such as peripheral lymph nodes, kidneys, brain and bones.
All parts of the body can be affected by the disease, though for unknown reasons it RARELY AFFECTS the heart, skeletal muscles, pancreas and thyroid.
42
TB disease develops when the immune system can't keep the tubercle bacilli under control and the bacilli begin to multiply rapidly.
About 10% of all people with normal immune systems who have LTBI will develop TB disease at some point of their lives.
The remaining 90% will stay infected but free of disease for the rest of their lives.
43
Environmental actors that increase risk for transmission
1. Exposure to small, enclosed spaces
2. Inadequate ventilation
3. Recirculating air containing infectious droplets
4. Inadequate cleaning and disinfection of equipment
5. Improper specimen-handling procedures
44
Factors to be considered in the management of persons exposed to TB
1. Likelihood that contact is newly infected
2. Likelihood that strain is multidrug resistant
3. Estimated likelihood that contact, if infected, will develop active TB
45
Mode of action of ethambutol
Inhibits Mycolic acid synthesis in bacterial cell wall (bacteriostatic)
46
TB patient characteristic that increase risk for infectiousness
1. Coughing
2. Undergoing cough-inducing or aerosol-generating procedure
3. Failing to cover cough
4. Having cavitation on chest radiograph
47
Staining for M.tuberculosis
Ziehl-Neelsen staining
| Acid fast staining
48
A person with active but untreated TB may infect ___ other people per year.
10-15 people/yr
49
TB class and type:
Positive culture
Positive TST
Clinical, Bacteriological and X-ray evidence of TB disease
Class 3 - TB disease (active)
50
Occurs when an antibiotic has lost its ability to effectively control or kill bacterial growth.
Antibiotic resistance
| Bacteria are resistant and continue to multiply in the presence of therapeutic levels of an antibiotic.
51
The main route of TB transmission in children
From adult ps who have infectious cavitation or pulmonary TB
52
M.tuberculosis may be expelled when an infectious person...
Coughs
Sneezes
Speaks
Sings
53
T or f: BCG protects against miliary, meningitic and pulmonary TB in children.
Only protective against miliary and meningitic TB but pulmonary disease is inconsistent.
54
T or F: no tuberculous mycobacteria are NOT usually spread from person to person.
True.
55
Mantoux tuberculin skin test us a method of testing for TB infection. A needle and syringe are used to inject ___ ml of ___ tuberculin units of liquid tuberculin between the layers of skin (intradermally), usually on the forearm.
1 ml of 5 tuberculin units of liquid tuberculin
56
TB disease that occurs in the places other than the lungs.
Extrapulmonary TB
| Most of it are not infectious.
57
The bacteria evade macrophage killing by neutralizing the reactive nitrogen intermediate.
Yes.
58
T or F: the length if TB incubation arises depending on the individual risk factors
True. Within 6 wks of being exposed, an infected person develops a primary infection in the lungs which may have no symptoms. The disease then enters a dormant state that can last for weeks to years.
59
Mantoux skin test is measured ___ hrs after injection.
48-72 hrs
60
Flow chart for the exposure of individual to droplet nuclei from source case of open TB.
1. Duration and intensity of exposure (infected/not infected) [not infected: no infection]
2. Protective immune response (weak/ strong) [weak: primary progressive TB]
3. Strong immune response: limited initial bacterial growth
4. Bacterial growth arrest (some persist/ eliminated) [eliminated: sterilizing immunity]
5. Immune response (compromised/ persists)
[compromised: reactivation TB] [persists: clearance of latent infection]
61
The length of time required for TB patient to be non infectious after starting TB therapy varies.
However, once the standard TB therapy is started, and as long as the patient followed the prescribed TB regimen, the infectiousness can rapidly decline.
62
M.tuberculosis also carry _____ which prevents acidification of the phagosome.
UreC gene
63
Rare type of MDR TB that is resistant to isoniazid and rifampin, plus resistant to any fluoroquinolone and at least of three injectable 2nd line drugs (amikacin, kanamycin, capreomycin)
Extensively drug resistant TB (XDR TB)
64
Symptoms of TB
```
(Pulmonary TB)
Productive cough
Night sweats
(Afternoon) Fever
Poor appetite
Weight loss
Weakness
```
65
Cells that aggregate to form granuloma
Macrophages, T or B lymphocytes and fibroblasts.
| Lympho surr the infected macro
66
Mycobacterium the do not cause TB often called non tuberculous mycobacteria. Example?
M.avium complex
67
When in lungs, M.tuberculosis is taken up by ____, but they are unable to digest the bacterium.
Its cell wall prevents _______.
Specifically, it blocks the bridging molecule ______. However this blockade does not prevent fusion of vesicles filled with nutrients.
When in lungs, M.tuberculosis is taken up by ALVEOLAR MACROPHAGE, but they are unable to digest the bacterium.
Its cell wall prevents PHAGOSOME-LYSOSOME FUSION.
Specifically, it blocks the bridging molecule EARLY ENDOSOMAL AUTOANTIGEN 1 (EEA1). However this blockade does not prevent fusion of vesicles filled with nutrients.
68
Persons with LTBI carry the organisms that cause TB but their are asymptomatic and can not spread germs to others
Persons with LTBI usually have positive mantoux tuberculin skin test or quantiferon TB-gold test
69
Conditions that increase risk
Infection with HIV
Chest X-ray suggestive of previous TB
Substance abuse (esp illegal injection drug use)
Recent TB infection (within past 2 yrs)
Prolonged therapy with corticosteroids and other immunosuppressive therapy
70
TB class and type:
History of exposure
Negative result to TST
Class 1 - TB exposure / No evidence of infection
71
WHO recommends that BCG should not be given to HIV infected infants
Yeah!
72
Persons at higher risk for Exposure to infection with M.tuberculosis
1. Close contact
2. Foreign born persons from or areas with high TB incidence
3. Residents and staff if high-risk congregate settings
4. Health care workers who serve high risk clients
5. HCWs unknowingly exposed to TB patient
6. Low-income, medically underserved groups
7. Locally define high risk groups
8. Young persons exposed to high risk adults
73
Pre clinical state of TB
Class 2
74
Anti TB drugs that blocks B unit of bacterial RNA polymerase. Stops bacterial RNA synthesis. Bactericidal.
Rifampin
75
Ocular TB
Phlyotenular keratoconjunctivitis
76
M, tuberculosis infects human only, while m. Bovis infects...
Cattle and human
77
(+/-) history of exposure
(-) s&s
(+) mantoux tuberculin tesT
(-) chest radiograph
Class 2 : TB infection
78
(+) exposure to an adult with TB
(-) s&s
(-) mantoux tuberculin tesT
(-) chest radiograph
Class 1: TB exposure
79
Cd8 T cells are
Cytotoxic T cells
80
A BCG resistance gene linked with the molecule Nramp (natural resistance asso macrophage protein) has been characterized in mice. Likewise, a human homologous has been found on chromosome___.
Chromosome 2
81
One cough = _____ droplets nuclei
3000
82
Side effects of ethambutol
Reversible retrobulbar (behind eyeballs) neuritis
Loss of central vision
(Patients must have baseline ophthalmogic exam prior to treatment)
83
Therapeutic use of ethambutol
15mg/kg/d
| 10-15mg/kg/d - children >5yrs/old
84
High risk groups
Children less than 4 yrs of age
Person with HIV coinfection
Persons with close contact to person with TB
Person whose tuberculin skin test converted to positive in the past 1-2yrs
Persons who have chest radiographs suggestive of old TB
Persons with certain medical conditions: DM, silicosis, prolonged therapy with corticosteroid, immunosuppressive therapy, leukemia, Hodgkin disease, head and neck cancers, severe kidney disease, certain intestinal conditions, malnutrition
85
Introduction of BCG vaccination program with assistance from UNICEF
1951
86
All of the anti TB drugs is administered parenterally and orally, except one.
Streptomycin is administered intramuscularly.
87
Contraindicated to children less than 5 years old
Ethambutol
88
Side effects of isoniazid
Peripheral neuropathy
Hepatitis
Hepatotoxicity
89
RIFATER
50mg isoniazid
120mg rifampin
300mg pyrazinamide
90
Stage of pulmonary TB where bacilli undergo unrestrained replication. With time, more and more macrophages and more and more bacilli accumulates in the developing lesion called tubercle or granuloma.
2nd stage - symbiosis
91
Stage of pulmonary TB where the logarithmic increase in number of bacilli is inhibited by CMI and DTH. Infected macrophages presented tuberculous antigen set to t lymph.
3rd stage
92
Stage of pulmonary TB where liquefaction occurs. Liquefaction of the caseous center provides am excellent growth medium for the bacilli.
4th stage
93
Lesions involving bones and joints are seen in ___% of infected children and appear ___yr after infection.
Occurs in 5-10% of children after 1yr of initial infection
94
Anti TB drugs with hepatic excretion
Rifampin
95
Strain of m.tuberculosis
Aka Oshkosh strain
Isolated from a male children's clothing factory worker which is highly virulent in mice but not caused widespread epidemics in man
CDC-1551
96
Primary defenses against TB
Macrophage and T lympho
97
Decreased Th1
Pulmonary TB.
98
In class 1, the development of DTH to tuberculin may take up ___ months after the infectious droplets has been deposited in the lung, and before the clinical s&s develop.
3 months
99
Single tuberculin test is considered positive in an immunocompetent patient if the induration a tithe skin test site measures...
1cm
100
DTH acts on the large ag load resulting in cavity formation and destruction of bronchial wall.
The bacillus and liquefied caseous material are discharged into the airways and spread to other parts of the lungs and the outside environment
101
T to F: the relative contribution of other cell types to the total pattern of cytokines production in TB is also not known.
True
102
Combination of calcified peripheral lung lesions and calcified hilar nodes.
Ghon complex
103
Lesions of the ghon complex heal by..
Shrinkage, fibrous scarring and calcification
104
TB is prevalent in economically underdeveloped countries. Other contributing factors aside from poverty are..
Parasitic disease, malnutrition, ignorance, superstition, and over-crowding.
105
Suggested media for cultivation of mycobacteria
```
Solid media
A. Agar-based
B. egg-based
Liquid media
A. Bactec TB medium
B. middlebrook 7H9 broth
C. Septi-check AFB
D. BBL mycobacteria growth indicator tube (MGIT)
```
106
High prevalence groups
Persons born in countries with high prevalence of TB
Groups with poor access to health care
Persons who live or spend time on certain facilities (eg. Nursing homes, homeless shelters, drug treatment centers)
Persons who inject drugs
107
Strain of m.mycobacteria which w first isolated in 1905 bit which has retained it's virulence over the years in animal models, is drug susceptible and can be genetically manipulated
H37Rv
108
Lung lesion of primary TB
Ghon focus
109
Conventional culture of mycobacteria
```
Solid media
(For sputum that is contaminated with normal bacterial flora, mitchison's selective 7H11 agar should be inoculated)
```
110
Anti tb drugs that is Never used alone due to rapid resistance
Pyrazinamide
111
It is added to promote dispersed growth of mycobacteria
Tween (nonionic detergent)
112
Mycobacteria retain carbolfuchsin dye when decolorized with acid-ethanol by the _____ method.
Zehl-neelson method
113
Lesions involving renal appear ___yr after infection.
5-25 years
114
Relatively poor immune response leads to ...
Advances, progressive pulmonary disease
115
Virulence factor of mycobacteria that inhibits fusion of secondary lysosomes with bacilli-containing phagosome within macrophage
Sulfatides
116
Anergy indicated by neg tuberculin test reflects suppression of DTH from processes which interfere with Th1 response.. Such as..
Malnutrition, HIV infection, Steroid therapy and severe TB itself
117
A miracle drug streptomycin was first used for TB treatment
1949
118
Creation of tuberculosis commission by virtue of Act 3743 under Philippine health service (now DOH)
1930
119
The interval between initial infection and disease in adolescents is (longer, shorter).
Shorter interval
120
Elevated Th1 means
Pleural effusion
121
Risk of acquiring infection is determined mainly by
Exogenous/extrinsic factors
122
Side effects of pyrazinamide
Hepatitis
| Hyperuricemia with Gouty arthritis
123
CD4 T cell subset which is pro inflammatory cytokines
Th1
124
Therapeutic use of rifampin
600mg/d 1hr before or 2hrs after meal
| 10-20mg/kg - children
125
Immunological reaction that causes caseous necrosis
DTH
126
Anti-TB drugs that inhibits mycolic acid synthesis in wall of m.tuberculosis. Bactericidal.
Isoniazid
127
The pathologic events in the initial TB infection seem to defend on the balance among the mycobacterial ag load, CMI and tissue hypersensitivity. When does the vigorous granulomas produced?
Small ag load
128
Cd8 T cells can also be against m.bovis-infected macrophage
True
129
High oxygen tension areas
```
Apical posterior areas of Lung
Lymph node
Kidney
Epiphysis of long bone
Vertebral bodies
```
130
A less common alternative course is _____ which occurs in situation where the immune response fails to control multiplication. The ghon focus, hilar and mediastinal lymph nodes are enlarged = compression of bronchi = atelectasis of distal lung = "middle lobe syndrome"
Primary Progressive TB
131
Anti TB drugs that inhibits my colic acid synthesis in bacterial cell wall. Bacteriostatic.
Ethambutol
132
MOTT includes what species
M. Avium-intracellulare
| M. Kansasii
133
MTBC includes what species
M. Tuberculosis
| M. Bovis
134
The ghon focus with an infected lymph nodes and associated lymphangitis forms..,
Ghon complex
135
The CDC recommends that the culture system used should detect growth within 14 days. In this case, what is the most widely used culture media?
Bactec TB medium
136
Entry into the body occurs largely by inhalation of Aerosolized particles containing ____tuberclenbacilli that are deposited in alveoli.
1-3 tubercle bacilli
137
Anti TB drugs that penetrate cns
Rifampin
| 50% ethambutol
138
TB enteritis
Tabes mesenterica
139
A relatively good immune response is seen in patient with...
TB pleuritis
140
Primary mode of transmission
Inhalation of droplet nuclei
141
Virulence factor of mycobacteria that differs on the ability to stimulate cytokines release from mononuclear cells
Lipoarabinomanam
142
The pathologic events in the initial TB infection seem to defend on the balance among the mycobacterial ag load, CMI and tissue hypersensitivity. When does the caseous necrosis occurs?
High ag load
143
Th1 produces what cytokines
IFN-gamma
TNF-alpha
IL-2
144
Factors contributing to the rise in TB
```
HIV infection
Poorly managed TB programs
Increase international travel
Poverty
Increase in number of refugees and displaced people
Multidrug resistant TB
```
145
T or f: in solid caseous material, the tubercle bacilli can survive even for years, and can multiply.
False. It cannot multiply due to the anoxic condition, reduced pH and presence of inhibitory FA
146
Side effects of rifampin
Secretions turn red
Hepatitis (esp.alcoholics)
Flu symptoms
Induces cyp450 thus increases metabolism of oral contraceptives and other drugs
147
RIFAMATE
150mg isoniazid
| 300mg rifampin
148
Side effects of streptomycin
Vestibular toxicity
| Nephrotoxicity
149
Lesions involving hematogenous spread is seen in ___% of infected children and appear ___mos/yr after infection.
Occurs in only 0.5-3% of infected children and occurs after 3-6months of initial infection.
150
Risk of developing disease after being infected depends largely on...
Endogenous/intrinsic factors
151
When does the WHO declared tuberculosis as a global emergency
1993
152
TB bacilli can also induce macrophages to produce variety of cytokines. What are those?
TGF
IL-6 (suppress T cell response)
IL-12 (enhance T-helper responses)
153
Advantage and disadvantage of conventional culture (solid media)
Advantage: allows visualization of colony morphology and pigmentation
Disadvantage: prolonged time of growth ( 3-4wks) and low sensitivity
154
Virulence factors of mycobacteria
1) trehalose dimycolate
2) sulfatides
3) lipoarabinomanam (LAM)
155
TB bacilli has a slow doubling time of...
18-24hrs
156
Refers to the period from the time the tubercle bacillus enter the body until tissue hypersensitivity develops.
Time interval between the initial infection with tubercle bacilli and the development of an altered tissue reaction to the bacilli and their metabolic products.
Incubation period
157
Gold standard Laboratory diagnosis for TB
PCR (culture)
158
Depression of CMI may lead to ..
Re activation of TB
159
Anti TB drugs excreted renally
Isoniazid
Pyrazinamide
Streptomycin
160
In mice, protective immunity against TB can be induced by live, but NOT dead mycobacteria while ______ can be induced by either dead or live organisms or by cell wall components
Delayed-type hypersensitivity (DTH)
161
Anti TB drug that is the first aminoglycoside (inhibits protein synthesis) by binding 30/50s ribosome site. Bactericidal.
Streptomycin
162
T or f: depletion of CD4 T cell results in severe TB
True
163
Cells mediating the tuberculin skin test are CD4-positive producing mostly Th1 cytokines. DTH response is asso with but not identical to CMI. The reasons may be (3)
1. DTH responses are function of Cd4 T cells whereas protective immunity involves CD8 T cells.
2. PPD does not contain all the ag derived from m.tuberculosis
3. In TB with granuloma formation who have neg tuberculin test, T cells may be trapped in granuloma s reflecting their accumulation at the site of defense
164
Mycobacteria are (anaerobe, aerobe); (motile, nonmotile)
Obligate aerobe and nonmotile
165
Founding of Philippine tuberculosis society (PTS), a private agency with government subsidy.
1910
166
Bacille Calmette-Guerin (BCG) used for vaccination is presumed to be derived from what species of mycobacteria?
M. Bovis
167
Anti TB drug that is a nicotinamide analog with unknown mechanism.
Pyrazinamide
168
Other rare mode of transmission
By ingestion of contaminated milk causing infection with M.bovis
Skin inoculation from contamination of an abrasion
169
Demonstration of bacilli in children is limited because primary TB is often paucibacillary and young children can't raise up sputum. What specimen is of greater importance for children?
Gastric aspirate specimen
170
```
3 or more of the ff:
(+) history of exposure
(+) s&s
(+) mantoux tuberculin tesT
(+) chest radiograph
(+) lab findings suggestive of TB
```
Class 3 : TB disease
171
While intracellular killing follows phagocytosis, m.tuberculosis can evade such killing mechanism by (3)
1. Prevention of acidification of phagosomes
2. Neutralization of effects of reactive oxygen intermediates by mycobacterial cell wall components (more likely?)
3. Probable inhibition of phagosome-lysosomal fusion
172
Cytotoxic T cells kills cells harboring intracellular pathogens such as m.tuberculosis. These cells either exhibit..
1. Granzyme/perforin mediated killing of target cells
| 2. Or induce apoptosis
173
Specimens for culture
```
Pulmonary secretion
Urine
Genital discharge
CSF
Blood
Pleural fluid
```
174
Excellent results for patients with nondrug resistant TB can be obtained with ___ month course
6 months
1st 2 months: PIRE
Last 4 months: IR
175
Therapeutic use of pyrazinamide
15-30mg/kg/d
Not to exceed 2g/d
176
Poor inflammatory and DTH responses may develop
Military TB
177
Ghon focus is usually located in..
Sub pleural area of upper segment of lower lobe or lower segment of upper lobe
178
T or F: a positive culture with or without a positive smear of m.tuberculosis is the gold standard for dx of TB and must be ought for whenever possible.
True
179
T or f: both DTH and CMI inhibit multiplication of bacilli equally
True
180
Therapeutic use of isoniazid
5mg/kg/d (300mg max)
10-20mg/kg/d (600mg max) - severely ill patients
10-20mg/kg/d (300mg max) - children
181
Cd4 T cells are
T helper cells
182
TB of cervical lymph nodes
Scrofula
183
The interval between initial infection and disease in infants is (longer, shorter).
Longer interval.
184
The stage of pulmonary TB where there's is scavenging non activated alveolar macrophages ingests the tubercle bacilli which gets destroyed or inhibited depending on virulence of org and the innate microbicidal ability of macrophage.
First stage
185
Virulence factor of mycobacteria responsible for its morphologic appearance - serpentine cords if bacilli in close parallel arrangements.
Trehalose dimycolate
186
Incubation period of TB
19-56 days (3-8wks)
187
M.bovis is intrinsically resistant to ...
Pyrazinamide
188
Advantage and disadvantages of bactec TB medium
Advantage:
Rapid detection of growth (5-12days)
Increased sensitivity
Ability to distinguish MTBC from other mycobacterial species
Rapid susceptibility testing of isolates of m.tuberculosis
Disadvantage: its radioactivity in which its disposal is expensive and may be problematic for some institutions.
189
First line TB drugs
```
RESPI
rifampin
Ethambutol
Streptomycin
Pyrazinamide
Isoniazid
```
190
Refers to infection at disseminated sites where the multiple small yellow nodular lesions are produced in several organs like lungs, lymph nodes, kidney, adrenal, bm, spleen and liver.
Miliary TB
191
Cutaneous TB
Scrofuloderma
192
Classification of TB
```
M. Tuberculosis complex (MTBC)
Nontuberculous mycobacteria (MOTT or mycobacteria other than TB)
```
193
CD4 T cell subset that produces cytokines important for humoral immunity
Th2
194
TB of the spine
Pott's disease
195
2 ends spectrum of TB
Healthy tuberculin reactor
Severe miliary TB
(Reflecting extremely effective and poor immune response to m.tuberculosis respectively)
196
Single tuberculin test is considered positive in an immunocompromised patient if the induration a tithe skin test site measures...
0.5 cm
197
It is inhibited by higher tension of oxygen
M.bovis
198
Therapeutic use of streptomycin
15mg/kg/ 12hr
20-40mg/kg/12 hrs - children
Not to exceed 1g/d
199
T or F: transmission does not occur from large droplets.
True, since these fall to the ground, or if inhaled, are removed by mucociliary action and coughing.
