Tuberculosis Flashcards
1
Q
TB is caused by bacteria of the ____
A
Mycobacterium tuberculosis complex.
2
Q
TB most often affects the ____
A
lungs
3
Q
Mode of transmission of TB
A
Airborne spread of droplet nuclei
4
Q
The most common and important agent of human disease by far is ___
A
M. tuberculosis (sensu stricto)
5
Q
It is resistant to pyrazinamide and historically caused TB from unpasteurized milk.
A
M bovis
6
Q
Morphology and structure of M Tuberculosis
A
Rod-shaped, non-spore-forming, thin aerobic bacterium
Size: 0.5 μm by 3 μm.
7
Q
Acid fastness attributed to high ____ and lipid content in the cell wall.
A
mycolic acid
8
Q
Low permeability due to ____ and ____reducing antibiotic effectiveness
A
arabinogalactan and peptidoglycan
9
Q
ALso contains _____, which aids in survival within macrophages.
A
lipoarabinomannan
10
Q
High ____ content (65.6%), indicative of an aerobic “lifestyle.”
A
guanine-plus-cytosine
11
Q
Most commonly transmitted from a person with infectious pulmonary TB by ________ containing M Tuberculosis bacteria
A
droplet nuclei
12
Q
Droplets dry rapidly and the smallest (____) remain airborne for hours and may reach terminal air passages
A
<5–10 μm
13
Q
A single cough may release up to ____ infectious droplet nuclei.
A
3000
14
Q
Who are the most likely to transmit the infection>
A
Sputum smear–positive cases with visible AFB
15
Q
The most infectious patients have cavitary pulmonary TB or much less commonly laryngeal TB and produce sputum containing ____
A
105–107 AFB/mL
16
Q
Smear-negative/culture-positive TB patients are less infectious but responsible for ~___% of transmissions in some studies.
A
20
17
Q
T/F
Culture-negative pulmonary TB and extrapulmonary TB are essentially noninfectious.
A
T
18
Q
Persons with BOTH HIV Infection and TB are less likely to have cavitations and may be less infectious than persons without HIV Infection T/F
A
T
19
Q
One of the most important factors in transmission of tubercle bacilli because it increases the intensity of contact with a case
A
Poorly ventilated, crowded settings
20
Q
In high-prevalence settings, up to___ contacts may be infected per AFB-positive case before diagnosis.
A
20
21
Q
Most potent risk factor for TB among infected individuals, directly related to degree of immunosuppression
A
HIV co-infection
22
Q
Incidence of TB is highest during ___
A
late adolescence
early adulthood
23
Q
Clinical illness following initial infection is classified as
A
Primary TB
24
Q
In the early phases of infection, the predominant cells infected by M Tuberculosis
A
Myeloid dendritic cells
25
Plays a role in determining susceptibility to TB
NRAMP 1
26
Used primarily for the diagnosis of M tuberculosis infection in persons without symptoms.
TST
27
T/F
TST positive persons are less susceptible to a new M Tuberculosis infection than TST negative persons
T
28
Which cell type is primarily responsible for the initial phagocytosis of Mycobacterium tuberculosis in the alveoli?
A. CD4+ T lymphocytes
B. Dendritic cells
C. Alveolar macrophages
D. Neutrophils
C
Alveolar macrophages are the first immune cells to phagocytose M. tuberculosis in the alveoli, although they are initially unactivated and susceptible to bacillary growth.
29
Which protein antigen of Mycobacterium tuberculosis is critical for granuloma formation by inducing the secretion of matrix metalloproteinase 9 (MMP9)?
A. Lipoarabinomannan
B. ESAT-6
C. 19-kDa lipoprotein
D. CFP-10
B
ESAT-6 induces epithelial cells in contact with infected macrophages to secrete MMP9, which recruits naïve macrophages and promotes granuloma maturation.
30
What is the main cytokine produced by TH1 cells that activates macrophages in TB immunity?
A. IL-10
B. TNF-α
C. IL-4
D. IFN-γ
D
TH1 cells produce IFN-γ, which is crucial for activating macrophages to kill M. tuberculosis and initiate bactericidal responses.
31
Which component of M. tuberculosis inhibits phagosome-lysosome fusion within macrophages?
A. Phosphatidylinositol 3-phosphate
B. Lipoproteins
C. Lipoarabinomannan
D. Cyclic AMP
C
Lipoarabinomannan interferes with the Ca²⁺/calmodulin pathway, blocking phagosome-lysosome fusion and enabling bacillary survival within macrophages.
32
Which gene product of M. tuberculosis is responsible for its persistence during chronic infection in mice by facilitating growth on fatty acid substrates?
A. katG
B. RD1
C. icl1
D. carD
C
33
What is the function of the NRAMP1 gene in resistance to Mycobacterium tuberculosis?
A. Phagosome-lysosome fusion
B. Regulation of reactive oxygen intermediates
C. Resistance to oxidative stress
D. Regulation of macrophage susceptibility
D
34
Which term is increasingly used to describe bacilli that remain active but undetectable during the so-called “latent” stage?
A. Biofilm bacilli
B. Dormant bacilli
C. Persisters
D. Latent bacilli
C
35
In HIV-infected individuals, which T-cell defect is most responsible for uncontrolled M. tuberculosis proliferation?
A. CD8+ T-cell lysis
B. CD4+ T-cell quantitative and qualitative defect
C. Regulatory T-cell dysfunction
D. Natural killer cell depletion
B
36
Which cytokines are primarily produced by TH2 cells?
A. IFN-γ and IL-2
B. IL-4, IL-5, IL-10, and IL-13
C. TNF-α and IL-1
D. IL-17 and IL-22
B
37
What is the role of the 19-kDa lipoprotein of M. tuberculosis?
A. Inhibits macrophage apoptosis
B. Triggers Toll-like receptor signaling in dendritic cells
C. Promotes granuloma formation
D. Blocks phagosome-lysosome fusion
B
38
How do granulomas inhibit bacillary growth in their necrotic centers?
A. By recruitment of CD8+ T cells
B. By maintaining low oxygen tension and pH
C. By inducing TNF-α secretion
D. By phagolysosome fusion
B
39
Which cytokine is most critical for macrophage activation during the macrophage-activating response?
A. IL-1
B. IFN-γ
C. TNF-α
D. IL-10
B
40
Which type of T cell has been associated with cytotoxic responses and lysis of M. tuberculosis-infected cells?
A. TH1 cells
B. TH2 cells
C. CD8+ T cells
D. γδ T cells
C
41
18. What mechanism allows M. tuberculosis to prevent autophagy within infected macrophages?
A. Inhibition of phagosome acidification
B. Blockade of Ca²⁺/calmodulin pathway
C. Reduction in phosphatidylinositol 3-phosphate production
D. All of the above
D
42
Which member of the Mycobacterium tuberculosis complex is most commonly associated with zoonotic transmission through unpasteurized milk?
A. Mycobacterium africanum
B. Mycobacterium bovis
C. Mycobacterium caprae
D. Mycobacterium orygis
B
43
What characteristic of M. tuberculosis justifies its classification as an acid-fast bacillus (AFB)?
A. Its high lipid content in the cell wall, including mycolic acids
B. Its rod shape and non-spore-forming nature
C. Its aerobic metabolism
D. Its ability to grow on fatty acid substrates
A
The high content of mycolic acids and other lipids in the M. tuberculosis cell wall makes it resistant to decolorization by acid alcohol, a defining feature of acid-fast bacilli (AFB).
44
What genomic feature of M. tuberculosis contributes to its persistence and adaptability in the host?
A. High guanine-plus-cytosine content
B. Absence of an environmental reservoir
C. Limited genetic variability among global strains
D. Lack of a complete vesicular proton-ATPase
A
The M. tuberculosis genome has a high guanine-plus-cytosine content (65.6%), reflecting its aerobic lifestyle and ability to adapt to hostile environments, which aids its persistence in the host.
45
Which of the following organisms is part of the Mycobacterium tuberculosis complex and infects marine animals such as seals and sea lions?
A. Mycobacterium africanum
B. Mycobacterium pinnipedii
C. Mycobacterium mungi
D. Mycobacterium microti
B
46
What is the role of the katG gene in M. tuberculosis?
A. It encodes the catalase/peroxidase enzyme that activates isoniazid.
B. It is required for the glyoxylate shunt in chronic infections.
C. It facilitates the secretion of ESAT-6 and CFP-10 antigens.
D. It enhances the resistance of M. tuberculosis to acid-fast staining.
A
47
What is the primary route of transmission of Mycobacterium tuberculosis?
A. Skin contact with infected individuals
B. Inhalation of droplet nuclei containing bacilli
C. Ingestion of contaminated food
D. Direct blood contact with infected individuals
B
The primary mode of M. tuberculosis transmission is via inhalation of droplet nuclei (<5–10 μm) that remain suspended in the air for hours after being expelled by coughing, sneezing, or speaking by individuals with infectious TB.
48
Which factor most strongly influences the likelihood of transmission of M. tuberculosis?
A. The type of immune response in the exposed individual
B. The virulence of the transmitted organism
C. The shared environment and duration of contact with an infectious patient
D. The nutritional status of the exposed individual
C
The likelihood of transmission depends on factors such as the shared environment, the intimacy and duration of contact, and the infectiousness of the TB patient, especially sputum smear–positive cases.
49
What is the role of sputum smear–positive cases in TB transmission?
A. They are less infectious but account for the majority of TB cases.
B. They are the most infectious and primarily responsible for disease spread.
C. They are only minimally infectious but can cause reactivation in latent cases.
D. They are noninfectious but can trigger hypersensitivity reactions.
B
50
Why are HIV-infected individuals with TB generally less infectious than non-HIV-infected individuals with TB?
A. They produce fewer droplet nuclei during coughing.
B. They lack cavitary disease, which reduces bacillary load.
C. Their immune suppression eliminates transmission risk.
D. They typically have extrapulmonary TB, which is noninfectious.
B
51
In high-prevalence settings, how many individuals might an undiagnosed AFB-positive TB case infect before diagnosis?
A. 1–5 contacts
B. 3–10 contacts per year, up to 20 total contacts
C. 50–100 contacts per year
D. None, as they are typically noninfectious until symptoms develop
B
52
Why is the incidence of tuberculosis highest during late adolescence and early adulthood in infected individuals?
A. Poor nutrition during this period
B. Immunologic changes associated with puberty
C. Reasons for this age-specific peak remain unclear
D. Increased risk of reinfection due to high social activity
C
53
What is the primary difference between primary and secondary (postprimary) tuberculosis?
A. Secondary TB is less infectious than primary TB.
B. Primary TB occurs years after infection, while secondary TB occurs immediately.
C. Secondary TB often involves cavitation and is more infectious.
D. Primary TB occurs only in immunocompromised individuals
C
54
How does reinfection contribute to the development of active TB in high-prevalence areas?
A. It is the primary mechanism of TB disease in low-prevalence areas.
B. Reinfection is uncommon in areas with high TB transmission.
C. Reinfection leads to the development of active disease in previously infected individuals.
D. It is responsible for less than 5% of active TB cases in endemic regions.
C
55
In which lung zones is primary pulmonary TB most commonly located?
A. Apical and posterior segments of the upper lobes
B. Middle and lower lung zones
C. Superior segments of the lower lobes
D. Anterior and basal segments of the lungs
B
56
What is the characteristic lesion formed during primary pulmonary TB called?
A. Caseating granuloma
B. Ghon focus
C. Cavitary lesion
D. Miliary nodule
B
57
What is the cause of pleural effusion in primary pulmonary TB?
A. Lymphatic spread of bacilli
B. Bacillary penetration into the pleural space from a subpleural focus
C. Hematogenous dissemination of infection
D. Compression of pulmonary vessels
B
58
What radiographic finding may indicate healed primary TB?
A. Consolidation with air bronchograms
B. Cavitation in the upper lobes
C. Small calcified nodule
D. Reticulonodular pattern
C
59
What is the most common site of involvement in postprimary (adult-type) pulmonary TB?
A. Middle lung zones
B. Apical and posterior segments of the upper lobes
C. Lower lung zones
D. Superior mediastinum
B
60
What is the most common origin of postprimary TB in endemic areas?
A. Endogenous reactivation of distant infection
B. Exogenous reinfection
C. Reactivation of latent TB in immunocompromised individuals
D. Recent infection (primary or reinfection)
D
61
. Which of the following is a hallmark feature of cavitary postprimary TB?
A. Necrotic contents are contained within the lesion.
B. Liquefied necrotic contents are discharged into the airways.
C. Lesions heal by fibrosis without cavitation.
D. Cavities are rarely involved in bronchogenic spread.
B
62
What is the most common symptom in postprimary pulmonary TB?
A. Night sweats
B. Persistent cough
C. Hemoptysis
D. Weight loss
B
63
Which hematologic abnormality is commonly associated with postprimary pulmonary TB?
A. Leukopenia
B. Thrombocytopenia
C. Mild anemia and thrombocytosis
D. Pancytopenia
C
Mild anemia.
Leukocytosis.
Thrombocytosis.
Elevated erythrocyte sedimentation rate (ESR).
Increased C-reactive protein (CRP).
63
What is Rasmussen’s aneurysm in the context of postprimary TB?
A. An aspergilloma forming in an old cavity
B. A dilated vessel in a cavity wall that can rupture
C. A necrotic lymph node rupturing into a bronchus
D. A granuloma forming in the lung parenchyma
B
64
Typical Chest Radiograph Findings (Immunocompetent Patients):
Upper-lobe infiltrates with cavitation.
Cavitary disease more likely with delayed diagnosis.
65
Chest Radiograph Findings (Immunosuppressed Patients):
Atypical
Lower-zone infiltrates without cavitation.
Interstitial patterns.
Common in patients with HIV co-infection or other immunosuppressive conditions.
66
Preferred first line diagnostic tests
NAAT
67
Xpert MTB/Rif Assay simultaneously detects TB and rifampin resistance in <___hours.
2
68
Recommended by WHO as the first-line diagnostic test for:
Adults and children with suspected active TB.
HIV-infected patients with suspected TB.
Xpert MTB/Rif Assay
69
The initial test applied to CSF from patients in whom TB meningitis is suspected
Xpert MTB/RIF and Ultra
70
High sensitivity for certain specimen types:
____ 97%.
____100%.
Synovial fluid
Lymph node biopsy
71
Diagnostice test for HIV Infected patients in whom TB is suspected remains unclear
TB Lamp Assay
72
Used for presumptive TB diagnosis due to accessibility and low cost
AFB Microscopy
73
WHO-recommended microscopy tool of choice
Light-Emitting Diode (LED) Fluorescence Microscopy
73
AFB Sputum sample
1–2 specimens, preferably collected early in the morning
74
The WHO standard of care for all TB patients
Universal DST
75
Primary tool for pulmonary TB detection.
CXR
76
Classic picture of TB in CXR
Classic Presentation:
Upper-lobe disease with infiltrates and cavities
77
Test indicated for:
HIV-positive adults with:
CD4+ ≤100 cells/μL.
Severe illness, regardless of CD4+ count.
Mycobacterial Lipoarabinomannan Antigen Tests
78
Which of the following is the preferred first-line diagnostic test for tuberculosis in adults and children according to the WHO?
A) AFB smear microscopy
B) Chest X-ray
C) Xpert MTB/RIF assay
D) Culture on Löwenstein-Jensen medium
C
79
What is the major improvement of the Xpert MTB/RIF Ultra assay over the original Xpert MTB/RIF assay?
A) Higher specificity
B) Detection of rifampin and pyrazinamide resistance
C) Improved sensitivity for smear-negative, culture-positive cases
D) Elimination of false-positive results
C
80
Which of the following specimens has the lowest sensitivity for tuberculosis diagnosis using the Xpert MTB/RIF assay?
A) Synovial fluid
B) Pleural fluid
C) Gastric lavage
D) Lymph node biopsy
B
Sensitivity is lowest for pleural fluid (50%) compared to synovial fluid (97%) and lymph node biopsy (100%). This variability highlights the assay's limitations based on specimen type.
81
Which group of patients should always have CSF tested using the Xpert MTB/RIF or Ultra assay as the initial diagnostic test?
A) Patients with suspected miliary TB
B) Patients with suspected tuberculous meningitis
C) Patients with pulmonary TB symptoms and a positive TST
D) Patients with drug-resistant TB
B
82
Which staining method is most commonly used for traditional AFB microscopy?
A) Gram staining
B) Ziehl-Neelsen staining
C) Auramine–rhodamine staining
D) Periodic acid–Schiff staining
B
83
What is the advantage of LED fluorescence microscopy compared to traditional Ziehl-Neelsen microscopy?
A) Lower cost of reagents
B) Reduced biosafety requirements
C) Higher sensitivity
D) Faster specimen preparation
C
84
Which specimen type is least likely to yield a positive result with AFB microscopy?
A) Sputum
B) Lymph node biopsy
C) Urine
D) Blood
C
85
What is the WHO recommendation regarding the use of AFB microscopy in laboratories?
A) Replace AFB microscopy with culture-based methods entirely
B) Use only Ziehl-Neelsen microscopy for all specimens
C) Transition to LED fluorescence microscopy where feasible
D) Limit AFB microscopy to sputum specimens
C
86
Which genetic mutation is most commonly associated with rifampin resistance?
A) katG
B) inhA promoter region
C) rpoB
D) pncA
C
87
What is the current WHO standard of care for drug susceptibility testing (DST) in tuberculosis?
A) Routine testing only for first-line drugs
B) Universal DST for all TB patients
C) DST only in patients with treatment failure
D) DST only for MDR-TB cases
B
88
Which method provides the fastest results for detecting rifampin resistance?
A) Liquid culture-based DST
B) Solid culture-based DST
C) Molecular line probe assays (LPAs)
D) Whole genome sequencing (WGS)
C
89
What is the typical reporting time for direct DST using liquid culture systems?
A) 24–48 hours
B) 7–10 days
C) ~3 weeks
D) ≥8 weeks
C
D. Indirect
90
Which second-line drug group is prioritized for DST in cases of rifampin-resistant TB?
A) Fluoroquinolones
B) Aminoglycosides
C) Pyrazinamide
D) Ethambutol
A
91
Which method is recommended by the WHO for rapid detection of resistance to fluoroquinolones?
A) Phenotypic culture-based DST
B) Second-line molecular line probe assays (LPAs)
C) Automated nucleic acid amplification tests
D) Whole genome sequencing
B
RRTB or MDRTB
92
What is the primary advantage of whole genome sequencing (WGS) in DST?
A) Rapid results from sputum samples
B) Detection of all resistance-associated mutations in a single test
C) Elimination of the need for culture samples
D) Minimal cost compared to other DST methods
B
93
Which culture system is recommended by the WHO as the reference standard for the isolation of Mycobacterium tuberculosis?
A) Löwenstein-Jensen (solid culture)
B) Middlebrook 7H11 (solid culture)
C) Mycobacterial Growth Indicator Tube (MGIT)
D) Modified Thayer-Martin medium
C
94
How long does it typically take for MGIT liquid cultures to become positive for M. tuberculosis growth?
A) 24–48 hours
B) 3–5 days
C) 10 days to 2–3 weeks
D) 6–8 weeks
C
95
Which technique is used in the MGIT system to detect mycobacterial growth?
A) Detection of pH changes
B) Fluorometric detection of oxygen consumption
C) Measurement of CO₂ production
D) Visual observation of colony morphology
B
96
Which chest radiographic pattern is classically associated with pulmonary TB?
A) Lower-lobe infiltrates with no cavities
B) Upper-lobe infiltrates with cavitation
C) Diffuse ground-glass opacities
D) A normal radiograph
B
97
In the era of HIV/AIDS, why is no single radiographic pattern considered pathognomonic for TB?
A) HIV-positive patients typically have normal CXRs.
B) TB presents with a wider variety of patterns in HIV-positive patients.
C) TB is less likely to cause radiographic abnormalities in HIV-positive patients.
D) Radiographic findings are only relevant in non-HIV patients.
B
98
What is the primary limitation of using CXR as a diagnostic tool for TB?
A) It is time-consuming.
B) It cannot detect cavitary lesions.
C) It has poor specificity.
D) It is ineffective in immunocompromised patients.
C
99
Which of the following diagnostic techniques is most useful for patients who cannot spontaneously produce sputum?
A) Bronchoalveolar lavage
B) Fiberoptic bronchoscopy
C) Sputum induction with hypertonic saline
D) Gastric lavage
C
100
In the evaluation of suspected extrapulmonary TB, which diagnostic method is most appropriate for diagnosing tuberculous meningitis?
A) Pleural fluid analysis
B) Bronchoscopy with transbronchial biopsy
C) Lumbar puncture with CSF testing
D) Gastric lavage
C
101
When is biopsy and culture of bone marrow or liver tissue particularly useful in TB diagnosis?
A) In patients with pulmonary TB
B) In patients with disseminated TB, especially HIV-positive individuals
C) In patients with pleural TB
D) In patients with primary TB infection
B
102
WHO recommends that this assay be used to assis in the diagnosis of TB in HIV-positive adults who have signs and symptoms of TB and a CD4+ T vell count of
Lateral flow urine lipoarabinomannan assay
103
What is the correct technique for administering the tuberculin skin test?
A) Subcutaneous injection into the deltoid muscle
B) Intramuscular injection into the vastus lateralis
C) Intradermal injection into the volar surface of the forearm
D) Multipuncture test on the dorsum of the hand
C
104
Which factor can cause a false-positive result on a tuberculin skin test?
A) HIV infection
B) Recent BCG vaccination
C) Advanced TB disease
D) Use of immunosuppressive therapy
B
False-positive TST results may occur due to prior BCG vaccination or infection with nontuberculous mycobacteria. HIV infection and immunosuppressive therapy are more likely to cause false-negative results.
105
What is the primary antigen used in IFN-γ release assays (IGRAs) to measure the immune response to Mycobacterium tuberculosis?
A) Purified Protein Derivative (PPD)
B) ESAT-6 and CFP-10
C) BCG vaccine-derived proteins
D) Lipopolysaccharides
B
106
Which of the following is an advantage of IGRAs over the tuberculin skin test (TST) in diagnosing TB infection?
A) Higher sensitivity in HIV-infected individuals
B) Lower cost of implementation
C) Reduced cross-reactivity with BCG vaccination
D) Better prediction of progression to active disease
C
107
Which version of QuantiFERON incorporates the stimulation of CD8+ T cells in addition to CD4+ T cells?
A) QuantiFERON-TB Gold
B) QuantiFERON-TB Gold In-Tube (QFT-GIT)
C) QuantiFERON-TB Gold Plus (QFT-Plus)
D) T-SPOT.TB
C
108
Bactericidal
HR
109
Peak serum levels HRZE
2-4 hrs
110
Nearly complete elimination of HRZE after
24 hrs
111
Aims to rapidly kill most tubercle bacilli, resolve symptoms, and render patients noninfectious.
Intensive Phase
112
Eliminates residual mycobacteria to prevent relapse.
Continuation Phase (Sterilizing)
113
Given to prevent Isoniazid-Related Neuropathy
pyridoxine (10–25 mg/day)
Alcoholics.
Malnourished individuals.
Pregnant/lactating women.
Patients with conditions associated with neuropathy (e.g., diabetes, HIV, renal failure).
114
>80% of DSTB patients have negative sputum cultures by __months.
2
115
Nearly all patients should have negative sputum cultures by ___
3 months.
116
Persistent positive sputum cultures at ≥2 months warrant:
Immediate testing/retesting for drug resistance.
117
Persistent positivity at ≥3 months suggests
Treatment failure
118
In settings were mycobacterial cultures are not yet available, monitoring by AFB smear exam should be undertaken
2, 5, 6 months
119
The most common adverse reaction of significance among people treated for drug susceptible TB is
hepatitis
120
All adult patients should undergo baseline assessment of _
liver function
121
Suspend treatment if symptomatic hepatitis with at least ___ fold increase in serum AST and or ALT
3
122
Suspend treatment for patients wo symptoms of hepatic injury who have marked (at least __-fold) elevations in serum levels of AST or ALT
5
123
hyperuricemia and arthralgia caused by _____ can be managed by administration of ____
pyrazinamide
acetylsalicylic acid
124
Pyrazinamide should be stopped if patient develops ____
gouty arthritis
125
patients who develop autoimmune thrombocytopenia secondary to ____ should not receive the drug thereafter
rifampin
126
Indication for permanent discontinuation of ethambutol
Optic neuritis
127
Suspected when cultures or sputum smears remain positive after ___ months of treatment.
3
128
Retest the current isolate for:
First-line agent resistance, particularly isoniazid and rifampin.
Second-line agent resistance if ___ resistance is detected.
rifampin
129
Standard Rule:
Add more than one drug to the failing regimen, preferably two or three at a time pending results of susceptibility
130
Relapsed patients are less likely to harbor drug-resistant strains than those with treatment failure. T/F
T
131
Resistance associated mutations:
Rifampin:
Isoniazid:
Pyrazinamide: p
Ethambutol:
Fluoroquinolones:
Aminoglycosides:
Rifampin: rpoB gene (~95% of cases).
Isoniazid: katG gene (50–95%) and inhA gene promoter (up to 45%).
Pyrazinamide: pncA gene (~98%).
Ethambutol: embB gene (50–65%).
Fluoroquinolones: gyrA–gyrB genes (75–95%).
Aminoglycosides: rrs gene (~80%) and eis promoter region (especially in Eastern Europe).
132
Recommended regimen for isoniazid resistant TB
Rifampin, Ethambutol, Pyrazinamide, Levofloxacin for 6mmonths
133
Prior to treatment for isoniazid resistant TB, ensure rifampin resistance has been excluded and perform susceptibility testing for fluoroquinolone and pyrazinamide T/F
134
When fluoroquinolones are contraindicated (intolerance or resistance):
Drugs for Isoniazide resistant TB:
Rifampin.
Ethambutol.
Pyrazinamide.
Duration: 6 months.
135
Which of the following drugs is considered a first-line agent for the treatment of tuberculosis due to its bactericidal activity?
A) Streptomycin
B) Levofloxacin
C) Rifampin
D) Cycloserine
C
136
Which of the following drugs is most closely associated with peripheral neuropathy, particularly in patients with risk factors like malnutrition or diabetes?
A) Isoniazid
B) Ethambutol
C) Pyrazinamide
D) Rifampin
A
137
Which first-line TB drug is associated with dose-dependent optic neuritis, warranting routine visual monitoring?
A) Pyrazinamide
B) Rifampin
C) Ethambutol
D) Isoniazid
C
138
What is the role of pyrazinamide in TB treatment regimens?
A) Provides rapid bactericidal action
B) Enhances sterilizing activity and shortens treatment duration
C) Prevents the emergence of drug resistance
D) Targets drug-resistant TB strains exclusively
B
139
Which second-line drug is classified as a Group A agent and is strongly recommended for use in multidrug-resistant tuberculosis (MDR-TB)?
A) Linezolid
B) Cycloserine
C) Clofazimine
D) Ethambutol
A
Other Group A
Levofloxacin
Bedaquiline
140
Which anti-TB drug requires monitoring for hyperuricemia as a potential side effect?
A) Isoniazid
B) Rifampin
C) Pyrazinamide
D) Ethambutol
C
141
What is the recommended treatment duration for drug-susceptible TB with the standard regimen including isoniazid and rifampin?
A) 4 months
B) 6 months
C) 9 months
D) 12 months
B
142
Which TB drug inhibits RNA synthesis by targeting the bacterial RNA polymerase enzyme?
A) Rifampin
B) Isoniazid
C) Ethambutol
D) Pyrazinamide
A
143
Which drug is associated with reddish-orange discoloration of body fluids, including urine, tears, and saliva?
A) Isoniazid
B) Rifampin
C) Pyrazinamide
D) Ethambutol
B
144
What is the primary role of fixed-dose combination (FDC) anti-TB drugs in treatment?
A) Decrease the incidence of side effects
B) Improve patient adherence and prevent selective drug intake
C) Eliminate the need for monitoring liver function
D) Provide targeted therapy for drug-resistant TB
B
145
What is the standard duration for the intensive phase in the treatment of drug-susceptible tuberculosis?
A) 1 month
B) 2 months
C) 4 months
D) 6 months
B
146
What is the primary purpose of the continuation phase in TB treatment regimens?
A) To resolve clinical symptoms
B) To prevent the emergence of drug resistance
C) To eliminate persisting mycobacteria and prevent relapse
D) To minimize drug toxicity
C
147
What is the recommended treatment duration for TB meningitis according to the ATS, CDC, and IDSA guidelines?
A) 6 months
B) 9 months
C) 12 months
D) 18 months
C
148
Why is intermittent dosing in the intensive phase (e.g., thrice-weekly regimens) no longer recommended by the WHO?
A) Increased risk of hepatotoxicity
B) Decreased patient adherence
C) Increased rates of treatment failure and relapse
D) Lack of efficacy in extrapulmonary TB
C
149
What is the recommended TB treatment regimen during pregnancy?
A) Isoniazid, rifampin, pyrazinamide, and ethambutol for 6 months
B) Isoniazid and rifampin for 9 months, with ethambutol for the first 2 months
C) Rifampin, isoniazid, and streptomycin for 6 months
D) Isoniazid and pyrazinamide for 9 months
B
150
A 45-year-old man presents with a two-week history of cough, fever, and night sweats. Chest X-ray reveals findings suggestive of pulmonary tuberculosis (PTB). Which diagnostic test should be prioritized?
a. Tuberculin Skin Test (TST)
b. Sputum smear microscopy (SM)
c. Xpert MTB/RIF
d. Chest CT scan
C
151
A 28-year-old woman with known HIV infection is being screened for TB. Which symptom duration threshold is used to identify presumptive TB in PLHIV?
≥ 2 weeks
≥ 3 weeks
Any duration
≥ 1 month
Any duration
152
Which of the following is NOT a cardinal symptom of TB?
Cough lasting ≥2 weeks
Night sweats
Hemoptysis
Unexplained weight gain
hemoptysis
153
In a patient suspected of TB but with negative bacteriological tests, what is the next diagnostic step?
Perform a biopsy
Initiate empiric anti-TB treatment
Do chest X-ray if not done
Conduct a second TST
Do Chest Xray if not done
Fig 5
154
A 32-year-old man with a history of treated TB presents with a persistent cough and fever. Which risk factor most strongly suggests possible multidrug-resistant TB (MDR-TB)?
Previous incomplete TB treatment
Recent exposure to a crowded environment
Smoking history
Diabetes mellitus
Prev incomplete TB tx
155
A 10-year-old child has been in close contact with a family member diagnosed with active TB. The child has no symptoms. What is the appropriate management?
Initiate latent TB treatment (TPT)
Start full anti-TB treatment
Perform a chest X-ray and reassess
Monitor without intervention
Chest Xray
156
A 25-year-old man with drug-susceptible TB (DS-TB) is being treated with a standard regimen. Which combination of drugs is part of the intensive phase of DS-TB treatment?
a. Rifampicin, isoniazid, pyrazinamide, and ethambutol
b. Rifampicin, isoniazid, and streptomycin
c. Isoniazid and rifampicin only
d. Pyrazinamide and ethambutol only
A
157
Which group is prioritized for TB preventive treatment (TPT)?
a. Adults with a history of smoking
b. Children under 5 in close contact with a TB case
c. Patients with asthma
d. Elderly individuals with no TB exposure history
B
158
A health care worker with a chronic cough undergoes annual screening and is found to have an abnormal chest X-ray. What is the next best step?
a. Repeat the X-ray in one year
b. Perform sputum examination using Xpert MTB/RIF
c. Prescribe a trial of antibiotics
d. Initiate full anti-TB treatment immediately
B
159
A 50-year-old male patient with multidrug-resistant TB (MDR-TB) is initiated on a second-line regimen. Which drug class is most commonly included in such a regimen?
Fluoroquinolones
First-line injectables
Broad-spectrum antibiotics
Antiviral agents
Fluoroquinolones
160
Which of the following is the recommended follow-up test for monitoring a patient with drug-susceptible pulmonary TB during treatment?
a. Monthly chest X-ray
b. Sputum smear microscopy at 2 months
c. Blood culture every 2 weeks
d. Routine TST every mont
b
161
A 40-year-old HIV-positive male is diagnosed with drug-susceptible TB. What additional consideration is required in his treatment plan?
a. Avoidance of rifampicin
b. Early initiation of antiretroviral therapy (ART)
c. Delayed initiation of TB treatment
d. Substitution of isoniazid with a less hepatotoxic drug
B
162
