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Tuberculosis notes Flashcards

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1
Q
A
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2
Q

What is pulmonary tuberculosis (TB)?

A

An infection of the lung caused by the bacterium Mycobacterium tuberculosis (MTB)

TB can also affect surrounding structures.

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3
Q

What are the two major clinical forms of M. tuberculosis infection?

A
  • Primary (acute) tuberculosis
  • Secondary (reactivation) tuberculosis
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4
Q

What characterizes primary (acute) tuberculosis?

A

It develops in a previously unexposed and unsensitized patient, with about 5% developing significant disease

This form is the initial response to infection.

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5
Q

What characterizes secondary (reactivation) tuberculosis?

A

It arises in a previously sensitized (infected) patient, often from reactivation of dormant lesions

This can occur many decades after the initial infection.

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6
Q

What percentage of the world’s population is infected with TB?

A

One fourth of the world’s population

TB remains one of the deadliest diseases known to humans.

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7
Q

True or False: Only newly infected individuals can develop significant TB disease.

A

False

Both newly infected and previously infected individuals can develop TB.

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8
Q

What is the principal causative organism of TB?

A

Mycobacterium tuberculosis (MTB)

Humans are the only reservoir for Mycobacterium tuberculosis.

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9
Q

What type of organism is Mycobacterium tuberculosis?

A

Strict aerobe bacilli that are slow-growing and acid-fast

Mycobacteria have specific growth requirements and characteristics.

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10
Q

True or False: Humans are not the only reservoir for Mycobacterium tuberculosis.

A

False

Mycobacterium tuberculosis is exclusively found in humans.

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11
Q

What is the most common form of TB?

A

Pulmonary TB

Excluding patients with HIV infection, about 80 - 85% of adults have exclusively pulmonary parenchymal disease.

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12
Q

What is miliary (disseminated) pulmonary TB?

A

Occurs when MTB bacilli reach the bloodstream through lymphatic vessels and recirculate to the lung via the pulmonary arteries.

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13
Q

What is systemic miliary TB?

A

Occurs when MTB bacilli spread hematogenously throughout the body, prominently involving the liver, bone marrow, spleen, adrenal glands, meninges, kidneys, vertebra, and long bones.

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14
Q

What types of TB may develop from the spread of MTB-infective material?

A

Endobronchial, endotracheal, and laryngeal TB

These may develop through lymphatic channels or from expectorated infectious material.

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15
Q

How do MTB organisms usually enter the body?

A

By inhalation

MTB organisms can also enter through the gastrointestinal tract or by cutaneous or subcutaneous inoculation.

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16
Q

Where are inhaled MTB commonly deposited in the lungs?

A

In alveoli immediately beneath the pleura, usually in the distal airspaces of the lower part of the upper lobe or the upper part of the lower lobe

This specific location is crucial for understanding the pathophysiology of primary tuberculosis.

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17
Q

What are the initial symptoms of the turbeclousis infection?

A

Slight abnormalities, slight malaise, and mild fever

These symptoms indicate a low-level response to the infection.

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18
Q

What happens to MTB organisms during the first few weeks after infection?

A

They multiply freely and enter the bloodstream and lymphatics, disseminating to other parts of the body

This occurs due to the lack of sensitized CD4+ T-cells.

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19
Q

What is the role of sensitized CD4+ T-cells in the initial infection?

A

They are lacking, allowing MTB organisms to multiply freely

This absence contributes to the spread of the infection.

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20
Q

Fill in the blank: The initial infection may cause _______ abnormalities.

A

slight

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21
Q

True or False: The initial infection causes severe symptoms immediately.

A

False

The initial infection produces only slight symptoms.

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22
Q

What type of immunity is mainly responsible for the response to MTB?

A

Cell-mediated immunity (mainly by CD4+ T-cells)

MTB refers to Mycobacterium tuberculosis, the bacteria that causes tuberculosis.

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23
Q

How long does it take for cell-mediated immunity to develop against MTB?

A

3 to 6 weeks

This timeframe refers to the period for T-cell sensitization and immune response development.

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24
Q

What is the area of gray-white granulomatous inflammation in the lung called?

A

Ghon focus

The Ghon focus is characterized by a 1.0 - 1.5 cm area of inflammation.

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25
What typically occurs at the center of the Ghon focus tubercle?
Caseous necrosis ## Footnote Caseous necrosis is a type of tissue death that resembles cheese.
26
Where do tubercle MTB bacilli drain after infection?
Regional hilar lymph nodes ## Footnote Hilar lymph nodes are located at the root of the lungs.
27
True or False: The regional hilar lymph nodes often undergo caseation.
True ## Footnote Caseation refers to the formation of caseous necrosis in the lymph nodes.
28
Fill in the blank: The Ghon focus develops due to _______ to MTB.
T-cell sensitization and immune response ## Footnote This response leads to granulomatous inflammation.
29
What percentage of normal adults have development of cell-mediated immunity that controls MTB infection?
About 95% ## Footnote MTB refers to Mycobacterium tuberculosis, the bacterium that causes tuberculosis.
30
What is the outcome of the cellular immune response to MTB infection?
It controls the multiplication of MTB but does not eliminate it.
31
What happens to the lesions of the Ghon complex in the lung and lymph nodes?
They heal, undergo shrinkage, fibrous scarring, and radiologically detectable calcification.
32
What is the term for the radiologically detectable calcification that occurs in the Ghon complex?
Ranke complex.
33
What develops in other organs despite the seeding of MTB?
No lesions (granulomas) develop.
34
Fill in the blank: The cellular immune response to MTB infection is sufficient to control the multiplication of _______.
MTB.
35
True or False: In most adults, the cellular immune response completely eliminates MTB infection.
False.
36
What happens to most of the MTB organisms?
Most of the MTB organisms die, but a few remain viable but dormant for years.
37
What host responses are important in controlling latent MTB infection?
Host responses include: * Macrophage activation * Maintenance of granuloma structure * CD4+ T-cells * CD8+ T-cells * IFN-gamma * TNF-alpha
38
What can cause dormant MTB organisms to reactivate?
A decrease in immune function, such as immunocompromised states due to diseases like AIDS or from immunosuppressive drugs.
39
What is the term for the serious infection caused by reactivation of dormant MTB organisms?
Reactivation tuberculous infection.
40
Fill in the blank: Immune surveillance includes the activation of _______.
[macrophages].
41
True or False: All MTB organisms die when encountered by the host immune system.
False.
42
What is progressive primary tuberculosis?
A rarer course of TB where the immune response fails to control MTB bacilli multiplication.
43
In which population is progressive primary tuberculosis most common?
Common in children under 5 years of age and in adults with suppressed or defective immunity.
44
What is the percentage of normal adults that experience progressive primary TB?
Less than 10%.
45
What happens to the primary Ghon focus in progressive primary tuberculosis?
It enlarges rapidly, erodes the bronchial tree, and spreads to adjacent 'satellite' lesions.
46
What can the highly active lesions in progressive primary tuberculosis lead to?
They may seed the bloodstream with MTB bacilli, resulting in life-threatening dissemination.
47
What are the clinical manifestations of progressive primary tuberculosis?
Abrupt high fever, pleurisy with effusion, and lymphadenitis.
48
Fill in the blank: Progressive primary tuberculosis occurs in less than _______ of normal adults.
10%
49
True or False: Progressive primary tuberculosis is common in healthy adults.
False
50
What is secondary (cavitary) tuberculosis?
A condition that usually results from reactivation of dormant, endogenous tubercle bacilli in a sensitized patient who has had previous contact with the tubercle bacillus.
51
What can cause secondary tuberculosis aside from reactivation?
Reinfection with exogenous bacilli.
52
When can secondary tuberculosis develop after primary infection?
Any time after primary infection, even decades later.
53
What are the known precipitating factors for endogenous reactivation of dormant tuberculous foci?
Presence of an immunosuppressive disease (e.g., HIV/AIDS) or immunosuppressive drug therapy (e.g., corticosteroids).
54
True or False: The precipitating factors for secondary tuberculosis are well understood.
False
55
What is a nearly universal symptom of pulmonary tuberculosis?
Cough that initially is dry but progresses to purulent secretions and may include blood streaking or gross hemoptysis ## Footnote Cough is often the first noticeable symptom in TB patients.
56
What temperature range is common in patients with advancing pulmonary tuberculosis?
From subnormal to extreme elevations, with peaks as high as 104.0 to 105.8°F ## Footnote Fever typically occurs in the evening.
57
What type of sweating is typical in pulmonary tuberculosis?
Drenching night sweats ## Footnote Night sweats are a classic symptom often reported by TB patients.
58
List other common complaints associated with pulmonary tuberculosis.
* Malaise * Fatigue * Weight loss * Non-pleuritic chest pain * Dyspnea ## Footnote These symptoms can significantly affect the quality of life.
59
What are the early signs of pulmonary tuberculosis?
* Localized rales * Coarse rhonchi ## Footnote Rales and rhonchi are abnormal lung sounds that indicate respiratory distress.
60
What might cause wheezing and regionally diminished breath sounds in pulmonary tuberculosis?
Peri- or endobronchial airway compression ## Footnote This occurs when the airways are obstructed or compressed by the disease.
61
True or False: Signs of pulmonary tuberculosis are often limited until the disease is in advanced stages.
True ## Footnote Early stages may not present significant signs, making diagnosis challenging.
62
Fill in the blank: Classic symptoms of TB include cough, fever, ________, and fatigue.
drenching night sweats ## Footnote Night sweats can be a debilitating symptom for patients.
63
What percentage of patients may have a falsely negative tuberculin skin test (TST) at the time of tuberculosis diagnosis?
20 to 25% ## Footnote This indicates that a significant number of patients may not test positive despite having tuberculosis.
64
What common symptom do most patients with tuberculosis report?
Feeling 'feverish' ## Footnote This symptom may not always correspond with an actual fever.
65
True or False: A clinician should disregard the possibility of tuberculosis if a patient has a non-reactive tuberculin skin test.
False ## Footnote Clinicians should consider the diagnosis of TB even with a non-reactive TST.
66
What should a clinician consider when diagnosing tuberculosis despite a lack of fever?
Other typical features of tuberculosis ## Footnote This emphasizes the importance of comprehensive clinical assessment.
67
What are the common forms of oral lesions in tuberculosis?
Nodular, granular, ulcerated, or firm leukoplakic areas ## Footnote Oral lesions of tuberculosis are uncommon.
68
What do most oral lesions in tuberculosis represent?
Secondary infection from the initial pulmonary lesions.
69
What areas are usually involved in the oral manifestation of primary tuberculosis?
Gingiva, mucobuccal fold, areas of inflammation adjacent to teeth or in extraction sites ## Footnote These areas are commonly affected by primary tuberculosis in the oral cavity.
70
Where do secondary oral lesions of tuberculosis predominantly appear?
Tongue, palate, and lip ## Footnote Secondary lesions manifest in these specific regions of the mouth.
71
What is usually associated with primary oral lesions in tuberculosis?
Enlarged regional lymph nodes ## Footnote This is a common clinical finding in cases of primary oral tuberculosis.
72
What condition can tuberculous osteomyelitis affect in the oral cavity?
The jaws ## Footnote Tuberculous osteomyelitis can lead to complications in the jawbone.
73
How does tuberculous osteomyelitis appear radiographically?
As ill-defined areas of radiolucency ## Footnote This radiographic appearance is indicative of the underlying pathology.
74
What are the risk factors for primary TB infection?
* Urban populations * The homeless * Medically underserved, low-income populations * Migrant workers * Long-term residents of correctional institutions, nursing homes, and mental institutions * Close contact with infected individuals * Persons from countries with a high incidence of tuberculosis in Asia, Africa, and Latin America * Healthcare workers ## Footnote These populations are more susceptible to primary TB infection due to various social and environmental factors.
75
Which population is at the highest risk for progressive primary TB or reactivation TB?
Immunocompromised patients ## Footnote HIV infection is the most important risk factor for the development of TB.
76
List additional risk factors for progressive primary TB or reactivation TB.
* Intravenous drug users * Diabetes mellitus * Chronic renal failure * Leukemia * Lymphoma * Other malignancies * Malnutrition * Silicosis * Immunosuppressive drug therapy (e.g., corticosteroids, TNF-alpha antagonists, cytotoxic cancer chemotherapy) ## Footnote These conditions compromise the immune system, increasing susceptibility to TB.
77
True or False: Close contact with an infected individual is a risk factor for primary TB infection.
True ## Footnote Close contact can lead to transmission of the bacteria.
78
Fill in the blank: _______ has emerged as the most important risk factor for the development of TB.
HIV infection ## Footnote HIV significantly weakens the immune response, making individuals more susceptible to TB.
79
What is the definitive diagnosis for MTB?
Recovery of MTB from cultures or identification of the organism by other methods ## Footnote MTB stands for Mycobacterium tuberculosis, the causative agent of tuberculosis.
80
What is required for a positive AFB smear?
Very high organism load and expertise to read the stained sample ## Footnote AFB stands for acid-fast bacilli.
81
What are traditional mycobacterial cultures on solid media?
Löwenstein-Jensen and Middlebrook 7H11 ## Footnote These cultures require 2 to 8 weeks for growth and identification.
82
What is the advantage of newer technologies in MTB identification?
MTB identification within 24 hours ## Footnote This is significantly faster than traditional culture methods.
83
What do molecular diagnostics use to identify species of clinically significant isolates?
Probes specific for mycobacterial ribosomal RNA ## Footnote These probes are used after recovery of the organism.
84
What technique can detect MTB-specific DNA sequences?
Polymerase chain reaction (PCR) amplification ## Footnote PCR can detect small numbers of mycobacteria in clinical specimens.
85
What does NAAT-TB stand for?
Nucleic acid amplification testing for tuberculosis ## Footnote NAAT-TB identifies MTB within 24 hours of sputum processing.
86
What is a limitation of NAAT-TB in smear-negative patients?
Low negative predictive value ## Footnote This means that a negative result may not reliably rule out the disease.
87
What does NAAT-R identify?
Antibiotic resistance markers ## Footnote NAAT-R allows rapid identification of primary drug resistance.
88
In which patients is NAAT-R indicated?
* Those treated previously for tuberculosis * Those born (or lived for more than 1 year) in a country with moderate tuberculosis incidence or high incidence of multiple drug-resistant isolates
89
What is the time frame for NAAT-R to identify primary drug resistance?
24 to 48 hours ## Footnote This rapid identification can guide treatment decisions.
90
What analysis is used for DNA fingerprinting of MTB?
Restriction fragment length polymorphism (RFLP) analysis ## Footnote RFLP analysis helps identify individual strains of Mycobacterium tuberculosis (MTB) and can reveal transmission from person to person.
91
When is antibiotic susceptibility testing (AST) considered routine for MTB?
For the first isolate of MTB, when treatment regimen is failing, and when sputum cultures remain positive after 2 months of therapy ## Footnote Routine AST is critical for effective TB management.
92
What should patients suspected of having TB submit for diagnosis?
Sputum for AFB smear and culture ## Footnote AFB stands for acid-fast bacilli, which are indicative of Mycobacterium tuberculosis.
93
When should sputum be collected from patients suspected of TB?
In the early morning on 3 consecutive days ## Footnote This timing increases the likelihood of detecting MTB due to higher bacterial loads in early morning samples.
94
How often can sputum be collected from hospitalized patients?
Every 8 hours ## Footnote Frequent collection can improve diagnostic accuracy in a hospital setting.
95
What alternative method can produce a good specimen in children suspected of TB?
Early-morning gastric aspirate ## Footnote Children often have difficulty producing sputum, making this method useful.
96
What should be attempted if a patient cannot produce sputum spontaneously?
Sputum induction with hypertonic saline ## Footnote This method can stimulate coughing and aid in specimen collection.
97
What procedure can be used if other attempts at obtaining sputum specimens are unsuccessful?
Fiberoptic bronchoscopy with bronchoalveolar lavage ## Footnote This invasive procedure allows for direct sampling from the lungs.
98
What is the Ziehl-Neelsen staining process used for?
Staining sputum to detect mycobacteria ## Footnote This method is specific but requires a high bacterial load for reliable detection.
99
How long does the Ziehl-Neelsen staining process take?
Approximately 10 minutes ## Footnote Quick processing is essential for timely diagnosis.
100
What is the sensitivity of Ziehl-Neelsen staining for detecting mycobacteria?
Relatively insensitive; requires at least 10,000 bacilli per mL ## Footnote This limitation can lead to false negatives in low-bacterial-load samples.
101
What stain do most clinical laboratories currently use instead of Ziehl-Neelsen?
Auramine-rhodamine fluorescent stain (auramine O) ## Footnote This stain is more sensitive for detecting mycobacteria.
102
What are the radiographic abnormalities in primary tuberculosis?
* Small homogeneous infiltrates (usually in the upper lobe) * Hilar and paratracheal lymph node enlargement * Segmental atelectasis * Pleural effusion may be present, especially in adults * Ghon and Ranke complexes are detected as residual evidence
103
Where are small homogeneous infiltrates typically found in primary tuberculosis?
Usually in the upper lobe
104
What type of lymph node enlargement is associated with primary tuberculosis?
Hilar and paratracheal lymph node enlargement
105
What is segmental atelectasis?
A condition where a segment of the lung collapses
106
True or False: Pleural effusion is rarely present in adults with primary tuberculosis.
False
107
What are Ghon and Ranke complexes?
* Ghon complex: calcified primary focus * Ranke complex: calcified primary focus and calcified hilar lymph node
108
In which type of patients are Ghon and Ranke complexes detected?
In a minority of patients
109
Fill in the blank: Pleural effusion may be present, especially in adults, sometimes as the sole radiographic ______ in primary tuberculosis.
abnormality
110
What are the radiographic abnormalities in reactivation tuberculosis?
Fibrocavitary apical disease, nodules, pneumonic infiltrates ## Footnote These abnormalities are key indicators in diagnosing reactivation tuberculosis.
111
Where is the usual location of radiographic findings in reactivation tuberculosis?
Apical or posterior segments of the upper lobes, superior segments of the lower lobes ## Footnote These locations are critical for identifying the disease in imaging studies.
112
What percentage of patients may present with radiographic evidence of disease in locations other than the usual sites?
30% ## Footnote This is particularly noted in elderly patients.
113
True or False: Reactivation tuberculosis only presents in the upper lobes of the lungs.
False ## Footnote Though the upper lobes are common sites, other locations can also show disease.
114
What does the tuberculin skin test (TST) identify?
Individuals who have been infected at some time with MTB ## Footnote MTB refers to Mycobacterium tuberculosis, the bacteria that causes tuberculosis.
115
What does the TST not distinguish between?
Current disease and past infection
116
What is the standard test for establishing exposure to tuberculosis?
Mantoux (PPD) test
117
What is the purpose of the multiple puncture test (tine test)?
Used for population screening
118
How much purified protein derivative (PPD-S) is injected in the Mantoux test?
0.1 mL
119
How many tuberculin units (TU) does the PPD-S contain in the Mantoux test?
5 tuberculin units (TU)
120
What gauge needle is used for the Mantoux test?
27-gauge needle
121
Where is the PPD-S injected in the Mantoux test?
Intradermally on the volar surface of the forearm
122
When should the transverse width of induration be recorded after the Mantoux test?
After 48 to 72 hours
123
Does a negative reaction in the Mantoux test rule out the diagnosis of tuberculosis?
No
124
What is the reaction size that indicates a positive Mantoux test for HIV-positive persons?
≥ 5 mm ## Footnote This group also includes recent contacts of individuals with active tuberculosis, persons with fibrotic changes on chest films, and patients with organ transplants or other immunosuppressed patients.
125
List the groups that are considered positive for a Mantoux test reaction of ≥ 5 mm.
* HIV-positive persons * Recent contacts of individuals with active tuberculosis * Persons with fibrotic changes on chest films * Patients with organ transplants and other immunosuppressed patients
126
What is the reaction size that indicates a positive Mantoux test for recent immigrants from high-prevalence countries?
≥ 10 mm ## Footnote This includes immigrants from Asia, Africa, and Latin America.
127
Identify the groups that are considered positive for a Mantoux test reaction of ≥ 10 mm.
* Recent immigrants (< 5 years) from high-prevalence countries * HIV-negative injection drug users * Mycobacteriology laboratory personnel * Residents and employees in high-risk congregate settings * Persons with medical conditions increasing TB risk * Children younger than 4 years or exposed to high-risk adults
128
What are some of the medical conditions that increase the risk of tuberculosis for a Mantoux test reaction of ≥ 10 mm?
* Gastrectomy * 10% below ideal body weight * Jejunoileal bypass * Diabetes mellitus * Silicosis * Advanced chronic kidney disease * Some hematologic disorders (e.g., leukemias, lymphomas) * Specific malignancies (e.g., carcinoma of head or neck and lung)
129
What is the reaction size that indicates a positive Mantoux test for all other persons with no risk factors?
≥ 15 mm ## Footnote This indicates that these individuals do not have any identified risk factors for tuberculosis.
130
True or False: A Mantoux skin test reaction is considered positive if the transverse diameter of the indurated area reaches the size required for the specific group.
True ## Footnote All other reactions are considered negative.
131
Fill in the blank: A Mantoux skin test reaction is considered positive if the transverse diameter of the indurated area reaches the size required for the _______.
[specific group]
132
What causes false-positive reactions in tuberculin skin tests?
Infection with nontuberculous mycobacteria, serial TB testing, or BCG vaccination ## Footnote BCG stands for bacillus Calmette-Guerin, a vaccine for tuberculosis.
133
What are some reasons for false-negative reactions in tuberculin skin tests?
Recent infection, malnutrition, old age, immunologic disorders, lymphoreticular malignancies, corticosteroid therapy, chronic renal failure, virus vaccinations, fulminant tuberculosis, improper testing technique ## Footnote Patients with AIDS are often anergic, meaning they do not react to the test.
134
How long does BCG vaccination render the PPD test positive?
At least 1 year ## Footnote After this period, interpretation of the PPD skin test should be the same as for those who have not had BCG.
135
What should be done if a patient is likely to be anergic during tuberculin testing?
An anergy skin test panel should be placed ## Footnote This helps assess whether the patient has an immune response.
136
What is the booster effect in tuberculin testing?
Re-stimulation of remote hypersensitivity that has deteriorated ## Footnote This can result in a positive test after a previous negative one.
137
When does the booster effect develop after the first tuberculin injection?
Within several days ## Footnote It may persist and lead to interpretative problems in test results.
138
How can the problem of interpretative confusion from booster effects be circumvented?
Retesting non-reactors 1 week later ## Footnote A positive second test indicates boosting rather than recent infection.
139
In which groups is tuberculin positivity only after boosting more common?
Older persons, persons infected with nontuberculous mycobacteria, BCG vaccine recipients ## Footnote Those with a booster response are considered at low risk.
140
True or False: Tuberculin can sensitize an uninfected person.
False ## Footnote Tuberculin cannot sensitize an uninfected person.
141
What are Interferon Gamma Release Assays (IGRAs)?
IGRAs are tests developed for the detection of MTB infection by measuring IFN-γ release in response to MTB antigens. ## Footnote Interferon gamma (IFN-γ) plays a critical role in regulating cell-mediated immune responses to MTB infection.
142
What was the only practical immunologic test for MTB infection approved in the US before 2001?
The tuberculin skin test was the only practical and commercially available immunologic test for MTB infection approved in the US before 2001. ## Footnote This test was widely used for many years until the development of IGRAs.
143
How do IGRAs detect sensitization to MTB?
IGRAs detect sensitization to MTB by measuring IFN-γ release in response to antigens representing MTB. ## Footnote This method allows for a more specific detection of MTB infection compared to traditional tests.
144
What is the QuantiFERON-TB test (QFT)?
The first IGRA approved by the FDA for diagnosing MTB infection.
145
What type of sample does the QuantiFERON-TB test utilize?
A whole blood sample from the patient.
146
What does the QuantiFERON-TB test detect?
The presence of IFN-γ secreted from stimulated T-cells previously exposed to MTB.
147
When was the QuantiFERON-TB Gold In-Tube (QFT-GIT) test approved by the FDA?
In 2007.
148
How quickly are results usually obtained from the QuantiFERON-TB test?
Within 24 hours.
149
What is another IGRA available for detection of TB?
The T-Spot TB test.
150
In what situations can an IGRA be used instead of a TST?
In all situations recommended by the CDC for tuberculin skin testing.
151
What is one situation where an IGRA is preferable to a TST?
For testing persons from groups with low rates of returning for TST reading.
152
Why might the use of an IGRA be beneficial for homeless persons and drug-users?
It can increase test completion rates.
153
In which population is an IGRA preferred due to increased diagnostic specificity?
Persons who have received BCG (vaccine or for cancer therapy).
154
Fill in the blank: The QuantiFERON-TB test detects IFN-γ secreted from _______.
[stimulated T-cells]
155
True or False: The QuantiFERON-TB test requires more than 24 hours for results.
False.
156
List two groups for whom an IGRA might be preferred over a TST.
* Homeless persons * Drug-users
157
What is the expected outcome of using IGRAs in populations that have received BCG?
Increased diagnostic specificity and improved acceptance of treatment.
158
What should be done with positive IGRA results during routine screening?
Positive results should be repeated routinely due to a high rate of false-positive results. ## Footnote IGRA stands for Interferon Gamma Release Assay.
159
What novel antigen is used in the Elispot plus assay for TB?
RV3879c. ## Footnote The Elispot plus assay is used in combination with tuberculin testing.
160
What is the purpose of the Xpert MTB/RIF test?
It provides sensitive detection of TB and rifampin resistance directly from untreated sputum in less than 2 hours. ## Footnote Xpert MTB/RIF is an automated molecular test.
161
What is the Hain Line Probe Assay used for?
It is used to assess resistance to the primary drugs used to treat TB. ## Footnote The assay helps in rapid determination of drug resistance.
162
What is the significance of combining Elispot plus with tuberculin testing?
It enables rapid exclusion of active infection in patients with moderate to high pretest probability of TB. ## Footnote This combination improves diagnostic accuracy.
163
Fill in the blank: The Xpert MTB/RIF test can detect TB and _______ resistance.
rifampin. ## Footnote Rifampin is one of the primary drugs used to treat tuberculosis.
164
True or False: The Xpert MTB/RIF test takes more than 2 hours to provide results.
False. ## Footnote The test provides results in less than 2 hours.
165
What is the preferred duration of treatment for previously untreated pulmonary tuberculosis?
6-month regimen ## Footnote A 9-month regimen is also effective but less preferred.
166
What type of therapy is recommended for all patients with active TB?
Supervised directly observed therapy (DOT) ## Footnote Mandatory for patients with high likelihood of loss to follow-up.
167
What are the two phases of active TB treatment?
Intensive phase and continuation phase ## Footnote Treatment consists of these two distinct phases.
168
What is the 4-drug regimen used in the intensive treatment of TB?
Isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), and ethambutol (EMB) ## Footnote This regimen is started for initial empiric treatment.
169
What should be given with INH to prevent peripheral neuropathy?
Pyridoxine (vitamin B6, 25 mg/day) ## Footnote This is a preventive measure during treatment.
170
What happens during the continuation phase of TB treatment after 8 weeks?
Treatment is usually decreased to just INH and RIF ## Footnote This is dependent on MTB susceptibilities.
171
What factors influence the ultimate duration of TB therapy?
* Patient’s HIV status * Extent of TB disease * Antibiotic regimen used * Treatment response ## Footnote These factors determine how long the treatment will continue.
172
What specific pharmacologic therapy regimens exist for patients with HIV infection?
Active (or latent) TB treatment regimens ## Footnote Includes therapies tailored for those co-infected with HIV.
173
What does MDR-TB stand for?
Multidrug resistant TB ## Footnote Refers to TB that is resistant to both isoniazid and rifampin.
174
What characterizes XDR-TB?
Resistance to isoniazid, rifampin, at least one fluoroquinolone, and at least one injectable drug ## Footnote Injectable drugs include amikacin, kanamycin, or capreomycin.
175
Fill in the blank: TB that is resistant to both isoniazid and rifampin is known as _______.
MDR-TB
176
True or False: XDR-TB is resistant only to isoniazid and rifampin.
False
177
List the injectable drugs associated with XDR-TB resistance.
* Amikacin * Kanamycin * Capreomycin ## Footnote These drugs are critical in treatment regimens for XDR-TB.
178
What is Preventive Therapy (Chemoprophylaxis) for TB?
Treatment for patients infected with MTB but without active disease (latent TB)
179
What indicates a patient has latent TB?
A positive result on tuberculin skin testing or a positive interferon-gamma release assay (IGRA) result
180
When should therapy for latent TB be initiated?
Once active infection and disease are ruled out
181
What should be done if clinical suspicion for active tuberculosis is low?
Begin treatment with combination chemotherapy or defer treatment until additional data are available
182
How long can the deferral for treatment last to clarify the situation?
Usually within 2 months
183
Should treatment for latent tuberculosis infection be initiated if active tuberculosis has not been excluded?
No
184
What are the preferred regimens for latent TB according to the CDC (2020)?
* Isoniazid and rifapentine taken once a week for 3 months * Rifampin taken daily for 4 months
185
What is the purpose of surgical resection in patients with MDR-TB?
To reduce the bacillary burden in infected lungs
186
What are the surgical procedures considered for treating MDR-TB?
* Segmentectomy * Lobectomy * Pneumonectomy
187
Are pleurectomies commonly indicated for thick pleural peel in TB treatment?
No, they are rarely indicated
188
What complication has been observed during surgery for TB?
Intraoperative infection of uninvolved lung tissue
189
What are some complications associated with surgical treatment of TB?
* Usual perioperative complications * Recurrent disease * Bronchopleural fistulas
190
Fill in the blank: Surgical procedures for MDR-TB include segmentectomy, lobectomy, and _______.
Pneumonectomy
191
True or False: Pleurectomies are frequently performed for thick pleural peel in TB patients.
False
192
What does BCG stand for in the context of tuberculosis vaccines?
Bacillus Calmette-Guerin ## Footnote BCG is the original strain of bacterium used in the vaccine.
193
What is the primary age group that the BCG vaccine provides protection for?
Early childhood ## Footnote Immunity begins to wane as early as 3 months after administration.
194
When is BCG vaccination indicated in the United States?
When isoniazid chemoprophylaxis cannot be used
195
Who should BCG vaccination be considered for?
Tuberculin-negative persons, especially children, who are repeatedly exposed to untreated tuberculosis ## Footnote This applies to those who cannot receive standard preventive therapy.
196
Under what circumstances should a community consider BCG vaccination?
High rate of new infections despite aggressive treatment and surveillance programs
197
What is one effectiveness noted for BCG vaccination?
Reducing the risk of tuberculosis in selected populations
198
Fill in the blank: The BCG vaccine provides protection mostly until _______.
early childhood
199
True or False: Immunity from the BCG vaccine lasts indefinitely.
False
200
What is a key factor in considering BCG vaccination for individuals?
Repeated exposure to individuals with untreated tuberculosis
201
What is the risk of TB for individuals infected with HIV?
Increased risk for TB, beginning within the first year of HIV infection. ## Footnote This elevated risk is due to the immunocompromised state caused by HIV.
202
What effect does the initiation of antiretroviral therapy have on TB risk in HIV patients?
Decreases the risk of developing TB in these patients. ## Footnote Historical data supports the effectiveness of antiretroviral therapy in reducing TB incidence.
203
What testing is required for patients with TB?
Must be tested for HIV. ## Footnote This is important for managing co-infections and treatment strategies.
204
What periodic evaluation is needed for patients with HIV?
Periodic evaluation for TB with tuberculin skin testing and/or chest radiography. ## Footnote Regular monitoring is crucial for early detection of TB in HIV-positive patients.
205
What is the annual rate of developing active TB for HIV patients with a positive tuberculin skin test?
3-16% per year. ## Footnote This statistic highlights the significant risk of TB in this population.
206
How does TB presentation differ in patients with HIV?
More likely to have disseminated disease and less likely to have upper-lobe infiltrates or classic cavitary pulmonary disease. ## Footnote This reflects differences in immune response and disease progression.
207
What may patients with a CD4 count of less than 200/µL experience?
Mediastinal adenopathy with infiltrates. ## Footnote This finding is associated with advanced immunosuppression.
208
How do treatment regimens for TB in HIV-positive patients compare to those in HIV-negative patients?
Similar, but dose adjustments may be necessary. ## Footnote Treatment must account for drug interactions and the patient's immune status.
209
What is a significant difference in TB treatment for HIV patients on protease inhibitors?
Avoidance of rifampin. ## Footnote Rifabutin may be used instead of rifampin to prevent drug interactions.
210
What is a paradoxical response in patients with HIV starting antiretroviral therapy?
A stronger immune response to MTB leading to clinical findings such as fever, worsening pulmonary infiltrates, and lymphadenopathy. ## Footnote This response can complicate the management of TB in HIV-positive patients.
211
What is the prognosis for properly treated patients with tuberculosis?
Almost all are cured ## Footnote Patients who complete therapy have a relapse rate of only 0% to 4% within the first 2 years.
212
What is the relapse rate for tuberculosis after appropriate completed therapy?
0% to 4% ## Footnote This relapse occurs within the first 2 years after completion of therapy.
213
What is the main cause of treatment failure in tuberculosis?
Noncompliance ## Footnote Ensuring patient adherence to treatment is crucial for success.
214
Is re-treatment usually necessary for tuberculosis patients after DOT?
No ## Footnote Re-treatment is typically unnecessary, especially after Directly Observed Therapy (DOT).
215
Fill in the blank: The relapse rate for tuberculosis patients following appropriate treatment is _______.
0% to 4%
216
What is the primary goal of dental evaluation in patients with a history of or active TB?
To identify patients with active TB.
217
What do CDC guidelines state about the risk for dental health care workers regarding exposure to active TB?
The overall risk is probably quite low.
218
Why will no patient with active tuberculosis be treated at the ULSD?
Due to the special treatment facilities required, such as TB isolation rooms.
219
Do standard face masks protect against TB transmission?
No, they do not.
220
What should be assessed during the initial medical histories and periodic updates for patients regarding TB?
History of TB and symptoms suggestive of active TB.
221
What signs and symptoms suggestive of TB should patients be questioned about?
* Fever * Chills * Night sweats * Bloody sputum production * Weight loss
222
What information should be recorded regarding prior tuberculin skin tests (TSTs)?
Dates and results of prior TSTs.
223
What should patients with a history of TB be asked about?
* Degree of disease involvement * Type and duration of therapy received * Current status of disease activity
224
What is necessary to confirm information about a patient's TB history?
A medical consult with the patient's physician.
225
What is required for any patient who reports a history of active or suspected TB?
Medical consultation ## Footnote TB stands for Tuberculosis, a serious infectious disease.
226
What should be done if a patient has been exposed to a person with TB?
Medical consultation ## Footnote Exposure can lead to potential infection and requires evaluation.
227
Which patients require medical consultation due to HIV status?
Any HIV-positive patient ## Footnote HIV-positive individuals are at higher risk for various infections.
228
What category of risk includes patients with active, AFB-positive sputum tuberculosis?
High Risk (infectious / active disease) ## Footnote This category also includes patients with oral manifestations of tuberculosis.
229
Which patients are categorized as Moderate Risk for dental treatment?
Patients with: * positive tuberculin skin tests but no evidence of active disease * chest x-ray findings suggestive of prior tuberculosis involvement but no evidence of active disease * inadequately treated tuberculosis but no evidence of active disease ## Footnote Moderate Risk patients are infected but not infectious.
230
What defines Low Risk in dental treatment for tuberculosis?
Patients with: * known tuberculosis who have been adequately treated with no evidence of active disease * history of exposure to tuberculosis but negative skin tests and no evidence of disease ## Footnote These patients show no current active disease.
231
True or False: Patients with symptoms of active tuberculosis are considered Low Risk.
False ## Footnote Such patients fall under the High Risk category.
232
Fill in the blank: Patients with ___________ but no evidence of active disease are categorized as Moderate Risk.
positive tuberculin skin tests
233
What is the recommended treatment setting for patients with clinically active sputum-positive tuberculosis?
Hospital setting with appropriate isolation
234
What personal protective equipment should be used when treating patients with clinically active tuberculosis?
NIOSH N95 respirators, face shield, gloves, gown
235
What environmental controls are necessary in the treatment of patients with clinically active tuberculosis?
High-efficiency particulate air filters, UV-germicidal irradiation, negative room pressure
236
What type of dental treatment is recommended for patients with clinically active sputum-positive tuberculosis?
Urgent (emergency) care only
237
After how many weeks of chemotherapy can a tuberculosis patient be treated on an outpatient basis?
Several weeks
238
What must be confirmed by a physician before a tuberculosis patient can be treated on an outpatient basis?
Noninfectious status and lack of complicating factors
239
Fill in the blank: Patients with recently diagnosed clinically active tuberculosis and AFB-positive sputum cultures should not be treated on an _______.
outpatient basis
240
True or False: Dental treatment for tuberculosis patients should include routine care immediately after diagnosis.
False
241
What is the role of ventilation systems in the treatment of tuberculosis patients?
To maintain negative room pressure
242
What is the likelihood of infection with multidrug-resistant TB for a patient to be considered noninfectious?
Negligible likelihood of infection with multidrug-resistant TB ## Footnote This indicates that the patient is not likely to transmit a resistant strain of TB.
243
How long must a patient have received standard multidrug anti-TB therapy to be considered noninfectious?
At least 2 to 3 weeks ## Footnote This duration is critical for the therapy to take effect and reduce infectiousness.
244
What must a patient demonstrate to be considered noninfectious regarding their treatment?
Demonstrated compliance with treatment ## Footnote Compliance ensures the effectiveness of the therapy and reduces the risk of transmission.
245
What clinical sign indicates a patient with pulmonary TB may be noninfectious?
Demonstrated clinical improvement ## Footnote Clinical improvement suggests a positive response to treatment.
246
How many consecutive AFB-negative morning sputum specimens are required for a patient to be considered noninfectious?
3 consecutive AFB-negative morning sputum specimens ## Footnote AFB-negative results indicate a reduced likelihood of transmission.
247
What must be done regarding close contacts of a patient with pulmonary TB for the patient to be considered noninfectious?
All close contacts of the patient have been identified, evaluated, advised and, if indicated, started on treatment for latent TB infection ## Footnote This ensures that other individuals at risk are managed appropriately.
248
What is the typical treatment setting for a child with active tuberculosis receiving chemotherapy?
Outpatient ## Footnote Bacilli are found only rarely in the sputum of young children.
249
When is a child with tuberculosis considered noninfectious?
When a positive sputum culture has not been obtained ## Footnote This should be verified with the physician.
250
What are the reasons a child with tuberculosis is considered noninfectious?
* Rarity of cavitary disease in children * Inability to cough up sputum effectively
251
What is the general age guideline for treating children with tuberculosis?
Under the age of 6 years can be confidently treated ## Footnote Over the age of 6, some degree of concern may exist.
252
Who should be consulted before beginning treatment for a child with tuberculosis?
The physician
253
What is a greater concern when treating a child with tuberculosis?
Family contacts of the patient
254
What should family members who have had contact with the child provide?
History of skin testing and chest radiograph
255
What should be done if assurances of family members' health are not obtained?
Contact the physician or health department
256
Fill in the blank: Bacilli are found only _______ in the sputum of young children.
rarely
257
What should be done before treatment?
Consult with physician before treatment ## Footnote This ensures that the treatment plan is appropriate for the patient's condition.
258
What is the protocol for urgent care when a contained facility is not available?
Palliate urgent problems with medication ## Footnote Medication should be used to manage urgent issues until proper facilities are accessible.
259
Where should urgent care requiring the use of a handpiece for patients over 6 years be performed?
Only in a hospital setting with isolation, sterilization, and special ventilation ## Footnote This is to ensure the safety and health of both the patient and healthcare providers.
260
What is the treatment protocol for patients under 6 years old?
Treat as normal patient after consultation with physician to verify status ## Footnote This allows for appropriate treatment without the concerns of infection.
261
When can a patient be treated as a normal patient after being infectious?
When the patient has become non-infectious as verified by physician ## Footnote Verification is crucial to ensure the safety of treatment.
262
What is the likelihood of relapse in patients with a past history of tuberculosis who received adequate treatment?
Relapse is rare in patients who have received adequate treatment for the initial infection. ## Footnote Adequate treatment significantly reduces the risk of relapse.
263
What factors increase the risk of tuberculosis relapse?
Patients who have not received adequate treatment and those who are immunosuppressed. ## Footnote Immunosuppressed individuals have a higher risk due to a weakened immune response.
264
What should dentists obtain from patients with a past history of tuberculosis?
A medical history including diagnosis, dates of treatment, and type of treatment. ## Footnote This information is crucial for assessing the patient's current health status.
265
What follow-up measures should be taken for patients with a history of tuberculosis?
Periodic physical examinations and chest radiographs to check for evidence of reactivation of the disease. ## Footnote Regular check-ups help in early detection of any complications.
266
When is it advisable to consult a physician for patients with a past history of tuberculosis?
When verifying the current status of the patient. ## Footnote Physician consultation ensures that any active disease is ruled out.
267
Under what conditions can treatment be rendered normally for patients with a past history of tuberculosis?
If the patient is found to be free of active disease and immunosuppression. ## Footnote Normal treatment protocols can be followed in these cases.
268
What is important to conduct with patients who have a past history of tuberculosis?
A good review of systems. ## Footnote This helps in identifying any potential issues that may require further investigation.
269
What should be done if questionable signs or symptoms are present in patients with a history of tuberculosis?
Referral to a physician is indicated. ## Footnote This ensures that any potential complications are addressed promptly.
270
What is the first step when approaching a patient?
Approach patient with caution and obtain a good history of disease and its treatment duration ## Footnote A thorough review of systems is mandatory.
271
What should a patient provide regarding their medical history?
History of periodic chest radiographs and physical examination to rule out reactivation or relapse ## Footnote This is essential for assessing the patient's current health status.
272
Under what conditions should treatment be postponed?
Treatment should be postponed if there is: * Questionable history of adequate treatment time * Lack of appropriate medical follow-up since recovery * Signs or symptoms of relapse ## Footnote Consulting with a physician is crucial in these situations.
273
What should be verified before treating a patient as normal?
Present status must be free of clinically active disease as outlined in Table 3 and verified by a physician ## Footnote This ensures that the patient is stable before proceeding with treatment.
274
What does a positive Tuberculin Test indicate?
A person has been infected with tuberculosis ## Footnote This indicates recent conversion to a positive skin test.
275
What evaluations should a patient with a positive Tuberculin Test undergo?
Physical examination and chest radiograph ## Footnote These evaluations are necessary to check for active disease.
276
What is the recommended prophylactic treatment for a patient without clinically active disease?
Isoniazid for 6 months to a year ## Footnote This regimen aims to prevent the development of clinical disease.
277
What should occur once a patient is confirmed to be free of clinically active disease?
They can be treated in a normal manner ## Footnote No special precautions are required after confirmation.
278
Fill in the blank: A regimen of prophylactic _______ may be started for 6 months to a year.
isoniazid
279
What symptoms suggestive of undiagnosed active TB should prompt a referral for medical evaluation?
Dry nonproductive cough, pleuritic chest pain, fatigue, fever, dyspnea, hemoptysis ## Footnote These symptoms indicate potential infectiousness and require urgent attention.
280
What precautions should patients with symptoms suggestive of TB take while in a facility?
Wear surgical masks and cover their mouths and noses when coughing or sneezing ## Footnote This helps to minimize the risk of transmission.
281
When should elective dental treatment be deferred for patients with TB symptoms?
Until a physician confirms that the patient does not have infectious TB ## Footnote Elective procedures should not occur if the patient is diagnosed with active TB.
282
What should be assumed if immediate dental treatment is necessary for a patient with TB symptoms?
Assume the patient may have active TB ## Footnote Treatment should follow precautions as outlined in the relevant guidelines.
283
What is the minimum duration of a cough that should prompt evaluation for TB?
Longer than 3 weeks ## Footnote Persistent cough, especially with other symptoms, is a significant indicator.
284
What other symptoms, in addition to a persistent cough, are compatible with active TB?
* Weight loss * Night sweats * Bloody sputum * Anorexia * Fever ## Footnote These symptoms can indicate a more serious underlying condition.
285
What should happen to an individual with a persistent cough and compatible symptoms until TB is excluded?
They should not return to the workplace ## Footnote This is crucial until a diagnosis is confirmed or treatment is initiated.
286
What is the protocol for staff members with a persistent cough and other TB symptoms?
They should be evaluated promptly for TB ## Footnote Early evaluation helps prevent the spread of infection.
omed pt 2
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