Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

2025 PHPM Royal College Study - based on AN Summary Notes > CD - tuberculosis - part 1 > Flashcards

CD - tuberculosis - part 1 Flashcards

You may prefer our related Brainscape-certified flashcards:
Royal College: Emergency Medicine flashcards
1
Q

what is the agent for TB (1)

A

1- mycobacterium tuberculosis complex (MTC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the epidemiology of TB in Canada (2)

A

1- incidence rate between 4-5 individuals per 100 000 population as per 2022 standards
2- mostly amongst Indigenous and foreign-born populations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are risk factors for acquiring TB - (SDoH - 3;
close contact/facilities- 4;
int’l- 1) (8)

A

1- precariously housed
2- indigenous populations
3- persons who inject drugs
4- residents of LTC
5- inmates at correctional facilities
6- healthcare workers - HCW
7- close contacts of an active case of pulmonary TB
8- immigrants from countries with high incidence (Afghan, China, India, Pakistan, Philipp, Viet)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the reservoir for TB (2)

A

1- mostly humans
2- rarely, other primates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the reservoir for M. Bovis? (2)

A

1- cattle and some other animals
2- M. bovis is largely eradicated via pasteurization of milk and tuberculin testing of cattle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the mode of transmission for TB (2)

A

1- airborne
2- via inhalation of bacilli-containing droplet nuclei that reach alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what factors increase the probability of TB transmission?*
(‘testing’- 2
‘symptoms’- 1
‘anatomy’- 2
‘environment - person/place/time’- 3)
(8)

*was on practice exam

A

1- bacterial burden
2- delays in diagnosis and/or effective treatment
3- amount/severity of cough
4- pulmonary TB with cavitary or upper lung zone disease
5- laryngeal TB > pulmonary TB
6- duration of exposure to case (time)
7- (physical) proximity to source case (person)
8- crowding and poorer room ventilation (place)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe the ‘bacterial burden’ factor increasing TB transmission (1)

A

1- smear-positive/culture-positive disease is more transmissible than smear-neg/culture-neg disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe the ‘laryngeal TB > pulm TB’ factor increasing TB transmission (1)

A

1- laryngeal TB symptom of hoarseness is linked with inflammation/ulceration of vocal cords, which is MORE contagious than pulm TB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the incubation period for TB (1)

A

1-
2-10 weeks up to decades

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the period of communicability for TB (1abc)

A

1- from first discharge of viable bacilli in sputum (active pulm TB disease) up to:
1a- receipt of 2-4 weeks of antibiotics +
1b- smear-neg x3 +
1c- clinically improving

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

are young children with TB infectious? (2)

A

1- no- younger children with TB are rarely infectious
2- because they have few bacilli and often no sputum production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the clinical presentation of pulmonary TB (4)

A

1- chronic cough >3 weeks, from non-productive to productive
2- sputum sometimes with hemoptysis
3- chest pain
4- shortness of breath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the presentation of systemic TB symptoms (B symptoms) (4)

A

1- fever
2- nightsweats
3- weight loss
4- fatigue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are potential sites for extra-pulmonary TB (5 examples)

A

1- brain
2- spine
3- bones
4- kidney
5- lymph nodes

could affect other organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is an example presentation of extra-pulmonary TB (1)

A

1- depends on site affected (e.g. spine TB can have back pain)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

is non-respiratory (i.e. non-pulm, non-throat) TB contagious? (1)

A

1- generally not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

of people infected with TB, what is the breakdown between those who stay LTBI and those who become active disease:
A: of total people infected
B: of all the people with LTBI

(4)

A

A: Of total people infected with TB:
1- ~5% will develop active tuberculosis disease within 18 to 24 months
2- about 95% will develop LTBI

B: Of this 95% LTBI people,
3- ~90% will never develop active TB (stay as LTBI)
4- ~5% will have reactivation TB and develop active disease at any point after initial infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the 2 types of tests that identify TB infection (LTBI) (2)

A

1- tuberculin skin test (TST)
2- Interferon gamma release assay (IGRA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the tuberculin skin test (TST) (1)

A

1- intradermal injection of purified protein derivative (PPD) from M. tuberculosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the expected reaction in a person after TST has been administered (2)

A

1- in someone who was previously infected and developed cell-mediated immunity to these antigens, a delayed hypersensitivity reaction occurs within 48 to 72 h
2- reaction will cause localized swelling/ induration of the skin at injection site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are contraindications to receiving TST (5)

A

1- those with previous positive blistering reaction at injection site
2- active TB disease
3- documented hx of adequate TB treatment
4- those with current major viral infections (e.g. measles, mumps, varicella)
5- those received live virus vaccine in past 4 weeks (increases likelihood of false negative)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is considered a positive result interpretation of a TST, read between 48-72h post-injection (3)

A

1- <5mm is generally negative
2- ≥5 mm may be positive in select populations (e.g. HIV, known contact with active TB case, immunosuppressed)
3- ≥10 mm is positive in any population considered low risk of disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

define TST conversion (2)

A

1- TST of 10mm or more when an earlier test was <5mm
2- TST conversion occurs within 3-8 weeks of exposure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

who should get a two-step TST (2)

A

1- health care workers, correctional workers, and other populations at increased risk of TB exposure
2- done if subsequent TSTs will be conducted at regular intervals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

why should the defined population group(s) get the two-step TST (2)

A

1- undergo two-step TST before an exposure to account for “booster effect”
2- i.e. a single TST may elicit little response but may stimulate anamnestic immune response so that a second TST given anytime from 1 week to 1 year later, will elicit a much greater response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

how often does two-step TST protocol need to be done (3)

A

1- needs to be performed and documented ONCE only
2- never needs to be repeated
3- any future TST can be one-step, regardless of duration since last TST

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

which populations have been seen to have the booster effect from TST testing (3)

A

1- people with remote TB infection e.g. older adults
2- those with sensitivity to non-tuberculous mycobacterial antigens
3- those with prior BCG vaccination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what is the likelihood that a greater reaction to a second TST test is due to actual infection, if there has not been a TB exposure? (1)

A

1- in absence of an exposure, the likelihood that the greater reaction to the second test indicates true infection, is LOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

why is it important to make note of the booster effect with TST testing (2)

A

1- this booster effect is important to detect as it can be confused with new infection if the second test is only performed following exposure to a person with infectious pulmonary TB (I.e. false positive)
2- i.e. if second test was performed w/o exposure, it would still be positive and therefore is just the booster effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is the interferon gamma release assay (IGRA) (2)

A

1- an in-vitro blood test of cell-mediated immune response
2- they detect interferon-gamma released by T cells following stimulation by M. tuberculosis-specific antigens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is the goal of LTBI diagnosis (1)

A

1- to identify those at increased risk of developing active TB disease and therefore would benefit from tuberculosis preventive treatment (TPT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

which of TST and/or IGRA can be used for LTBI testing? general (2)

A

1- both can be used generally when testing for LTBI is needed
2- however there are circumstances where one is preferred over the other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

when is IGRA the preferred test for LTBI (4)

A

1- person received BCG vaccine after 1yo or received multiple BCG vaccine doses
2- personnel trained to administer/read TST are not available
3- person is unlikely or unable to return to have TST read
4- TST is contraindicated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

when is TST the preferred test for LTBI (1 + 2 examples)

A

1- TST preferred when there is a plan to repeat the test later
2- e.g. serial testing in contact investigation
3- e.g. serial testing of HCW or other populations with potential for ongoing exposure

36
Q

when can both TST and IGRA be used sequentially for LTBI testing? (2)

A

1- if either TST or IGRA are negative, the other test can be done to increase sensitivity (snOUT), if risk of infection/progression to active disease is high
2- if initial TST is positive but risk of infection is low/risk of false positive is high with hx BCG, can do IGRA to increase specificity (spIN)

37
Q

in which circumstances is testing for LTBI NOT recommended? (4)

A

1- testing people who have low risk of infection and a low risk that they will progress to active TB if infected
2- active TB disease in adults and those 12+ old
3- routine/mass screening for LTBI outside contact investigations or occupational screening programs
4- monitoring response to active TB treatment

38
Q

what are the two testing components of diagnosing active TB disease (2)

A

1- Chest x-ray for screening
2- microbiology (acid fast bacilli smear, and culture, or NAAT) for confirmation

39
Q

what CXR findings are indicative of active TB disease (3)

A

1- upper lobe infiltrates
2- lung volume loss
3- +/- cavitation

40
Q

why is CXR alone not diagnostic for active TB (1)

A

1- because CXR findings by themselves are not specific to TB, and therefore the test has low specificity (spIN)

41
Q

how many samples should be collected for AFB smear and culture? (1)

A

1- at least 3 sputum samples (induced or spontaneous)

42
Q

when, and how far apart should samples should be collected for AFB smear and culture? (2)

A

1- collect all samples on the same day to improve convenience for patients
2- collect samples minimum of 1 hour apart

43
Q

what kind of sample concentration should lab testing for AFB smear microscopy be done (1)

A

1- testing should be done on concentrated samples

44
Q

what kind of microscopy should be done for AFB smear (1)

A

1- fluorescent microscopy, to maximize sensitivity

45
Q

when should sputum TB mycobacterial culture be performed (1)

A

1- with every sputum sample, alongside AFB smear

46
Q

how long does it take for TB mycobacterial culture results to arrive (1)

A

1- 2-8 weeks

47
Q

how does nucleic acid amplification tests (NAAT) results compare with TB culture results in terms of turnaround time (1)

A

1- NAAT results are much faster than conventional culture

48
Q

is NAAT as a test highly sensitive or specific, and in what case (3)

A

1- sensitive
2- NAAT is more sensitive in smear-positive samples
3- negative NAAT alone should not be used to r/o TB disease

49
Q

how often should NAAT be done as part of active TB diagnosis (1)

A

1- at least one AFB+ respiratory sample should have NAAT done on it, in all new smear-positive patients

50
Q

On what kind of culture sample should phenotypic (culture) drug susceptibility testing be done as part of active TB diagnosis? (1)

A

1- phenotypic DST should be done routinely for all first-positive-culture isolates obtained from a new TB case

51
Q

what tests are NOT recommended for diagnosing active TB disease (3)

A

1- IGRA
2- TST
3- serologic antibody-based tests

52
Q

what are the 2 recommended regimens for treating LTBI, i.e. tuberculosis preventive treatment (TPT) (2)

A

1- 3HP - once-weekly rifapentine + isoniazid for 3 months, OR
2- 4R - daily rifampin for 4 months

53
Q

what is the difference in administration of the first-line treatments for LTBI, 3HP and 4R (2)

A

1- 3HP needs to be directly observed (DOT)
2- 4R can be self-administered and not DOT

54
Q

is rifapentine licensed for use in TPT for LTBI in Canada? (1)

A

1- currently no; however it is on the ‘list of drugs for an urgent public health need’

55
Q

what is the second-line TPT regimen in Canada (1)

A

1- 9H - daily isoniazid for 9 months (take Vit B6 with each dose to prevent neuropathy)

56
Q

if a patient with LTBI takes other medications, what needs to be considered before starting TPT (1)

A

1- interactions between patients’ baseline medications and TPT meds must be considered

57
Q

TPT meds do have s/e; what must be considered in the patient-provider shared decision-making process in terms of starting TPT vs. not (1)

A

1- decision to use TPT should consider risk of tuberculosis preventive therapy (TPT) vs. risk of developing active TB disease

58
Q

can you use TPT in active TB disease (1)

A

1- NO - active TB disease must be excluded to use TPT

59
Q

what are alternative TPT regimens in Canada after 3HP, 4R and 9H (3)

A

1- 6H - daily isoniazid for 6 months
2- intermittent - twice-weekly isoniazid for 9 months
3- 3HR - daily isoniazid and rifampin for 3 months

60
Q

can pregnant patients receive TPT for LTBI? (1)

A

1- generally TPT should be deferred till after delivery, unless risk of TB reactivation is high

61
Q

If TPT is indicated, can the both first-line regimens for TPT be used during pregnancy? (2)

A

1- NO. Only recommended to use 4R (daily rifampin for 4 months)
2- 3HP (once-weekly isoniazid + rifapentine for 3 months) should be avoided

62
Q

how long should isoniazid-based TPT regimens be avoided in a pregnant person (1)

A

1- should avoid isoniazid-based TPT until 3 months postpartum

63
Q

if a pregnant person is a contact of a rifampin-resistant TB case and has a high reactivation risk, what is the TPT regimen option (1)

A

1- in this highly exceptional circumstance, isoniazid-based TPT can be an option

64
Q

TPT is given when there is a risk of conversion from LTBI to active disease.

What are very high risk factors for conversion to active TB? (4)

A

1- HIV/AIDS
2- child <18yo with recent TB exposure (contact)
3- adult >18yo with recent TB exposure (contact)
4- silicosis

65
Q

TPT is given when there is a risk of conversion from LTBI to active disease.

What are high risk factors for conversion to active TB? (5)

A

1- Stage 4/5 chronic kidney disease with or w/o dialysis
2- all transplant recipients
3- fibronodular disease
4- receiving immunosupressive drugs (e.g. TNF alpha inhibitors, steroids)
5- certain cancers

66
Q

TPT is given when there is a risk of conversion from LTBI to active disease.

What are moderate risk factors for conversion to active TB? (4)

A

1- granuloma on CXR
2- diabetes
3- heavy alcohol use (3+ drinks/d)
4- heavy tobacco use (at least 1 pack/d)

67
Q

TPT is given when there is a risk of conversion from LTBI to active disease.

Who is at low risk for conversion to active TB? (2)

A

1- general (adult) population with no known risk factors
2- positive two-step TST booster and no known risk factor

68
Q

what is directly observed treatment (DOT) for TB (1)

A

1- Comprehensive, patient-centred care to ensure 100% of prescribed doses are taken

69
Q

in what setting is DOT recommended to be based out of as per 8e Canadian TB stds (1)

A

1- community-based DOT (as opposed to clinic-based DOT)

70
Q

what are some potential indicators of TB treatment non-adherence that might necessitate DOT
(‘medical’- 3’
‘SDoH’- 2
‘host factors/behaviour’- 2)

(7)

A

1- Disease due to multidrug-resistant organisms
2- Major mental illnesses
3- Treatment failure or disease relapse
4- Injection drug use/other substance use
5- Homelessness or unstable housing
6- Previous non-adherence
7- Children and adolescent cases

71
Q

how many phases is treatment for active TB given in (2)

A

1- two phases
2- intensive phase and continuation phase

72
Q

what are the 4 objectives for treating active TB disease (4)

A

1- rapid killing of TB bacilli (bactericidal)
2- prevent emerging/worsening drug resistance
3- prevent relapse of disease
4- optimize long-term health with comprehensive care - linkage to services, mitigating social/econ vulnerabilities

73
Q

in the intensive phase of TB treatment, how many drugs are used and why (2)

A

1- 3-4 drugs are used, guided by drug susceptibility testing (DST) results
2- in order to rapidly kill TB organisms and prevent the selection of drug-resistant organisms

74
Q

what are the 4 drugs used to treat active TB in intensive phase - RIPE (4)

A

1- rifampin
2- isoniazid (+ pyridoxine to prevent neuropathy)
3- pyrazinamide
4- ethambutol

75
Q

how long should the intensive phase of active TB treatment last in drug-susceptible disease (1)

A

1- two (2) months

76
Q

during the intensive phase of active TB treatment, how often should drugs be dosed (1)

A

1- daily (no intermittent option)

77
Q

is there a daily maximum dose for rifampin (1)

A

1- NO (this is a change in the 8e Canadian TB stds)

78
Q

how long is the continuation phase for treatment of active TB? (1abc, 2)

A

1- duration varies based on:
1a- drug regimen
1b- adherence
1c- risk of relapse

2- typically 4 months

79
Q

in the continuation phase for treatment of active TB, how many drugs are used (1a), how often are they dosed (1b), and what is a c/i to the first dosing option (1c)

A

1a- minimum 2 drugs
1b- intermittent (thrice-weekly) under DOT option can be done, but daily is preferred
1c- intermittent dosing is c/i in those with HIV

80
Q

briefly describe rifampin (RMP) (active TB treatment) (4)

A

1- most important anti-TB drug
2- has good bactericidal activity
3- prevents acquired drug resistance
4- important in preventing disease relapse

81
Q

briefly describe isoniazid (INH) (active TB treatment) (3)

A

1- powerful bactericidal activity
2- effective in preventing emergence of resistance
3- peripheral neuropathy is common s/e so pyridoxine (Vit B6) is routinely added

82
Q

briefly describe pyrazinamide (PZA) (active TB treatment) (2)

A

1- bactericidal
2- only of benefit in first 2 months

83
Q

briefly describe ethambutol (EMB) (active TB treatment) (4)

A

1- least bactericidal
2- least effective in preventing relapse
3- but effectively prevents drug resistance
4- can be discontinued in continuation phase if DST fully susceptible to all first-line drugs

84
Q

what is the total duration of standard active TB treatment regimen in drug-susceptible cases (intensive + continuation phases) (1)

A

1- standard duration is 6 months - 2 (intensive) + 4 (continuation)

85
Q

what is the preferred treatment regimen for suspected drug-susceptible active TB (2)

A

1- INH + RMP + PZA + EMB daily (intensive phase, first 2 months) - RIPE
2- INH + RMP + EMB daily (continuation phase, 4 months) - RIE

86
Q

what is the preferred treatment regimen for known drug-susceptible active TB (2)

A

1- INH + RMP + PZA daily (intensive phase, first 2 months) - RIP
2- INH + RMP daily (continuation phase, 4 months) - RI

*EMB can be discontinued

2025 PHPM Royal College Study - based on AN Summary Notes (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions