Tuberculosis Flashcards

1
Q

What organisms are in mycobacterium tuberculosis complex? [7]

A

M. tuberculosis.
M. africanum.
M. bovis (commonly associated with intestinal tract TB via consumption of unpasteurized dairy products).
M. canetti (cases seen in the Horn of Africa).
M. pinnipedii (exposure to seals).
M. microti (a rodent pathogen).
Bacillus Calmette–Guérin (BCG).

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2
Q

What is multidrug resistant TB?

A

Resistance to both isoniazid (INH) and rifampin (RIF).

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3
Q

What is extensively drug-resistant (XDR) TB?

A
MDR
AND
Resistance to any fluoroquinolone (FLQ)
AND
Resistance to at least one of the three injectable agents (amikacin, capreomycin, or kanamycin).
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4
Q

Risk factors for progression in TB? [7]

A
Diabetes
Intravenous drug use, Intestinal bypass
TNF-α inhibitors [high risk]
CXR abnormalities c/w prior inadequately treated infection
HIV [high risk] or other immunosuppression
End-stage renal disease
Recent TB infection [high risk]
Silicosis

DITCHERS

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5
Q

Is TB infection more likely to become latent or active?

A

Latent [90%]

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6
Q

Risk of LBTI infection to become active if HIV positive vs HIV negative

A

5-10% life long if HIV negative

5-10% per hear if HIV positive

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7
Q

In whom is a PPD of 5 mm or more positive? [4]

A
  1. HIV
  2. Close contact with active TB case
  3. CXR consistent with TB
  4. Immunosuppressed (patients with transplant or on prednisone ≥15 mg/day for >3 weeks), receiving anti-tumor necrosis factor (TNF) agents
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8
Q

In whom is a PPD of 10 mm or more positive? [7]

A
  1. Dialysis
  2. diabetes
  3. IV drug users
  4. lymphoma/leukemia
  5. head/neck cancer
  6. foreign born from countries of higher incidence
  7. high-risk patients (i.e., healthcare workers, incarcerated, homeless, nursing home or long-term care facility residents, microbiology lab personnel)
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9
Q

In whom is a PPD of 15 mm or more positive?

A

Healthy persons without risk factors for TB

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10
Q

What might cause a false negative PPD? [5]

A
  1. Live virus vaccinations
  2. Hypoproteinemia
  3. Lymphoproliferative disorders
  4. Old age
  5. Use of immunosuppressants (corticosteroids),
    improper administration, interpretation, or storage
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11
Q

Difficulty with treating LTBI in pregnancy regarding medication side effects?

A

Increased risk of hepatotoxicity due to INH, extending up to 3 months postpartum.

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12
Q

When should those who are pregnant be treated for LTBI? [3]

A
  1. recently exposed
  2. those living with HIV
  3. significant immunosuppression.
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13
Q

Approved treatments for LTBI? [5]

A
  1. INH + RPT once a week for 3 months [best adherance]
  2. RIF daily 4 months
  3. INH daily 6 months
  4. INH daily 9 months
  5. INH twice weekly 6–9 months
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14
Q

Treatment of LTBI if exposed to MDR strain of TB?

A

Fluoquinolone + Ethambutol for 1 year

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15
Q

Who should get baseline LFTs and bilis done prior to TB treatment? [5]

A
Underlying liver disease.
Active alcohol consumption.
Concomitant hepatotoxic drugs.
Pregnancy, up to 3 months postpartum.
People living with HIV.
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16
Q

How does primary TB infection typically look in the lungs [lobe involvement, lymphnodes, pleural effusion]?

A

Mid-lower lobe disease in >80% of patients
Hilar adenopathy in 2/3 of patients (R>L)
Pleural effusion in 1/3 of patients

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17
Q

How does reactivation TB present?

A

Fever and night sweats are seen in 50% of cases.
Upper lobe involvement with cavitation
Hemoptysis is seen in 25%
Cavitation is more common (20%–40%) than in primary TB

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18
Q

What is Rasmussen’s aneurysm?

A

Aneurysm in the setting of a cavitation

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19
Q

How is TB pleuritis diagnosed?

A
  1. Lymphocytic predominant exudative effusion with an adenosine deaminase (ADA) >40 IU/L
  2. Presence of caseating granulomas on pleural biopsy (>70% of cases).
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20
Q

Role of AFB smear, NAAT, pleural fluid culture, and pleural fluid biopsy culture in the diagnosis of TB pleuritis?

A

AFB smear: <10% sensitivity
Fluid Culture: <30% sensitivity
NAAT: 45% sensitivity
Pleural fluid biopsy: 40-80% sensitivity

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21
Q

Granulomatous pleuritis ddx [5]

A
TB in 95% of cases
rheumatoid arthritis
fungal infection
tularemia
sarcoidosis
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22
Q

What is endobronchial TB?

A

Infection of the tracheobronchial tree is more commonly seen in extensive TB disease as extension from lung focus

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23
Q

Presentation of endobronchial TB?

A

Barking productive cough, wheezing, rhonchi and, rarely, lithoptysis.

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24
Q

Complications of endobronchial TB? [3]

A

Bronchial stenosis is present in 90%
bronchial ulceration (hemoptysis)
perforations (fistulas)

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25
Q

Endobronchial TB diagnosis/work up

A

CXR negative in up to 20%
CT would show endobronchial lesions
Definitive diagnosis is via culture from bronchoscopy

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26
Q

What examination should every patient with miliary TB have done?

A

funduscopy

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27
Q

High yield biopsy sites for patients with miliary TB? [4]

A

bone marrow, liver, lymph nodes, pleura/bronchi.

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28
Q

How is TB lymphadenitis diagnoised?

A

FNA first with AFB smear, culture, and histologic evaluation

Excisional biopsy if negative

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29
Q

Three CNS manifestations of TB? [3]

A

meningitis
intracranial tuberculoma
spinal arachnoiditis.

30
Q

Presentation of TB meningitis

A

subacute/chronic basilar meningitis (i.e., general malaise, headache, confusion, low-grade fever).
can progress quickly to coma, seizures, and paresis.

31
Q

Diagnosis of TB meningitis?

A

New molecular test, the Xpert MTB/RIF Ultra (Xpert Ultra) showed above 90% sensitivity and specificity for tuberculous meningitis.

32
Q

What is Poncet’s disease

A

Acute, symmetrical, immune-mediated polyarthritis that may be seen in patients with active TB.

33
Q

What are the 4 stages of TB pericarditis?

A

Fibrinous exudation → Serosanguineous → Granulomatous caseation → Constrictive scarring.

34
Q

Three ways to diagnosis of TB pericarditis?

A
  1. Pericarditis develops in someone with known TB disease elsewhere
  2. lymphocytic pericardial exudate with ADA level (>30 IU/L)
  3. Clinical response to antituberculous therapy.
35
Q

How common is TB pericarditis?

A

Rare, occurs in only 1% of cases

36
Q

What drug is M. bovis inherently resistant to?

A

Pyrazinamide

37
Q

Treatment of M. bovis infection

A

RIF, INH, and EMB.

38
Q

Who gets M. bovis infection

A

Immunosuppressed patients getting direct bladder instillation

39
Q

How does M. bovis present

A

prostatitis, diskitis/osteomyelitis, pneumonitis, hepatitis, miliary disease/sepsis
–> Abdominal lymphadenitis in those who ate unpasteurized imported dairy products

40
Q

Describe testing relationship between HIV and TB?

A

All with diagnosed TB should be tested for HIV

All with HIV should be screened for TB

41
Q

What media should TB be cultured on?
How long does it take to grow?
How do colonies look?
What media type produces faster growth?

A

Löwenstein–Jensen
4-8 weeks
Rough and Buff
Liquid broth grows in 6-10 days

42
Q

For all patients with signs and symptoms of pulmonary TB what tests should be ordered?

A
  1. AFB smear
  2. NAAT
  3. Culture
43
Q

How often are cultures obtained in an active TB patient?

A

monthly until negative on 2 consecutive months

44
Q

When is a patient considered no longer infectious for pulmonary TB?

A

Three consecutive negative smears over at least 2 separate days after 2 weeks of therapy with clinical response.

45
Q

Which organisms are acid fast? [6]

A
  1. TB
  2. NTM
  3. Legionella micdadei
  4. Rhodococcus
  5. Nocardia
  6. Isospora, Cyclospora, and Cryptosporidium (modified stool AFB)
46
Q

How is the treatment of culture negative TB different from culture positive TB?

A

Four for 2 months

2 for two months [rather than 4-7]

47
Q

Duration of TB therapy for CNS TB

A

9-12 months

48
Q

Duration of TB therapy for pulmonary TB with cavitation and persistent positive cultures after 2 months of therapy

A

9 months

49
Q

Duration of TB therapy for TB in people living with HIV not on ART

A

9 months

50
Q

Duration of TB therapy for CNS bone and joint TB

A

9-12 months

51
Q

Outpatient follow up for patient undergoing active TB treatment?

A
  1. Baseline CBC and CMP
  2. After 2 weeks of therapy, obtain weekly sputum smears until smear-negative.
  3. Once a negative sputum smear is first documented, obtain two additional sputa on separate days to confirm the patient is noninfectious.
  4. Monthly sputum culture until two consecutive cultures are negative.
  5. Monthly clinical (including Ishihara color discrimination test while/if on EMB) evaluation until completion of therapy.
52
Q

How is TB treatment failure defined?

A

Positive cultures after 4 months of therapy.

53
Q

What is TB relapse?

A

Recurrent TB after completion of treatment and apparent cure

54
Q

What is bedaquiline?

A

M. tuberculosis ATP synthase inhibitor

55
Q

What is Delamanid

A

New nitroimidazole drug used for MDR and XDR-TB but is not approved in the United States.

56
Q

WHO recommended treatment for MDR TB?

A

INH + PZA + EMB + kanamycin (KAN) + moxifloxacin (MXF) + clofazimine (CFZ) + prothionamide (PTO). for 4-6 months
5 months PZA + ETB + MXF + CFZ.

57
Q

Limitations of AFB sputum smear

A

Low sensitivity
Negative does not exclude active TB
WORSE sensitivity in HIV

58
Q

What HIV medications must be avoided when rifampin is used?

A

TAF

Protease inhibtors

59
Q

What HIV medications are safe with rifampin?

A

Efavirenz
DTG
RAL

60
Q

Rifabutin and PI considerations

A

Cut rifabutin levels in half or do every other day dosing.

61
Q

When a patient with HIV is diagnosed with TB when should ART be started when…
CD4 is >50
CD4 is <40

A

> 50 start ART within 8 weeks of starting TB therapy [start as soon as possible]
<50 start ART within 2 weeks of starting TB therapy [Mortality benefit]

62
Q

When should a pregnant woman with HIV and TB be started on ART

A

ASAP

63
Q

When should a patient diagnosed with TB meningitis be started on ART?

A

8 weeks after TB treatment to reduce risk of IRIS

64
Q

Considerations when using rifampin in a transplant patient?

A

DONT!
Use rifabutin instead
Monitor immunosuppressant levels

65
Q

How does TB in a transplant patient present?

A

Disseminated disease

Extrapulmonary disease

66
Q

How long after treating for LTBI is it okay to start a TNF alpha agent?

A

2-8 weeks

67
Q

NOTE:

A

Test and treat ALL who are going on a TNF alpha agent for LTBI.

68
Q

What is the booster effect?

A

Some people infected with Mtb may have neg rxn to a TST if many years have
passed since Mtb infection. However, the TST PPD stimulates immune response to
Mtb antigens, and a subsequent TST can be positive. This can be mistaken for a TST conversion.

69
Q

What causes a false positive IGRA? [2]

A

M. kanasii

M. marinum

70
Q

Risk factors for obtaining MDR TB [4]

A

Prior TB treatment
Noncompliance to TB treatment
Exposure to someone with MDR TB
Travel to Eastern Europe