iPTX 3 exam 4 - Tuberculosis (TB)

What makes up the MTB complex?

M. tuberculosis, M. bovis, M. africanum

T or F:

M. tuberculosis grows very slowly

True

what are the 3 factors in which TB progresses into Active TB?

# of organisms inhaled, virulence of MTB, patient's cell-mediated immunity

what is a latent TB infection?

Asymptomatic infection that has a normal CXR

T or F:

A Latent TB Infection means that you're not contagious to others

True

what is active TB diease?

Symptomatic disese that has abnormal CXR and positive AFB smear/culture/PCR

What are the risk factors related to Active TB?

HIV/AIDS, residents and employees of high-risk congregate settings

What is primary active TB disease?

Directly exposed to TB that commonly occurs in children and immunocompromised patients

what is reactivation/secondary active TB disease?

A latent TB infection that lies dormat and progresses into an active disease once it is "triggered"

What is pulmonary TB?

Cavitary TB that is the most contagious type

what is the pathophysiology of pulmonary TB?

Bursting of the alveolar granuloma that leads into lesions

what are disseminated/Miliary TB?

hematogenous spread of tubercle bacilli with multiple lesions

What is extrapulmonary TB?

All organ systems can be affected

What organ system is most commonly affected by extrapulmonary TB?

Lymph nodes, Pleural

What organ system is least commonly affected by extrapulmonary TB?

Peritoneum, Pericardium

what are the 2 types of TB tests?

Mantoux Tuberculin Skin test (TST), Interferon Gamma Release Assay (IGRA) QuantiFERON-TB

how is TST test used?

uses a Tuberculin-purified protein derivative (PPD) with results that read after 48-72 hours

how is the IGRA Assay test used?

Blood mixed in with mycobacterial agents that gives results within 24 hours

What is the diagnosis of Active TB disease?

Clinical presentation, Radiologic evidence, Samples collected from the possible site of infection, AFB smears/cultures and MTB PCR assay confirm or negate diagnosis

What is the clinical presentation of Active Pulmonary TB disease?

Bad cough that lasts > 3 weeks, weight loss, chills, nights sweats

what do HIV patients with TB presents itself as?

Atypical presentation; disseminated/extrapulmonary disease is more common

How is the culture collection for Pulmonary TB done?

Recommend 3 consecutive, early morning sputum collections 8 - 24 hours apart

How is the culture collection of Extrapulmonary TB done?

Collect the sample of draining fluid or biopses of infected site

What are the usual traditional Microbiologic diagnosis for TB?

Solid agar, Broth-based culture, Rapid PCR test

T or F:

Infection Prevention is not only needed for Active TB patients

False

T or F:

By law, active TB cases must be reported to the local Heatlh department

True

What are the preferred ABx(s) for active TB infection in the intensive phase?

RIPE; Rifampin, Isoniazid, Pyrazinamide, Ethambutol

How often should sputum cultures be taken to document culture conversion?

Monthly

What ABx(s) are used for Active TB infections in the Continuation phase?

Isoniazid + Rifampin

what is the usual druation of therapy for continuation phase of Active TB infections?

4 months

what patients require 7 months of continuation phase for active TB infection?

Pulmonary TB patients, initial phase of treatment did NOT include PZA, HIV patients not on ART during TB treatment

what is the dosing interval for an Active TB infection?

Daily

T or F:

A 4-month regimen of rifapentine (RPT) and Moxifloxacin (MOX) is just as effective and safe as RIPE

True

what are the strengths of using RPT/MOX therapy for an active TB infection?

similar risks for hepatotoxicity

What are the limitations of RPT/MOX therapy?

Pill burden, high costs, limited in HIV/AIDS, must perform directly observed treatment for more than 5 days

What does the 2025 ATS/CDC/IDSA guidelines say about RPT/MOX therapy?

It is a conditional recommendation for > 12 YO with drug-susceptible pulmonary TB

what is the duration of therapy of RPT/MOX in the intestive phase?

8 weeks

What ABx(s) are include in the intensive phase for RPT/MOX therapy for active TB infections?

Daily RPT + MOX + INH (isoniazid) + vit B6 (pyridoxine) + PZA

what is the duration of therapy for the consolidation phase for RPT/MOX therapy for an active TB infection?

9 weeks

What ABx is the first-line therapy in Active TB infections?

Isoniazid (INH)

what is the daily dosing and the max daily dosing for INH?

5 mg/kg, max 300 mg

what are the common adverse effects of INH?

Hepatotoxicity, peripheral neuropathy

what can be given to help treat peripheral neuropathy for patients taking INH?

Pyridoxine (Vit. B6) 25 - 50 mg PO daily

T or F:

Rifampin resistance is not often associated with INH resistance

False

what is the dosing for Rifapentine (RPT) for RPT/MOX therapy?

1200 mg daily

What is the dosing for Rifampin in active TB infections?

10 mg/kg/daily (max: 600 mg)

what are the common adverse effects of rifamycins?

Rifampin - flu-like syndrome, GI upset

Rifabutin - pancytopenia, uveitis, arthalgias

Rifapentine - similar to rifampin

Rifamycins are potent inducers of what CYP enzymes?

3A4, 2C8, 2C9

From most potent to least potent, list the rifamycins that induce CYP450 enzymes

Rifampin = Rifapentine >> Rifabutin

Pyrazinamide (PZA) is only given for how many weeks in the intensive phase of treatment in RIPE and RPT/MOX?

8 weeks

T or F:

PZA dosing is based on actual body weight (20 - 25 mg/kg/day)

True

what are the common adverse effects of PZA?

hepatotoxicity, GI upset, polyarthalgia

what is the purpose of using ethambutol in RIPE?

Used to inhibit Rifampin resistance

what are the adverse effects of Ethambutol (EMB)?

ocular toxicity; loss of green and red perception

what is the first-line agent for drug-resistant TB?

Moxifloxacin

what is the main adverse effect of Moxifloxacin?

QTc prolongation

T or F:

Ethambutol can be D/C if no drug-resistance is confirmed

True

what are the 3 ABx regimen used for Latent TB infections (LTBI)?

Isoniazid + Rifapentine (3HP), Isoniazid + Rifampin (3HR), Rifampin (4R)

what is the adult dose and frequency of Isoniazid (INH) + Rifapentine (3HP)?

INH 15 mg/kg (900 MG) once weekly AND Rifapentine 900 mg once weekly

what is the duration of therapy for 3HP?

3 months

what is the adult dose and frequency of Isoniazid + Rifampin (3HR)?

INH 5 mg/kg (300 mg) daily AND Rifampin 10 mg/kg (600 mg) daily

what is the duration of therapy for 3HR?

3 months

what is the adult dosing and frequency of Rifampin (4R)?

Rifamycin 10 mg/kg (600 mg) daily

what is the duration of therapy of 4R?

4 months

T or F:

Rifampin is used as alternative for HIV patients in LTBI treatment

True

T or F:

TB and HIB have a synergistic relationship as active TB can occur at ANY CD4 lymphocyte cell count

True

what is the preferred rifamycin for HIV/TB treatment?

Rifabutin

What is an important clinical pearl about Bictegravir for treating patients with HIV/TB?

DO NOT co-administer with Rifamycins when giving Bictegravir

Multidrug-resistant TB (MDR-TB) means TB is resistant to what ABx?

INH AND Rifampin

what kind of regimens are considered the "New Avengers" of DR-TB?

BPaLM, BPaL regimens

What does each letter of BPaLM stand for?

Bedaquiline, Pretomanid, Linezolid, Moxifloxacin

what is the total duration of therapy for DR-TB?

6.5 months/26 weeks with Direct Observed therapy > 5 days/week

BPaLM regimen is used for what kind of TB microbe?

Rifampin resistant BUT fluoroquinolone susceptible

BPaL regimen is used for what kind of TB microbe?

Rifampin AND Fluoroquinolone resistant

What is the frequency of dosing for Linezolid for DR-TB?

once daily

Bedaquiline adverse effects are what?

QTc prolongation, hepatotoxicity, arthralgias, CP

what are the Pretomanid (PA) adverse effects?

QTc prolongation, hepatotoxicity, myelosuppression, neuropathy

T or F:

PA is considered a pro-drug

True

what is the renal dose adjustment for PZA on a patient that has a CrCl < 30 mL/min or HD?

25 - 35 mg/kg/dose thrice weekly

what is max daily dosing for Rifampin?

300 mg

what is the max weekly dosing for Rifampin?

900 mg

what is the max dosing of Rifapentine?

1200 mg daily