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pharmacotherapy 2 > TB > Flashcards

TB Flashcards

1
Q

Risk Factors for TB

A
  • Previous TB infection ( 10% chance and more in first 2 yrs)
  • HIV infection
  • Young children, the elderly, and other immunocompromised
  • exposure to close contacts, and smoking.
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2
Q

transmission of TB

A
  • TB is an airborne disease, spread in particles called droplet nuclei (contain 1-3 bacilli and are small enough to reach the alveolar space (1-5mm)
  • These droplets may be passed by an infected person through coughing, sneezing, or shouting.
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3
Q

The progression to clinical disease depends on three factors:

A
  • Infecting dose (the number of M. Tuberculosis organisms inhaled )
  • The virulence of the organism
  • host immune system
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4
Q

pathopysiology of tb

A
  1. tubercle bacilli inahled
  2. macrophage alveoli engulf and tries to kill the bacteria
  3. if it succed in kiiling infection aborted
  4. if didnt, bacteria replicate and rupture the macrophaes and relies
  5. the cycle will continue for weeks. primary infection
  6. after 3 weeks macrophages accumulate form granulomas. with nacrotic hardened tissue, and baciili domornate in it
  7. 90% of this sucessful and infection remaon in latent phase
  8. some percent of it will start replicating and remission and progession of active disease it will transfer to other organs:

N.B. M. tuberculosis can inhibit the fusion of lysosomes to phagosomes inside macrophages preventing their destruction inside macrophages.

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5
Q

patient assesment for tb

A
  • fever, chills, night sweats, weight loss, and changes on chest radiograph.
  • Hemoptysis (blood in sputum)
  • HIV screening is recommended
  • respiratory isolation.
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6
Q

Diagnosis of active disease of tb include ?

A
  • Identification of acid-fast bacilli bacteria in sputum
  • Chest radiography
  • Tuberculin skin testing (PPD) – Mantoux Test
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7
Q

Culture Testing

A
  • suptum smear on glass slide, to detect AFB
  • M.T doesnt strain with gram strain so the Ziehl-Neelson strain with carbol fushin is used to strain microorganism.
  • On culture, M. tuberculosis grows slowly doubling every 20 hours (other bacteria double every 30 mins)
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8
Q

Antimicrobial susceptibility testing

A

important for proper treatment but require 8 weeks to obtain until mt not detected emperical therpy started.

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9
Q

Rapid-identification tests include

A

1- NAAT( nuclie acid amplification test) using pcr
2- IGRAs ( interferon gamma rays assay)

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10
Q

Tuberculin Skin Test (TST) steps

A
  1. inject 0.1 ml of ppd on dorsal surface of arm 4cm below elbow. intradermly
  2. Mark the site with an indicator and wait for 48-72 hrs
  3. Measure the mm of induration (wheal – hard elevated area) - not the erythema
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11
Q

Interpretation of tst test
Induration of≥5 mm is considered positive in

A

HIV-infected persons
Recent contacts of TB case patients
Immunosuppressed patients

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12
Q

Interpretation of tst test
Induration of≥10 mm is considered positive in

A
  • Recent immigrants (i.e., within the last 5 years)
  • Injection drug users
  • Residents and employees of the high-risk congregate settings like; prisons, hospitals and health care facilities, residential facilities for patients with AIDS and homeless shelters
  • Mycobacteriology laboratory personnel

Induration of≥15 mm is considered positive in Persons with no known risk factors for TB

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13
Q

flase positive and false negative tst

A

FALSE POSITIVE
* Prior BCG vaccination
FALSE NEGATIVE
* Concurrent viral, bacterial or fungal infection
* Chronic renal failure
* Diseases affecting lymphoid organs (e.g., lymphoma, chronic leukemia)
* Immunosuppressive drugs (e.g., medical steroids)
* Children aged 6 months or less or elderly patients (i.e., immature or waning immunity)
* Stress (e.g., surgery)
* Recent TB infection (test needs 2 – 12 weeks to become positive

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14
Q

Interferon-gamma release assays (IGRAs)

A

Blood test the measures T-cell release of interferon-gamma following stimulation by antigens unique to Mycobacterium tuberculosis and a few other mycobacteria.
Unaffected by previous BCG vaccine

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15
Q

Treatment of Latent TB

A

first line: isoniazide
* 300mg daily ( 5-10 mg/kg) for 9 months (can be 6 mnth also)
* twice weekly (15mg/kg) for 6-9 mnths
* pyridoxine 25mg added to reduce risk of neuropathy peripheral

second line: rifampin
( 600mg) daily for 4 months

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16
Q

best drugs avalible for prevention drug resistance

A

isoniazid and rifampin

17
Q

Treatment of Active Disease

A

the RIPE therapy for a total of 6 months of treatment:

  • Rifampin, Isoniazid, Pyrazinamide + Ethambutol for 2 months, followed by
  • Rifampin + Isoniazid for 4 months.
18
Q

Extending treatment to 9 (or sometimes 12) months of isoniazid and rifampin treatment is recommended for:

A
  1. risk of failure and replase, cavity lesion on radiograph, sputum after 2 mnth of treatment,
  2. no pyrazinimide initially
  3. hiv patient without treatment
  4. cns involment 12mnths
  5. joint or bone involment 6-9mnths
19
Q

extending treatment to 9mnths for culture test

A

positive cultures mean that bacteria causing TB were found in a sample (like sputum) even after the initial 2-month treatment phase.If both these conditions are present,extending treatment for at least 6 months after cultures become negative is recommended.This ensures all bacteria are eliminated.

20
Q

when intermittent dosing can be considered:

A

Patients who have a low risk of relapse with non-cavitary TB and/or smear is negative at start of treatment
HIV negative patients

21
Q

3 types of drug-resistant TB exist:

A

MDR-TB: resistance to both isoniazid and rifampin.

Extensive drug-resistant TB (XDR-TB): resistance to isoniazid & rifampin among first line agents, resistance to fluoroquinolones, and resistance to at least one second-line injectable drug.

Totally drug-resistant TB (TDR-TB): resistance to all first- and second-line agents.

22
Q

Risk factors for drug-resistant TB

A

1- history of tb treatment
2- patient from area high prevelance of drug resisitance tb
3- children born from area high prebelance of drug resistance
4- hiv patient
5- patient with positive smaear after 2 mnth treatment
6- Tuberculosis in persons who are homeless, IV drug abusers, and HIV infected

23
Q

Group A:

A

Levofloxacin OR Moxifloxacin
Bedaquiline
Linezolid

24
Q

Group B:

A

Clofazimine
Cycloserine OR Terizidone

25
Q

Group C:

A

Ethambutol
Delamanid
Imipenem OR Meropenem
Amikacin (Or Streptomycin)
Ethionamide OR Prothionamide
P-aminosalicylic acid

26
Q

Intensive Phase (4 drugs): drug resistant

A

Levofloxacin (or Moxifloxacin) + Bedaquiline +Linezolid + Clofazimine (or Cycloserine or Terizidone)

27
Q

Continuation Phase (3 drugs)

A

: Levofloxacin (or Moxifloxacin) +Linezolid + Clofazimine (or Cycloserine or Terizidone)

28
Q

Extra-pulmonary tuberculosis

A

Extra-pulmonary tuberculosis is TB within a location in the body other than the lungs.

This occurs in 15 – 20% of active cases

Example of extra-pulmonary tuberculosis: Meningitis TB, Pericarditis TB, GI TB, Lymphadenitis TB, TB of the liver, etc.

29
Q

Vaccination

A

BCG (Bacillus Calmette-Guerin) is a live attenuated vaccine derived from M. bovis
a 60– 80% reduction in the incidence of TB.not recommended in countries if the risk of exposure to TB is low.
BCG vaccination is contraindicated in pregnancy and in patients who are or will become immunocompromised (e.g. HIV or organ transplant).
The local tissue response begins 2–3 weeks after vaccination, with scar formation & healing within 3 months

30
Q

Isoniazid, rifampin, and pyrazinamide hepatotoxicity:

A

Rifampin: cholestatic pattern, with elevations in serum bilirubin and AlkPhos.
Isoniazid and pyrazinamide: Hepatocellular pattern, with elevation in serum transaminase concentrations (ALT - AST)

31
Q

discontinuation of all hepatotoxic drugs if:

A
  • The serum bilirubin is ≥ 3 mg/dL
  • Serum transaminases are more than 5x the upper limit of normal
  • Individuals with symptoms of hepatitis and serum transaminases more than 3x the upper limit of normal
32
Q

isoniazid alternative treatment

A

Rifampin, pyrazinamide, and ethambutol may be administered for six months.
In case of poorly tolerated prolonged use of pyrazinamide: rifampin and ethambutol may be given for 12 months, preferably with pyrazinamide during at least the initial two months.

33
Q

Rifampin alternative treatment

A

Isoniazid and ethambutol may be given for 12 to 18 months, with pyrazinamide during at least the first two months.
-An injectable agent may be added for the first two to three months for individuals with extensive disease or to shorten the overall treatment duration to 12 months.

34
Q

Pyrazinamide (hepatotoxicity, gout, or pregnancy)

A

Isoniazid and rifampin should be administered for nine months (supplemented by ethambutol until isoniazid and rifampin susceptibility are demonstrated)

35
Q

Regimen Needed with no hepatotoxic drug

A

Ethambutol , levofloxacin or moxifloxacin, an injectable agent, and other second-line oral drugs

pharmacotherapy 2 (15 decks)

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