TB Flashcards
What is the pathogen causing tuberculosis?
Mycobacterium tuberculosis (acid fast staining bacillus)
What are the different types of TB infections?
silent
latent
progressive,active
What groups are most at risk for active disease TB?
children under 2yrs
adults over 65 yrs
What are the 2 most important drugs in the treatment of TB?
isoniazid
rifampin
multidrug resistant TB is resistant to both :o
Why do we use Directly Observed Treatment?
to reduce treatment failures and the selection of drug resistant isolates
What are the diagnostic tests for TB? (2)
Mantoux test (tuberculin unit PPD dose) - read w/in48-72 hrs
Interferon y release assays
**What are the first line agents in the treatment of TB?
(in approx order of preference)
isoniazid
rifampin
pyrazinamide
ethambutol
**Rifampin: MOI
inhibits RNA synthesis (inhibits RNA polymerase –> blocks RNA production)
**Isoniazid: MOI
inhibits cell wall synthesis (inhibits synthesis of mycolic acid)
**Pyrazinamide: MOI
exact target unclear
disrupts plasma membrane
disrupts energy metabolism (ATP synthesis)
**Ethambutol: MOI
inhibits cell wall synthesis (inhibits formation of arabinogalactan)
**What is an appropriate therapeutic plan for latent TB? (drug, duration, dosing)
ISONIAZID: -9mo daily: 270 doses twice/wk: 76 dose -6mo daily: 180 twice/wk: 52
ISONIAZID + RIFAPENTINE
- 3mo
weekly: 12
RIFAMPIN
- 4mo
daily: 120
**What is an appropriate therapeutic plan for active TB? (How many drugs do we use? Which drugs?)
combination chemotherapy is required
use at least 2 drugs to which the isolate is susceptible
outset of tx: all 4 drugs
rifampin
isoniazid
pyrazinamide
ethambutol
“trying to use some synergism putting these 4 drugs together”
**Rifampin: ADEs
turns bodily fluids orange cholestasis (hepatitis) rash flu like syndrome (with intermittent dosing) thrombocytopenia nephritis
cutaneous reactions, GI reactions (nausea, anorexia, abdominal pain), flu-like syndrome, hepatotoxicity, severe immunologic reactions, orange discoloration of bodily fluids (sputum, urine, sweat, tears), drug interactions due to induction of hepatic microsomal enzymes
**Isoniazid: ADEs
hepatic toxicity
peripheral neuropathy: vitamin B6 deficiency
asymptomatic elevation of aminotransferases, clinical hepatitis, fatal hepatitis, peripheral neurotoxicity, CNS effects, lupus-like syndrome, hypersensitivity, monoamine poisoning, diarrhea
**Pyrazinamide: ADEs
hepatotoxicity hyperuricemia rash GI disturbance arthralgias
hepatotoxicity, GI symptoms (nausea, vomiting), nongouty polyarthralgia, asymptomatic hyperuricemia, acute gouty arthritis, transient morbilliform rash, dermatitis
**Ethambutol: ADEs
retrobulbar neuritis (sudden loss of vision) -reversible if drug is stopped
retrobulbar neuritis, peripheral neuritis, cutaneous reactions
**What is multiple drug resistant TB (MDR-TB)?
TB caused by organisms that are resistant to isoniazid and rifampin
**What is the treatment for MDR-TB?
Bedaquiline
First: once daily for 2 wks
Then: 3x/wk for 22 weeks
combination w/ at least 3-4 other antibiotics
can take up to 24 months to cure
Is a patient with latent TB able to transmit the disease to others?
no
In what type of patient does latent TB become active?
immunocompromised
*What is the preferred treatment regimen for patients with drug susceptible TB?
intensive phase: 2 months
continuation phase: 4-7 months
total: 6-9months for treatment
Regimen 1: INTENSIVE PHASE: (inh, rif, pza, emb) 7 d/wk for 56 doses (8wks) OR 5 d/wk for 40 doses (8wks)
CONTINUOUS PHASE: (inh, rif) 7 d/wk for 126 doses (18wks) OR 5 d/wk for 90 doses (18wks)
What treatment regimen that has an A rating/evidence for LATENT TB in adults?
isoniazid
daily for 9 months
What other infections can be treated with Rifampin?
atypical mycobacterial infections
eradication of meningococcal colonization
staphylococcal infections (including MRSA)
