TB & NTM Flashcards
Eligibility of neonates for BCG vaccine in low incidence area?
1) Born in area of high incidence
2) Have at least one parent or grandparent born in high-incidence country
3) Fhx of TB in past 5 years
Which new entrants should get BCG?
High incidence country, Mantoux negative, not had vaccine before, <16 (or <35 if sub-saharan africa or country with incidence >500/100000)
Managing TB contacts - who should be vaccinated?
<35 and no previous vaccine. Or >36 if healthcare or lab worker
Which other jobs should get BCG vaccine?
Vets, Abattoir, Prison staff working directly with prisoners, Care home staff, Hostel staff for homeless/refugess/asylum seekers, those going to work with local people in high-incidence country
New employee check - what does it entail?
Hx, IGRA tests within last 5 years OR BCG scar
How to you screen TB contacts?
Mantoux but if lots then IGRA
How to you screen for latent TB in severe immunocompromise e.g. CD4<200
IGRA and Mantoux
How do you screen for latent TB in immunocompromised?
IGRA
What are risk factors for people with latent TB for developing active TB?
HIV
<5yrs
ETOH excess or IVDU
Solid organ tx
Haematological malignancy
Chemotherapy
Jejunoileal bypass
Diabetes
CKD or on HD
Gastrectomy
Anti-TNF or other biologic
Silicosis
What is treatment of latent TB?
3 months isoniazid (with pyridoxine) and rifampicin
OR 6 months isoniazid (with pyridoxine)
OR 4 months rifampicin if isoniazid resistance
What is the eligibility for latent TB treatment?
35-65 years without concern of hepatotoxicity
What tests do prior to starting treatment for latent TB?
HIV, Hepatitis B&C
When should TB treatment be started if symptoms and signs consistent with TB?
Immediately - don’t wait for culture
Should TB treatment be stopped if already started and culture turns out to be negative?
Consider completing treatment
When should rapid TB PCR be carried out?
HIV
Rapid info would alter care
Need for large contact-tracing
What is the sensitivity and specificity of Gene Xpert?
Sensitivity around 90% - Xpert Ultra is higer
Specificity 100%
What is an adenosine deaminase assay?
ADA can be used to test for TB. False positive if have lymphoma, empyema, malignancy. Present even if small number of bacteria. Can do on e.g. pleural fluid, CSF
What is MDR TB?
Rifampicin and Isoniazid resistant - note that lone R resistance rare, where as lone I resistance common
How long should drug-sensitive TB be treated if no complicating factors?
2 months RIZE (rif, ison, pyraZ, etham0
4 months RI
Note E can be stopped if culture confirms fully sensitive
How does CNS involvement change TB management?
Continuation phase increased to 10 months
High dose pred or dex should be given and tapered over 4-8 weeks
Note that spinal TB without cord involvement is treated normally
What dosing regimens of TB meds are there?
Daily is best
Can do 3/week if DOT/VOT
Does HIV affect the duration of TB treatment?
Not if well controlled
When should steroids be used in TB treatment?
CNS invovlement - high dose of dex or pred tapered over 4-8 weeks
Pericardial TB - given 60mg a day for 2-3 weeks then taper
What is MDR TB?
Resistance to Rifampicin and Isoniazid
What is XDR TB?
Resistance to Rifampicin, Isoniazid, Fluroquinolone (levo/moxi) and another group A drug (bedaq/linez)
What does the GeneXpert MTB/RIF test for?
TB and common rpoB gene mutation
When should MDR TB be suspected and Gene Xpert done?
Hx of TB treatment
Contact of MDR-TB
Birth or residence in country where >5% cases MDR
How treat Isoniazid resistant TB?
2 months Rifampicin, Pyrazinamide and Ethambutol
7 -10 months Rifampicin and Ethambutol
How treat Pyrazinamide or Ethambutol resistant TB?
2 months R, I and Z or E
4 months RI if E resist, 7 months RI if Z resist
How treat Rifampicin resistant TB?
Like MDR - at least 6 drugs
How manage MDR TB?
At least 6 drugs
Do patients with active TB need to be isolated?
If in hospital, then isolate until 2 weeks after starting treatment
Side effects of Rifampicin?
Hepatotoxicity, Drug interactions, GI upset, Rash
Side effects of Isoniazid?
Hepatotoxicity, Peripheral neuropathy, Optic neuritis, Drug interactions
Side effects of Pyrazinamide?
Hepatotoxicity, GI upset, Arthralgia, Gout
Side effects of Ethambutol?
Optic neuropathy (particularly in T2DM and CKD)
Pt with new diagnosis of pulmonary TB is still smear positive at 2 months. What treatment should they have?
Continue standard treatment
By how much does treatment of latent TB reduce risk?
Down to 1-2% (otherwise approx 5-10%)
How does HIV affect chance of TB?
Much more likely to get early progressive disease following exposure.
3-14% risk/year if latent (compared to 5% lifetime risk for non-HIV)
What are RFs for NTM?
Chronic lung disease
Thin, tall, post-menopausal lady
High humidity
How is NTM diagnosed?
Symptoms
AND
Radiology (tree-in-bud, bronchecitasis, cavities, nodules, consolidation) –> nb all should get CT
AND
exclusion of other diagnoses
AND
+ve culture x2 sputum (separate days) or x1 BAL/biopsy
How treat M.avium complex? (nb. same for M.malmoense)
Rifampicin + Ethambutol + Macrolide
+/- 3/12 amikacin (IV or neb) if severe
nb. use Isoniazid +/- amikacin instead if macrolide-resistant
Until 12 months post-sero conversion
–> need to test all isolates for clarithromycin and amikacin resistance
How treat M.kansasii?
Rifampicin + Isoniazid + Ethambutol
–> need to test all isolates for Rifampicin resistance
How treat M.xenopi?
Rifampicin + Ethambutol + Azithromycin + moxifloxacin or isoniazid
+ 3/12 amikacin (IV or neb) if severe
How treat M.abscessus?
1month: IV amikacin + tigecycline + imipnem + PO clarithromycin
Then: Neb amikacin + clarithromycin + 1-3 of: clofazimine/linezolid/minocycline/moxi/cotrim
–> need to test all isolates for clarithromycin, cefoxitin & amikacin (and preferably more)
When should CT scan be done in NTM disease?
Prior to starting treatment and at end of treatment (or earlier if concern)
Is M.abscessus a contraindication to lung tx?
No but high risk of recurrence with disseminated disease
What is considered refractory NTM disease?
Presence in sputum after 6/12 guideline-based treatment
What causes worse prognosis in NTM?
Low BMI, cavity, more symptoms, fungus, burden of disease
Pt diagnosed with HIV and TB at the same time. What treatments should be started when?
TB straight away
HIV
- CD4<50: ASAP & within 2 weeks
- CD4 ≥50: 8 weeks
- Preg: ASAP
- TB meningitis: when initiating ART early, closely monitor as high rates of adverse events
What is the difference between paradoxical IRIS and unmasking TB-IRIS?
Paradoxical - onset of IRIS within 3months of ART in pt previously diagnosed with TB + an initial response to treatment
Unmasking - TB with 3 months of ART with exaggerated immune response to sub-clinical infection (e.g. abscess, resp failure, SIRS, lymphadenitis)
Pt has a single positive sample for NTM. What is next appropriate step?
HRCT - if consistent with NTM, then BAL
Nb. same for no positive samples but clinical suspicion
What is disseminated BCG infection?
Rare granulomatous disease follwoing BCG immunotherapy used in treatment of bladder cancer. Looks like miliary TB
Caused by M.bovis = negative for AAFB
How might you need to alter TB treatment in HIV?
Rifampicin will interact with protease inhibitor (ritonavir) –> use rifabutin instead at lower dose as less potent inducer.
Regimen still 6 months
Nb. rifampicin will also interact with methadone
Employee has positive Mantoux on employee check. They have had BCG vaccine. What should happen next?
If from high incidence country, assess for active TB and if not signs then treat for latent (ie. BCG vaccine not relevant).
If not a high incidence country, then they shouldn’t have Mantoux if BCG. If Mantoux positive then do IGRA. Then assess for active TB etc
What is considered a positive Mantoux test?
What is considered a positive Quantiferon?
Induration ≥5mm
>0.35IU/mL
When restart TB treatment after hepatotoxicity?
- Investigate other causes of acute liver reaction
- Wait until ALT or AST falls below twice the ULN, bilirubin level normal and hepatotoxic symptoms resolved
- Sequentially re-introduce drugs at full dose over 10 days - start with ethambutol + isoniazid or rifampicin
Nb. if severe/high infectious TB and hepatotoxicity, continue 2 drugs e.g. ethambutol and streptomycin +/- levo/moxifloxacin and monitor
What do you do with TB treatment after cutaneous reaction in pt with severe/highly infectious tb?
Use two TB drugs e.g. ethambutol and streptomicin and monitor
Who should be considered for DOT?
Don’t adhere (or haven’t in past)
Previously treated for TB
Hx of homelessness, drug or alcohol misuse
In prison, or have been <5 years ago
Major psych, memory or cognitive disorder
Denial of TB diagnosis
MDR
Request DOT
Too ill to give treatment to themselves
What is treatment of M.bovis?
2 months Rif, Iso, Etham
7 months Rif, Iso
