TB Flashcards
What is a TB chancre?
Caused by Multibacillary inoculation
Primary cutaneous TB (exogenous source)
What is a scrofuloderma
Classically on the neck
Fistula forming draining from underlying stuctrue such as LN, bone or epidydimis
Secondary TB
What are Gummas
Cold abscesses which ulcerate
Caused by haemaogenous spread
What is TB periorificalis? Or perianal
Multibacillary TB
Lesions in mouth or round anus
What is lupus vulgaris?
Paucibacillary
Through haemaogenous spread to face
Can be on face/soles/hand
Hand is typically people who work with cattle
What is TB verrucosa cutis
Whole plaque is warty
What is papular necrotic Tuberculids?
Looks like molluscum
How do you treat cutaneous TB?
It is usually paucibacillary
Tx same pulmonary TB
Resistant strains uncommon
Who should get tested for latent TB?
Active TB contacts
Current or planned immunosuppression
Individuals from TB endemic countries
Prisoners/homeless
Who is a 5mm PPD test considered positive in?
HIV patients
Recent contacts
Immunosuppressed
Fibrotic changes on lung consistent with old TB
10mm PPD test considered positive in who?
IVDU
Recent arrival from endemic country
Lab tec
Health workers
What are Tuberculids?
A cutaneous allergic reaction to TB, no AFB are actually in the skin.
-erythema nodosum
-papulonecrotic TB
-lichen scrofuloderma
Most common site of spinal TB
Thoracolumbar
What typically accompanies Potts disease?
Gibbus deformity of spine
Cold paravertebral abscesses
What is the most common form of TB CNS disease? Who is it most dangerous in?
TB meningitis followed by tuberculoma
Most dangerous in children <2yrs
How do you diagnose TB meningitis?
Xpert CSF (after centrifuging)
Monoresistant TB
Polyresistant TB
Resistance to one drug
Resistance to multiple but not RR-TB or MDR
MDR definition
At least rifampicin and isoniazid resistance
R-R TB definition?
Rifampicin Resistant TB, considered same as MDR TB (90% rif is also resistant to INH)
Pre XDR?
Fulfills definition of MDR TB plus resistant to fluoroquinolone
XDR definition
Extensive Drug Reisistance: resistant to isoniazid and rifampicin plus any fluroquionolone plus at least one additional group A drug
Examples of Group A drugs?
Bedaquiline
Linezolid
What is early bactericidal activity and why is it necessary?
Fall in log 10 colony forming units of mycobacterium TB per ml sputum per day during first 2 days. PREVENTS RESISTANCE
Most bactericidal TB drug?
Isoniasid>rifampicin>ethambutol
What is sterilising activity? What drugs are most sterilising?
Kills dormant bacteria. PREVENTS RELAPSE. most sterilising is pyrizinamide>rifampicin>isoniazid
Complications of TB meningitis?
Vasculitis mainly- give aspirin
Hyponatrameia
Tuberculomas
Treatment of drug susceptible Pulmonary TB?
RIPE 6 month treatment
Rifapentin/moxifloxacin/isoniasid/pyrazinamide for 4 months
Tx of TB meningitis?
Isonasid and rifampicin for 7-9 months
Ethambutol and pyrazinamide 2 months
Needs steroids and consider aspirin for vasculitis cx
When do you give ARVs in HIV postive patients with TB meningitis?
Not start ARV until intensive phase (8 weeks) of TB tx complete
WHO states within 2 weeks if CD4<50
Tx of cavity disease TB
CDC suggests extending therapy to 9 months
If culture positive at 2 months, extend intensive phase to 3 months long
Tx duration of bone disease in TB?
9-12months duration
RI for 7-9 months in continuation phase following 2 months of RIPE
Which smear microscopy is better?
Auramine>ZN staining
More sensitive, quicker reading time
What type of culture is superior?
Liquid medium, faster turnaround for positive and negative result
Which DST culture are best?
Liquid medium MGIT; 5-7 days
Detects multiple drug resistances
Agar place and LJ also goof but take 4-6 weeks
What are disadvantages to using MODS liquid medium?
Contamination rate very high
Only test for rifampicin and isoniazid resistance
Benefits of using TRUENAT
Battery operated, good in low income settings
But Low sensitivity in smear negative
Benefits of using LaMP
Results in 1hr
Can do large volume of tests
Uses sputum only, no drug susceptibility testing!
Benefits of XPERT?
Looks for rif resistance only
Results fast, expensive
When do you use urine LAM TB Test?
Only in HIV positive inpatients who have low CD4 counts/are very unwell
How do you dx pleural TB?
Pleural fluid superior to pleural tissue
How do you treat Hr TB?
6 months of rifampicin, ethambutol, pyrazinamide and levofloxacin
How do you treat MDR or RR TB?
BPaL (9 months) or BPaLM (6 months)
Bedaquiline, pretomanid and linezolid
Now all oral regimen of 7 drugs:
4-6 months bedaquiline
4-6months levo/moxi, clofazamine, ethionamide, pyraziamide and isoniaside
Followed by 5 months of levo/moxi, pyrazinamide, ethambutol and clofazamine
MDR TB individualised tx regimen
Choose at least four drugs from Group A, B and C
Need tx for 18 months
XDR tb Treatment
5 drugs from group a through to C
Treatment is in hospital!
When can you not use BPaL/ BPaLM
CNS or Bone disease or milairy disease only Pulmonary and LN disease
Important SE of linezolid?
Myelosuppression, peripheral amd optic neuropathy
SE of ethionamide?
Hypothyroid
SE of pretonamide?
Hepatotoxic
SE ethambutol?
Colour blindness (optic neuritis)
SE pyrazinamide?
Hyperuricemia (gout)
Arthralgia
Hepatitis
Isoniasid SE?
Sideroblastic anaemia
Peripheral neuritis (give B6)
Hepatitis
What age most at risk in children of severe TB?
Infancy <2yrs
At risk of disseminated disease
When do most cases occur in children?
<5yrs
Majority cases occur within 1yr of exposure
What kind of TB do children get?
Mostly pulmonary
Mostly smear negative, smear positive seen in older children
How do you prevent TB in HIV positive children?
6 or 9 months isoniazid
3 months of Weekly isoniasid and rifapentine or daily
How do you dx TB in children?
Plot on growth chart, kids get failure to thrive
CXR
Sputum in order children
What are atypical presentations of TB in children?
Acute severe pneumonia not getting better with abx, especially in HIV positive children.
Suspect if asymmetrical, persistent wheeze
Most common CXR finding in PTB in children?
Asymmetrical lymphadenopathy
Can look like widened mediastinum
What are common extrapulmonary TB findings in children?
TB adenitis: asymmetrical painless usually cervical LN. Visibly enlarged
TST usually strongly positive
TB pleural effusion: school- aged children, need pleural tap for dx
Miliary and CNS TB more common <2
Bone TB often monoarticular painless effusion
When do you admit a child with TB ro hospital?
Severe TB
Severe malnutrition
Severe resp distress and other comprbidities
What is most accurate sample for Xpert in children?
Sputum sample
Gastric aspirate slightly lower
How do you tx TB in children?
Same as adults
Doses are weight based- not age
From 24kg change to adult dosing
Tb drug toxicities in children?
Rare
Watch out for hepatotoxicity
Tx of TB HIV confection in children
First line drugs
Commence ART within 2-4 weeks
Cotrimoxazole preventative therapy
Pyridoxine supplement
What is a good indication of response to tx in children with TB?
Weight!!
Dx of congential TB
Proven TB in the infant PLUS;
- lesions occurring in first week of life
- a primary hepatic complex
-maternal gentian tract or placental TB
-exclusion of postnatal transmission by investigating contacts
When is BCG CI in children?
<34 weeks
<2kg
Tx of congential TB?
RIPE for 6-9 months for mother and baby
Tx of latent TB in HIV patient?
If positive TST need to give isoniasid
If TST not possible give IPT to;
-PLHIV in areas >30%
-health workers, prisoners, contacts, miners
How to screen for TB in PLHIV
1)Four symptoms screen- cough, fever, weightless, night sweats
2) CRP >5
3) CXR
4) RDTs
5) any inpt with HIV on wards where TB prevalence >10%
Xpert sensitivity in Pulmonary vs EP?
Much more sensitive for pulmonary specimens
When do you use TB LAM?
HIV patients with CD4 <50
RDT
When do you start ART in HIV patients with TB?
Within 2 weeks if CD4 <50
No later than 8 weeks irrespective of CD4 count
Immediate ART does increase mortality
What ARVs good with rifampicin?
Efavirenz
Dolutegravir
Raltegravir
Double dose of dolutegravir and raltegravir, efavirenz same dose
When do you start ARVs with TB meningitis?
Within 8 weeks
Tx of latent TB?
ISH for 6 months or rifampicin for 3-4 months or isoniasid and rifampicin for 3 months
Can give weekly rifapentine and isoniasid for 3 months
What is the general epidimology of TB-who has symptoms/ who tests positive?
Most people don’t have symptoms
Lower concentrations of mycobacterium in sputum so test is false negative in about 1/3 of people
How can you reduce transmission of TB in clinics?
Open windows
Wear masks
Who are superspreaders of TB?
People with MDR TB who are not yet identified and on incorrect treatment
How much more likely are people with HIV and malnourishment to get TB?
Malnourishment and air pollution more important risk factors than TB in LMIC as malnourishment and air pollution affect a much larger proportion of population
