TB Flashcards
caused by which bacteria
mycobacterium tuberculosis complex
how is it spread
by breathing in infected respiratory droplets from a person with infectious TB
can you get TB from someone who has latent TB?
no they are not infectious and cannot spread it to other people
do all people with latent go on to develop active TB
no only a small proportion will develop active TB
how many phases of treatment of active TB are there and what are they called
two phases, initial phase (4 drugs) and continuation phase (2 drugs)
what are the two regimens in the UK recommended for the treatment of TB and how do you know which one to select
supervised and unsupervised
choice depends on risk assessment to identify if pt needs enhanced case management
initial phase of TB treatment is with the following drugs
RI(P)PE
- rifampicin
- isoniazid (+ pyroxidine)
- pyrazinamide
- ethambutol
how long is initial phase with RIPE taken for
2 months
a pt has clinical signs and symptoms consistent with a TB diagnosis. should you wait for culture results to start treatment?
no, start treatment without waiting for results
continuation phase of TB treatment is with ….
RI (rifampicin and isoniazid (+pyroxidine))
continuation phase of TB treatment with RI(P) is taken for how long
4 months in pt with active TB without CNS
longer treatment for 10 months should be offered in people with active TV of the CNS, with or without spinal involvement
who would you give unsupervised regimen to
people who are likely to take anti-TB drugs reliably and willingly without supervision
who would you give supervised regimen (aka directly observed therapy DOT) to
- non-adherence
- previous treatment for TB
- homelessness, drug or alcohol misuse
- in prison or young offender, or have been in past 5 years
- major psychiatric, cognitive or memory disorder
- denial of TB diagnosis
- MDR TB
- request it
- too ill to self administer
a 23 year old man has tuberculosis and you are in charge of his regimen. you are looking into whether you should give supervised DOT or unsupervised. he seems adherent, is not in denial of his diagnosis, and has no psychiatric, cognitive or memory disorder. he is not in prison, however he was in a young offender institution 3 years ago for 12 months. what do you offer him
offer DOT because he was in a prison in the past 5 years
with supervised treatment, the preferred option is ….. but a …….. schedule can be considered in individuals with TB if they require enhances case management and daily DOT therapy is not available
Daily supervised treatment is the preferred option wherever feasible.
A 3 times weekly dosing schedule can be considered in individuals with tuberculosis if they require enhanced case management and daily directly observed therapy is not available.
Antituberculosis treatment dosing regimens in supervised treatment of fewer than ……. are not recommended
3x a week
for pt who are HIV +ve and have active TB, treatment with standard regimen should not routinely exceed …… unless the TB has CNS involvement, in which case it should not routinely exceed beyond …. months
shouldn’t routinely exceed 6 months
if CNS involvement it should not routinely exceed beyond 12 months
RIPE - which one colours bodily fluids, and may do it to soft contact lenses, red-orange?
rifampicin
this drug can stain soft contact lenses and cause bodily fluids to turn red-orange
rifampicin
rifampicin is an enzyme… which means
inducer so it can decrease the exposure of other drugs that are metabolised by CYP enzymes
side effects of rifampicin (3)
nausea
vomiting
thrombocytopenia
rifampicin and hormonal contraceptives
Effectiveness of hormonal contraceptives is reduced and alternative family planning advice should be offered.
monitoring requirements for rifampicin
- renal before treatment
- liver before treatment. if no liver disease, further checks only need if pt develops fever, malaise, vomiting, jaundice etc. always monitor LFTs on prolonged therapy
- blood counts in pt on prolonged therapy
- alcohol dependance: frequent checks of hepatic function, esp in first 2 months, and also blood counts
a patient who takes rifampicin comes to the pharmacy and complains of persistent nausea, vomiting, malaise and jaundice. what do you do
stop treatment and seek immediate medical attention
hepatic disorder
rifampicin - 3 labels
- do not stop taking unless dr says
- may colour urine, harmless
- take on empty stomach - 1 hour before or 2 hours after food
isoniazid is contraindicated in
drug induced liver disease.
pyridoxine should be given prophylactically in ALL patients from the start of treatment with this drug to reduce the risk of ….
isoniazid - to reduce risk of peripheral neuropathy
peripheral neuropathy with isoniazid is more likely to occur when there are pre existing RF e.g.
diabetes
alcohol dependence
chronic renal failure
pregnancy
malnutrition
HIV
isoniazid food interactions
Avoid tyramine-rich foods (such as mature cheeses, salami, pickled herring, Bovril®, Oxo®, Marmite® or any similar meat or yeast extract or fermented soya bean extract, and some beers, lagers or wines) or histamine-rich foods (such as very mature cheese or fish from the scromboid family (e.g. tuna, mackerel, salmon))
tachycardia, palpitation, hypotension, flushing, headache, dizziness, and sweating reported.
tyramine rich foods and histamine rich foods should be avoided with this drug because there have been reports of tachycardia, palpitations, hypotension, flushing, headache, dizziness and sweating
isoniazid
isoniazid is …. toxic
hepatotoxic
hepatitis with isoniazid is more common in
pt ages over 35 and those with daily alcohol intake
monitoring requirements of isoniazid
- renal before
- hepatic before
- if no evidence of HI, further checks only needed it pt develops fever, malaise, vomiting, jaundice etc
- alcohol dependence: frequent checks of hepatic function esp in first 2 months
isoniazid instructions - with food or before food or after food
30-60 mins before food
pyrazinamide is contraindicated in
acute attack of gout
monitoring requirements or pyrazinamide
- renal before
- hepatic before
- if no evidence of HI, only need to check when indicated by pt presentation
- alcohol dependence: freq checks of hepatic function, esp in first 2 months
RIPE - with ones are hepatotoxic and which one is oculotoxic
RIP - hepatotoxic
E - oculotoxic
ethambutol contraindications
poor vision
optic neuritis
isoniazid increases the risk of ….. when given with ethambutol
optic neuropathy
ocular toxicity with ethambutol is more likely if …..
excessive dosage or renal function impaired
will early discontinuation of ethambutol recover eyesight
Early discontinuation of the drug is almost always followed by recovery of eyesight.
what to do if a pt develops deterioration in vision with ethambutol
The earliest features of ocular toxicity are subjective and patients should be advised to discontinue therapy immediately if they develop deterioration in vision and promptly seek further advice.
monitoring of pt parameters with ethambutol
Renal function should be checked before treatment.
Visual acuity should be tested by Snellen chart before treatment with ethambutol.
Visual acuity should be tested by …… before treatment with ethambutol.
Snellen chart
what is Snellen chart
used to test visual acuity before ethambutol treatment
what is the treatment and how long is treatment of TB for people with CNS TB
- initial phase RI(P)PE for 2 months
- then continuation phase RI(P) for another 10 months
- total 12 months
- also give initial high dose of dexamethasone or prednisolone at the same time as anti-TB treatment, then slowly withdraw over 4-8 weeks
when would you refer pt with CNS TB for surgery
only consider in pt who have raised intracranial pressure; or spinal TB with spinal instability or evidence of spinal cord compression
additional treatment for pericardial TB
initial high dose of oral prednisolone should be offered to individuals with active pericardial tuberculosis, at the same time as antituberculosis treatment, then slowly withdrawn over 2–3 weeks
some individuals with latent TB are at increased risk of developing active TB:
HIV positive
diabetic
injecting drug users
receiving treatment with an anti-tumour necrosis factor-a inhibitor
what is a close contact
prolonged, frequent or intense contact e.g. household contacts or partners
do close contacts need to be tested and treated for latent TB
- anyone under 65 who is a close contact of a person with pulmonary or laryngeal TB needs to be tested for latent TB
- offer drug treatment to all pt under 65 with evidence of latent TB, if the close contact has suspected infectious or confirmed active pulmonary or laryngeal drug sensitive TB
immunocompromised pt are tested for latent TB. if they test positive then assess them for active disease. if active disease is negative, do you offer them any treatment
yes offer treatment for latent TB
treatment of latent TB (for people under 65, including those with HIV where treatment for latent TB id indicated)
either 3 months of RI(P) or 6 months of I(P)
test for these 3 before starting latent anti TB treatment as this may affect choice of therapy
HIV
Hep B
Hep C
latent TB - only offer treatment in pt 35-64 if …… not a concern
hepatotoxicity
latent TB - what treatment to offer pt where interactions with rifampicin are a concern (e.g. HIV or transplant)
6 months I(P)
latent tb - under 35, what treatment if hepatotoxicity is a concern after assessment of LFTs including transaminases and RF
3 months I (P) and rifampicin if hepatoxicity is a concern after assessment of both LFTS (including transaminases) and RF
what is treatment interruption classified as
break in anti TB treatment of at least 2 weeks during initial phase, or missing >20% prescribed doses
Name the vaccine that is indicated for prevention of TB, and the type of vaccine it is
BCG vaccine contains a live attenuated strain derived from Mycobacterium bovis and is indicated for the prevention of Tuberculosis.
