Tuberculosis Flashcards
What is pyridoxine supplementation given for ?
To prevent B6 deficiency due to Isoniazid
What anti tb medication needs alteration in face of renal impairment ?
Ethambutol
What is treatment regimen for Mycobacterium Bovis?
Rifampicin, Ethambutol and Isoniazid for 2 months followed by Rifampicin and Isoniazid for 7 months
M.Bovis is naturally resistant to pyrazinamide hence not used inland the treatment duration is prolonged for 9months
Who gets BCG vaccine?
New entrants to UK who :
- are from high incidence countries
- previously unvaccinated
- <16 years or 16-35 from sub Saharan Africa or a country where TB incidence of 500 per 100,000 more
All healthcare workers and other NHS employees, vets /prison staff/ care home staff /hostel staff
If contacts of ppl with pulmonary and laryngeal TB , not vaccinated previously and Mantoux -ve <35 or >35 and HCW
What is a positive Mantoux test ?
≥ 5mm
Who is at risk of developing active TB who has latent ?
HIV
Younger than 5
XS EtOH
Injecting drug users
Solid Organ Transplant
Haematological malignancy
Having chemo
Having jejunal biopsies
Diabetes
CKD or on dialysis
Having anti TNF or other biologic
Silicosis
What are the treatments for LTBI?
3 months Rifampicin and Isoniazid (with pyridoxine)
6 months Isoniazid (with pyridoxine)
- preferred for transplant /HIV pts
What does CSF show in Meningeal TB?
Lymphocytosis
High Protein
Low glucose
What is the treatment for sensitive Pulmonary TB?
INITIATION: Rifampicin, Isoniazid, Pyrazinamide and Ethambutol (+Pyridoxine) for 2 months
CONTINUATION: Rifampicin and Isoniazid (+pyridoxine) for 4 months
What is the treatment for sensitive CNS TB?
INITIATION: Rifampicin, Isoniazid, Pyrazinamide and Ethambutol (+Pyridoxine) for 2 months
CONTINUATION: Rifampicin and Isoniazid (+pyridoxine) for 10 months
NB CNS TB includes spinal TB
NB do not extend beyond 6 months for those with residual effects
** If disseminated TB check for spinal involvement , if there is treat as CNS TB
How do we treat lymph node TB?
As per standard TB therapy
How do we dose anti TB meds?
OD unless risk assessment identified need for DOT
Do we routinely extend TB tx in patients w HIV?
No, as per NICE , we should not be extending these treatments
Who gets adjunctive steroids in TB tx ?
Pericardial TB
CNS TB
NB spinal TB don’t routinely give , only if spinal cord compression
If CNS TB how do we grade for steroid dosing ?
Stage 1 : GCS 15 without focal neurology deficits, alert and orientated 0.3mg/kg
Stage 2: GCS 11-14 or 15 with focal neurology 0.4 mg/kg
Stage 3: <10 with or without focal neurology
For stage 2 and 3 they get 4 weeks IV steroids
What dose of steroids do pericardial TB patients get ?
60mg /day usually gradually weaning over 2-3 weeks
What increases your risk of MDR TB?
- Hx of previous TB treatment, particularly if known to have poor adherence
- Contact with known MDR TB
- Birth or residence in a country where WHO reports >5% new TB is MDR
How do we treat pulmonary TB with Isoniazid Resistance ?
Initiation: Rifampicin, Pyrazinamide, Ethambutol (for 2 months ?
Continuation: Rifampicin and Ehtambitol for 7/12 (NB for 10/12 if extensive)
How do we treat Pyrazinamide resistant pulmonary TB?
Initiation: Rifampicin, Isoniazid and Ethambutol (2/12)
Continuation: Rifampicin and Isoniazid (7/12)
How do you treat Ethambutol resistant Pulmonary TB?
Initiation: Rifampicin, Isoniazid , Pyrazinamide (2/12)
Continuation: Rifampicin and Isoniazid (4/12)
How treat Rifampicin resistant pulmonary TB?
As MDR TB
Bedaquiline, Levofloxaxin/Moxifloxacin and Linezolid
How does case finding on aircraft work?
Do not routinely carry out contact tracing on all airline passengers ; really should be <3 months has elapsed and flight >8 hours ; index case smear +ve and “coughed frequently” during flight
If teacher TB pos ; smear pos how does tracing work?
Pupils in class in preceding 3/12
Who gets DOTs treatment ?
Those who don’t adhere to tx
Have been tx for previous TB
Homelessness/drug/EtoH
Prison
Psych issues
In denial re dx
MDR TB
Requests DOTs
Unable to self administer
What happens if someone with TB is lost to follow up?
They have to be reported to the Local Authority
When do you re-introduce anti-TB drugs following pause due to Hepatoxicity ?
When AST/ALT fall below twice upper limit of normal , bili has returned to normal and symptoms have resolved
Sequentially reintroduce ; start with ethambutol and either Isoniazid/Rifampicin
What do we do if highly infectious TB and need to interrupt treatment due to a reaction?
- If due to hepatotoxicity ; a combo of at least 2 anti TB drugs of low hepatotoxcitiy (Ethambutol and streptomycin with or without a fluoroquinolone such as Levofloxacin or Moxifloxacin ) and monitor with liver specialist
- If cutaneous reaction at least 2 anti TB meds with lower risk for cutaneous reactions (such as ethambutol and streptomycin and monitor with dermatologist)
How long should TB patients be followed up?
Single drug resistance 2/12 after follow up
MDR- prolonged f/u
What does haemoptysis mean in TB?
Most common with cavitatory disease; 2/3 will be smear positive
Haemoptysis usually small volume
What is the AFB sensitivity on sputum?
50-80%
Outline IGRA
High sensitivity but low specificity ; so a negative / low result rules out latent /active but positive not so sure
What is the advantage of DOT
Increases treatment compliance
Reduces relapse
Reduces development of drug resistsnxe
If someone declining treatment for TB what laws can help us ?
Patient can be detained under the Public Health Act Section 37 and 38 but compulsory tx not allowed
What are the bactericidal TB meds ?
Rifampicin, Isoniazid , Pyrazinamide
Ethambutol has some bactericidal effect
What are the bacterostatic TB meds ?
Ethambutol
What are the main side effects with Isoniazid ?
Liver Tox
Peripheral Neuropathy
Incr levels of: Phenytoin, Carbamazepine, Warfarin
What are the side effects with Rifampicin?
Increased clearance of hepatic metabolized drugs (reduces Phenytoin, Steroids, Digoxin, Methadone , Sulphonylureas , Ciclosporin)
Red/orange discolouration to secretions
GI upset
What are the side effects with Pyrazinamide ?
GI upset
Hepatotoxicity
Renal excretion leads to hyperuricaemia
What are the side effects of ethambutol?
Optic Neuritis
Avoid in renal failure
What are the side effects of streptomycin ?
Bactercidal; given parenterally
Incr Ototoxicity in fetus and elderly
What increases the risk of Isoniazid Peripheral neuropathy?
Renal failure
Alcohol
HIV
Diabetes
Outline treatment of TB in pregnancy
Presentation is the same
TST not affected ; (NB BCG not given to pregnant women as can’t have live vaccines)
If dx first trimester disease has same outcome as non pregnant, if diagnosed 2nd/3rd trimester more variable. Late dx of pulmonary TB can lead to four fold increase in obstetric mortality and nine fold increase in pre term labour
Treat w Rifampicin, Isoniazid and Ethambutol - 6 months (limited data on pyrizinamide)
Babies of sputum +ve mothers who had <2 weeks treatment prior to delivery should be treated with Isoniazid and have skin test at 6 weeks
Outline TB treatment when breastfeeding
Most anti- TB meds are safe ; need to monitor infant for Isoniazid toxicity as theoretical risk of convulsions and neuropathy
(Baby also gets prophylactic pyridoxine)
If AST and ALT x2 ULN what do you do with TB tx?
Monitor weekly
If AST and ALT x5 ULN what do you do with TB tx?
Stop meds; if unwell from TB may need IV tx
What happens to anti TB meds in renal failure ?
Rifampicin and Isoniazid have biliary excretion so can be given as normal
Pyrazinamide - renally cleared so may need to reduce the dose frequency
Ethambutol can accumulate causing optic neuritis
** Dialysis patients should receive drug after dialysis
What is XDR TB?
MDR TB plus resistance to fluroquinolones
Why do we worry about anti-TNF meds and TB?
3.5 fold increase in developing TB with anti TNF
All patients should have CXR and IGRA prior to starting treatment (IGRA less sensitive in those taking Pred /AZT)
What generally is the recommend chemoprophylaxis for active TB in patients due to start Anti TNF?
2 months prior to starting
Who needs TB screening prior to entry?
For visa to reside in UK > 6 months and individuals coming from countries with >40/100,000
How effective is the BCG vaccine against TB in children ?
70% efficacy
What is the BCG?
Live attenuated M. Bovis
(M.Bovis is cattle TB, low risk in humans)
What is disseminated BCG infection? (BCGosis)
Live attenuated BCG immunotherapy is the most effective treatment and prophylaxis of superficial bladder cancer
Due to breaks in epithelium risk of infection
High fever and Gram -ve sepsis
susceptible to Rifampicin and isoniazid
(Remember M.Bovis, which is what the BCG is, is not susceptible to Pyrazinamide)
What is an example for an interrupted TB regimen?
2 months HRZES/ 1 month HRZE / 5 HRE
