Tuberculosis Flashcards by Nicola Smallcombe

What is pyridoxine supplementation given for ?

To prevent B6 deficiency due to Isoniazid

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What anti tb medication needs alteration in face of renal impairment ?

Ethambutol

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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

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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

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What is a positive Mantoux test ?

≥ 5mm

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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

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What are the treatments for LTBI?

3 months Rifampicin and Isoniazid (with pyridoxine)

6 months Isoniazid (with pyridoxine)
- preferred for transplant /HIV pts

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What does CSF show in Meningeal TB?

Lymphocytosis
High Protein
Low glucose

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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

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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

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How do we treat lymph node TB?

As per standard TB therapy

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How do we dose anti TB meds?

OD unless risk assessment identified need for DOT

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Do we routinely extend TB tx in patients w HIV?

No, as per NICE , we should not be extending these treatments

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Who gets adjunctive steroids in TB tx ?

Pericardial TB
CNS TB

NB spinal TB don’t routinely give , only if spinal cord compression

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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

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What dose of steroids do pericardial TB patients get ?

60mg /day usually gradually weaning over 2-3 weeks

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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

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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)

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How do we treat Pyrazinamide resistant pulmonary TB?

Initiation: Rifampicin, Isoniazid and Ethambutol (2/12)

Continuation: Rifampicin and Isoniazid (7/12)

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How do you treat Ethambutol resistant Pulmonary TB?

Initiation: Rifampicin, Isoniazid , Pyrazinamide (2/12)
Continuation: Rifampicin and Isoniazid (4/12)

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How treat Rifampicin resistant pulmonary TB?

As MDR TB

Bedaquiline, Levofloxaxin/Moxifloxacin and Linezolid

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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