W. J. Fenton MD, FRCPC, FACPClinical Professor of Medicine, U of S

TB 101 for Primary Care

Providers

Patient First

Patient First

TBC & partners have always put the patient first:• Mobile clinics• Try to be flexible concerning drug delivery• Incentives if need be

In all we do collectively, we constantly should strive to make the patient first in our thinking and our actions.

Think TB

While you are thinking ….

While you are thinking ….

If you are dealing with TB – THINK HIVTBC tests for HIV in those wesee with a positive TST age 14and up

If you are dealing with HIV – THINK TB

Look for Early TB

Look for Early TB

• Cough 4/52 or more (If a smoker look for persistent change in cough of 4/52)

• Unexplained fever of > 1/52• Antibiotic resistant pneumonia (on CXR)

May not be TB but check for it:sputumCXR

Get Specimens

Get Specimens

Specimens help to:– Confirm/exclude diagnosis• Without a + culture the diagnosis remains presumptive

– Identify the organism– Identify drug sensitivities

Get Specimens

• “If they are coughing get sputum” – do it now while they are in clinic– but also try to get some morning sputa

• 3 AM sputa maximizes yield• Consider inducing the sputum if necessary• With Miliary TB may also consider urine, bone

marrow• With very low CD4 count consider blood culture

for TB

Understand the Limitations of Radiology

Understand the Limitations of Radiology

• CXR & CT are crucial parts of TB evaluation BUT

Understand the Limitations of Radiology

• CXR & CT finding may suggest TB but do not prove it– e.g. recent case

• Normal CXR does not exclude active TB– (Marciniuk Chest 1999;115:445-452)

• TB has typical patterns but can look like anything on CXR

Look at the Whole Picture

Look at the Whole Picture

As with any illness, look at the whole picture don’t just treat a test.

historyphysicaltests, CXR’senvironment

Focus of Contact Tracing

Focus of Contact Tracing

Primary TB – looking for someone who is coughing (looking for source)

- age 15 & up

Active smear + (culture +) TB – looking for spread

- age <5- HIV+, other immunosupression

Never Monotherapy

Never Monotherapy

Why?

Never Monotherapy

Monotherapy will inevitably lead to drug resistance

Why two drugs?

• The organisms in a large active population e.g. cavity, will innately have some organism resistant to a drug.

• The chance of an organism being resistant to two drugs is so small as to be non-existent .

• When starting active treatment, want two drugs that the person has not been previously exposed to

How treatment failure can occur

Treatment Failure• Non-compliance

• No drugs work if you don’t take them

• Large rapidly growing population - selection of resistant organisms

• Must have at least two drugs the organisms are sensitive to• Prescription error• Patient decides to delete one drug

• Slow growing population - persistent organisms• Drugs not continued long enough• Long enough but not enough doses in the alotted time

Where TB organisms live

Location Vs Drug Effectiveness

Activity on organismsCavity

Macroph CaseumSM +++ 0

0INH ++ +

0RMP ++ +

+EMB +/- +/-

0PZA 0 +

+ 0

Activity of First-Line Drugs

Why DOT?

Why DOT?

Cochrane Review trashed it!

407 cases of SAT, then switched to 581 of DOT, results are despite higher IV drug use, more homelessness and rising TB rates

Weis et al NEJM 1994;330:1179-1184

DOT•Identifies compliance issues quickly (audit)•Ensures drugs are taken together

Active Disease Risks

Active Disease Risk

1st yr, 2nd yr, 3-4, 5-10, 10+

10%

50%Pulm 30-40M/M 10-20

20-30%

Untreated TB Infection

Pulm 1-20M/M 2-5

Infection Risks

Can StdsP 184

Active Disease Risks

20-30%2-5x 20-30x 100+x

Granuloma on CXR (2) fibronodular on CXR (6-19) HIV infection (50-110)Smoke 1 ppd (2-3) TB infection within 2 yrs (!%) AIDS (110-170)infected age 0-4 (2.2-5) CA head & neck (16)<90% ideal wt (2-3) CRF on hemodialysis (10-25)DM (2-3.6) silicosis (30)TNF inhibitors (1.5-4) Transplantation (20-74)CS Rx (4.9)

Untreated TB infectionCompared with infected person with

No risk factors & normal CXR

Active TB Risk Factors

Infection Risks

Can StdsP 65

TST Screening & BCG status

Saskatchewan study comparing young kids who had or did not have neonatal BCG vaccination:

At age 4 – no difference – TST 10 mm valid

< age 4 - TST 15 mm validTST < 15 “grey area”

consider community & age risk

Reid et al: Chest 2007;131;1806-1810

Can doctors or nurses predict which patient will be compliant

with medications use?

NO!

What is this?

6 months earlier

* usually resolves spontaneously* active TB will develop in up to 60%* usually unilateral*more common in young men* DTH reaction to a few bacilli* smear negative fluid, culture positive in only 1/3*pleural biopsy for diagnosis* Induced sputum may be positive

Tuberculous Pleural Effusion

How does HIV change TB Management

How does HIV change TB Management

• Test for HIV– All active TB cases– Contacts if at risk for HIV – Contacts if index cases is HIV-TB co-infection

• TST– 5 mm is positive IN HIV+ PATIENT– Sensitivity decreases as CD4 count decreases

How does HIV change TB Management

• Active TB in HIV+– May lack typical clinical & CXR features• More LN, pleural, meningeal, pericardial involvement• CXR may be normal

– Aggressive sampling• Sputums even if CXR normal• Blood culture if CD4 <50-100

– If negative TST, consider repeat after ART & immune reconstitution

How does HIV change TB Management

• LTBI in HIV+– Treat unless well documented previous treatment– ? Benefit of Rx in TST- or anergic HIV+– HIV+ with recent infectious TB exposure – treat for

LTBI regardless of TST status• High re-infection risk in HIV+

– Consider LTBI Rx for HIV+ TST-:• High epidemiologic risk• CXR features suggest past TB

– Treat LTBI in pregnancy

How does HIV change TB Management

• Tx of TB in HIV+– The good news – for fully sensitive TB the

following are the same as in HIV- cases:• Cure rates• Clinical response rate• Culture conversion time• Relapse rates

How does HIV change TB Management

• Tx of TB in HIV+– RMP (rifamycins) very important– BUT .. RMP interferes with some AR drugs

• TB & HIV docs need to connect

– Rx for 9/12 may be wiser than shorter courses– If CD4 <100 do not use RMP less than 3x/wk

• Increased RMP resistance

– ? Reduced absorption of RMP & EMB in HIV+– DOT is standard– HIV+ may be more prone to INH neuropathy

• B6 25 mg

– Initiate ART early

If you want things to happen(want service)

If you want things to happen(want service)

Phone

Don’t just send a letteror requisition

e.g. x-ray req’n

TheEnd