TB After infection 4 possibilities

1. Cleared by host immune system 2. Contained - inactive: latent tuberculosis infection (LTBI) 3.Reactivated 4.Not contained and progresses through lungs and possibly extra-pulmonary sites

Acid-Fast Infections Flashcards by Leslie Mancini

Pulm TB

non distiguishable Sx

Fatigue, weight loss, fever, night sweats, and productive cough w possible blood smears.

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Pulm TB

Risk factors

household exposure, incarceration, drug use, travel to/from an endemic area.

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Pulm TB

Transmission

resp droplets

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TST terminology

TB Skin Test

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LTBI term infection

Latent TB infection

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Active TB term

primary TB, progressive primary TB

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non specific
acid fast smear

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who is disproportionally affected?

Malnourished
Homeless
Overcrowded, substandard housing
Prisoners
HIV-positive
Endemic areas

DISPROPORTIONALLY AFFECTED

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additional risk factors

Diabetes mellitus
Immunosuppressive meds
Chronic renal failure
Hematologic malignancy
Head/neck cancer

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After infection

4 possibilities

Cleared by host immune system
Contained - inactive: latent tuberculosis infection (LTBI)
3.Reactivated
4.Not contained and progresses through lungs and possibly extra-pulmonary sites

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Clinical manifestations

Constitutional symptoms: malaise, anorexia, weight loss, fever, night sweats.
Chronic cough is most common pulmonary symptom, productive of purulent sputum as disease progresses. Blood-streaked sputum common
Dyspnea unusual unless extensive disease

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Extrapulmonary

~20% (higher in HIV+)

Sites in order of frequency:
Lymph nodes (mediastinal, retroperitoneal, cervical)
Pleura
Genitourinary
Bones and joints (vertebral bodies)
Meningitis
Serosal surfaces-pericarditis, peritonitis
Cutaneous
Intestinal

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Pott’s disease

TB of the vertebrae

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Scrofula

TB lymphadenitis of cervical in the cervical region
Think dracula!

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Dx imagining

Chest x-ray to diagnose primary/secondary TB

CT more sensitive

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difference between primary and secondary TB in imaging

Primary = middle/lower lobe consolidation

Reactivation = apices

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Ghon Focus

calcified granuloma

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Ghon complex

Ghon focus + enlarged/calcified hilar nodes

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Cautions about pulm imaging

Non specific

Cavitary lesions

Necrosis progresses to wall of airway and liquid necrotic material is discharged into bronchial tree

If swallowed, GI tract infection may result

Miliary TB

massive dissemination of M. tuberculosis bacilli in lungs(tiny widespread nodules)

looks like bird seed

testing

Sputum AFB smear and/or nucleic acid amplification testing, 3 consecutive morning specimens
NAAT (PCR) more specific than AFB stain smear
AFB stain is quick but requires very high organism load
*Isolate bacteria in AFB and then confirm from M. tuberculosis with NAAT/PCR

Sputum culture very slow but most sensitive and specific (can take 2 months)

Screening for LTBI

Mantoux test

Purified Protein Derivative (PPD)

Extract of killed tubercle bacilli
Stimulates CMI at injection site
Injected into skin & read in 48-72 hours

Measure area of induration, not area of erythema

BCG vaccine

Live strain of Mycobacterium bovis. Produces some protection against M tb Immune response to common mycobacterial antigens May cause a false +PPD

# TB **PPD interpretation**

>or= to 15 is + for healthy > or= to 10 for people at risk of reactivation/high risk from work > or= to 5 is + for HIV/close contact w + TB | slide 32

# TB One time blood test

single patient visit, results available within 24 hours, not affected by BCG vaccine However, it’s expensive

# TB what does + screen mean?

tells us those alveolar macrophages did not succeed in killing all the bacilli Doesn’t tell us if TB is latent or active we need to confirm w further testing

# TB How long do we keep pts isolated?

until sputum smears are negative x 2-3

# TB Managing LTBI

Isoniazid +/- Rifampin, varying duration

# TB Tx active TB

Active TB disease (ill with TB): usually 4-drug regimen for 6-9 months (9-12 months when extrapulmonary/miliary) *Rifampin – ADR: turn secretions red *Isoniazid – ADR: peripheral neuropathy (take B6) *Pyrazinamide – ADR: uric acid stones, photosensitive *Ethambutol – ADR: optic neuritis All **RIPE** drugs are hepatoxic

# TB ADR for RIPE

Adverse Dx rxn Rifampin - turns secretions red Isoniazid - peripheral neuropathy(take B6) Pyrazinamide - Uric acid stones and photo sensitivity Ethambutol - optic neuritis All are hepatotoxic

# TB What are the proportion of TB presented?

90% of TB represents reactivation of LTBI. DNA fingerprinting suggests 30% of new cases in urban populations are primary infections resulting from person-to-person transmission

What does leprosy rash look like? How does it feel to pt?

Pale/pink colored patches that are sensitive to temp Feels like insects

Leprosy digits

Shortened and deformed due to secondary infection

How is leprosy transmitted

Respiratory droplets

What pathogen causes leprosy

Mycobacterium Leprae

Leprosy presentations

1. Paucibacillary 2. Multipaucibacillary

Paucibacillary leprosy / multi

5 or fewer numb skin patches More than 5

Tx for leprosy

Dapsone Rifampin Clofazamine

Where does atypical mycobacterium live

Soil and water

Clinical presentation of atypical mycobacteria

Pulm disease (most common) Lymphadenitis Skin/soft tissue/bone disease Disseminated disease

Dx atypical mycobacterium

Sputum culture

MAC Sx

More coming in men Apical fibrocavitary lung disease More common in women Nodular bronche disease -aka lady Windermere syndrome

MAC Tx

Rifampin Ethambutol Macrolide