Acid-Fast Infections Flashcards
Pulm TB
non distiguishable Sx
Fatigue, weight loss, fever, night sweats, and productive cough w possible blood smears.
Pulm TB
Risk factors
household exposure, incarceration, drug use, travel to/from an endemic area.
Pulm TB
Transmission
resp droplets
TB
TST terminology
TB Skin Test
TB
LTBI term infection
Latent TB infection
TB
Active TB term
primary TB, progressive primary TB
TB
Dx
non specific
acid fast smear
TB
who is disproportionally affected?
Malnourished
Homeless
Overcrowded, substandard housing
Prisoners
HIV-positive
Endemic areas
DISPROPORTIONALLY AFFECTED
TB
additional risk factors
Diabetes mellitus
Immunosuppressive meds
Chronic renal failure
Hematologic malignancy
Head/neck cancer
TB
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
TB
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
TB
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
TB
Pott’s disease
TB of the vertebrae
TB
Scrofula
TB lymphadenitis of cervical in the cervical region
Think dracula!
TB
Dx imagining
Chest x-ray to diagnose primary/secondary TB
CT more sensitive
TB
difference between primary and secondary TB in imaging
Primary = middle/lower lobe consolidation
Reactivation = apices
TB
Ghon Focus
calcified granuloma
TB
Ghon complex
Ghon focus + enlarged/calcified hilar nodes
TB
Cautions about pulm imaging
Non specific
TB
Cavitary lesions
Necrosis progresses to wall of airway and liquid necrotic material is discharged into bronchial tree
If swallowed, GI tract infection may result
TB
Miliary TB
massive dissemination of M. tuberculosis bacilli in lungs(tiny widespread nodules)
looks like bird seed
TB
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)
TB
Screening for LTBI
Mantoux test
TB
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
- Paucibacillary
- 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
