L17 Granulomatous Lung Disease: Tuberculosis and Sarcoidosis Flashcards
____________ discovered hat TB was caused by the infectious agent _______________
characterized by formation of ________ in the lungs and other tissues
Robert Koch discovered hat TB was caused by an infectious agent Mycobacterium Tuberculosis
characterized by formation of granulomas in the lungs and other tissues
Treatment for Tuberculosis?
Treatments:
Streptomycin
Isoniazid
Rifampicin
Risk factors for TB?
Risk factors:
- HIV MOST IMPORTANT
- Travel to endemic countries
- Homelessness/incarceration
- IVDU
- Healthcare
- Immunosuppressants
- Healthcare worker
Key Elements in Pathogenesis of TB?
Key elements in pathogenicity:
- Ability to evade macrophage-induced killing
- Ability to induce delayed Type IV hypersensitivity response
Outcomes from exposure to TB?
10% exposed develop infection!
4 possible outcomes:
- Immediate clearance of the organism
- Primary disease
- Latent infection
- Reactivation disease
Primary TB
Location/Source of Infection?
Demographic?
Result of infection?
Located MID LUNG
Source of infection is exogenous: M tuberculosis inhaled →Tubercles enlarge → bacteria enter lymphatics → hilar lymph nodes
Typically affects young kids
Foci of scarring harbors bacilli for years => reactivation when host immune system is compromised
Ghon focus = subpleural parenchymal lesion
Ghon complex = Ghon focus + enlarged lymph nodes
Immunity response to TB
After 2-3 weeks T-cell mediated immunity develops:
CD4+ helper T cell response
Secrete IFN-Ƴ→ activation of macrophages → production of reactive nitrogen intermediates → kill intracellular mycobacteria
Associated with formation of epithelioid cell granulomas
CD8+ suppressor T cell response
Kill mycobacteria-infected macrophages → formation of caseating granulomas
Necrotic center of granuloma is acidic and anaerobic and does not support the growth of mycobacteria
Possible Outcomes Following Primary TB Infection?
Possible Outcomes Following Primary TB Infection
Calcified lymph nodes/ scarring visible on Chest X -Ray
Spreads in lung +/- other parts of body
Latent TB can reoccur
Primary TB
Location/Source of Infection?
Result of infection?
Granulomas classically located at APEX of one/both lungs
caseating/necrotizing granulomas are seen
Infectious/Open Case: IMPACTS UPPER LOBE
Destruction of tissue results in cavitation
=> dissemination along the airways
=> releasing mycobacteria in aerosols
______________________:
Disease that arises in a previously sensitized host
Shortly after primary TB or years later
May arise from?
Secondary / Reactivation TB
Disease that arises in a previously sensitized host
Shortly after primary TB or years later
May arise from:
Reactivation of dormant primary (5-10% of cases) Check for latent TB before immunosuppressing drugs
Exogenous re-infection
Complications of Post-Primary TB?
_________________:
Consequence of either primary or secondary TB
Severe impairment of host resistance
Widely disseminated disease results in granulomas in many organs
Lungs, meninges, kidneys, bone marrow, liver, spine (e.g. _____________)
Miliary TB:
Consequence of either primary or secondary TB
Severe impairment of host resistance
Widely disseminated disease results in granulomas in many organs
Lungs, meninges, kidneys, bone marrow , liver, spine (e.g. Pott’s disease)
____________ is a multisystem NON-NECROTIZING granulomatous disorder of unknown etiology characterized pathologically by the presence of ____________ granulomas in many organs
Sarcoidosis is a multisystem NON NECROTIZING granulomatous disorder of unknown etiology characterized pathologically by the presence of non-caseating granulomas in many organs
Epidemiology of Sarcoidosis vs. TB
Sarcoidosis usually affects adults under the age of 40
TB affects elderly predominantly
Classical presentation of Sarcoidosis?
Classical presentation
–Bilateral hilar lymphadenopathy
–Pulmonary infiltrates
–Skin, joint and/or eye lesions (small skin tumors can develop)
–Rarely nervous system (brain, meningitis, nerves and spinal cord)
Clinical Complications of Sarcoidosis?
Stages of Progression?
Clinical Complications
Inflammation can impair the function of the involved organs
Ie. Cardiac arrhythmias due to active cardiac sarcoidosis
Healing and repair resulting in scarring => tissue loss and ultimate organ failure
–Pulmonary fibrosis due to chronic pulmonary sarcoid
–Respiratory failure (Honeycomb Lung)
–Cor pulmonale
