10: Pulm 3 Flashcards
What are predisposing factors for pulmonary infection?
Anything that alters your normal defense mechanisms.
- Loss of cough reflex
- Altered physical barriers
- Defect in mucocilliary apparatus
- Accumulation of secretions
- Decreased function of macrophages
- Underlying pulmonary pathology
- Immunodeficiency
What are the common characteristics of community-acquired acute pneumonias?
- most are bacterial
- usually follow a viral upper respiratory tract (URT) infection
- abrupt onset
- high fever, chills, pleuritic chest pain, productive cough
What is the most common cause of community acquired acute pneumonias?
Streptococcal pneumoniae –> “pneumococcal pneumonia”
What three groups of people are more predisposed to pneumococcocal pneumonia?
- Underlying chronic diseases (COPD, CHF, diabetes)
- Congenital or acquired immunoblobulin defects
- Decreased/absent splenic function (spleen macrophages are the largest means to remove pneumococci from the blood)
What are the two types of acute bacterial pneumonia?
- Bronchopneumonia
- Lobar pneumonia
In which type of acute bacterial pneumonia would you expect to see patchy consolidation and suppuration, acute suppruative exudate in airspaces, and abscesses?
Bronchopneumonia
In which type of acute bacterial pneumonia would you expect to see these four stages of inflammatory response:
- congestion
- red hepatization
- gray hepatization
- resolution
Lobarpneumonia
Which image shows the pathology associated w/ lobar pneumonia?
A. Bronchopneumonia
B. Lobar pneumonia
What is the general cause of atypical pneumonia?
Viral infections
Atypical pneumonia: peribronchiolar and interstitial inflammation without consolidation
What are the pathological characteristics you would see in atypical (viral) pneumonia?
- patchy or diffuse
- interstitial edema and mononuclear infiltrate
- alveolar damage with acute inflammation and hyaline membranes
What condition might atypical (viral) pneumonia lead to?
Adult Respiratory Distress Syndrome (ARDS)
w/ the histological correspondent: diffuse alveolar damage
What are the possible causes of necrotizing bronchitis/bronhiolitis?
- Influenza virus
- adenovirus
- varicella
- herpes simplex virus
What viruses cause the very distinctive viral inclusions (“viral cytopathic effects”) in viral pneumonia infections?
- CMV
- HSV
What is the cause of “walking pneumonia”?
Mycoplasma pneumonia
What three intracellular bacteria can cause atypical pneumonia?
- Chlamydia
- Coxiella burnetti (Q fever pneumonia)
- Ricckettsiae (Rocky mountain spotted fever)
What are the most common causative agents of chronic pneumonia?
- fungi
- mycobacteria
What four pulmonary conditions have a granulomatous component?
- Chronic pneumonias
- Fungal pneumonia
- Sarcoiditis
- Hypersensitivity pneumonitis
What stain is used to visualize necrotizing granulomas in primary pulmonary tuberculosis?
Acid Fast stain
**remember: necrotizing granulomas are the characteristic histological component in primary pulmonary Tb
In what pulmonary condition would you see a Ghon complex?
Primary pulmonary tuberculosis
Ghon complex: parenchymal subpleural lesion and caseous lymph node draining the focus
What are the main differences between primary and secondary pulmonary Tb?
Primary: original infection, probably will not progress to miliary Tb
Secondary: reactivation of old infection, may progress to cavitary fibrocaseous Tb, Tb bronchopneumonia, or miliary Tb
How is fungal pneumonia acquired?
By inhalation of infected spores
What is the gold standard of fungal pneumonia?
Culture diagnosis
*Remember that fungal pneumonias tend to have a limited geographic distribution
What causative agent of fungal pneumonia is a small yeast with a narrow-based bud and multiplies within macrophages?
a. histoplasma capsultum
b. coccidioides immitis
c. blastomyces
Correct answer: a (histoplasma capsulatum)
b. coccidioides immitis –> thick walled nonbudding large speherules with endospore
c. blastomyces –> round to oval thick walled yeast, broad-based bud
Pick the correct fungus with its general geographic endemic location:
a. histoplasma capsultum–> southwest US, Mexico
b. coccidioides immitis–> Ohio, Mississippi river valleys, Caribbean
c. blastomyces–> central/southeast US, Florida
C is correct
Correct pairings:
a. histoplasma capsultum–> Ohio, Mississippi river valleys, Caribbean
b. coccidioides immitis–> southwest US, Mexico
c. blastomyces–> central/southeast US, Florida
Which opportunistic fungus is also an endogenous organism for humans?
Candida albicans
Small yeast with pseudo-hyphae
Which opportunistic fungus causes invasive infections in immunosuppressed pts, diseminates systemically through the blood vessels, and is visualized by GMS stains?
Aspergillus spp
Also note:
- septae hyphae branching @45 degrees
- causes allergic bronchopulmonary aspergilosis
Which opportunistic fungus has a mucicarmine positive mucoid capsule and is disseminated cereomeningeally from primary pulmonary focus?
(Hint: its harbored in GI tract of pigeons/birds)
Cryptococcus neoformans
Also note: small yeast
Which opportunistic fungus is commonly implicated in nasal, pulmonary, and disseminated infection and infects diabetic and leukemia pts?
Mucor
Also note:
broad irregular, non-septae hyphae, 90 degrees bunching
Which opportunistic fungus has diffuse pulmonary infiltrates, foamy alveolar exudate containing proliferating organisms, and commonly infects immunocompromised AIDS patients?
Pneumocystis jiroveci (carinii)
