9/14- Cases 2: Pulmonary Infections Flashcards
What is seen here?
- Pneumonia
- Meniscus sign
- Likely pleural effusion
What is seen here?
Inflamed lung in infectious pneumonia
- Inflammatory cells, blood, and fibrin in alveolar spaces (leaky capillaries)
What is seen here?
- More inflammatory cells
- Fibrin (stringy material in background)
What is seen here?
Congestion and edema phase of pneumonia
- Can see congested capillaries
- Leaky, so fluid gets out into alveolar spaces (pulmonary edema)
What is seen here?
Red hepatization stage
- Lung has become very firm (like liver tissue)
- All alveolar spaces are filled with blood and edema fluid
What is seen here?
Predominant cell in alveolar spaces = RBCs
What is seen here?
Gray hepatization stage
- Over time, RBCs disintegrate and predominant cell becomes neutrophil
- Involved area has grey color; blood gone and replaced with neutrophilic exudate
What is seen here?
Abscess- localized are of necrotic tissue (surrounded by wall)
What is seen here?
Abscess (common complication of pneumonia)
- Necrotic center
- Wall of abscess = organizing fibrous tissue
What is seen here?
Extra-pulmonary abscess (osteomyelitis)
- Due to dissemination of infection through blood
- Complication of pneumonia
What is seen here?
Very necrotic lung tissue
What is seen here?
CMV infection (cytomegalovirus pneumonitis)
- “Owl-eyed” inclusions with marginated chromatin
What is seen here?
CMV infection has cytoplasmic as well as nuclear inclusions!
What cells does CMV typically attack?
- Alveolar macrophages
- Endothelial cells
- Fibroblasts
What organ is the most common site of opportunistic infections?
Lungs
What pts are considered immunosuppressed?
- AIDS
- Chemotherapy (neutropenia, lymphopenia)
- Cancer itself Immunosuppression (anti-TNF, steroids…)
- Autoimmune disease
- Transplant
- Congenital immune deficiencies (or acquired)
Pts who are severely immunocompromised and infected with virulent organism may get lobar pneumonia from the onset (rather than progression from bronchopneumonia)
What is seen here?
Gross example of bronchopneumonia
- Grossly patchy consolidation around airway
What is seen here?
Bronchopneumonia
- Inflammatory exudate within bronchiole
- Few detached bronchial epithelial cells
- Wall of membranous bronchiole
What is seen here?
Aspergillosis
- Nodule is a thrombus; angioinvasive organism
- Targetoid lesion: central reddish area (area of hemorrhagic infarction)
What is seen here?
Wall of blood vessel with aspergillosis
- Hyphae stained black
- Septated dichotomous, Y-shaped branching
What is seen here?
Crytptococcus
- Thin-necked buds
- Capsule represented as clear halos around budding yeast forms
- Commonly seen in immunocompromised pts
What is seen here?
Pneumocystis infection
- Very frothy/foamy exudate within alveolar spaces
- Lung architecture mostly preserved
What is seen here?
Pneumocystis infection
- Characteristic squashed ping-pong/football-shaped appearance
What is seen here?
TB
- Can see multiple cavities (at least 2)
- Located in upper lung fields
What are some epidemiological risk factors for TB?
- Substance abuse
- Low socioeconomic background
What is seen here?
TB infection
- Acid fast positive organisms (fuschin stain)
