Lung Infections Flashcards
What is an acute inflammation of the tracheobronchial tree?
bronchitis
What is inflammation of bronchiolar epithelium?
bronchiolitis
What is inflammation of airways & alveoli?
pneumonia
What is focal infection/inflammation of parenchyma?
abscess
What are the 5 major risk factors for pneumonia?
- Loss/suppression of cough reflex
- Injury/dysfunction of mucociliary apparatus
- Accumulation of secretions
- Interference with phagocytic or bacterial action of alveolar macrophages
- Pulmonary congestion & edema
What are the predisposting conditions that make people more vulnerable to community-acquired pneumonia?
- extremes of age
- comorbid conditions
- immunodeficiency
- absent/decreased splenic function
What is the most common cause of communit-acquired pneumonia?
Describe the shape & gram stain of the bacteria.
Streprococcus pneumoniae
lancet-shaped, gram-positive diplococci

Is there a vaccine to protect against Streptococcus pneumoniae?
yes
What is the most common bacterial cause of acute exacerbation of COPD?
Describe the shape & gram stain of the bacteria.
What type is most virulent?
In what situation is pneumonia caused by this organism an emergency?
Haemophilus influenzae
- Pleomorphic gram-negative coccobacilus
- +/- capsule
- Type b most virulent
- Pneumonia in pediatric population is an emergency

Is there a vaccine to protect against Haemophilus influenzae?
yes
What type (gram stain & shape) of bacteria is Moraxella catarrhalis?
Gram-negative diplococci in clusters

What type (gram stain & shape) of bacteria is Staphylococcus aureus?
Gram-positive coccus in clumps

What type of bacteria is shown in the provided image of lung tissue?
What type of stain is this?

Gram-negative rods
Klebsiella pneumonia (specifically)
Brown-Hopps stain
Klebsiella pneumoniae is most commonly associated with what type of pneumonia?
What is a classic symptom associated with this infection?
Aspiration pneumonia
red-currant jelly sputum
What pathogen is the most common cause of hospital acquired pneumonia & community acquired pneumonia for CF and immunocompromised (neutropenic) patients?
Describe gram stain & shape of bacteia.
Pseudomonas aeruginosa
gram-negative rod

What is a major complication that can occur when immunocompromised patients develop pneumonia caused by Pseudomonas aeruginosa?
invasion of blood vessels and spread to a fulminant infection
What type (gram stain and shape) of bacteria is Legionella pneumophilia?
What special stain is used to identify this pathogen?
gram-negative rod
Silver stain

What is the most common cause of bacteial pneumonia in children and young adults?
Gram stain?
Mycoplasma pneumonia (walking pneumonia)
do not gram stain b/c no cell wall
What pattern of pneumonia is depicted in the provided image?
How do you know?

Bronchopneumonia
patchy
What pattern of pneumonia is depicted in the provided image?
How do you know?

Lobar pneumonia
wide-spread involvement of one lobe & consolidation of that inflammation and infection
What stage of lobar pneumonia is shown in the provided image?
Describe the features of this stage

Red hepatization (after congestion & before gray hepatization)
lobe is red and firm, with liver-like consistency
mostly airless, inflammation, red blood cells
What stage of lobar pneumonia is shown in the provided image?
Describe the features of this stage.

Gray Hepatization (after red hepatization)
consolidated, most of the RBC have lyced, lots of leukocytes, & varying degrees of necrosis
lots of fibrin and neutrophils
What stage of lobar pneumonia is shown in this image?

Red Hepatization
massive confluent exudation wth neutrophils, red blood cells and fibrin filling the alveolar spaces
Identify which photos are examples of early and advanced organizing pneumonia.
How do you know?

- Left: Early
- focally seem to be streamign through pore of Kohn
- fluid being resorbed, macrophages, chronic inflammation
- Right: Advanced
- exudates converted to small nodular masses rich in macrophages adn fibroblasts
- fibroblast pulgs within the airway
What factors favor viral pneumonia in adults?
old age, malnutrition, alcoholism, underlying debilitating illnesses
What tyep of pneumonia is shown in the provided image?

Viral (Influenza A)
Left: intralumenal necro-inflammatory debris (variable)
Right: Advanced case with hyaline membranes
The provided imae is an example of pneumonia caused by what pathogen?
How do you know?

SARS-COV-2
extensive areas of congestion, edema (black curved arrows), and hyaline membranes (black solid arrows)
all are compatable with diffuse alveolar damage, caused by the virus in severe infections
What are the most common organisms that cause hospital acquired pneumonia?
Gram positive cocci (Staphylococcus aureus & Streptococcus pneumoniae)
Gram negative rods (Enterobacteriales & Pseudomonas species)
What are the most common organisms that cause atypical pneumonia?
not seen on gram stain & don’t gro on standard bacteriology media
- Mycoplasma pneumoniae*
- Chlamydophila pneumonia*
- Coxiella burnetti*
Viruses
What are common complications associated with aspiration pneumonia?
lung abscess
necrotizing pneumonia

What pathology is shown in the provide image?

Lung abscess
What are the most common causes of lung abscesses?
Where do they most commonly occur in the lungs?
Aspiration of foreign material
complication of pneumonia
secondary infections of lung carcinomas
Most common: (1) right lower lobe (2) right upper lobe (3) left lower lobe
What pathology is shown in the provided image?
What features is indicated by the arrows?

Lung abscess
notice necrotic debris, inflammation & neutrophils
arrows: abscess wall
What pathology is shown in the provided image?

Diffuse alveolar damage, early phase
Hyaline membranes and type 1 pneumocyte damage
Chronic pneumonia is most commonly caused by what type of etiological agents?
What features are commonly seen with this type pneumonia?
What are the most commonly affected demographics?
Usually caused by mycobacteria & fungi
+/- regional lympho node involvement & granulomatous inflammation
immunocompromised host
What features is indicated by the red arrow?
What feature is indicatd by the blue arrow?
This is characteristic of what pathology?

Red arrow: Ghon compled - gray-white parenchymal focus under the pleura in the lower part of the upper lobe
Blue arrow: Hilar lymph nodes with caseating necrosis
Primary Tuberculosis
What is secondary tuberculosis & what are its features?
Occurs in a previously sensitized host, usually reactivation of latent infection
involves apices of upper lobes of one or both lungs – cavitations occur readily

What pathology is shown in the provided image?

Secondary tuberculosis
What pathology is depicted by the provided images?

Miliary Tuberculosis
This histological slide is indicative of what pathology?
Describe the features of the image.

- Left:
- Tubercle
- granuloma with central caseation surrounded by epithelial histiocytes & multinucleated gian cells
- Tubercle
- Right:
- higher power of the tubercle rim – showing giant cells & epitheliod histiocytes
The provided slide is an example of tuberculosis with what stain?
What is the stain for?
Ziehl-Neelsen for AFB
mycolic acid will retain the red stain
What pathology is indicated by the provided image?

Histoplasmosis
concentric fibrosis
What pathology is shown in the provided image?

Histoplasmosis
Concentric fibrosis
Where are budding yeasts commonly found during a histoplasmosis infection?
Often seen intracellularly
Typically seen in macrophages – they are NOT encapsulated
What pathology is shown in the provided image?

Blastomycosis
epitheloid granuloma wiht central necrosis & many neutrophils
What are the cellular features of blastomycosis?
Thick-walled, broad-based organisms
Not encapsulated

What patholgen is shown in the provided images?
Blastomycosis
Left: yeast
Right: fungus

What pathology is shown in the provided image?

Coccidiodes immitis
Spherules – start of empty with a thick membrane (right), then progress to thin capsule with numbeorus endospores (left)
What viral pathogens are immunocompromised patients most susceptible to cause pneumonia?
CMV, adenovirus
What fungal pathogens are immunocompromised patients most susceptible to?
- Pneumocystis jiroveci
- Cryptococcus neoformans
- Mucor
- Rhizopus
- Aspergillus
- Candida
What bacterial pathogens are immunocompromised patients most susceptible to?
- Legionella pneumophila
- mycobacteria
- Listeria
- gram-negative rods
What pathology is shown in the provided image?

CMV pneumonia
cell with cytomegaly wiht large, single-intranuclear inclusion surrounded by a clear halo in the periphery
What pathology is shown in the provided image?
This stain helps with what differentiation?

Pneumocystis pneumonia
Refractile organisms within the pap-stained casts
Distinguishes it from mimivs ie. alveolar proeinosis
What organism is shown in the provided image?

Pneumocystis cysts
central dot (black open) & collapsed “coffee cup” cross sectional contour (black curved)
What patological organism is shown in the provided image?

Candida albicans
budding yeast pseudohyphae on gram stain
How would you describe the shape of Cryptococcus neoformans?
encapsulated yeast with very narrow base buds

What pathology is shown in the provided image?

Cryptococcomas in periphery of upper lobe
they are sharply separated from the surrounding uninvolved parenchyma
What pathology is shown in the provided image?

Cryptococcus neoformans
Halo-like capsules surround round/oval yeast (blue arrow)
pink hisiocytes between the yeast
What pathogen is shown in the provided image?

Pulmonary Aspergillosis
culsters of hyphal organisms
septate hypae that show branching in acute angles