- What do you call inflammation of the lung?
- What are 2 general mechanisms of lung infection?
- Pneumonia
- Hematogenous & airborne
Pair the following with its appropriate mechanism of infection, hematogenous OR via the airway (airborne):
- Interstitial pneumonia
- Embolic pneumonia
- Aspiration pneumonia
- Interstitial pneumonia = hematogenous
- Embolic pneumonia = hematogenous
- Aspiration pneumonia = via the airway
- What is the most common route for developing a pneumonia?
- What type of pneumonia does this route lead to?
- Airborne (inhaled)
- Bronchopneumonia
What are the 5 clinical signs of pneumonia?
Cough (+/- expelled mucus or exudate)
Fatigue
Fever
Shortness of breath
Chest pain
What are the 3 mechanisms of developing an interstitial pneumonia?
- Diffuse type I pneumocyte injury
- Diffuse alveolar capillary injury
- Systemic dissemination of infectious agents
What is the distribution of the vast majority of interstitial pneumonias?
Diffuse
This is a flow chart for development of an interstitial pneumonia. Fill in the missing pieces of the puzzle:
Inhaled noxious agent (virus, toxic gas, ingested volatile chemicals) –> ____A____ –> Serofibrinous exudate accumulation in alveolar walls & on denuded surfaces –> ___B___ –> death if severe OR –> survive 48-72 hours –> ____C____ –> type II pneumocytes mature to type I –> recovery
A. Diffuse injury to type I pneumocytes
B. Hypoxia
C. Hypertrophy & hyperplasia of type II pneumocytes
Describe an interstitial pneumonia grossly:
Color: dark
Consistency: rubbery
Heavy
Non-collapsing
- What is your diagnosis?
- What is a distinguishing feature?
- Interstitial pneumonia
- Dilated interstitial spaces filled with fluid
True or False:
- A normal lung should bound back when indented.
- An interstitial pneumonia lung should hold an indentation.
- FALSE - normal lung will hold an indentation
- FALSE - interstitial pneumonia lung will bounce back when indented
What 2 changes would you see microscopically for an interstitial pneumonia?
- Alveolar hyaline membranes
- Type II pneumocyte hyperplasia
- What change are the arrows depicting?
- What will happen to these cells?
- What type of pneumonia is this?
- Hyperplasia of the type II pneumocytes
- These cells will become type I pneumocytes
- Interstitial pneumonia
The following refers to an acute interstitial pneumonia due to vascular injury. Fill in the missing pieces:
Septicemia, especially gram (-) –> ___A___ –> activation of pulmonary intravascular macrophages –> ___B___ –> exudate accumulation in alveolar walls
A. Diffuse injury to alveolar capillary endothelium by endotoxins
B. Increased vascular permeability
The following refers to an acute, diffuse, interstitial pneumonia due to bacterial septicemia:
- What is 1 causative agent in swine?
- What is 1 causative agent in cattle?
- Salmonella cholerasuis
- Salmonella dublin
This is a lung with an interstitial pneumonia.
- What microscopic change is present?
- What causes this change?
- Thickening of the alveolar walls
- An influx of inflammatory cells causes this
The following refers to a chronic, diffuse, interstitial pneumonia. Fill in the missing pieces:
An agent is disseminated via the bloodstream to the alveolar walls or alveolar macrophages –> ___A___ –> cytokines recruit additional inflammatory cells into the alveolar wall and adjacent interstitium –> ___B___
A. Macrophages release cytokines
B. Lungs become diffusely dark, heavy, rubbery, and non-collapsing
Are the following agents of an acute or chronic interstitial pneumonia?
- PRRS virus
- Blastomyces dermatitidis
- Salmonella dublin
- PRRS virus = chronic
- Blastomyces dermatitidis = chronic
- Salmonella dublin = acute
Are the following agents associated with an acute or chronic interstitial pneumonia?
- Ovine progressive pneumonia virus
- Salmonella cholerasuis
- Ovine progressive pneumonia virus = chronic
- Salmonella cholerasuis = acute
Which type of pneumonia might this pattern best illustrate?
Embolic pneumonia
The following is the pathogenesis of an embolic pneumonia. Fill in the misisng pieces:
Bacteria enter the bloodstream –> Lung acts as a filter for ____ –> ____ get removed from the bloodstream –> get a _____, random, pulmonary abscessation
Bacteria enter the bloodstream –> lung acts as a filter for circulating particulates/bacteria–>bacteriaget removed from the bloodstream –> get amultifocal, random, pulmonary abscessation
Name 2 of the common causes of an embolic pneumonia (there are 4 provided)
- Liver abscesses
- Navel infections
- Contaminated catheters
- Vegetative valvular endocarditis
As for an aspiration pneumonia:
- Which lung lobe is most affected in a bovine?
- Which lung lobe is most affected in a canine?
- Bovine = right cranial lung lobe
- Canine = right middle lung lobe
- What is the most economically significant disease of production animal species?
- What are 4 general factors that contribute to respiratory disease?
- Bacterial bronchopneumonia
- Stress, exposure to new pathogens, environment, lack of acquired immunity
Complete the pathogenesis of bronchopneumonia:
Particles 1-2 um in daimeter enter the respiratory tract –> ___A___ –> damages epithelium –> ___B___
A. Particles are deposited in the terminal bronchioles and/or alveoli
B. Exudate accumulates in the alveoli and associated airways
What is one of the most common bacterial causes of bronchopneumonia?
Mycoplasma
- Provide 1 example of something that “overwhelms” the URT and LRT defense mechanisms, possibly leading to bronchopneumonia.
- Provide 3 examples of things that “impair” the URT and LRT defense mechanisms, possibly leading to bronchopneumnoia.
- Massive exposure (crowing with diseased animals)
- Stress, poor dirty environment, viral infection resulting in immunosuppression or decreased mucociliary clearance
Complete the extensive pathogenesis of bronchopneumonia :
Crowding of diseased animals –> overwhelm the URT and LRT of a non-diseased animal –> ___A___ –> bacteria persist, replicate, and produce toxins –> ___B___ –> generation of chemical mediators –> acute inflammation –> ___C___ –> bronchopneumonia
A. Bacteria get to the respiratory bronchioles and alveoli of the cranioventral lung
B. Respiratory bronchiolar and alveolar epithelium is damaged
C. Exudate accumulates in the lumen of respiratory bronchioles and alveoli
True or False:
Bacteria capable of causing bronchopneumonias commonly colonize the upper respiratory tract and can then easily cause disease
FALSE
Bacteria capable of causing bronchopeumonias commonly colonize the upper respiratory tract, BUT, they rarely cause disease without a predisposing factor.
What is the process of becoming solid, as changing of lung tissue from aerated and alstic to firm in certain diseases?
Consolidation
- Based on the gross changes, what is your diagnosis?
- What is one factor that tells you the duration (acute vs chronic)?
- Acute, cranioventral hemorrhagic bronchopneumonia & fibrinous pleuritis
- Acute becuase of the hyperemia
Let’s say grossly this lung had a cranioventral pattern to it.
- What is your morphologic diagnosis?
- What helps you determine its duration?
- If you placed this lung in formalin, would it float or sink?
- Acute, fibrinopurulent bronchopneumonia with hyperemia
- Hyperemia = acute
- Sink
Can you name 3 indicators of chronicity in a pneumonia?
(There are 5 total)
- Organization of fibrinous exudate in AIRWAYS
- Bronchilitis obliterans
- Organization of fibrnious exudate in ALVEOLI
- Alveolar fibrosis
- Organization of fibrinous exudate in INTERLOBULAR SEPTA
- Septal fibrosis
- Organization of fibrinous pleural exudate
- Pleural fibrosis +/- fibrous pleural adhesions
- Sequestration of necrotic parenchyma & purulent exudate
- Abscesses
This is an image of a lung:
- Is the area circled in yellow acute or chronic?
- What features helped you determine that duration?
- What is your morphogoligcal diagnosis?
- Chronic
- Fibrous connective tissue is causing the lung to appear nodular because the interstitial septa are contracting
- Chronic, cranioventral bronchopneumonia
- What is the duration of this lesion?
- What features helped you determine the duration?
- What is your morphologic diagnosis?
- Chronic
- Chronic characteristics:
- Interstitial and pleural fibrosis
- Nodular appearance due to the contraction of the fibrin
- Dilated airways (bronchiectasis)
- Chronic cranioventral bronchopneumonia
List everything you know to identify an ACUTE bronchopneumonia!
Hyperemic
Serous exudate/fibrin/hemorrhage/pmns
Acute coagulative necrosis
Same contour as normal lung
0-72 hours
List everything you know to identify a CHRONIC bronchopneumonia!
Less hyperemia than acute
Fibrosis: pleural adhesions, thickened septa, abscesses, sequestered necrotic tissue
Bronchiectasis
Bronchiolitis obliterans
Depressed, distorted contour
7+ days
Is this an acute or chronic bronchopneumonia?
Acute
Is this an acute or chronic bronchopneumonia?
Chronic
For the following, determine if the statement best describes a bronchopneumonia OR an interstitial pneumonia:
- Inflammation of the alveolar walls & interlobular septa.
- Route: air borne introduction
- Route: hematogenous (most commonly)
- Interstitial pneumonia
- Bronchopneumonia
- Interstitial pneumonia
For the following, determine if the statement best describes a bronchopneumonia OR an interstitial pneumonia:
- Diffuse, heavy, rubbery, non-collapsing
- Causes: viruses, toxins, toxic gas, septicemia
- Inflammation of the respiratory bronchioles & alveolar lumens
- Interstitial pneumonia
- Interstitial pneumonia
- Bronchopneumonia
- What is the most common site within the respiratory tract to find a neoplsm?
- Which type of neoplasm is more common at this site, carcinoma or sarcoma?
- Nasal cavity
- Carcinoma (2/3rd of the time)
What are 3 differentials for a neoplasm of epithelial orgin in the nasal cavity?
- Adenocarcinoma
- Squamous cell carcinoma
- Undifferentiated carcinoma
What are 4 differentials for a neoplasm of mesenchymal origin in the nasal cavity?
- Fibrosarcoma
- Chrondrosarcoma
- Osteosarcoma
- Undifferentiated sarcoma
- What are 3 clinical signs of a upper respiratory tract tumor? (there are 5 total)
- Explain the typical biologic behavior of a tumor in the upper respiratory tract (invasiveness, prognosis, etc.).
- Epistaxis (bleeding from nose)
- Mucopurulent nasal discharged
- Facial deformity
- Epiphor (overflow of tears onto the face)
- +/- neurologic signs
- Locally invasive
- Difficult to excise
- Rarely metastasize
- Poor long-term prognosis
What feature of the neoplasm in this picture may cause neurologic signs, such as seizures, to develop?
Invassion through the cribiform plate into the cranium
True or False:
- Primary lung cancer in animals is uncommon.
- Primary lung tumors make up about 10% of all tumors.
- TRUE
- FALSE - less than 1% of ALL tumors are primary lung tumors
Why are primary lung tumors so extensive?
Local invasion
+
Intrapulmonary lymphatic metastasis
What are these?
Tumor implants on the chest wall (pleural implantation)
True or False:
- Secondary lung tumors are much more common than primary lung tumors.
- When you observe multiple random tumor nodules in the lung as depicted here, it is time to search for the primary tumor.
- TRUE
- TRUE
- What are 3 common tumors of epithelial orgin that tend to metastasize to the lungs?
- What are 3 common tumors of mesenchymal origin that tend to metastasize to the lung? (there are 5 total)
- Mammary
- Thyroid
- Transitional cell carcinoma
- Osteosarcoma
- Hemangiosarcoma
- Malignant melanoma
- Lymphoma
- Vaccine-associated sarcoma
- What are 2 likely differentials for these lung lesions?
- The lesions bleed on cut surface. Now which differential would you lean towards?
- Differentials:
- Hemangiosarcoma
- Melanoma
- Hemangiosarcoma
Provide the proper term for the following forms of thoracic effusion:
- Transudate
- Blood
- Chyle
- Pus
- Hydrothorax
- Hemothorax
- Chylothorax
- Pyothorax
What are 3 causes of pneumothorax?
Provide 3 general causes and a specific example for each.
- Air enters externally (Ex: puncture wound)
- Air leaks from the lungs (Ex: emphysema)
- Air enters from the mediastinum (Ex: damage to the esophagus or trachea)
- What general clinical sign might you associate with a pneumothorax?
- What gross lung lesions would you see on necropsy?
- Respiratory distress
- Atelectic lungs & lack of negative pressure on the diaphragm
- What is this called?
- What gross change would occur to the lung along with this?
- The level of severity of that change is dependent on what factor?
- Thoracic effusion
- Atelectasis
- Severity of atelectasis is dependent on volume of the thoracic effusion
Can you name 3 general causes of a pleuritis? (there are 6 provided)
- Hematogenous spread
- Puncture wound/migrating foreign body
- Extension for lung infection
- Extension from thoracic lymphadenitis
- Migration down fascial planes of the neck
- Intra-thoracic esophageal perforation
This is tissue from a horse:
- What is your morphologic diagnosis?
- Explain the pathogenesis starting with an infection in the region of the larynx!
- Diffuse, fibrinopurulent pleuritis (with atelectasis)
- Infection in the region of the larynx –> exudate/infection follows the fascial planes of the neck into the chest cavity –> pleuritis
This is tissue from a bovine:
- What do you see covering the lungs?
- Where is that material localized to?
- What change can you recognize underneath that material?
- Fibrinous material covering the lungs
- Localized to the ANTERIOR and VENTRAL portions of the lung
- Hyperemia of the lung beneath the fibrinous material
Further questions to come!
This is tissue from a bovine:
Based on your conclusions so far, what is the name of the disease process here?
Pleuropneumonia
Bronchopneumonia + pleuritis = pleuropneumonia
Name 2 sequela to an acute pleuritis
- Atelectasis
- Due to accumulation of fluid exudate and compression of the lungs
- Fibrous adhesions
- Due to organization of fibrin in that area
This is a neoplasia of the thoracic cavity known as mesothelioma.
- What is one sequela of this?
- What general sign might you see clinical?
- Thoracic effusion
- Respiratory distress
This is histology assocaited with what type of neoplasm?
Hint: it is rare in domestic animals
Mesothelioma