Lab 7: Acute Inflammation

Question 1

Lung, porcine. Clinically the pig may have had a left side heart murmur.

1. What is 1
2. 2
3. 3

Answer 1

1. Pleura
2. Subpleural lymphatics
3. Interlobular lymphatics

Question 2

Lung, porcine. Clinically the pig may have had a left side heart murmur.

• What is 4?
• 5?
• 6?

Answer 2

• 4- Lymphatic with edema
• 5- Alveolar hyperemia
• 6- Alveolar edema (with increased protein)

Question 3

Lung, porcine. Clinically the pig may have had a left side heart murmur.

1. What is the pale pink material in alveoli?
2. What are the dilated clear spaces?

Answer 3

1. Edema fluid that has some increase in protein (hence the pink color)
2. These are lymphatics in the interlobular septa that are filled with and expanded by edema fluid. They are more evident because they are serving to carry away the excess fluid present in the lungs.

Question 4

Lung, porcine. Clinically the pig may have had a left side heart murmur.

• Give a possible cause of this lung lesion.

Answer 4

• A lesion on the left AV valve causing insufficiency or stenosis of this valve would lead to increased back pressure into the pulmonary veins and pulmonary capillaries leading to increased hydrostatic pressure in post capillary venules and capillaries resulting in edema.
• Something wrong with the muscle of the left ventricle could also cause this.

Question 5

Lung, porcine. Clinically the pig may have had a left side heart murmur.

• What would this lung look like grossly?

Answer 5

• Grossly the lung would look diffusely dark red (venous congestion) and would be heavy and wet with expansion of the interlobular lymphatics with clear fluid (edema).
• Foamy pink material (pulmonary and tracheal edema fluid) might be found in the lumens of the bronchi.

Question 6

Lung, porcine. Clinically the pig may have had a left side heart murmur.

• Histomorphologic diagnosis?

Answer 6

Moderate diffuse pulmonary congestion (passive hyperemia) and edema

Question 7

Artery, canine

1. What is 1?
2. 2
3. 3

Answer 7

1. Artery wall
2. Granulation tissue
3. Arteritis

Question 8

Artery, canine

• What is 4
• 5
• 6
• 7

Answer 8

• 4- Luminal thrombus
• 5- Lines of Zahn
• 6- Fibrin
• 7- Leukocytes from blood

Question 9

Artery, canine

1. What are possible sequelae if fragments of this thrombus were to break free into the arterial lumen (antemortem of course)? Chose a location for the thrombus to elaborate on the consequences or assume that this is right renal artery
2. Mesenteric artery?
3. What will happen if there is bacteria in the thrombus?

Answer 9

1. The consequences of embolism occurring from this thrombus depend on where the thrombus is. If it is in the renal artery, emboli will lodge downstream and cause infarction of all or part of the kidney, depending on the size of the embolus and the size of the vessels occluded.
2. If the embolus goes into a mesenteric artery, there may or may not be vascular compromise to a section of gut depending on the degree of collateral circulation. It is conceivable that no noticeable affect may occur.
3. Because there are bacteria present, where ever the embolus comes to rest, it can cause another site of infection and possibly abscess formation.

Question 10

How would you name this arterial lesion?

Answer 10

Arterial thrombus (chronic) with chronic arteritis

Question 11

Nasal mass, horse. This specimen is from a mass that has been present in the nasal cavity of a horse for several weeks. Because of the mass, the horse has exhibited epistaxis.

1. What is 1?
2. 2
3. 3

Answer 11

1. Nasal epithelium
2. Fibrosis (from granulation tissue)
3. Hemorrhage resulting in a mass–hematoma

Question 12

Nasal mass, horse. This specimen is from a mass that has been present in the nasal cavity of a horse for several weeks. Because of the mass, the horse has exhibited epistaxis.

• The mass is covered by stratified squamous epithelium. If this epithelium should be ciliated, pseudostratified, columnar epithelium, what do you term this alteration?

Answer 12

Squamous metaplasia of nasal mucosa.

Question 13

Nasal mass, horse. This specimen is from a mass that has been present in the nasal cavity of a horse for several weeks. Because of the mass, the horse has exhibited epistaxis.

• What is the term for the free blood in the tissue?

Answer 13

Hemorrhage, which when it forms a swelling is a hematoma.

Question 14

Nasal mass, horse. This specimen is from a mass that has been present in the nasal cavity of a horse for several weeks. Because of the mass, the horse has exhibited epistaxis.

1. What is the arrow pointing at?
2. How did it get there?

Answer 14

1. Hemosiderin containing macrophages
2. Phagocytosis of free red blood cells by macrophages resulted in breakdown of hemoglobin.
   • You will recall that heme is processed to biliverdin and bilirubin while the iron component is processed to hemosiderin seen here.

Question 15

Nasal mass, horse. This specimen is from a mass that has been present in the nasal cavity of a horse for several weeks. Because of the mass, the horse has exhibited epistaxis.

1. What is 1?
   
   • How did 1 get there?
2. 2?

Answer 15

1. Hematoidin
   
   • The yellow pigment is local bilirubin (sometimes termed hematoidin when seen in tissue histologically), an early breakdown pigment when there are large areas of hemorrhage.
2. Hemosiderin in macrophage

Question 16

Nasal mass, horse. This specimen is from a mass that has been present in the nasal cavity of a horse for several weeks. Because of the mass, the horse has exhibited epistaxis.

• What is 3?
• 4?
• 5?

Answer 16

• 3- Stratified squamous epithelium (Squamous metaplasia)
• 4- Hemosiderin in macrophages
• 5- Dilated capillaries (hyperemia)

Question 17

Nasal mass, horse. This specimen is from a mass that has been present in the nasal cavity of a horse for several weeks. Because of the mass, the horse has exhibited epistaxis.

• Less commonly there are areas of dark purple to black granular pigment. What would this be? (not entirely sure what she is pointing out on the slide)

Answer 17

calcification of chronically injured tissue—dystrophic calcification

Question 18

Signalment and history: Tissue from a 2 year old Thoroughbred stallion that presented for fever and dyspnea. Ultrasound revealed moderate amounts of fluid within the thoracic cavity.

• What organ is this?

1. What is this?
2. ?
3. ?

Answer 18

• Lung
  1. Multiple pulmonary thrombi
  2. Perivascular necrosis
  3. Atelectasis

Question 19

Signalment and history: Tissue from a 2 year old Thoroughbred stallion that presented for fever and dyspnea. Ultrasound revealed moderate amounts of fluid within the thoracic cavity.

1. What is this?
2. this? (image is a fresh version of the lung lesions)

Answer 19

1. Fibrinous pleuritis
2. fibrin, appearance when fresh.

Question 20

Signalment and history: Tissue from a 2 year old Thoroughbred stallion that presented for fever and dyspnea. Ultrasound revealed moderate amounts of fluid within the thoracic cavity.

• Describe the lesion: (some you may not be able to unless it was infront of you)

Answer 20

• The lung lob is firm (atelectatic) and dark red (congested).
• There are multiple dark red friable thrombi (.5-2cm) occluding pulmonary vessels.
• The parenchyma around these vessels had a gray/green discoloration (necrosis).
• The surface of the lung is covered by a shaggy layer of partially adherent tan friable material that is easily avulsed from the pleural surface(fibrin).
• The pleura is thickened

Question 21

Signalment and history: Tissue from a 2 year old Thoroughbred stallion that presented for fever and dyspnea. Ultrasound revealed moderate amounts of fluid within the thoracic cavity.

1. Why are there areas of pallor within the lung parenchyma?

Answer 21

The thrombus occluded blood flow to large areas of the pulmonary parenchyma, inducing ischemic necrosis and probable inflammation of the tissue.

Question 23

Signalment and history: Tissue from a 2 year old Thoroughbred stallion that presented for fever and dyspnea. Ultrasound revealed moderate amounts of fluid within the thoracic cavity.

• Name at least 3 pulmonary lesions

Answer 23

1. Diffuse pulmonary atelectasis
2. multifocal thrombosis and locally extensive ischemic necrosis of pulmonary parenchyma
3. Fibrinopurulent pleuritis

Question 24

Signalment and history: Tissue from a 10 year old Paint horse who presented for colic with a distended stomach, producing large volumes of reflux fluid. Abdominal lactate was elevated. Patient improved with analgesics but deteriorated overnight.

• Describe the lesion

Answer 24

A ~2” long segment of small intestine is twisted along its axis (volvulus). The affected segments are distended with fluid and gas, appear dark red to purple in color

Question 25

Signalment and history: Tissue from a 10 year old Paint horse who presented for colic with a distended stomach, producing large volumes of reflux fluid. Abdominal lactate was elevated. Patient improved with analgesics but deteriorated overnight.

1. What is 1?
2. ?
3. ?
4. ?

Answer 25

1. Volvulus point
2. Duodenum proximal to volvulus (distended)
3. Duodenum distal to volvulus (normal diameter)
4. Distended infarcted loops of bowel

Question 26

What is the difference between intestinal volvulus and torsion?

Answer 26

1. Volvulus – rotation of a bowel loop along its own axis (as in this case). 2. Torsion – rotation along mesenteric root.

Question 27

Signalment and history: Tissue from a 10 year old Paint horse who presented for colic with a distended stomach, producing large volumes of reflux fluid. Abdominal lactate was elevated. Patient improved with analgesics but deteriorated overnight. * Name the lesion

Answer 27

Intestinal (duodenal) volvulus with venous congestion/infraction.

Question 28

Signalment and history: Tissue from a 2 month old calf with a large ventricular septal defect (communication between left and right ventricles) * Describe the lesion

Answer 28

* The lung is heavy, dark red, spongy. * Interlobular septa are pronounced due to expansion with fluid. * When squeezed, airways and parenchyma elaborates a foamy fluid (arrow)

Question 29

Signalment and history: Tissue from a 2 month old calf with a large ventricular septal defect (communication between left and right ventricles) On histology, the lungs vessels were congested, there was marked expansion of alveoli and interlobular spaces with seroproteinaceous fluid (edema). * Name the lesion:

Answer 29

Pulmonary congestion and edema.

Question 30

Signalment and history: Tissue from a 2 month old calf with a large ventricular septal defect (communication between left and right ventricles) * How does the heart lesion relate to the lung findings?

Answer 30

* The ventricular septal defect allowed blood from the high-pressured left ventricle to be shunted into the right ventricle, resulting in a volume overload of the right ventricle and increasing blood pressure in the pulmonary tissues. * The increased hydrostatic pressure across pulmonary alveolar capillary beds resulted in efflux of fluid into the alveoli and interlobular septa, accounting for the congestion and edema

Question 31

Tissues from a 1 week old calf that was observed in severe respiratory distress and expired. He was found to have severe pneumonia on necropsy. * Describe the lesion:

Answer 31

The epicardium, myocardium and endocardium contain numerous hemorrhages ranging from 1mm to 2 cm in diameter (petechiations and ecchymoses

Question 32

Tissues from a 1 week old calf that was observed in severe respiratory distress and expired. He was found to have severe pneumonia on necropsy. 1. ? 2. ? 3. ?

Answer 32

1. Epicardial hemorrhages 2. myocardial hemorrhages 3. endocardial hemorrhages

Question 33

Tissues from a 1 week old calf that was observed in severe respiratory distress and expired. He was found to have severe pneumonia on necropsy. * Name the lesion:

Answer 33

Multifocal epicardial, myocardial and endocardial hemorrhage (petechiation and ecchymoses). Agonal hemorrhage

Question 34

Tissues from a 1 week old calf that was observed in severe respiratory distress and expired. He was found to have severe pneumonia on necropsy. * What is the significance of this lesion?

Answer 34

* This is an example of agonal hemorrhage, a relatively common phenomenon in horses and cattle. * The hemorrhage occurs peri-mortem and is **not related to the cause of death.**

Question 35

Signalment and history: Umbilicus from a calf whose dam died from a ruptured umbilical artery shortly after parturition. The calf did not receive colostrum. He died 2 weeks later after becoming first febrile, then hypothermic and recumbent. On necropsy, serosal surfaces were covered by numerous pinpoint hemorrhages (picture bellow) 1. Describe the lesion: 2. Name the lesion:

Answer 35

1. The umbilical stalk is thickened (2cm diameter) and distended by a friable caseous tan exudate. * The umbilical arteries are thickened and contain a similar exudate. 2. Caseous omphalophlebitis.

Question 36

Signalment and history: Umbilicus from a calf whose dam died from a ruptured umbilical artery shortly after parturition. The calf did not receive colostrum. He died 2 weeks later after becoming first febrile, then hypothermic and recumbent. On necropsy, serosal surfaces were covered by numerous pinpoint hemorrhages (picture bellow) 1. Relate the history and serosal lesions to the umbilical change. 2. What was the likely cause of death?

Answer 36

1. Failure to obtain colostrum left this calf with no defenses against environmental pathogens. * The umbilicus became infected via contact with an unsanitary environment, the inflammation and bacterial proliferation tracked up the umbilical vessels, resulting in septicemia. * With no antibodies to neutralize bacteria or their toxins, the calf succumbed to septic shock. * The serosal petechiations are a frequently associated with sepsis, and are a manifestation of endothelial damage by endotoxins. 2. Cause of death- septic shock

Question 37

Signalment and history: Tissue from a horse presenting for colic. 1. ? 2. ?

Answer 37

1. Cranial mesenteric artery 2. Aorta

Question 38

Signalment and history: Tissue from a horse presenting for colic. * Describe the lesion.

Answer 38

* The cranial mesenteric artery had a dilation of the most proximal aspect of the vessel with a 2 cm lumen diameter. * Contained within the dilated vessel was red-brown, amorphous, gelatinous material. * The vessel wall was very thick and firm. * External to the cranial mesenteric artery were several collateral vessels with lumen sizes ranging from 1/2 to 1mm in diameter.

Question 39

Signalment and history: Tissue from a horse presenting for colic. * Give a pathogenesis of the lesion.

Answer 39

These lesions are cranial mesenteric arteritis associated with thrombus formation due to disruption of the vessel wall from Strongylus vulgaris larval migration.

Question 40

Signalment and history: Tissue from a horse presenting for colic. * What are some potential clinical signs/complications that would stem from this lesion?

Answer 40

* Dilation of the cranial mesenteric artery would lead to turbulent blood flow and an increased risk of thrombus formation. * Any organ/area downstream could potentially be affected if its blood supply is compromised by a thrombus. * In this case the thrombus formation led to venous infarction of segmental portions of the small intestines.