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Flashcards in Spleen Deck (41):
1

Shape of spleen: HORSE

Wedge

2

Shape of spleen: RUMINANTS

Flat, oval

3

Shape of spleen: PIG

Triangular on cross section

4

Shape of spleen: DOG

Boot-shaped

5

Shape of spleen: CAT

Long & flat

6

Shape of spleen: BIRD

Small & round

7

Normal histology of CAPSULE & TRABECULAE

-Collagen
-Elastic fibers
-Smooth muscle

8

Normal Histology of WHITE PULP

-Periarterial lymphoid sheath (PALS)
- (T lymphocytes)
- around the central artery or arterioles
-lymphoid follicles
- (B lymphocytes)
- surrounded by marginal zone (dendritic cells, macrophages, B, T)

9

Normal Histology of RED PULP

-Venous sinusoids separated by cords of reticular cells with macrophages

10

What is the major fx of Red pulp?

Phagocytosis

11

What is the major fx of White pulp?

Immune

12

Functions of the spleen

1. Blood storage
2. Blood formation --EMH
3. Hb breakdown --Storage of iron
4. Blood filtration (abnormal blood cells/ particulate matter)
5. Initiation of immune response (Ab production, Cell mediated immunity)

13

Causes of Ruptured spleen

1. HBC
2. Hemangiosarcoma
3. Splenomegaly

14

Sequelae of Ruptured spleen

1. Exanguination
2. Scarring
3. Splenic fragments
4. Splenosis

15

What is Splenosis?

--

16

Species commonly associated with Splenic Torsion

Dogs with GDV
Pigs

17

In what species does splenic duplication occur?

Pigs
-incidental finding

18

Features of Sidero-fibrosis (Siderotic plaque)

aka Gandy Gamma bodies
- Aged dogs
- Yellow thickened elevated area on capsule
- Hemosiderosis w/ fibrosis of capsule

19

Mechanism of Amyloidosis

1. Monoclonal Plasma cell proliferation (myeloma)
--> fragments of Ig --> increased AL production

2. Chronic inflammation (ex. TB)
--> increased serum AA proteins (acute phase proteins) --> production of AA

20

Features of Amyloidosis

- prominent white pulp
- Pale homogenous deposits w/in follicles

21

What stains help ID amyloid?

Grossly --Lugoi's Iodine --> Deep brown
Microscopic --Congo Red --> deep orange red

22

Causes of Splenic Lymphoid Necrosis

1. Stress (cortisol = toxic to Tcells)
2. Viral infection (immunosuppressive)
3. Septicemia/toxemia
4. Mycotoxicosis

23

Microscopic appearance of Lymphoid Necrosis

"starry-sky" appearance
-Lymphocyto-lysis

24

Causes of Hemosiderosis

1. Aging
2. Hemolytic anemia
3. Anemia of chronic Dz

25

Appearance of Hemosiderosis

Gross: Brown to Black spleen
Microscopic: Golden-brown hemosiderin-laden Mphage

26

Pathogenesis of hemosiderosis

RBC lysis --> Iron / globulin / biliverdin --> Iron binds APOFERRITIN--> becomes Ferritin molecule --> ferritin molecules aggregate = Hemosiderin

27

Acute splenic congestion (appearance / cause)

-Reddish-black to purple
-Swollen w/ blood

Causes:
-Shock
-Barbiturates

28

Causes of Splenic Thrombosis, embolism, infarct

1. 2ndary to endocarditis
2. Endothelial damage
-Septicemia
-Hog Cholera
3. Thrombotic dz
-IMHA
-Purpura hemorrhagica
-Acute pancreatic necrosis

29

Types of Acute Splenitis

1. Hemorrhagic splenitis
2. Suppurative splenitis
3. Necrotizing splenitis

30

Hemorrhagic splenitis (Appearance / causes)

aka Blackberry jam spleen
-Swollen Bloody Soft

Causes:
-Anthrax
-Erysipela Septicemia
-Hog cholera Viremia

31

Suppurative Splenitis (Appearance / causes)

-Swollen or nodular, Dull yellow
-Neutrophil infiltration

Causes:
- Strep. suis Septicemia
- Acanobacterium pyogenes
- Hardware Dz

32

Necrotizing Splenitis (Appearance / causes)

Multifocal white foci, irregular mottled areas

Causes:
- Immunosuppressive viruses
- Septicemia/ toxemia
- Toxoplasma gondii

33

Acute to subacute inflammation

Hyperplastic splenitis--Monocyte-Macrophage hyperplasia
-Swollen, Red, Slightly firm
-meaty consistency, bulge on cut surface

Cause:
-subacute septicemia --Salmonella

34

Types of Chronic Splenitis

1. Chronic suppurative splenitis
2. Chronic granulomatous splenitis

35

Chronic suppurative splenitis

-walled off abscess

Causes:
-Caseous Lymphadenitis (sheep/goat)
-local extension from traumatic reticuloperitonitis

36

Chronic Granulomatous splenitis

Multifocal mottled firm nodules
OR
Diffusely swollen and firm

-necrotic center surrounded by Mphage, epitheliod cells, multinucleate giant cells, lymphocytes, plasma cells, fibrosis

Causes:
-Mycobacterium (TB)
-Tularemia
-Mycosis
-Toxoplasma

37

Causes of Atrophic spleen

1. Aging
2. Cachexia
3. Stress
4. Viral infection
5. Septicemia/toxemia

-lymphoid depletion

Thick wrinkled capsule

38

Ddx for Nodular hyperplasia

1. Neoplasia -Lymphoma, leukemia, mets)
2. Chronic Abscess
3. Granuloma
4. Hematoma
5. Lymphoid Hyperplasia

39

Neoplastic Dz

1. Lymphoma
2. Hemangioma/sarcoma
3. Leiomyoma/sarcoma
4. Metastatic neoplasia

40

Lymphoma

Nodular OR diffuse enlargemnt

Involving LN, Spleen, marrow, other tissue

41

Hemangiosarcoma (appearance/ common sites/ clinical signs)

Dark red mass
Common sites: Right atrium, spleen

Clinical signs:
-Splenic rupture
-intra-abdominal hemorrhage
-sudden death