Haemolymphatics

Question 0

Give an example of lymphoid hypoplasia

Answer 0

Severe Combined Immunodeficiency (SCID)

Question 1

Haemolymphatic system consists of:

Answer 1

Bone marrow
Spleen
Lymph nodes
Thymus
circulating cells
vascular connection between the above organs

Question 2

What is the pathogenesis of SCID in horses?

Answer 2

Inability to recombine genes necessary to generate functional receptors on lymphocytes

Question 3

What is the pathogenesis of SCID in dogs?

Answer 3

A mutation that impairs cytokine signals for lymphocytes to respond to antigen.

Question 4

What are pathologic hallmarks of congenital immunodeficiency?

Answer 4

Opportunistic infection at young age
Gender (male dogs)
Undetectable lymph nodes
Lymphopenia

Question 5

What cell type is typically prominent in Reactive Lymphoid Hyperplasia?

Answer 5

B cells (plasma cells)

Question 6

List 5 causes of Splenomegaly

Answer 6

Lymphoid hyperplasia
extramedullary hematopoeisis 
congestion
neoplasia
phagocytic activity (IMHA)

Question 7

What are some clinical signs of Lymphadenitis?

Answer 7

Enlarged lymph nodes -> due to infiltration of inflammatory cells (neutrophils and/or macrophages)
Tender lymph nodes
Pyrexia

Question 8

List some causes for pancytopenia

Answer 8

virus eg feline leukemia virus
Ehrlichia spp. infection
Idiopathic or autoimmune such as aplastic anemia
Chemotherapy or radiation
Leukemia
Estrogen toxicity in dogs or bracken fern toxicity in cows
Myelofibrosis

Question 9

Describe Myelofibrosis

Answer 9

Bone marrow gets “overgrown” by fibrocytes that produce collagen.
Excessive proliferation of fibrocytes is due to aberrant cytokine production. This results in myelophthisis of the bone marrow.

Question 10

How is leukemia diagnosed?

Answer 10

Abnormal changes in the peripheral blood:
persistent non-regenerative anemia
neutropenia
thrombocytopenia
abnormal cells

Question 11

Define Leukemia:

Answer 11

neoplastic cells in circulation or hematopoeitic tissues (i.e. spleen)

Question 12

List 5 conditions that could affect the hemolytic system:

Answer 12

Hypoplasia or atrophy (= immunodeficiency)
Hyperplasia (= immune reactivity)
Inflammation (= lymphadenitis)
Infection
Neoplasia

Question 13

What is the function of the Red Pulp in the spleen?

Answer 13

Extramedullary Hematopoeisis
Blood filter
Storage (RBC, iron)

Question 14

What is the function of the White pulp of the spleen

Answer 14

Immune response

Question 15

What is the function of the fibromuscular capsule/trabeculae?

Answer 15

Splenic contraction

Question 16

What are some general types of splenic disease?

Answer 16

Inflammation (splenitis)
Circulatory alteration
Adaptive growth response (hyperplasia, atrophy, aplasia/hypoplasia)
Neoplasia

Question 17

Causes for diffuse “bloody” splenomegaly:

Answer 17

Red pulp disfunction:
Blood - 'engorgement' 
barbiturates
vascular pooling
septicemia / endotoxemia
torsion

Question 18

Causes for diffuse “meaty” splenomegaly:

Answer 18

White pulp:
phagocytosis
cellular proliferation (lymphocytes, monocytes etc)
storage (amyloid, storage disease)
Cancer:
Leukemia
Lymphoma
Mast cell tumor
Histiocytic sarcoma

Question 19

Causes for nodular “bloody” splenomegaly:

Answer 19

Hematoma
Splenic vascular neoplasia:

Infarcts - hemorrhagic

Question 20

Causes for nodular “solid” splenomegaly:

Answer 20

Infarcts
Nodular hyperplasia
HSA
Hemangioma
Nonangiomatous neoplasia
  lymphoma
  histiocytic sarcoma
Inflammatory nodules (granulomas, abscess)

Question 21

“Other” splenic disease:

Answer 21

Siderotic nodules

Trauma

Question 22

Where is the Thymus located?

Answer 22

Cranial mediastinum

Question 23

List three types of Thymic disease

Answer 23

1. Adaptive growth response (aplasia, atrophy)
2. Neoplasia (thymoma, thymic lymphoma)
3. Inflammation (rare)