Path 2- Hemolymphatic System- 2

kelseyfmeyer's version from 2015-08-16 23:26

Spleen continued

Question Answer
what are the 4 categories of splenomegaly?bloody spleen, meaty spleen, Splenic nodules with a bloody consistency, Splenic nodules with a firm consistency
What are the three main causes of a "bloody spleen" splenomegaly? explain each a little bit(1) congestion (this could be from something like torsion, or barbiturate anesthesia) (2) acute hyperemia (this could be from something like Septicemias, bacteremias, inflammation, or anthrax) (3) acute hemolytic anemias (these could be caused by babesiosis, or EIA)
Enlargement and firm consistency of meaty spleen is due to what?PROLIFERATION OF CELLS (esp macrophages in the red pulp)
Congestion causes what kinda splenomegaly?bloody
acute hyperemia causes what kinda splenomoegaly?bloody
acute hemolytic anemias cause what kinda splenomegaly?bloody
Bacteremias and low-grade septicemias cause what kinda splenomegaly? why?meaty (Hyperplasia of macrophages and accumulations of neutrophils)
Chronic infectious diseases cause what kinda splenomegaly, and why?meaty, because Macrophage hyperplasia in the red pulp to phagocytose organisms, bacteria, or parasitized erythrocytes
Prolonged hemolytic anemias cause what kinda splenomegaly, and why?meaty, because Spleen is firm and red but not as congested (as in acute hemolysis) since fewer erythrocytes are being phagocytosed; because of EV hemolysis of altered RBCs, the red pulp may be red to dark red but does not ooze blood; hyperplasia of T- and B-lymphocyte areas also contributes to splenomegaly.... EIA falls into this category. EMH contributes to the meaty as well
Lymphoid hyperplasia causes what kinda splenomegaly, and why?MEATY, because PALS and splenic follicles become hyperplastic in response to chronic antigenic stimulation
Neoplasia can cause what kinda splenomegaly?Could be meaty, or firm nodules. if the neoplasms are vascular it can lead to bloody nodules
Stored deposits of material (such as Lysosomal storage diseases, or amyloidosis) lead to what kinda splenomegaly?MEATY
Extramedullary hematopoiesis (EMH) leads to what kinda splenomegaly?meaty! (inc in cellularity)
Splenic myeloid metaplasia, histiocytosis, and hypersplenism in the dog causes what kinda splenoegaly?meaty
Hematomas induced by lymphoid hyperplastic nodules leads to what kinda splenomegaly?bloody nodules (Arise idiosyncratically in canine and feline spleens, not associated with antigenic stimulation. Distortion of this marginal zone area by hyperplastic lymphocytes disrupts the normal blood flow, resulting in accumulation of pooled blood)
Hematomas induced by splenic vascular neoplasms leads to what kinda splenomegaly?bloody nodules (Bleeding into the red pulp, which is confined by the splenic capsule, produces a red to dark red soft bulging, usually solitary mass of varying size)
Incompletely contracted areas of the spleen lead to what type of splenomegaly?bloody nodules
Vascular neoplasms, such as Hemangioma or Hemangiosarcoma, result in what kinda splenomegaly?bloody nodules
Acute splenic infarcts result in what kinda splenomegaly, and why?bloody nodules! appear as discrete, deeply congested areas with focal capsular distention. As the lesion develops, it becomes wedge-shaped and gray-white with the base at the splenic capsule. Later a scar forms.
Nodular hyperplasia leads to what kinda splenomegaly?firm nodular
Granulomas (chronic infectious diseases) cause what kinda splenomgaly?firm nodular
Abscesses (acute infectious diseases) cause what kinda splenomegaly?firm nodular
splenomegaly-->pathogenic mechanisms--> increased function. What are three situations where there would be increased function leading to splenomegaly?(1) removal of defective RBCs such as spherocytes, or if there are Hemoglobinopathies (abnormal Hb will cause the RBC to be removed) (2) immune hyperplasia will cause enlargement, this type of hyperplasia usually happens with infections, or Disordered immunoregulation (IMHA) (3) EMH (extramedullary hematopoeisis)
splenomegaly-->pathogenic mechanisms--> Abnormal blood flow. What are three situations where abnormal blood flow would lead to splenomegaly?(1) organ failure such as cirrhosis or congestive heart failure will cause a backup of blood into the spleen and enlarge it (2) vascular abnormalities, such as OBSTRUCTIONS (hepatic vein, portal vein, splenic vein) will cause inc blood flow (3) infections can also affect blood flow
splenomegaly-->pathogenic mechanisms--> infiltration. what are two types of infiltration which can cause splenomegaly? (explain a little)(1) metabolic dzs such as amyloidosis, or glycogen storage dzs, fill the spleen up with stuff and cause it to be enlarged (2) neoplasias benign or malig, can cause megaly. leukemias, lymphomas, Hemangioma/hemangiosarcoma, or metastasized tumors are most common
what does a bloody spleen look like?enlarged, dark red to bluish-black; cut surface oozes blood
what does a meaty spleen look like?firm and red but not congested; does not ooze blood
If I say bloody nodules, you think...HEMATOMAS (either induced by lymphoid hyperplastic nodules or splenic vascular neoplasms), Incompletely contracted areas of the spleen, acute splenic infarcts
**Q: Chronic hemolytic anemia (EIA) leads to what splenomegaly??MEATY!!
bloody nodules in splenomegaly--> Hematomas induced by lymphoid hyperplastic nodules. Explain how this happens, and who is most prone.hyperplasia of PALS >> disrupts blood flow canine, feline spleens: “open” circulation in the white pulp >> pooling of blood >> hematoma
(developmental anomaly) what affect does a immunodeficiency have on the development of the spleen?causes a small spleen. IT will be small, firm, and pale red, a lack of lymphoid follicles and PALS, and very few plasma cells
what is an "Accessory spleen"super small spleen usually as result of a immunodeficiency developmental anomaly, it is usually located in gastrosplenic ligament
A small spleen can be due to aging changes. What does a spleen look like in this situation?lymphoid atrophy (loss of T & B lymphocytes), wrinkled capsule, reduction in the white pulp (PALS, follicles), sinusoids collapsed, lack blood (anemia?)
****Q: a small spleen can be due to Wasting and/or cachectic diseases. what parts of the spleen are affected to cause it to be small?There is atrophy of the T-lymphocyte areas, BUT there is little to no effect on B-lymphocyte areas (If I'm starving, I have no Tea, but I still have my Blood)
a spleen can be small if it is undergoing splenic contraction. what are some situations where this would happen? what would the spleen look like?usually occurs in shock, or if the animal is nervous. spleen is small; surface is wrinkled; cut surface is dry
*****WHATS THE DIFF BETWEEN LEUKEMIA AND LYMPHOMA??leukemia comes from the bone marrow, lymphosarcomas come from outside of the BM (like lymphnodes). both are lymphocyte tumors!
what are the 4 main neoplasias you'd find in the spleen?lymphoma, hemangiosarcoma(single or mult red masses), hemangioma (single red mass), or metastatic neoplasms (uncommon)

Lymph Nodes

Question Answer
what are the main functions of the LNs?filter lymph, hematopoeisis site, immune response (production of IgG)
response to injury--> hyperplastic changes. What becomes hyperplastic? Cells of the monocyte macrophage system, and lymphoid tissue (hyperplasia with the production of antibody, immediate cell-mediated immunity (CMI))
Inflammation (lymphadenitis) can be chronic or acute, what kinda situations tipify this?acute- micro-abscess and abscess formation. chronic- abscesses and granulomas
what is Lymphadenopathy?LN enlargement, often a sign of dz
(what is happening in Congenital hereditary lymphedema? who is prone?)lymphatics are aplastic and LNs (peripheral and central) are hypoplastic. Happens most often in cattle and dogs, and results in generalized subcutaneous edema, with fluid in serous cavities, and are often stillborn
(developmental disorders) what are the lymphnodes like in SCID dogs and horses?SMALL LNs! absence of lymphoid follicles and corticomedullary differentiation. Also few to no lymphocytes and plasma cells
what affect does a lack of antigenic stimulation have on the lymphnodes?It will cause a SMALL LN, because of depletion of lymphocytes in germinal centers, where mitotic figures will be absent (“depleted germinal centers” / “reactive depleted lymphoid follicles”)
what is the main reason that the lymphoid follicles and germinal centers are so variable?because they are NOT permanent structures. the number of follicles ↑ or ↓with changes in the intensity of the antigenic stimuli, and germinal centers go through a cycle of activation, depletion, and rest
**Q:small LNs--> Cachexia and malnutrition. How are the LNs affected by this, specifically?causes atrophy of T-lymphocyte areas, little or no effect on B-lymphocyte areas
how does ageing affect LNs (in terms of size?)results in a depression of the immune system, so the lymphnodes will be smaller. (cortex is reduced, loss of B lymphocytes and T lymphocytes, absence of follicles)
**what situation causes LYMPHOCYTOLYSIS in the lymphnodes??VIRUSES!! espeically BVDV and CDV (canine distemper virus)
what are the 4 major problems/results of a viral infection on the lymphnodes?(1) lymphocytolysis (2) stimulation of lymphoid tissue (other tissue, not node itself, so node still small) (3) neoplasia (4) inclusion bodies
small lymphnodes due to stimulation of lymphoid tissue (but not the nodes, so they remain SMALL) can be caused by what kinda viruses? maedi-visna virus, MCF (malig cat. fever) virus, Aleutian mink disease virus...
small lymphnodes can be caused by viruses, which cause neoplasia. what are some examples of this?FeLV, BLV, Marek‟s disease
small LNs---> viruses--> inclusion bodies can be caused by some viruses which also cause small LNs. what's an example of this?porcine inclusion body rhinitis
**the FOLLICULAR area is refering to what kinda cells in the LNs?B-CELLS!!
**the DIFFUSE area is referring to what kinda cells in the LNs?T-CELLS!!
What is happening in acute lymphadenitis?infection of the regional lymphnodes, resulting in enlarged lymphnodes. lymphangitis (afferent lymphatics) might also occur
what is lymphangitis?inflammation of the afferent (incoming) lymphatics
what makes chronic lymphadenitis different from the acute? (defining charateristics). and example of something which causes chronic lymphadenitis?Chronic suppurative (active) lymphadenitis with abscess formation, there is often ENCAPSULATION and inspissated caseous pus (concentric circles of pus). ovine caseous lymphadenitis is a cause of this.
Chronic lymphadenitis can be of a GRANULOMATOUS type. What are some examples (2 major) which cause a FOCAL granulomatous chronic lymphadenitis? (diffuse?)FOCAL: Tuberculosis, cryptococcus, actinobacillosis (wooden tongue. do NOT confuse with actinomycosis, which is lumpyjaw). DIFFUSE type examples are histoplasmosis(macrophage laden with yeasts forms), Leishmaniasis(Macrophage with amastigotes), johne's
in granulomatous inflammation, where is the causative agent?in the CENTER, enclosed in CT.
*what is a “club clony” /(“asteroid body”)?in a granulomatous inflammation, there will be eosinophilic material around the pathogen. That eosinophilic material is the club clony/asteroid body
what is the most common primary neoplasm of LNs?LYMPHOSARCOMAS!!!
pigmentation--> RED. what are some reasons LNs would be red? (3)(1) drainage of erythrocytes from a hemorrhagic or acutely inflamed area or from hyperemia of the LN in acute lymphadenitis (RBCs rapidly undergo erythrophagocytosis by sinus histiocytes -->hemosiderin deposits red also) (2) in porcine LNs, with large sinuses under the capsule, blood in these nodes is very obvious (3) frequently seen in acute septicemias: hemorrhage is due to endotoxin-induced vasculitis or DIC
pigmentation--> BLACK. what would cause black LNs?usually CARBON! often from pulmonary anthracosis which is draining into the LN, but can happen on its own also (expect lung involvement)
pigmentation--> melanin. what are some reasons there would be melanin in the LNs?(1) CHRONIC DERMATITIS. (melanocytes may be destroyed and their melanin released into the dermis (pigmentary incontinence), and the pigment is then transported in macrophages to the regional LN) (2) areas of CONGENITAL MELANOSIS (inc pigmentation) can be drained by the LNs and get stuck in them, this happens often in pigs (3) metastasizing malignant melanomas might drain and stain LNs black also
pigmentation--> Parasitic hematin. this is produced by what?excretory product of many flukes. Often liver flukes, and it drains to the liver LNs to stain them brown-black.
pigmentation--> BROWN. What would cause LNs to be brown?from hemosidirin, which is a breakdown product of RBCs
hemosiderin comes from where, and colors LNs how?brown to gold-brown staining from the breakdown products of Hb. (positive Fe stain)
**which animal would you be least concerned about if you saw they had brown-black LNs?the LNs of ruminants are often normallydiscolored by a brown to blackish pigment
when/where would you see chyle in the LNs? what exactly is this?youd see it post-prandial, there will be white, milky distention of mesenteric nodes (fat-impregnated lymph is chyle, fat from GI)
give three times of when there would be GAS in the LNs?(1) intestinal emphysema in pigs (mesenteric LNs) (2) pulmonary emphysema in cattle (tracheo-bronchial LNs) (3) anaerobic infection (LN draining this area) (clostridia is notorious for making gas)
HYPERPLASIA IS AN IMPORTANT CAUSE OF LYMPHADENOPATHY. 4 causes/types of hyperplasia are...(1) follicular and diffuse lymphoid hyperplasia (2) acute lymphadenitis (3) chronic lymphadenitis (4) neoplasia (primary or metastatic)