Path 2 - Hemolymphatic System 2

hipebiju's version from 2016-02-07 19:43

Spleen continued

Question Answer
What are the 4 categories of Splenomegaly?Bloody spleen
Meaty spleen
Splenic nodules w/ a bloody consistency
Splenic nodules w/ a firm consistency
What are the 3 main czs 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 czd by B abesiosis, or EIA)
Enlargement & firm consistency of meaty spleen is due to what?PROLIFERATION OF CELLS (esp macrophages in the red pulp)
Congestion czs what kinda Splenomegaly?Bloody
Acute hyperemia czs what kinda splenomegaly?Bloody
Acute hemolytic anemias cz what kinda Splenomegaly?Bloody
Bacteremias & low-grade septicemias cz what kinda Splenomegaly? Why?Meaty (Hyperplasia of macrophages & accumulations of neutrophils)
Chronic infectious Dzs cz what kinda Splenomegaly & why?Meaty, bc macrophage hyperplasia in the red pulp to phagocytose organisms, bacteria, or parasitized erythrocytes
Prolonged hemolytic anemias cz what kinda Splenomegaly & why?Meaty, bc spleen is firm & red but not as congested (as acute hemolysis) since fewer erythrocytes are being phagocytosed; bc of EV hemolysis of altered RBCs, the red pulp may be red to dark red but does not ooze blood; Hyperplasia of T-& B-lymphocyte areas also contributes to Splenomegaly.... EIA falls into this category. EMH contributes to the meaty as well
Lymphoid hyperplasia czs what kinda Splenomegaly & why?MEATY, bc PALS & splenic follicles become hyperplastic in response to chronic antigenic stimulation
Neoplasia can cz 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 Dzs, or amyloidosis) lead to what kinda Splenomegaly?MEATY
Extramedullary hematopoiesis (EMH) leads to what kinda Splenomegaly?Meaty! (↑ In cellularity)
Splenic myeloid metaplasia, histiocytosis & hypersplenism in the dog czs what kinda Splenomegaly?Meaty
Hematomas induced by lymphoid hyperplastic nodules leads to what kinda Splenomegaly?Bloody nodules (Arise idiosyncratically in canine & feline spleens, not associated w/ 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 & why?Bloody nodules! Appear as discrete, deeply congested areas w/ focal capsular distention. As the lesion develops, it becomes wedge-shaped & gray-white w/ the base at the splenic capsule. Later a scar forms.
Nodular hyperplasia leads to what kinda Splenomegaly?Firm nodular
Granulomas (chronic infectious Dzs) cz what kinda Splenomegaly?Firm nodular
Abscesses (acute infectious Dzs) cz what kinda Splenomegaly?Firm nodular
Splenomegaly → pathogenic mechanisms → ↑ fxn. What are 3 situations where there would be ↑ fxn leading to Splenomegaly?(1) Removal of defective RBCs such as spherocytes, or if there are Hbopathies (abnormal Hb will cz the RBC to be removed)
(2) Immune hyperplasia will cz enlargement, this type of hyperplasia usually happens w/ infxns, or disordered immunoregulation (IMHA)
(3) EMH (extramedullary hematopoiesis)
Splenomegaly → pathogenic mechanisms → Abnormal blood flow. What are 3 situations where abnormal blood flow would lead to Splenomegaly?(1) Organ failure such as cirrhosis or congestive heart failure will cz a backup of blood into the spleen & enlarge it
(2) Vascular abnormalities, such as OBSTRUCTIONS (hepatic vein, portal vein, splenic vein) will cz ↑ blood flow
(3) Infxns can also affect blood flow
Splenomegaly → pathogenic mechanisms → infiltration. What are 2 types of infiltration which can cz Splenomegaly? (Explain a little)(1) Metabolic dzs such as Amyloidosis, or glycogen storage dzs, fill the spleen up w/ stuff & cz it to be enlarged
(2) Neoplasias benign or malig, can cz 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 & 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
**TQ: Chronic hemolytic anemia (EIA) leads to what Splenomegaly??MEATY!!
Bloody nodules in Splenomegaly → Hematomas induced by lymphoid hyperplastic nodules. Explain how this happens & 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 an immunodeficiency have on the development of the spleen?Czs a small spleen. IT will be small, firm & pale red, a lack of lymphoid follicles & PALS & very few plasma cells
What is an "Accessory spleen"Super small spleen usually as result of an 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?)
****TQ: A small spleen can be due to Wasting and/or cachectic Dzs. what parts of the spleen are affected to cz 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 BTWN LEUKEMIA & LYMPHOMA??Leukemia comes from the bone marrow, Lymphosarcomas come from outside of the BM (like lymph nodes). 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)
Metastatic neoplasms (uncommon)

Lymph Nodes

Question Answer
What are the main fxns of the LNs?Filter lymph
Immune response (production of IgG)
Response to injury → hyperplastic changes. What becomes hyperplastic?Cells of the monocyte macrophage system & lymphoid tissue (hyperplasia w/ the production of antibody, immediate cell-mediated immunity (CMI))
Inflammation (lymphadenitis) can be chronic or acute, what kinda situations typify this?Acute-micro-abscess & abscess formation. Chronic-abscesses & granulomas
What is Lymphadenopathy?LN enlargement, often a sign of dz
(What is happening in Congenital hereditary lymphedema? who is prone?)Lymphatics are aplastic & LNs (peripheral & central) are hypoplastic. Happens most often in cattle & dogs & results in generalized subcutaneous edema, w/ fluid in serous cavities & are often stillborn
(Developmental disorders) what are the lymph nodes like in SCID dogs & horses?SMALL LNs! absence of lymphoid follicles & corticomedullary differentiation. Also few to no lymphocytes & plasma cells
What affect does a lack of antigenic stimulation have on the lymph nodes?It will cz a SMALL LN, bc 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 & germinal centers are so variable?Bc they are NOT permanent structures. The number of follicles ↑ or ↓w/ changes in the intensity of the antigenic stimuli & germinal centers go through a cycle of activation, depletion & rest
**TQ Small LNs → Cachexia & malnutrition. How are the LNs affected by this, specifically?Czs 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 lymph nodes will be smaller. (cortex is reduced, loss of B lymphocytes & T lymphocytes, absence of follicles)
**What situation czs LYMPHOCYTOLYSIS in the lymph nodes??VIRUSES!! Especially BVDV & CDV (Canine Distemper virus)
What are the 4 major problems/results of a viral infxn on the lymph nodes?(1) Lymphocytolysis
(2) Stimulation of lymphoid tissue (other tissue, not node itself, so node still small)
(3) Neoplasia
(4) Inclusion bodies
Small lymph nodes due to stimulation of lymphoid tissue (but not the nodes, so they remain SMALL) can be czd by what kinda viruses?Maedi-Visna virus
MCF (Malig Cat. Fever) Virus
Aleutian Mink Dz Virus...
Small lymph nodes can be czd by viruses, which cz neoplasia. What are some examples of this?FeLV
Marek’s Dz
Small LNs → viruses → inclusion bodies can be czd by some viruses which also cz small LNs. what's an example of this?Porcine inclusion body Rhinitis
**The FOLLICULAR area is referring 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?Infxn of the regional lymph nodes, resulting in enlarged lymph nodes. Lymphangitis (afferent lymphatics) might also occur
What is lymphangitis?Inflammation of the afferent (incoming) lymphatics
What makes chronic lymphadenitis different from the acute? (Defining characteristics) & example of something which czs chronic lymphadenitis?Chronic Suppurative (active) Lymphadenitis w/ abscess formation, there is often ENCAPSULATION & inspissated caseous pus (concentric circles of pus). Ovine Caseous Lymphadenitis is a cz of this.
Chronic lymphadenitis can be of a GRANULOMATOUS type. What are some examples (2 major) which cz a FOCAL granulomatous chronic lymphadenitis? (Diffuse?)FOCAL: Tuberculosis, Cryptococcus, Actinobacillosis (wooden tongue. do NOT confuse w/ Actinomycosis, which is Lumpy Jaw)
DIFFUSE: Histoplasmosis (macrophage laden w/ yeasts forms), Leishmaniasis (Macrophage w/ amastigotes), Johne's Dz
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 1° 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, w/ 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 cz 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 & their melanin released into the dermis (pigmentary incontinence) & the pigment is then transported in macrophages to the regional LN)
(2) Areas of CONGENITAL MELANOSIS (↑ pigmentation) can be drained by the LNs & get stuck in them, this happens often in pigs
(3) Metastasizing malignant melanomas might drain & stain LNs black also
Pigmentation → Parasitic hematin. This is produced by what?Excretory product of many flukes. Often liver flukes & it drains to the liver LNs to stain them brown-black.
Pigmentation → BROWN. What would cz LNs to be brown?From hemosiderin, which is a breakdown product of RBCs
Hemosiderin comes from where & 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 normally discolored 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 3 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 infxn (LN draining this area) (Clostridia is notorious for making gas)
HYPERPLASIA IS AN IMPORTANT CZ OF LYMPHADENOPATHY. 4 czs/types of hyperplasia are...(1) Follicular & Diffuse Lymphoid Hyperplasia
(2) Acute Lymphadenitis
(3) Chronic Lymphadenitis
(4) Neoplasia (primary or metastatic)