Path 2 - Hemolymphatic System 1

rilohoji's version from 2017-01-29 14:02


Question Answer
Component organs/tissues of the hemolymphatic system are...Thymus
Lymph nodes
Bone marrow
What is the Reticuloendothelial system (RES)? What does it contain? How is it divided?It is a part of the immune system which has phagocytic cells (Monocytes, Macrophages, Kupffer cells, Histiocytes, etc) in a reticular connective tissue. This system is divided into 1° & 2° lymphoid organs
What are the 1° organs of the lymphatic system? 2°? What is their purposes (as a 1° or 2° in general)PRIMARY: Thymus (T-cells), Bone marrow (B-cells). This is where the cells of the RES are produced
SECONDARY: Spleen, Lymph nodes, Tonsils, “MALT” & lymphatic vessels. This is where the cells of the RES fxn
The thymus is the reqd site for _________ maturationT-cell
What are the 3 lymphatic fxns?Fluid balance
Absorption of digested fats
Where is the thymus usually & which animal has a unique placement of it (& where)?Usually in the cranial mediastinum, but in the PIG it is in the ventro-lateral jugular grooves in the neck
What’s a thymocyte?A developing T-cell
*What kind of immunity does a Combined Immunodeficiency (CID) affect?Both humoral & cell mediated immunity (B & T cells) (remember: there is Innate (macrophages & shit) & acquired. & acquired is broken into humoral & cell mediated. & cell mediated is just T cells)
Who usually gets equine CID (combined immunodeficiency) & how?This is a congenital autosomal recessive trait most often seen in Arabian (or part Arabian) foals
What is the defect/problem occurring in equine CID? What does it lead to?Failure of fxnal B & T lymphocyte production → ↑ susceptibility to various pathogens → death before 5 months of age
How does a foal w/ CID end up dying & when?Usually dead by 5 mos. They have no B or T cells, so after the protective colostrum Abs are worn out, they are open to infxn. Usually due to an adenovirus infxn, but also could be bacterial/protozoal & often leads to pneumonia & death
What are the gross lesions of equine CID?Severe bronchopneumonia
Small thymus/spleen/LNs
Thymus might be difficult to ID
What are the microscopic lesions of equine CID?Reduction in the white pulp of the spleen due to absence of germinal centers & PALS, lymphocyte depletion in lymph nodes
Aside from horses, what other animals can get CID?X-linked severe CID (XSCID) in basset hounds & Immunodeficiency syndrome in juvenile llamas
Who gets XSCID & what are the problems/lesions?Male basset hounds, affected male pups lack mature, fxnal T-lymphocytes. Thymus is very small, tonsils, LNs & Peyer's patches usually unidentifiable at necropsy.
Thymitis can be czd by what 3 dzs he mentioned?(1) Porcine Circovirus 2 infxn (Post Weaning Multisystem Wasting Syndrome [PMWS])
(2) Enzootic Bovine Abortion (EBA)
(3) Salmon Poisoning Dz of dogs (Neorickettsia helminthoeca)
Degenerative disorders → acquired immunodeficiency → Viruses. What kinda damage do viruses cz to result in immunodeficiency? Give some examples of viruses which do thisLymphocytolysis of the cells of the germinal centers & cortex, leading to a loss of thymic architecture
CDV (Canine Distemper)
EHV-1 (Equine Herpes Virus 1)
Feline Parvovirus
FIV (Feline Immunodeficiency Virus)
BVDV (Bovine Viral Diarrhea Virus)
Degenerative disorders → acquired immunodeficiency → toxins. What are some toxins which can cz this through ATROPHY?Polychlorinated biphenyls (PCBs)
Pb (Lead)
Hg (Mercury)
Degenerative disorders → acquired immunodeficiency → toxins. What are some toxins which can cz this through lymphocytolysis?Fumonisins B1 & B2
Degenerative disorders → acquired immunodeficiency → toxins-which toxin can cz this in PIGS?Aflatoxins → lymphocyte depletion → thymic atrophy (aflack as a pig)
How can chemotherapy/radiation affect the thymus?It can cz acquired Immunodeficiencies by inhibition of cell division & activation of lymphocytes → immunosuppression
How can malnutrition affect the thymus?It can lead to an acquired immunodeficiency! The malnutrition leads to thymic atrophy + reduction in thymic hormone output, reduction of T-lymphocytes in the blood, depletion of T-lymphocytes from 2° lymphoid organs & impairment of T-lymphocyte fxns
**Which cz of immunodeficiency leads to LYMPHOCYTOLYSIS?VIRUSES!!!!
CDV (Canine Distemper)
EHV-1 (Equine Herpes Virus 1)
Feline Parvovirus
FIV (Feline Immunodeficiency Virus)
BVDV (Bovine Viral Diarrhea Virus)
Fumonisins B1 & B2
The thymus can get an acquired Immunodeficiency from what 4 things happening (results of things causing it)Lymphocytolysis
Loss of architecture
Reduced lymphocyte populations
*What are the 2 categories of neoplasias the thymus can get?Lymphoid & epithelial
*What is the lymphoid neoplasia that the thymus gets? Who usually gets it & what are the clinical findings?Thymic lymphoma. It is a T-lymphocyte neoplasm of young animals (cats, calves, dogs). There will be a large mass in the cr mediastinum which can lead to dyspnea. The thoracic aspirates will have medium to large lymphocytes w/ vacuolated cytoplasm, a feature unique to neoplastic lymphocytes in fluid + mitoses
*What is a property unique to neoplastic lymphocytes in fluid? (Such as in a thoracic aspirate)Medium to large w/ vacuolated cytoplasm
*Bovine Thymic Lymphoma usually occurs at what age, how does it present & what is the cz?Usually shows at 6 - 24 mo, there is a massive thymic enlargement (kinda looks like a giant lump coming off the top of their sternum) & it is IDIOPATHIC!
*How does Thymic Lymphoma appear in cats? What are the problems it czs?Large, white or gray mediastinal masses which will displace adjacent structures & result in fluid accumulation (can be chylous if lipid accumulation)
*What is the epithelial neoplasia of the thymus?Thymoma
*What is a thymoma? When is it usually seen? What does it look like & what does it behave like?Benign tumor of thymic epithelial cells + a mixture of nonneoplastic lymphocytes. It is uncommon but usually seen in older animals & is benign & slow-growing-encapsulated, nodular, firm masses w/ soft & cystic areas
****What 2 (or 3, 1 relates to 1 of the original 2) Dzs that thymomas are related to in DOGS?Myasthenia Gravis (+/- megaesopahgus) (epithelial cells can produce ACH & has an effect w/ this)
Immune-mediated polymyositis ("inflammation of many muscles")
*What does a thymoma look like cytologically?Small lymphocytes & round to spindle-shaped epithelial cells ±mast cells, but small lymphocytes w/ few medium & large lymphocytes
What might cz Thymic hyperplasia?Rare condition which results from the formation of B-lymphocyte follicles w/in the thymus, usually associated w/ Myasthenia Gravis in dogs & cats
Thymic hemorrhage & hematomas usually happen in WHO? What does it ultimately lead to?DOGS, the massive hemorrhage usually leads to hypovolemic shock → death
**What would be 3 main etiological czs of Thymic hemorrhage & hematomas?(1) Rupture of dissecting aortic aneurysms
(2) Trauma from automobile accidents
(3) Ingestion of anticoagulant rodenticides (Warfarin, Dicumarol, Diphacinone, Brodifacoum)

Spleen ("The filter of blood")

Question Answer
What is a unique feature of the horse spleen??Red foci of red pulp protruding through the capsule, they LOOK like hemorrhages, but they are normal!
Shape of horse spleenComma shaped
Shape of rumi spleenFlat & oval (organ is tightly adhered to the lateral surface of the rumen)
Shape of a pig spleenLong, triangular on cross section
Shape of dog spleen?Boot-shaped
Shape of cat spleen?Long & flat
Shape of bird spleen?Round
Which drugs can cz splenic mm relaxation, which can cz spleen engorgement during euthanasia?Barbiturates
What are 3 reasons a spleen could rupture?HBC (hit by car)
Rupture of neoplasm (hemangio(sarco)ma, lymphosarcoma)
Splenomegaly predisposes ("pathologic rupture” at sites of hematomas & infarcts)
What are 3 sequale which might result from a ruptured spleen?(1) Death from exsanguination
(2) Healing my scarring
(3) There may or may not be numerous fragments of spleen throughout the abdominal cavity & mesentery
What is splenosis? What is it a result from? Whats the cute nickname for it?"Splattered spleen syndrome" happens when the spleen ruptures. It's where there are numerous fragments of spleen throughout the abdominal cavity & mesentery
Torsion of the spleen is associated w/ what in dogs?GDV
**What are Gamna-Gandy bodies?Sidero-calcific plaques of capsule of spleen in old dogs (gamma is a `crusty-old` character now, doing `side`-jobs)
What is a unique sign of siderofibrosis in older dogs?Sidero-calcific plaques of capsule (Gamna-Gandy bodies) in aged dogs
What do the gross lesions of siderofibrosis on the spleen look like?(Has Iron content bc from hemosiderin, the siderin is the pigment)
Granular, whitish to yellow, firm, dry, encrustations on the capsule (especially along the margins) (Crusties on the SIDE…ero)
What do the microscopic lesions of siderofibrosis on the spleen look like?It would look multicolored in an H&E, at 1st it would be yellow (early, bile), then golden-brown (it becomes hemosiderin), then blue (Ca++ stained by hematoxylin ← the H in H&E)
What are 2 reasons you might see siderofibrosis?(1) Aging in dogs
(2) Sequale to previous hemorrhage (makes sense, since the pigment is coming from blood)
Amyloidosis of the spleen.... aka? What does it look like?Aka "Sago spleen". It has a prominent white pulp & homogeneous deposits around & w/in lymphoid follicles... stains positive for amyloid (Congo red stain!)
What does "starry sky effect" mean?Lysis of lymphocytes czs this effect (lymphoid necrosis)
What czs lymphoid necrosis of the spleen (3) & what are the lesions called?(1) Acute viral infxns
(2) Mycotoxicosis
(3) Stress
Lesions are: Lymphocytolytic = Lysis of lymphocytes ("starry sky effect")
What is hemosiderosis? Is this abnormal? What are the lesions?Pigmentation which is the storage form of iron. A normal amount of this varies w/ species & age
The lesions are usually:
(1) Holden brown granules in macrophages (positive by Fe stain)
(2) Brown to brownish-black (if severe)
What are some czs of hemosiderosis?Breakdown of erythrocytes (physiologic)
Reduced rate of erythropoiesis (less demand for iron) ie anemia of chronic Dz
Hemolytic Anemia
Chronic heart failure
Iron dextran injxn in pigs
Hemorrhage (trauma)
Pigmentation or degradation-siderofibrosis, hemosiderosis, amyloidosis?Siderofibrosis: Necrosis/degeneration
Hemosiderosis: Pigmentation
Amyloidosis: Necrosis/degeneration
Acute passive congestion of the spleen can be czd by? What does it look like? (2)Could be due to Barbiturates or shock. It is swollen w/ blood, reddish-black to purple
(Splenic hypermegaly w/ congestion "meaty spleen")
Chronic passive congestion (rare) of the spleen can be czd by?Right sided heart failure (blood backs up)
Portal hypertension
What is "Blackberry jam spleen" a nickname for? (What condition?)ACUTE splenitis
What is acute splenitis aka? What czs this? (2)"Blackberry jam spleen"
(1) Anthrax
(2) Septicemia (such as in Erysipelas)
Hyperplastic splenitis looks like what? What usually czs it?The spleen is swollen, red, firm, w/ reticular cell hyperplasia (the white pulp is prominent, spleen looks "spotty" on cross section). Usually czd by subacute septicemia (ie Salmonellosis) (SUBs go to HYPERspeed)
*Granulomatous splenitis looks like what & is czd by what? (Overall & 2 examples)The lesions are multiple pale *nodules* or diffusely swollen & firm. Czd by CHRONIC inflammation, such as in TB, or systemic mycoses
Purulent splenitis looks like what & what are the czs? (2 examples)The lesions are abscesses & 2 main czs are:
(1) Local extension from penetrating wounds in reticulum (hardware dz)
(2) Caseous lymphadenitis in goats & sheep
What are the lesions of splenic atrophy & what usually czs this?The spleen ↓ in size & weight, the capsule is thick & wrinkled & there is lymphoid depletion. This is usually due to AGING (esp dogs & horses), or prolonged cachexia (wasting)
Describe the lesions in nodular hyperplasia-& who gets this most often?White to red, single or multiple raised nodules which are usually 2cm or less in diameter (looks like a bigass knob). Histologically, there are variable proportions of white & red pulp. Sometimes w/ hemorrhage (-/+ hematoma). OLD DOGS get this the most!!!!
When is extramedullary hematopoiesis normal (physiological) in the spleen?In all YOUNG animals & rodents of any age
Histologically, you can tell the spleen is performing EMH bc youd see...Megakaryocytes
Erythroid precursors
Describe "Bloody spleen"Uniform Splenomegaly w/ a bloody consistency (wet)
Describe "Meaty spleen"Uniform Splenomegaly w/ a firm consistency (dry)