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213 Cards in this Set

  • Front
  • Back

What are the primary lymphoid organs?

Thymus and bone marrow- where the sites of the immune system are formed

What are the secondary lymphoid organs?

Spleen, lymph nodes and lymph nodules




responsible for immune responses

If the lymphoid organs are abnormally functioning, what disorders or things can result?

1. Hypersensitivity or Allergic reactions


2. Immune-mediated disease


3. Immunodeficiency

Describe the maturation cycle/style of both the B lymphocytes and the T lymphocytes

B lymphocytes- 2 phases, antigen independent and antigen-dependent phases. First phase is in the bone marrow, second phase is in the secondary lymphoid tissues




T lymphocytes- originate in the bone marrow, mature in the thymus and then migrates to the secondary lymphoid tissues

If an animal dies from bone marrow failure? What is the death actually a result of?

Lack of blood cells, NOT a lack of lymphoid cells

When evaluating the thymus histologically, in a general sense, what kind of things are you looking for?

Inflammation of the thymus, decreased size, decrease in lymphocytes, increased cellularity within the medulla, areas of asymmetry, etc.

What are the 6 things that cause a decrease in the size of the thymus?

1. Congenital immunodeficiency disorders (Ex. SCID in foals, and in Jack Russell Terriers)


2. Infectious agents, bacteria, viruses (Ex. Parvo, BVD)


3. Drugs or immunotoxins


4. Severe Stress


5. Irradiation


6. Starvation/malnutrition

What is the most common cause of an enlarged thymus?




What are the two different types?

Neoplasia-




1. Thymoma- neoplastic epithelial cells, non-neoplastic lymphocytes. Older animals, invasive, myasthenia gravis associated (dogs)




2. Lymphoma- neoplastic proliferation of lymphocytes- T cell neoplasm of young cattle and cats (less so in dogs)

What are the three more uncommon causes of an enlarged thymus?

1. Hyperplasia of unknown significance




2. Hematoma/Hemorrhage- can cause acute death of unknown cause, may be anti-coagulant toxicity?




3. Inflammation- porcine circovirus 2 infection and occasionally bacterial septicemias

What are the functions of the spleen?

1. Lymphocyte production and immune response to blood-borne particles




2. Storage of RBCs and platelets




3. Filtration and Phagocytosis (foreign antigens, aged cells)




4. Extramedullary Hematopoiesis

What is found in the red pulp of the spleen?




The white pulp?

White- germinal centers, lymphocytes




Red- monocytes, macrophages, red blood cells

How do you diagnose splenomegaly?

Physical Exam




Diagnostic Imaging




(can't be done definitively on serum chemistry)

What are the causes of splenomegaly?

(uniform spleens that ooze when you cut into it)
Acute or chronic congestion- obstruction of blood flow from spleen

(From drugs (euthanasia), acute/chronic right sided heart failure, portal hypertension from liver disease, splenic torsion, splenic vein thrombosis, anthrax)

Splenomegaly with Nodules is most commonly caused by what?

Hematomas, commonly confused with neoplasia (hemangioma, hemangiosarcoma)




*histology to diagnose

What changes are seen in a kidney due to extramedullary hematopoeisis?

Diffuse or nodular enlargement, due to the increased demand for blood cells




(can be due to many conditions)




Look for increased precursor cells on cytology/histology

If you had hyperplasia from an increased need of normal resident cells in the spleen, where would you expect the spleen to enlarge if you needed more;


B cells?


T Cells?


Macrophages?


Other reasons it may be grossly expanded?

B cells- nodules in white pulp


T cells- expansion of periarterial sheaths in white pulp


Macrophages- expansion of red pulp




Other bloodborne antigens, particulate material- infections, immune-mediated, hemolytic anemia, neoplasia

Splenitis causes what kind of changes in the spleen?

Diffuse to nodular enlargement, hyperemia, necrosis, lymphoid cell lysis, influx of non-lymphoid inflammatory cells




Abscess or granuloma formation




Seen when systemic infections occur

Nodular lymphoid hyperplasia of the spleen means what as far as a diagnosis?

Incidental, not a precursor to lymphoma, unknown cause




Seen in older dogs




NOT neoplasia!


*histopath is the only way to diagnose definitively, neoplasia will lose architecture. Nodular hyperplasia will maintain normal architecture

Neoplasia in the spleen causes what kind of gross and histologic changes?

Diffuse or nodular enlargement




Hemangioma/hemangiosarcoma- endothelial cell origin, presenting with acute hemorrhage into the abdomen


(need histopath to differentiate between)

If lymphoma was the diagnosis, what changes would you expect in the spleen?

Diffuse* sometimes nodular splenomegaly

What are the causes of a decreased splenic size?

Splenic contraction


Atrophy- old age or CWD


Immunosuppressive drugs or toxins


Congenital immunodeficiency syndromes

What are the things that would cause a spleen to rupture?

Physical trauma




May lead to the seeding of splenic fragments in the abdominal cavity

Define Siderotic Plaques

Yellow to tan dry plaques on the surface of the spleen that are in older dogs as an incidental finding. May be areas of old hemorrhage

What are the functions of the lymph nodes?

Filtration of lymphatic fluid- phagocytosis and immune response to antigens

in a germinal center of a lymph node, what type of immune cell predominates?




The paracortical area?

B cells




paracortical area- T cells

Define the medullary sinuses of lymph nodes




Medullary cords?

Sinuses- enlarges spaces with lymph and a few lymphocytes




Cords- masses of lymphocytes

What is the histology seen with lymph node hypoplasia?

Overall decreased lymphocyte density with normal architecture.




(cannot find hypoplasia on PE or on cytology)

What signs within a lymph node would make you suspicious of a congenital immunodeficiency (such as SCID in arabian foals and jack russel terriers)

Follicles- poorly developed/absent B cells (also seen in spleen)


Paracortical zones- hypocellularity (also seen in periarteriolar sheeths in spleen)




Blood- decreased immunoglobulins, lymphopenia


Thymus- atrophy

What are some causes of acquired atrophy of the lymph nodes?

Infections- viruses that target lymphoid cells


Immunosuppressive/immunotoxic drugs or toxins (cancer drugs)


Malnutrition/cachexia


Age

What is the cause of lymphadenopathy/hyperplasia of the lymph nodes?

Response to immune stimulation. Can be either localized (draining a specific area of infection) or systemic in response to a systemic disease/neoplasia




*RARELY idiopathic




Associated with an increase in B cells in germinal centers, T cells in paracortical areas, macrophages in sinuses. RETAINED ARCHITECTURE

What is lymphadenitis?

Influx of inflammatory cells into the lymph node. Can be systemic or local, depending on disease.




Often accompanied by hyperplasia but can be seen alone

What are the causes of lymphadenitis?

Infections!


Simple bacteria = neutrophillic response


Complex organisms = histiocytic or mixed neutrohilic/histocytic response




Eosinophilic due to allergies, parasites, some neoplasias (ex, mast cell tumors)


*look for a mixed healthy population of cells, rather than neoplastic cells

Corynebacterium Pseudotuberculosis causes what lesions in the lymph nodes?

caseous Lymphadenitis, onion like accumulation of necrosis in the lymph nodes of sheep

What does TB look like in the lymph nodes?

Multifocal caseous abscesses with mineralization, with a gritty texture




*look for lesions in mediastinal, retropharyngeal, hepatic, mesenteric, etc. (12 lymph nodes that are examined)




Definitive diagnoses with Ziehl-Neelson stain for the TB organisms

Define lymphoma

Malignant proliferation of neoplastic lymphocytes outside the bone marrow (inside the bone marrow would be leukemia)




One or more lymphoid organs are enlarged, either diffuse or nodular




Most common hematopoietic neoplasm- highest prevalence in dogs and cats

What clinical signs are presented with a case of lymphoma?

Depends on where it started- dyspnea, vomiting, diarrhea, polyuria/polydypsia, etc.




Most cats- ill with no lymphadenopathy


Dogs- completely fine except for lymphadenopathy




Difficult diagnosis to make if the small lymph nodes are the neoplastic lymph nodes

What are the ways that lymphoma can be classified grossly?

Multicentric- peripheral lymph nodes +/- internal organ systems




Alimentary- intestine, mesenteric LN +/- internal organ systems




Thymic/mediastinal


Cutaneous


Solitary, regional or extranodal (depending on site(s) involved)

What histology would you expect to find with lyphoma?

Disruption of normal architecture*


Loss of cellular heterogeniety


increased mitosis




Immunophenotyping- tells you if it's B cell or T cell tumor

What are the etiologic causes of lymphoma?

Viral associations- FeLV, FIV, BoLV




Others- tobacco smoke, herbicides/environmental pollutants, magnetic fields, hereditary predisposition


*no known viral association in dogs

What things are associated with a poorer prognosis in lymphoma?

T cell lymphomas


bone marrow involvement


Clinical signs seen upon presentation


Incomplete initial response to chemotherapy

What is the most common form of lymphoma in horses?

Multicentric- spleen and liver involvement




(alimentary form brings about profound weight loss)


(cutaneous form is chronic without blood or internal organ involvement)

In adult cattle, the most likely cause of lymphoma is what?

BLV infection, between 5-8 years old




In young animals, the thymic, cutaneous and multicentric forms are not BLV associated

What forms of lymphoma are found in cats?

FeLV associated- leading to mediastinal and multicentric forms of lymphoma




In FeLV negative cats- Alimentary form in cats 10 years old or older is the most common

In general, what is the normal heart weight to body weight percentage?




What is the species that we often use this comparison to determine if the heart is enlarged or not?

0.3%-1.25% of body weight is normal.


In cats, 17g is the magic number of heart weight, any higher, we start to think hypertrophy




(pigs, smallest heart, athletic dogs, largest, neonates larger than adults)

Compare/contrast the growth of the heart in neonates and adults

Neonates- hyperplasia occurs in first few months, regeneration is limited




Adults- hypertrophy only


Regeneration does NOT occur in "higher vertebrates", limited regeneration in some species

In acute situations, how does the heart compensate?




Chronic?

Acute- increased HR, increased peripheral resistance, redistribution of blood flow




Chronic- myocardial hypertrophy, cardiac dilation

Define hypertrophy of the heart cells.

Increase in mass of the cardiac mycotes but NOT number. (An increased number would be hyperplasia.) Due to an increase in work load in the heart




Seen as a normal physiologic process or can be pathologic or idiopathic


*physiologic is reversible, pathologic is usually not reversible

What are the two reversible morphologic changes seen in the heart muscle?

Hypertrophy of myocardium




Atrophy of the myocardiaum

What is the most common lethal injury of the heart cells?

Injury to the myocytes, leading to necrosis




Will see increased interstitial stroma and vessels, collapsed sarcolemma and fibrosis/collagen deposition




*fibosis is the most common end-stage response of the heart

What are the syndromes associated with cardiac failure?

Congestive heart failure


Acute heart failure


L sided heart failure-acute and chronic


R sided heart failure- acute and chronic


Cardiac hypertrophy


Cardiac dilation

Define Congestive Heart Failure.




What two things are commonly associated with it?

Gradual loss of cardiac pumping efficiency leading to forward or backward heart failure.




Impaired pump function and increased workload (increased hypertension) both associated with it.


*valvular disease is most common

What is the pathophysiology that ties the kidneys to congestive heart failure?

Decreased renal blood flow = renal hypoxia = activation of RAAS = Na/H2O retention in DCT = fluid retention = increased fluid in body cavities = hypervolemia = increased workload on the heart = continued compensation = eventual heart failure

Acute Forward heart failure would be associated with what clinical signs?

Intermittent weakness/syncope


Sudden/unexpected death




Minimal gross/histologic lesions would point you to this

What are the causes of left sided heart failure?




Clinical signs?

Loss of myocardial contractility (second most common)


Dysfunction of mitral* most common cause or aortic valves


Congenital heart disease




Dyspnea, Cough

Gross lesions of left sided heart failure would be what?

Pulmonary congestion, Edema




Tan hue of the lungs due to hemosiderin laden macrophages in the alveoli (associated with a chronic left sided heart failure)

What are the causes of right sided heart failure?

Cardiomyopathy* most common


Pulmonary hypertension (2nd common)


Tricuspid and pulmonary valve disease




Leads to increased right atrial pressure and systemic venous congestion (backward failure)

What clinical signs are associated with right sided heart failure?




Gross lesions?

Clinical signs- jugular distension, hepatomegaly and splenomegaly




Gross lesions- nutmeg liver (hepatic congestion), edema (ascites in dogs, hydrothorax in cats, ventral SQ in horses and ruminants)

What is concentric hypertrophy?

thickening of the wall, chamber gets smaller




Afterload problem, pressure load causes it




Most commonly due to restricted outflow- valvular stenosis, systemic hypertension, pulmonary disease

What is eccentric hypertrophy?

The wall gets thicker but the chamber gets larger (wall appears thinner)




Caused by volume/preload overload




Commonly due to incomplete emptying of the chamber from septal defects, valvular insufficiencies*most common

Whatis cardiac dilation?

There is an increase in the size of the chamber but there is no hypertrophy of the wall seen




This is compensatory to an increased workload, causing increased stretching that eventually will be detrimental to the heart




(usually end-stage cardiac failure)

What are the common causes of circulatory failure?

Acute internal or external hemorrhage


Dehydration


Endotoxic shock




(can lead to heart failure)

Describe how you perform a necropsy examination of the heart.

1. Incise pericardial sac- nature of volume and quality of the pericardial fluid


2. Remove heart and lungs together "pluck"


3. Examine great vessels


4. Examine gross appearance/shape of heart


5. open heart as if the blood was going through it (right atrium, right ventricle, apex, pulmonary outflow tract). Then flip it over and cut through left atrium, left ventricle, apex, and finally, aorta


*right side, follow the septa. Left side, don't.

If you want to take histologic sections of the heart, which sections do you want to take?

Left ventricular papillary muscle


Right and left ventricular free wall


Interventricular septa

What is the pathophysiology behind rigor mortis in the heart?

Lack of ATP, cannot keep the myofibrils relaxed so they contract and then autolysis of the myocytes occurs




Happens 15-30 min. after death


*if there is clotted blood in the left ventricle, suspect myocardial disease, this should empty out

What are the other post-mortem changes you can see in the heart?

1. Dark red mottling of the myocardium (uneven blood distribution)


2. Diffuse red staining of endo and epicardium (lysis of erthrocytes/imbibition of hemoglobin


3. Flabby ventricles (after rigor)


4. Crystalline deposits (intracardiac barbituates)


5. "currant jelly" clot not attached to the endocardium (no muscle to expel the clot)


6. "chicken fat" clot not attached (coagulation cascade pieces- indicative of anemia or prolonged agonal period, or found in horses due to rapid erythrocyte sedimentation)

What are the two very important shunts that get blood past the lungs in the fetus?

Foramen ovale- between the two atria

Ductus arteriosus- between aorta and pulmonary artery

Foramen ovale- between the two atria




Ductus arteriosus- between aorta and pulmonary artery

The stimuli for the closure of foramen and ductus ateriosus is what?

The animal breathing- changes in oxygen tension and intracardiac pressure

Define valvular insufficiency


Valvular stenosis

Insufficiency- failure to close


*preload increases with insufficiency




Stenosis- narrowing/failure to open


*afterload increases due to restricted outflow


*preload decreases



If the fetal shunts fail to close properly, what three anomalies will develop?

1. PDA


2. ASD


3. VSD

In a PDA, blood is abnormally shunted where?




What is the biggest change seen because of this abnormality?

From the aorta to the pulmonary artery, never reaching the body where the oxygenated blood should go




Biggest change is increased pulmonary arterial pressure! Increased afterload of the right ventricle, leading to concentric hypertrophy


(less common, increased blood returning from pulmonary system, increased preload of atria and ventricle, eccentric hypertrophy of both

What abnormality is seen in this image?

What abnormality is seen in this image?

Patent Ductus Arteriosus

Atrial septal defect is caused by what?




What changes are seen with this abnormality?

Failure of foramen ovale to close




Blood flows from left to right atrium, increasing the preload (eccentric hypertrophy) of the right ventricle, increased volume them causes pulmonic stensosis




In late stage, pulmonary hypertension may develop, resulting in reverse shunt

What is abnormality seen in this image?

What is abnormality seen in this image?

Atrial septal defect

Ventricular septal defects are seen in what species of animals?




What is the pathophysiology?

Horses, cattle and dogs




*most often by the AV valve leaflets, under the aorta or within membranous portions of the septa




Left to right shunt, increasing both preload and afterload in the right ventricle, increased preload in left atrium and ventricle, eccentric hypertrophy and bilateral dilation results

What is the abnormality in this image?

What is the abnormality in this image?

VSD




*most common a higher abnormality but can also be lower

What are the three classifications? 

What is the pathophysiology of this?

What are the three classifications?




What is the pathophysiology of this?

Supravalvular, valvular, subvalvular pulmonic stenosis


(this would be post-stenotic in this image)




Leads to increased afterload on the right ventricle (concentric hypertrophy), and poststenotic dilation of the pulmonary artery

What is the defect seen with tetralogy of Fallot?

1.*Hypoplasia and malpositioning of the conotruncal septum
2. Overriding (dextroposition) of aorta (covers the VSD)
3. High VSD
4. Pulmonic stenosis 
5. Hypertrophy of right ventricle is secondary defect

1.*Hypoplasia and malpositioning of the conotruncal septum


2. Overriding (dextroposition) of aorta (covers the VSD)


3. High VSD


4. Pulmonic stenosis


5. Hypertrophy of right ventricle is secondary defect

As a result of Tetralogy of Fallot, where does blood flow? What changes result?

The degree of the disease determines how much blood bypasses the lungs and goes into the aorta.




Leads to cyanosis and right ventricular hypertrophy because of the increased afterload

What compensatory changes are seen in a heart with aortic/subaortic stenosis?

A malformation of the aortic valve leads to increased afterload and left ventricular hypertrophy

Myocardial necrosis is also seen due to ventricular dysrhythmias

A malformation of the aortic valve leads to increased afterload and left ventricular hypertrophy




Myocardial necrosis is also seen due to ventricular dysrhythmias

What is the most common cardiac anomaly in cats? 

What gross changes are seen with this abnormality?

What is the most common cardiac anomaly in cats?




What gross changes are seen with this abnormality?

Mitral valve insufficiency/stenosis




Leads to an enlarged mitral valve opening, short, thickened valve leaflets and short, thickened chordae tendinae

What is the lesion seen in this image? What is the significance?

What is the lesion seen in this image? What is the significance?

Congenital valvular cysts (can be blood or lymph filled), common in young ruminants. There is no functional significance and they will regress spontaneously

What is the abnormality seen in this image?

What causes this lesion?

What is the abnormality seen in this image?




What causes this lesion?

Endocardial fibroelastosis




Caused by a heritable defect (or secondary to increased ventricular turbulence) in cats/foals where there is thickening of the endocardium with collagen and elastin, leading to restrictive cardiomyopathy

What is the lesion in this image? 

What developmental thing happens to lead to this?

What is the lesion in this image?




What developmental thing happens to lead to this?

Persistent right aortic arch develops (instead of left)- the left goes on to form ligamentum arteriosum


The esophagus and trachea get caught in a vascular ring, obstructing the esophagus

What is the most common non-lesion of the heart?

Hemorrhage on the surface of the heart

What etiologies can lead to hemorrhage in the heart?

Agonal (horses)


Anoxia


Septicemia


Toxemia (Clostridial enterotoxemia)


Nutritional Deficiency (Se, Vit. E)

What is hydropericardium?

Accumulation of normal straw colored fluid

Can cause sudden death if it rapidly fills, stretches out with a chronic slow fill. 
*Fibrin in the fluid if associated with vascular injury

Accumulation of normal straw colored fluid




Can cause sudden death if it rapidly fills, stretches out with a chronic slow fill.


*Fibrin in the fluid if associated with vascular injury

What are the causes of hydropericardium?

Congestive heart failure**


Systemic disease with vascular injury


Renal failure


Salt poisoning (poultry)


Anemia/hypoproteinemia


Generalized edema

What is hemopericardium?




What causes it?

Whole blood in the pericardium, death may occur from cardiac tamponade




Causes: iatrogenic puncture, foreign body, ruptured vessel/chamber, rupture of neoplasm*

What is seen in this image? 

What causes it?

What is seen in this image?




What causes it?

Metabolic alteration, associated with anorexia, starvation and cachexia or parasites, should normally be fat in that pericardial groove

What abnormality is seen in this heart?

What causes it?

What abnormality is seen in this heart?




What causes it?

Fibrinous exudate in the pericardium- gray/yellow/shaggy projections

Longstanding- granulation tissue superficial, fibrosis deep

Caused by bacterial infection! (causes death)

What abnormality is seen in this heart?

 What are the possible causes?

What abnormality is seen in this heart?




What are the possible causes?

Suppurative pericarditis




Thick, yellow pus, bread and butter lesions




Pyogenic bacterial agents present adjuct to pleuritis or bronchopneumonia

What is the classification scheme for endocardial disease?

Degeneration- mineralization, fibrosis, endocardiosis




Inflammation- endocarditis

If someone said it was "mural endocardium", what endocardium do they mean?

The endocardium lining the walls of the chambers

What are the portals of entry into the endocardium?

Hematogenous


Parasitic migration


Intravenous and intracardiac catheters in place for a long time


Uremia-induced vascular damage

Uremia induced endocardial mineralization is a pattern found where?

In the left atrium (and possibly other areas)

What are the overall causes of endocardial mineralization and fibrosis?

Increased intake of Vitamin D


Ingestion of plants containing Vitamin D


Chronic cardiac dilation


Cachexia


Healed uremic lesions


Chronic trauma from turbulent blood flow through diseased valves "jet lesions"

What is seen in the left atrium of this heart? 

What is the most likely cause?

What is seen in the left atrium of this heart?




What is the most likely cause?

This is endocardial mineralization, most likely caused by uremia




Would have gritty feel

What is the most common cause of congestive heart failure?




What kinds of animals is it seen in?

Endocardiosis, degeneration of the valvular collagen


*mitral valve being the most common




Seen most in middle aged to older small and toy breed dogs

Grossly, what lesions are seen with endocardiosis?




What can endocardiosis lead to?

Shortened, thickened valves


Nodular free margins


Thick chordae tendinae


Opaque-white, smooth/shiny appearance


Jet lesions in atria due to regurgitation




Sequelae- atrial dilation and CHF

What is this image showing?

What is this image showing?

Endocardiosis and "jet lesions"

Endocardiosis and "jet lesions"

What is the proposed pathogenesis of endocarditis?

Inflamatory process associated with adherence of bacteria and bacteremia.


Bacteria, with turbulent blood flow results in focal endothelial disruption, inflammation and dibrin deposition

What gross lesions are associated with endocarditis?




What are the sequelae to this disease?

Large, friable adherent vegetations
Rough edges
Fibrin, that can be peeled off

Mitral > aortic > triscupsid > pulmonary

Septic emboli in the myocardium, kidneys- infarction, abscesses, inflammation
Death due to effects of bacteremia and cardiac...

Large, friable adherent vegetations


Rough edges


Fibrin, that can be peeled off




Mitral > aortic > triscupsid > pulmonary




Septic emboli in the myocardium, kidneys- infarction, abscesses, inflammation


Death due to effects of bacteremia and cardiac failure from valve dysfunction

What is this a picture of?

What is this a picture of?

Endocarditis in the valves

What are the portals of entry into the myocardium?




What kind of things can lead to disease in the myocardium?

Hematogenous, embolic




Disturbances of growth (physiologic and pathologic hypertrophy), fatty infiltration, degeneration, necrosis, cardiomyopathies, inflammation

Fatty infiltration in the myocardium is a result of what disease processes?

Obesity (normal in these cases)


Hypothyroidism


Cardiomyopathy

What are the important causes of myocardial necrosis?




What gross lesions are associated with necrosis of the myocardium?

Ionophores


Catecholamines


Vitamin E-Selenium deficiency




Pale patches/streaks, gritty/mineralization throughout the myocardium, subendocardial or within the papillary muscles


(may be scattered, harder to find)

What toxicity leads to this necrosis (but no fibrosis) of muscle?

What toxicity leads to this necrosis (but no fibrosis) of muscle?

Ionophore toxicity, most likely a toxicity from feed additives




*very toxic to horses




Leads to this streaking of muscles but no mineralization

Vitamin E-Se deficiency is associated with what gross lesions?

Focal to extensive pale white streaks with mineralization (tongue, larynx, other larger muscles, heart)

Disease of young animals

Without these compounds, it reduces the free radical injury to cell membranes

Focal to extensive pale white streaks with mineralization (tongue, larynx, other larger muscles, heart)




Disease of young animals




Without these compounds, it reduces the free radical injury to cell membranes

If this was seen in the heart of a dog, what disease would you be suspicious of?

If this was seen in the heart of a dog, what disease would you be suspicious of?

"Brain-heart syndrome", associated with a catecholamine excess when there is neurologic disease, post-trauma, etc.




Gross lesion- multi-focal necrosis

What are the causes of cardiomyopathy?

Primary- idiopathic, progressive cardiac disease


THREE FORMS: hypertrophic, dilated, restrictive




Secondary- generalized myocardial disease of nown cause




*associated with right or left sided heart failure

What are the gross lesions associated with hypertrophic cardiomyopathy in cats?




Sequelae?

Enlarged heart
Prominent concentric hypertrophy of the left ventricle
Left atria may be dilated 

Sequelae- CHF and sudden death, left atrial thrombosis- saddle thrombi

Enlarged heart


Prominent concentric hypertrophy of the left ventricle


Left atria may be dilated




Sequelae- CHF and sudden death, left atrial thrombosis- saddle thrombi

What are the gross lesions associated with dilated cardiomyopathy?




Causes?

Round, enlarged heart
Thin walled, flabby chambers

Cats- taurine deficiency

Round, enlarged heart


Thin walled, flabby chambers




Cats- taurine deficiency

What are the sequelae of dilated cardiomyopathy?

CHF, nutmeg liver


Decreased contractility of myocardium


Decreased systolic contraction and cardiac output


Valvular regurgitation

what are the two types of restrictive cardiomyopathy?

Sequelae?

what are the two types of restrictive cardiomyopathy?




Sequelae?

Fibrosis of left ventricular endocardium


Excessive moderator bands in left ventricle




Impaired filling, signs of heart failure -> death




*primarily in cats

What is myocarditis?




Cause?

Inflammation of the heart muscle




Hematogenous spread of infection to the myocardium

What are the different categories of myocarditis? What causes each?

Suppurative- bacteria, abscesses with localized inflammation




Nonsuppurative- necrotizing, hemorrhagic, lymphocytic (viral, protozoa, toxic, immune-mediated)




Eosinophilic (look for green tissue)

What are the different neoplasms in the heart?

Primary- HEMANGIOSARCOMA, most common. Rhabdomyoma and rhapdomyosarcoma




Metastatic- hemangiosarcoma, lymphosarcoma




Heart base tumors (second most common)

Hemangiosarcomas are most commonly found in where in the heart?

Hemangiosarcomas are most commonly found in where in the heart?


Right atrium!

The  most common metastatic disease to the heart is what?

The most common metastatic disease to the heart is what?

Lymphosarcoma *especially in BLV with cattle




Seen in uterus, abomasum




May produce heart failure

The most common heart base tumor is what?

Aortic body tumor "chemodectoma"




May cause vascular obstruction/rupture

What are the reactions when each part of the vessel gets damaged?




Endothelium damage


Endothelium necrosis

Damage to endothelium- seperation from the underlying basement -> increased permeability to plasma protein movement into subendothelium




Necrosis- activate coagulation cascade -> thrombus formation




*endothelium can migrate and repair defects

What most likely caused this congenital malformation?

What most likely caused this congenital malformation?

Congenital hereditary lymphadema- caused by malformation of lymphatics




Can also be delayed development in which it will resolve itself postnatally




Causing stillbirth with generalized subcutaneous edema, edema in the ear tips, symmetrical swelling of head, neck, tail

What mineral deficiency can lead to rupture of vessels?

Copper deficiency - leads to abnormal development of elastic tissue (seen in turkeys and pigs)

Equine vascular rupture of the aorta is caused by what?




Sequelae?




Of the internal carotid artery?

Spontaneous or extreme exertion, parasites, trauma/falls with thoracic injury




Hemopericardium and cardiac tamponade (rapid death)




Internal carotid- guttural pouch mycosis, sees epistaxis clinically

In the dog, the parasite that lives in the wall of the aorta and can cause vascular rupture is what?

Spirocerca lupi

Idiopathic rupture of vessels can be caused by what condition in cats and dogs?

Chylothorax

The layer of the arteries that thickens in hypertrophy is what?

The tunica media- the smooth muscle in the middle layers

Pulmonary arterial hypertrophy is seen with what cardiac condition?




Normal in what types of animals?




Parasitic cause?

Left to right shunts




Normal in cattle in high altitudes




Aelurostrongylus abstrusus*, toxocara, dirofilaria immitis in cats

Define Aneurysm




How is this different from a false "dissecting aneurysm?

Localized dilation, thin-walled outpouching in the artery




False "dissecting aneurysm"- fracture in tunica media, splits the tissue into two layers and the blood flows between two tubes

What are the causes of aneurysm?

Copper deficiency


Lathyrism


Parasites




Verminous arteritis in horses- strongylus vulgaris infection causes cranial mesenteric artery dilation and rupture

What is the cause of varicose veins (varicosities)?




Sequelae?

Dilation of the vein for many reasons- can be an insufficiency of the valve, leading to more dilation and twisting in the valves


Seen most in the pampiniform plexus but relatively uncommon




Sequelae- thrombosis or sclerosis

Define telangiectasis 

What tissues are these found on?

Define telangiectasis




What tissues are these found on?

Foci of abnormally dilated capillaries, sinusoids, arterioles, or venules




Skin/mucous membranes most common


Dilated sinusoids in liver are common incidental finding in cats and cattle**

Define Arteriosclerosis




What gross signs are associated with this?

Intimal fibrosis of large elastic arteries, chronic degeneration and proliferation of arterial wall, narrowing the lumen




Gross lesions- slightly raised, firm, white plaques, branching sites,


*Abdominal aorta being the most common site

Define Atherosclerosis




What gross lesions are associated with it?

Intimal and medial lipid deposits in elastic and muscular arteries. Chronic accumulation of lipid, fibrous tissue and calcium

Dogs with hypothyroidism and hypercholesterolemia 

Thickened, firm, yellow-white arteries

Intimal and medial lipid deposits in elastic and muscular arteries. Chronic accumulation of lipid, fibrous tissue and calcium




Dogs with hypothyroidism and hypercholesterolemia




Thickened, firm, yellow-white arteries

What are the common causes of arterial medial calcification?




Gross lesions?

Calcinognic plant toxicity


Vitamin D toxicosis


Renal insufficiency


Severe debilitation


Spontaneous lesion in rabbits




Solid, dense, white, pipelike vessels


Raised, white, solid intimal plaques

What is fibrinoid necrosis?

Lesion of acute degeneration and inflammation of small arteries and arterioles




*Important diagnostic feature of selenium-Vitamin E deficiency

What are some common causes of thrombosis?

Aortic thrombosis in feline cardiomyopathy


Thromboembolic colic in horses


TEME in cattle, histophilus somni


In dogs with dirofilariasis


DIC

What are the sequelae of thrombosis?

Occlusion of blood supply, infarction, death, recanalization and restored blood flow

What are some of the specific examples of arteritis?


Erysipelothrix rhusiopathiae in pigs


Dirofilariasis in dogs


Strongylus vulgaris in horses

What are the causes of phlebitis?

Neonatal umbilical infection


Systemic infection- salmonellosis in pigs


Faulty intravenous infection


FIP

What gross lesions are seen with lymphangitis?

Thick, cordlike structures within the distal limbs, may be nodular and ulcerative (suppurative discharge)

What are the four layers of skin?

Stratum corneum (+/- stratum lucidum), granulosum, spinosum, basale




Thickness = spinosum + corneum

What is responsible for the regrowth of hair?

The hair bulge

e basement membrane is made up of what three structures?

Basal surface of basal keratinocytes


Basal lamina


Reticular lamina

is the hair growth cycle?

Anagen (growing phase), Catagen (transition phase), telogen (resting phase), exogen (shedding of hair)

What are the three things that can cause alopecia?

Hair cycling disorders


Dystrophy/dysplasia of hair follicle


Atrophy/miniaturization

Define Tylotrich hairs

Rapid-adapting mechanoreceptors, scattered among normal hair

What is the function of sebaceous glands?




Where are they located?

They provide the sheen to the coat by secreting a lipid component




They are located all over the body but are more numerous at mucocutaneous junctions, chin, lip, extremities




Modified structures: Meibomian glands, hepatoid glands

Where are the apocrine sweat glands located?




Eccrine?

Apocrine- throughout haired skin, responsible for sweating in horses




Eccrine- footpads, frog region of ungulates, carpus of pigs, nasolabial region of ruminants and pigs

What is different histologically between the footpads of cats and the footpads of dogs?

Cats- have smooth compacted skin layers in their digital pads




Dogs- conical papillae

What are the three vascular plexuses of the dermis, what do each supply?

Superficial- superficial follicles and epidermis

Middle- sebaceous glands, mid follicles, arrector pili muscles

Deep- subcutis and deep portion of follicles and apocrine glands

Whatare the four barrier functions of the skin?

Structural- stratum corneum (keratin protein is the brick, lipid between cells is the mortar)
Metabolic- stratum spinosum, detoxification
Immunologic- keratinocytes of stratum corneium, langherhan cells
Photoreceptive- hair, melanocytes, keratinocytes

Innate immunity of the skin is caused by what?




Adaptive immunity?

Innate- statum corneum with macrophages and neutrophils




Adaptive- langerhan cells and dendritic cells, T-lymphocytes and stimulated lymphocytes

What term is used to describe the changes seen on these skin samples?

What term is used to describe the changes seen on these skin samples?

This is a macule/patch

Flat/flush with surface, color of the skin, most common changes due to blood or melanin
Macule <1cm
Patch >1cm

This is a macule/patch




Flat/flush with surface, color of the skin, most common changes due to blood or melanin


Macule <1cm


Patch >1cm

What term is used to diagnose these bumps on the skin?

What term is used to diagnose these bumps on the skin?

This is a papule, <1cm solid elevation of the skin. usually a hyperplastic process due to inflammatory infiltrates 
(insect bite, papilloma, superficial folliculitis)

This is a papule, <1cm solid elevation of the skin. usually a hyperplastic process due to inflammatory infiltrates


(insect bite, papilloma, superficial folliculitis)

What term is used to describe these lesions?

What term is used to describe these lesions?

These are plaques, flat, slightly elevated solid large lesions that are "plateau-like" 

From coalescing papules or from eosinophils

These are plaques, flat, slightly elevated solid large lesions that are "plateau-like"




From coalescing papules or from eosinophils

What is the lesion seen here?

What is the lesion seen here?

These are wheels. Raised, solid, sharply demarcated with steep sides

Result from edema in the dermis, they will pit on pressure (insect bites, urticaria, allergic reaction)

These are wheels. Raised, solid, sharply demarcated with steep sides




Result from edema in the dermis, they will pit on pressure (insect bites, urticaria, allergic reaction)

How would you describe these grossly?

How would you describe these grossly?

These are nodules, round, solid elevated 3D structures that are more than 1cm in size

Can be inflammatory or neoplastic

These are nodules, round, solid elevated 3D structures that are more than 1cm in size




Can be inflammatory or neoplastic

What are these most likely?

What are these most likely?

These are neoplasms, abnormal masses of tissues that exceed and is uncoordinated with that of normal tissue.

These are neoplasms, abnormal masses of tissues that exceed and is uncoordinated with that of normal tissue.

What are these lesions?

What are these lesions?

These are vesicles/bulla. These are well circumscribed and contain serum. These result from separation of normally adherent tissues




When these rupture, they can lead to erosion or ulceration


Vesicle <1cm, bulla >1cm




Examples: burns, viral infection, immune-mediated disease

What are these lesions?

What are these lesions?

This is a pustule, a vesicle or bulla that contains purulent contents

From bacterial infections, pemphigus foliaceous *acantholytic cells = pemphigus

This is a pustule, a vesicle or bulla that contains purulent contents




From bacterial infections, pemphigus foliaceous *acantholytic cells = pemphigus

What are these lesions called?

What are these lesions called?

Papillomas, fingerlike projections above the skin surface




Associated with a hyperplastic dermis

What is this secondary lesion?

What is this secondary lesion?

This is a secondary lesion, a scale. 

This is an accumulation of the cornified layer of skin. 

Will appear white, yellow and dry

This is a secondary lesion, a scale.




This is an accumulation of the cornified layer of skin.




Will appear white, yellow and dry

What are these lesions called?

What are these lesions called?

These are epidermal collarette, flat regions of scale that grow in circular rings

Ex, superficial bacterial infection, *ringworm, insect bite, fungal infection

These are epidermal collarette, flat regions of scale that grow in circular rings




Ex, superficial bacterial infection, *ringworm, insect bite, fungal infection

These lesions are known as what?

These lesions are known as what?

This is a crust, composed of keratin, dried serum, blood, bacterial debris
Resulting from a transudative/exudative process, chronic stage of pustular disease 

Erosion or ulceration of epidermis is beneath

This is a crust, composed of keratin, dried serum, blood, bacterial debris


Resulting from a transudative/exudative process, chronic stage of pustular disease




Erosion or ulceration of epidermis is beneath

What are these lesions?

What are these lesions?

These are vegetations, multiple crusts on top on each other.

What are these lesions?

What are these lesions?

These are erosions, superficial defects of the epidermis
*basement membrane and dermis is in tact

Surface trauma or from a prior vesicle/pustule rupture

These are erosions, superficial defects of the epidermis


*basement membrane and dermis is in tact




Surface trauma or from a prior vesicle/pustule rupture

What are these lesions?

What are these lesions?

These are ulcers, complete defects of the epidermis into the dermis. 

Ex. Indolent ulcer, surface trauma, ischemia

These are ulcers, complete defects of the epidermis into the dermis.




Ex. Indolent ulcer, surface trauma, ischemia

What is this lesion?

What is this lesion?

This is lichenification, thickening of the skin due to chronic rubbing, scratching, irritation

Ex. chronic superficial pruritic dermatitis

This is lichenification, thickening of the skin due to chronic rubbing, scratching, irritation




Ex. chronic superficial pruritic dermatitis

What are these lesions?

What are these lesions?

These are fissure, cracks in the epidermis or through the epidermis and into the dermis secondary to loss of elasticity and moisture

Ex. footpad fissures, necrolytic dermatitis, digital hyperkeratosis

These are fissure, cracks in the epidermis or through the epidermis and into the dermis secondary to loss of elasticity and moisture




Ex. footpad fissures, necrolytic dermatitis, digital hyperkeratosis

What is hyperkeratosis?




Orthokeratotic hyperkeratosis?

Increase in the thickness of the stratum corneum




(Orthokeratotic hyperkeratosis is excess of the normal type of keratin), NO nuclei


Primary lesion- vitamin A deficiency




Usually secondary* to trauma and inflammation

What is parakeratotic hyperkeratosis?

Retention of nuclei in the stratum corneum, abnormal cornification as a result of increased epidermal turnover




Primary lesion- zinc responsive dermatosis


Secondary lesion*- chronic trauma or sun exposure

What is hyperplasia/acanthosis of the dermis?

Increased thickened of the epidermis, usually stratum spinosum




A result of chronic irritation




NOT the same as acantholytic!

Intracellular edema in the skin is due to what change?




Intercellular?


Intracellular- degenerative change of keratinocytes (cell swelling)




Intercellular- inflammation, accompanied by exocytosis (spongiosis)

What is dyskeratosis?

Premature keratinization of individual keratinocytes




Retained, condensed nuclei




Associated with benign cornification disorders of malignancies

What is acantholysis?

Loss of adhesion desmosomes between keratinocytes.




Usually pemphigus or bacterial dermatitis

What is exocytosis in the skin?

Migration of inflammatory cells into the epidermis or adnexal epithelium, associated with spongiosis

What are epidermal clefts?

Empty slit-like spaces that run parallel to the epidermis at the dermo-epidermal junction




Basal cell damage or basement membrane disease

What is the most common pattern of inflammation in the skin?

Perivascular dermatitis, a very nonspecific pattern of inflammation where the inflammatory cells aggregate around superficial dermal vessels




Seen in hypersensitivity disorders, ectoparasitism (sarcoptes), superficial bacterial infections




Early in inflammatory process, ALL are perivascular

hat are some things that help determine the underlying cause of perivascular dermatitis?

Character of the infiltrates


Type and degree of hyperkeratosis




*be aware of secondary changes which are common and can change the diagnosis

What diseases of the skin are characterized by perivascular dermatitis and parakeratosis?

zinc-responsive dermatosis


Superficial necrolytic dermatitis- severe systemic disease- liver disease


metabolic disease

What is interface dermatitis?




What two things must be there for it to be interface dermatitis?

pathology that targets basal keratinocytes and dermoepidermal junction




two things: INflammatory cells obscuring the dermoepidermal junction and hydropic degeneration of basal cells




Autoimmune or hereditary disease

Exfoliative cutaneous lupus erythematosus of the german shorthair pointer is what kind of inflammation?




What kind of gross lesions are seen?

Severe autosomal recessive disease causing interface dermatitis




Causes scaling with erosions, hair loss, depigmentation

What is the disease dermatomyositis?

Familial skin disease of collies, shelties and their crosses




Affects the skin, blood vessels and muscles resulting in interface dermatitis

If you have an acute skin disease characterized by crusting, erosions, ulcers with dyskeratosis seen histologically, what disease would you be suspicious of?

Erythema multiforme, causing interface dermatitis




Caused by adverse drug reactions, infections, neoplasia, or can be idiopathic

What is pemphigus vulgaris?

Autoantibody to desmoglein-3, an adhesion molecule




Causes acantholytis swith suprabasilar clefting (tombstoning), BIG bulla/erosions/ulcers on the oral mucosa

What are the viral infections that can cause infections in the skin?

Foot and mouth disease


Vesicular stomatitis


Contagious pustular dermatitis (contagious ecthyma/orf, sheep and goats, vesicles, pustules, crusts)

efine subepidermal vesicular dermatitis

vesicles that form within or below the basement membrane zone




Due to immune-mediated or genetics

What is Bullous pemphagoid?

An acquired cause of subepidermal vesicular dermatitis, affecting hemidesmosomal proteins

What is epidermolysis bullosa?

A congenital defect causing subepidermal vesicular dermatitis junctional- affecting the lamina lucida and dystrophic- affecting anchoring fibrils- look at where the cleft is forming to distinguish between

How is nodular to diffuse dermatitis characterized?




Where are they found?

Found scattered throughout thick skin,




Characterized by predominate cell type, caused by infectious agent or they can be noninfectious

What are the nonifectious causes of nodular to diffuse dermatitis?

Feline eosinophilic dermatitis complex- look for eosinophilic plaques, granuloma formation, indolent ulcers


Associated with hypersensitivities




Equine eosinophilic granuloma

The fungal diseases that have a dermatitis component are what

Blastomyces dermatidis


Cryptococcus neoformans


Coccidiodes immitis

Define Perifolliculitis




Folliculitis




Furunculosis

peri- inflammation around the hair follicle




folliculitis- inflammation of and within the hair follicle




Furunculosis- follicular rupture with inflammation

What are the three causes of folliculitis?

Bacteria- staphylococcus pseudintermedius




Dermatophytes- microsporum, trichophyton, epidermophyton




Demodex mites- proliferate with immunosuppression

What two things must be present for it to be vascultitis?

Inflammatory cells within or around vessel wall


Evidence of vascular injury




Typically part of a systemic disease

what is panniculitis

Inflammation of the adiopose tissue of the hypodermis




Often idiopatic and sterile, must rule out infectious agent, trauma, foreign body

What is atrophic dermatosis?

Constellation of changes associated with underlying endocrine disorders- hyperadrenocorticism




Epidermal atrophy, follicular atrophy, atrophy of sebaceous glands, calcinosis cutis




Grossly- bilateral symmetric alopecia, dull, dry, brittle hair, hyperpigmentation

What is fibrosing dermatosis

Chronic change- indicated s prior insult




Ranges from fibroplasia to fibrosis (scar)


Newly formed granulation tissue to mature fibrosis with connective tissue

What are the four disorders of hair follicles?

Nonscarring alopecia


Scarring alopecia


Folliculitis


Hypertrichosis

In non-scarring alopecia, what is unique about the hair follicle?

The hair shaft can be made but it is weak and can break off easily




Not usually associated with inflammation




Endocrine, congenital, cyclical flank, frictional, post-clipping, traction, immune-mediated

What is sebaceous adenitis?

Autosomal recessive mode of inheritance




Inflammatory destruction of the sebaceous gland leading to scaling and alopecia




Severe hyperkeratosis with follicular plugging

is alopecia areata?

Targeted destruction of anagen hair follicles, usually the dark hair

Scarring Alopecia is associated with what?

Destruction of the hair follicles




Folliculitis or severe pyoderma


Local wound/scarring that destroys adnexia


Scleroderma

What is hypertrichosis?

Either excessive hair and/or the hair is longer and coarser than normal




Equine Cushing's


Hirsutism is due to enlarged pars intermedia that regulates body temp, appetite and seasonal shedding of hair

fine Hamartoma

Normal looking tissue in the right place but arranged incorrectly




Epidermal hamartoma, follicular hamartoma, mesenchymal origin, vascular origin

What are the ectodermal neoplasms?

squamous cell carcinoma


Papilloma


Infundibular keratinizing acanthoma

What are the neoplasms of adnexal origin?

Sebaceous gland adenoma


Hair follicle tumors


Perianal gland adenoma


Carcinoma of the apocrine glands of the anal sac

What is an infundibular keratinizing acanthoma?

Common intracutaneous cornifying epithelioma




Common benign lesions in dogs

Perianal "hepatoid" gland adenomas are made up of what

Modified sebaceous glands, common in old, intact male dogs




Raised nodules on the perineum or ventral tail, frequently ulcerated

Hair follicle tumor are usually present as what?

Subcutaneous nodules, usually benign

What are the neoplasms of mesodermal neoplasms

Mesenchymal origin- fibrosarcoma in cats, soft tissue sarcomas in dogs, equine sarcoid (viral induced), hemangioma (vascular), lipomas




Leukocytic proliferations- canine cutaneous histiocytoma (langerhan's cells), mast cell tumor, lymphoma

What are the melanocytic neoplasms

Melanocytoma


Malignant melanoma


Variable biologic behavior- need histopath