Pericardium and Endocardium Flashcards
What is the pericardium?
double layered serosal mb that covers the heart & most proximal segment of great vessels
What is the epicardium?
thin layer of pericardium firmly attached to heart
What is in pericardial sac and what does it do?
pericardial sac contains small traces of fluid which act as lubricant to prevent friction btwn pericardium & epicardium
What are signs of serous atrophy of fat?
epicardial fat & fat in bone marrow will appear gelatinous, loss of normal fat on epicardium & kidney, prominent normal lymphatic vessels on heart.
What is serous atrophy of fat caused by?
could be due to chronic disease, chronic renal or hepatic failure, or neoplasia
what are pericardial hemorrhages?
common post-mortem findings in animals that have suffered hypoxia, sepsis of septicemia, toxemia, DIC, coagulopathies, & electrocution. also common terminal finding in large animals
3 sizes of hemorrhages from smallest to largest?
petechial, ecchymotic, & paint brush
What are the 3 types of pericardial effusion?
- transudate -> hydropericardium (clear fluid, low cellularity, low prot)
- blood -> hemopericardium (predominantly RBCs, high prot)
- exudate -> pericarditis (turbid, high cellularity, PMNs, high prot)
What causes the pericardial sac to enlarge to accommodate for?
- excess fluid in hydropericardium
- non-fatal progressive pericardial hemorrhage in hemopericardium
- exudate in pericarditis
- enlarged heart in cardiac hypertrophy & cardiomyopathy
What is hydropericardium?
low protein transudate in pericardial sac.
What is the appearance of hydropericardium?
pericardial surfaces remain smooth & glistening
pathogenesis of hydropericardium?
- hydrostatic: R heart failure, pulmonary hypertension
- hypoproteinemia: emaciation, protein losing enteropathy/nephropathy, etc.
- altered vascular permeability: mulberry heart
What is hemopericardium?
accumulation of blood in pericardial sac
what causes hemopericardium?
atrial or aortic rupture, hemangiosarcoma, cardiac trauma/puncture
What cause hemopericardium cause?
cardiac tamponade -> sudden death
When does hemopericardium occur that is not a concern?
blood tinged fluid occurs as post-mortem finding
What are the post mortem signs of hemopericardium?
enlarged cardiac silhouette & notably distended pericardial sac filled w/ blood
Why does a hemangiosarcoma appear dark?
neoplastic cells form blood-filled vascular channels
Types of pericarditis according to exudate
- fibrinous (most common)
- suppurative (purulent)
- fibrinohemorrhagic
- granulomatous
what is fibrinous pericarditis?
usually result of systemic bacterial infection. fibrinous exudate covers epicardium & pericardium. morphologic appearance is often referred to as “cor villosum”, “shaggy heart”, or “bread & butter”
Glasser’s disease?
Polyserositis (meningitis, polyarthritis, pericarditis, pleuritis, peritonitis, etc.). Caused by Glaesserella (Haemophilus) parasuis.
Will see fibrin, fluid, & fibrinopurulent exudate w/in body chambers.
What causes similar lesions in pigs to Glasser’s disease?
Streptococcus suis
What is black leg?
Clostridial myositis. Caused by Clostridium chauvoei. Signs are fibrinous pericarditis, black discolouration of leg muscle, & fibrin strands in pericardial sac
What is hardware disease?
Traumatic reticulopericarditis. ingestion of wire or nails that accumulate in reticulum and can perforate the pericardial sac, contaminating it w/ bact. Pericardial sac becomes filled w/ exudate, and the sac itself becomes dilated & thickened by fibrosis. Epicardial surface covered by exudate.
Signs of chronic pericarditis
- brisket edema due to R heart failure (compressive)
- distended pericardial sac
- pericardial sac filled w/ fibrin & blood, & organized fibrin on epicardium
What is chronic constrictive pericarditis?
heart encased in dense fibrous or fibrocalcific scar that may obliterate pericardial space (constrictive pericarditis limiting diastolic expansion (reduced ventricular filling) & CO). in extreme cases it can resemble plaster mold (“concretio cordis”)
What are 5 endocardial diseases?
1.endocarditis
2. valvular cysts
3. endocardial mineralization
4. endocardial fibrosis
5. myxomatous degeneration
What do normal heart valves look like & what should you do for proper gross examination?
Thin & translucent; gently wash them
What is acquired (secondary) fibrosis?
can be focal or generalized (diffuse) & most common causes are:
1. Focal: abnormal blood turbulences in atria or ventricles jet lesions
2. Diffuse: sub-endocardial fibrosis secondary to prolonged cardiac dilation
What are jet lesions?
occur w/ mechanical injury caused by turbulence damage endocardium. Commonly seen in valvular insufficiencies
What is primary endocardial fibroelastosis?
occurs as hereditary disease in humans & Burmese cats in which there’s no underlying cardiac disease. pathogenesis is uncertain.
Gross and microscopic lesions of endocardial fibrosis & fibroelastosis
on gross exam, endocardium appears thickened & may show smooth or corrugated surface. endocardial thickening is result of an abnormal deposition of collagen and elastic fibers
Clinical relevance of endocardial fibrosis & fibroelastosis?
severe generalized fibrosis can impair ventricular filling during diastole & reduce stroke vol leading to congestive heart failure
What often causes subendocardial fibrosis?
increased collagen deposition in sub-endocardium secondary to prolonged blood turbulence caused by congenital heart defects or other chronic conditions
What induces jet lesions on atrial endocardium leading to subendocardial fibrosis?
valvular insufficiencies
Endocardial mineralization?
abnormal deposition of calcium or minerals in endocardium
According to pathogenesis, endocardial mineralization could be:
- Metastatic: high levels of circulating calcium in hypercalcemic states
- dystrophic: secondary calcification in injured endocardium
Most common causes of endocardial mineralization in domestic animals are:
- hypervitaminosis D
- chronic granulomatous diseases (particularly bovines w/. paratuberculosis or tuberculosis, often show endocardial & arterial mineralization)
- uremia (mineralization also seen in uremic dogs (uremic endocarditis)
How do animals get hypervitaminosis D?
When animals are given excess amounts of vitamin D (iatrogenic hypervitaminosis) OR when animals ingest vit D analogs which are present in some rodenticides or toxic plants ex: solanum malacoxylon, cestrum diurnum, & trisetum flavescens
What would you see for subendocardial mineralization?
corrugation & thickening of endocardium. mineralization also present in aorta
Valvular cysts are particularly common in which animal?
calves
Valvular cysts
considered just incidental finding, cysts may regress & disappear, there is no clinical relevance
Classes of valvular cysts?
- Lymphocyst: when content is clear fluid
- hematocyst: when content is blood
What is most common cardiac lesion found @ necropsy in mature dogs?
myxomatous valvular degeneration (endocardiosis)
Myxomatous valvular degeneration (endocardiosis)?
typically affects mitral valve, nodular thickening of valve, w/ smooth shiny surface, may or may not cause valvular dysfunction & clinical signs
Incidence of myxomatous valvular degeneration (endocardiosis)?
incidence increases w/ age:
- 1 yr old (5%)
- 16 yr old (75%)
What is another presentation of valves in Myxomatous valvular degeneration (endocardiosis)?
may be seen as doming or hooding of leaflets toward atrium (valve prolapse)
rupture of chordae tendineae in endocardiosis can cause?
eversion of valve leaflet into atrium (prolapse as flail leaflet
What to do when you suspect ruptured chordae tendineae?
open L atrium, remove blood, fill ventricle & atria w/ water, & rhythmically compress heart. if there is rupture, 1 or more chordae will whip out during the “manual systole”
Endocarditis?
Inflammation of endocardium; most frequently caused by bact, & to much lesser extent, by fungi or parasites
What spp does endocarditis occur in?
all domestic spp
Classification of endocarditis according to location?
According to location:
- valvular (valves)
- mural endocarditis (ventricular or atrial wall)
classification of endocarditis according to gross appearance?
- vegetative: cauliflower-like mass of exudate & fibrin attached to heart valve or endocardium
- ulcerative: when endocardium is ulcerated (dogs w/ uremia)
common sequels to endocarditis?
thromboembolism: mitral or aortic endocarditis often causes renal infarcts; tricuspid & pulmonic endocarditis cause pulmonary infarcts or embolic pneumonia
What spp is vegetative valvular endocarditis found in?
particularly common in farm animals (Sw & Bo) suffering from bacteremia. it’s occasionally seen in Ca & Fe
most common bact isolated from endocarditis in domestic animals are?
- Streptococcus equi & Actinobacillus equuli in Eq
- Trueperella (Arcanobacterium) pyrogenes in Bo
- Erysipelothrix rhusiopathiae & Streptococcus suis type II in Sw
- Staphylococcus aureus in Ca
- Bartonella & Streptococcus in Fe
Vegetative valvular endocarditis on tricuspid valve could lead to?
R sided heart failure, hydrothorax, & nutmeg liver
Signs of vegetative valvular endocarditis of the aortic valve of Sw?
red discoloration of skin of ventral abdomen, legs, & tips of ears.
Histopathology of vegetative valvular endocarditis?
neutrophils, macrophages, cell debris, bacterial colonies on affected valve
What can vegetative valvular endocarditis of pulmonic valve lead to in the lungs?
embolic pneumonia. will see multiple embolic foci in lungs
Appearance of ulcerative endocarditis in dogs and is linked to what disease?
wht-red, thick, & wrinkled areas of endocarditis, mineralization, & fibrous tissue formation caused by uremia in dogs w/ chronic renal failure
In vegetative valvular endocarditis what could a colour change in the ears of Sw be due to?
Septicemia or thromboembolism from valves (these two conditions usually occur together)
