PATHOLOGY OF THE CARDIOVASCULAR SYSTEM

Transcription

1 PATHOLOGY OF THE CARDIOVASCULAR SYSTEM Lecture 3: Pericardium and Endocardium Shannon Martinson, 2018 VPM 2220 Systemic Pathology II

2 PERICARDIUM AND EPICARDIUM Normal structure Epicardium Double layered serosal membrane Covers the heart and the most proximal segment of the great vessels. Myocardium

3 Serous Atrophy of Fat PERICARDIUM AND EPICARDIUM Also occurs in bone marrow Normal fat Serous atrophy of fat Epicardial fat appears gelatinous Lymphatics may be prominent Seen with emaciation

4 PERICARDIUM AND EPICARDIUM Pericardial Hemorrhages Pericardial hemorrhages are common post-mortem findings in animals as a result of hypoxia, sepsis, toxemia, DIC, bleeding diatheses and electrocution Common agonal change in cattle According to size, hemorrhages are classified as: Petechiae Ecchymoses Paintbrush

5 PERICARDIUM AND EPICARDIUM Pericardial Effusions Distension of the Pericardial Sac The pericardial sac can notably enlarge to accommodate: Excess fluid Non-fatal progressive pericardial hemorrhage (hemopericardium) Exudate in pericarditis An enlarged heart

6 PERICARDIUM AND EPICARDIUM Pericardial Effusions Transudate Hydropericardium Clear fluid, low cellularity and low protein Blood Hemopericardium RBCs and protein Pericardiocentesis Diagnostic testing Therapeutic 52b6a1ed60b38f96f2e88d4a8cc.jpg Exudate Pericarditis Turbid fluid, high cellularity and high protein

7 Pericardial Effusions PERICARDIUM AND EPICARDIUM Hydropericardium Transudate in the pericardial sac Pericardial surfaces remain smooth and glistening Pathogenesis: 1. Hydrostatic pressure: Right heart failure 2. Hypoproteinemia: Emaciation, protein losing enteropathy / nephropathy, etc. 3. Vascular permeability: Sepsis, DIC, mulberry heart quizlet.com With vascular permeability may see fibrin / protein in the fluid

8 Pericardial Effusions Snake PERICARDIUM AND EPICARDIUM Duck Hydropericardium Courtesy: Dr. Carlos Lopez Mendez

9 Pericardial Effusions PERICARDIUM AND EPICARDIUM Hemopericardium Accumulation of blood in the pericardial sac Caused by atrial or aortic rupture Rupture of atrial hemangiosarcoma, chronic valvular regurgitation and atrial dilation, iatrogenic (cardiac puncture) Acute hemorrhage can cause cardiac tamponade if severe can cause sudden death If intrapericardial pressure > intracardial pressure compression of heart may prevent diastolic filling = cardiac tamponade

10 Pericardial Effusions PERICARDIUM AND EPICARDIUM Hemopericardium Idiopathic hemorrhagic pericardial effusion of dogs (cattle also)

11 Pericardial Effusions PERICARDIUM AND EPICARDIUM Hemopericardium

12 Pericardial Effusions PERICARDIUM AND EPICARDIUM Pericarditis Inflammation of the pericardium Usually diffuse Suppurative Fibrinous Bread and butter heart

13 Pericardial Effusions PERICARDIUM AND EPICARDIUM Pericarditis Jugular vein distension Murmur GI motility and scant feces Distended pericardium on US Pericardiocentesis fetid yellow fluid Adult Ayrshire cow Brisket edema and bottle jaw

14 Pericardial Effusions PERICARDIUM AND EPICARDIUM Traumatic reticuloperitonitis Pericarditis Metal object from reticulum penetrates the reticular wall, diaphragm and pericardium Pericardial sac filled with fibrinosuppurative exudate

15 Pericardial Effusions PERICARDIUM AND EPICARDIUM Black Leg Clostridial myositis Clostridium chauvoei Fibrinous pericarditis is common Pericarditis

16 Pericardial Effusions PERICARDIUM AND EPICARDIUM Pericarditis Glasser s Disease Haemophilus parasuis Causes fibrinous polyserositis Peritonitis, pleuritis, pericarditis, arthritis, meningitis Differentials Streptococcus suis*, Mycoplasma hyorhinis, Actinobacillus

17 Pericardial Effusions PERICARDIUM AND EPICARDIUM Pericarditis With chronicity organization of exudate leads to fibrosis and adhesions (organizing fibrinous pericarditis)

18 Pericardial Effusions Chronic constrictive pericarditis Heart is encased in fibrous tissue Obliterates the pericardial space Limits diastolic expansion PERICARDIUM AND EPICARDIUM Pericarditis

19 Pericardial Effusions PERICARDIUM AND EPICARDIUM Fibrin Pericarditis Chronic constrictive pericarditis Fibrosis Myocardium H&E stain Masson-Trichrome stain

20 ENDOCARDIUM The endocardium, the most internal layer of the heart is in intimal contact with the blood It lines the atria, ventricles, and valves Endocardium Myocardium

21 ENDOCARDIUM Normal Valves Aortic Valve Tricuspid valve Note how thin and translucent the valves are

22 PATHOLOGY OF THE ENDOCARDIUM Endocardial hemorrhage Endocardial Fibrosis Endocardial hemorrhage Endocardial Mineralization Valvular Cysts Myxomatous Degeneration Rupture of Chordae Tendinae Endocarditis

23 PATHOLOGY OF THE ENDOCARDIUM Endocardial Fibrosis and Fibroelastosis Jet lesions Right atrium Acquired localized endocardial fibrosis: "jet lesions" Abnormal blood turbulence in the atria or ventricles Turbulence can result in mechanical injury damaging the endocardium Most commonly seen in the atria in association with valvular insufficiencies Gross: The endocardium appears focally thickened with a rough or corrugated surface Clinical Relevance: None Image: Dr N Kaiser, AVC

24 PATHOLOGY OF THE ENDOCARDIUM Endocardial Fibrosis and Fibroelastosis Acquired diffuse endocardial fibrosis Occurs secondary to prolonged cardiac dilation. Gross: The endocardium appears diffusely thickened with a rough or corrugated surface Clinical Relevance: can impair and reduce stroke volume congestive heart failure Zachary, PBVD, 2017

25 PATHOLOGY OF THE ENDOCARDIUM Endocardial Mineralization Endocardial Mineralization = abnormal deposition of calcium or mineral in the endocardium and arteries Metastatic: High levels of circulating calcium in hypercalcemic states Dystrophic: Secondary calcification in injured endocardium The endocardium is hardened and the surface is roughened with pale yellow white gritty plaques Differentials for endocardial mineralization Hypervitaminosis D Iatrogenic Calciferol rodenticides Toxic plants (Solanum, Cestrum) Cachectic disease Johne s disease Tuberculosis Renal failure (uremia) Paraneoplastic syndrome

26 Valvular Cysts PATHOLOGY OF THE ENDOCARDIUM Particularly common in calves There is no clinical significance Incidental finding Cysts may rupture and disappear

27 Valvular Cysts PATHOLOGY OF THE ENDOCARDIUM Valvular Hematocyst According to content, cyst are classified as: Lymphocyst when the content is clear fluid Hemocyst when the content is blood Valvular Lymphocyst Zachary, PBVD, 2017 Zachary, PBVD, 2017

28 PATHOLOGY OF THE ENDOCARDIUM Myxomatous Valvular Degeneration Common in dogs Incidence increases with age: 1-yr-old = 5% 16-yr-old = 75% Toy and small- med. breed dogs Cavalier King Charles spaniel Mitral valve (80% of cases) Mitral and tricuspid (15% of cases Tricuspid only (5%) May or may not cause valvular dysfunction and clinical signs =Degenerative Heart Valve Disease =Endocardiosis

29 ENDOCARDIUM Myxomatous Valvular Degeneration Characterized by nodular thickening of the valve with a smooth shiny surface Zachary, PBVD, 2017

30 PATHOLOGY OF THE ENDOCARDIUM Myxomatous Valvular Degeneration The thickened nodular valve is composed of loose (myxomatous) connective tissue If mild typically no clinical signs When more severe can cause valvular regurgitation and volume overload eccentric hypertrophy

31 PATHOLOGY OF THE ENDOCARDIUM Myxomatous Valvular Degeneration Rupture of the Chordae Tendineae Sudden collapse and death If you suspect rupture of the chordae tendinae at the time of necropsy, it is recommended to open the left atrium, remove the blood, fill the ventricle and atria with water, and rhythmically compress the heart. Zachary, PBVD, 2017

32 PATHOLOGY OF THE ENDOCARDIUM Endocarditis It is most frequently caused by bacteria, and to a much lesser extent, by fungi or parasites Clinical signs: Pyrexia Lameness Murmurs According to location, endocarditis can be classified as: Valvular endocarditis (valves)*** Mural endocarditis (myocardial wall) According to gross appearance: Vegetative: cauliflower-like mass of exudate and fibrin attached to a heart valve or endocardium Ulcerative when the endocardium is denuded Mural endocarditis, RV

33 PATHOLOGY OF THE ENDOCARDIUM Vegetative Valvular Endocarditis Common isolates in cattle: Trueperella pyogenes Most often affects the right AV valve As a result of venal caval thrombosis

34 PATHOLOGY OF THE ENDOCARDIUM Vegetative Valvular Endocarditis Common isolates in pigs: Streptococcus suis Erysipelothrix rhusiopathiae

35 PATHOLOGY OF THE ENDOCARDIUM Vegetative Valvular Endocarditis Common isolates in horses: Streptococcus equi Actinobacillus equuli

36 PATHOLOGY OF THE ENDOCARDIUM Vegetative Valvular Endocarditis Endocarditis is not common in dogs and cats Common isolates in dogs: Staphylococcus aureus Streptococcus spp Bartonella Common isolates in cats: Bartonella Streptococcus

37 PATHOLOGY OF THE ENDOCARDIUM Vegetative Valvular Endocarditis Fibrin Histopathology Bacterial colonies Neutrophils and cell debris Connective tissue, neutrophils and macrophages VALVE

38 PATHOLOGY OF THE ENDOCARDIUM Vegetative Valvular Endocarditis Pulmonary trunk Common sequelae: Thromboembolism: Mitral or aortic endocarditis renal infarcts Tricuspid and pulmonic endocarditis embolic pneumonia or, less commonly, pulmonary infarcts Congestive heart failure because of valvular dysfunction *

39 PATHOLOGY OF THE ENDOCARDIUM Vegetative Valvular Endocarditis Passive hepatic congestion Yearling heifer with a history of poor doing and inappetence Pyrexia and anorexia some response to antibiotics recurrent Tachycardia, muffled heart sounds, and jugular pulses developed Died on the way to the barn for milking Right AV valve, vegetative endocarditis, fibrinous, chronic-active, severe Hydrothorax

40 PATHOLOGY OF THE ENDOCARDIUM Ulcerative Endocarditis Occurs with chronic kidney disease Uremia damages the endocardium (= uremic endocarditis) Thickened, wrinkled, ulcerated endocardium +/-mineralization

41 Sincere thanks to Drs A Lopez and E Aburto, AVC, for their contribution to this material.