Path 1 - Cardio 2

drraythe's version from 2016-03-02 23:38

Degeneration, Infiltration, Necrosis/Apoptosis & Mineralization

Question Answer
4 rxns to injury the heart has?(1) Growth disturbance
(2) Sublethal injury
(3) Lethal injury
(4) Neoplasia
2 growth disturbances the heart can experience? Are they permanent or reversible?Atrophy & hypertrophy - REVERSIBLE (remember it’s just ↑ SIZE of cells, not amt)
5 rxns heart tissue has to sublethal (REVERSIBLE) injury?(1) Fatty degeneration
(2) Lipofuscinosis
(3) Vacuolar degeneration
(4) Fatty infiltration
(5) Myocytolysis
Degeneration is _cellular, infiltration is _cellular (fatty degen vs fatty infil)Degen = INTRAcellular
Infil = EXTRAcellular
In Myocardial Necrosis, what histological things occur?Leukocytic infiltration
Persistence of sarcolemmal “tubes” of basal lamina & w/ SEVERE dmg
Fibroblasts will produce collagen → scarring
How often is there regeneration of the myocardiocytes?Usually NOT observed. You might see a limited amt in very young animals (esp. avian)
When is there hyperplasia of the heart?ONLY for 1st several months of life... after, all growth of the heart is due to hyperTROPHY until normal cell size reached
Explain what happens to a normal myocardial cell as it undergoes necrosisNormal cell → hyaline necrosis → macrophagic invasion → healing w/ fibrosis
Hyaline necrosis is aka?Zenker’s necrosis
What czs serous atrophy of fat? What does this look like?Anorexia, starvation, cachexia → mobilization of fat depots. This results in epicardial fat being replaced by gray wet gelatinous tissue
What czs fatty infiltration of the heart? How does the lesion appear?Obesity, an ↑ number of lipocytes w/in the myocardium
3 czs of fatty degeneration?(1) Anemia
(2) Toxemia
(3) Nutritional deficiency (Cu!)
What are the gross & histological lesions of fatty degeneration?GROSS: Mottled, Pale, Flabby ("Thrush-Breast Heart")
HISTO: Spherical vacuoles IN the myocytes which will (+) stain for fat w/ fat stains like oil red
Histological stain for fat?Oil red
Myofibrillar Degen (Myocytolysis) can happen in what 2 situations in which animals?(1) Furazolidone toxicosis in birds!! (an abx used in poultry)
(2) K+ def in rats
3 czs of vaculor degeneration?(1) Doxorubicin (Adriamycin) cardiotoxicity (anti-cancer drug)
(2) Antiviral drugs
(3) Mitochondrial swelling & disruption
How does vaculor degeneration appear histologically?Sarcoplasmic vacuolation due to distention of sarcoplasmic reticulum
Myofibrillar lysis
Myocyte atrophy
Hyaline or Zenker’s necrosis/apoptosis → What is this?A severe glassy or waxy hyaline (proteinaceous material) degeneration or necrosis
Which nutritional deficiency can lead to Nyaline/Zenker’s Necrosis of heart mm?Vit E / Selenium (THIS IS WHITE MM DZ!)
6 things that can cz Hyaline/Zenker’s Necrosis?(1) Ischemia
(2) Nutritional deficiency (Se-vit E) (→ lipid peroxidation → cell dmg)
(3) Toxins → chemical: (monensin, cobalt, gossypol), plant: (Cassiasp., Karwinskiasp., fluoroacetate-containing plants), bacterial
(4) Metabolic Dz (azoturia)
(5) Physical injury (defibrillator shock)
(6) 2⁰ to neural injury –“heart-brain syndrome” (→ excess catecholamine release)
Metabolic dz that czs hyaline/Zenker’s necrosis?Azoturia → aka Equine Exertional Rhabdomyolysis, aka Monday Morning dz, happens due to forced exercise after rest during which feed has not been restricted
3 chemicals that cz Hyaline/Zenker’s Necrosis?(1) Gossypol (Gossypium spp. - cottonseed oil)
(2) Colbalt
(3) Monensin
3 types of plants that cz hyaline/Zenker’s necrosis?(1) Cassia (coffee senna)
(2) Karwinskia (coyotillo)
(3) Fluoroacetate (numerous)
What plant TOXINS which can cz Zenker’s necrosis?Fluoroacetate
Cardiac glycosides
Adromedotoxin (grayanotoxin)
What plant/plant derivatives that cz Zenker’s necrosis?Yew & Ground hemlock (Taxus spp.)
Coffee senna (Cassia occidentalis)
Coyotillo (Karwinskia humboldtiana)
White snakeroot (Eupatorium rugosum)
Gossypol (Cottonseed oil meal).
Explain heart-brain syndromeNeuronal injury: neurons release too much catecholamines & this affects the heart negatively
Explain gross lesions for Zenker’s necrosis?Pale patches or streaks (often subendocardial & in papillary mm), may have yellow or white dry gritty areas of calcification & if it is chronic: pale collapsed areas of scarring
5 histopathological characteristics of Zenker’s necrosis of the heart?(1) Swollen, hypereosinophilic fibers w/ loss of striations
(2) Basophilic granules if mineralized
(3) Pyknotic nuclei (condensation)
(4) Leukocytic infiltration
(5) Fibrosis if chronic
What is Mulberry Heart Dz?Vit E deficiency in PIGS
What is Monensin? What does it do/who is susceptible?An abx used in cow feed, horses are suseptible
2 possible sequale to Zenker’s necrosis?(1) Death from heart failure
(2) Recovery & myocardial scarring
What should you know about Fluoroacetate & fluoroacetate-containing plants?They are toxicants which affect the heart
4 plant/plant derivatives that cz cardiotoxicities?(1) Yew, Ground hemlock (Taxus spp.)
(2) Coffee senna (Cassia occidentalis)
(3) Coyotillo (Karwinskia humboldtiana)
(4) White snakeroot (Eupatorium rugosum)
What plant-derived toxin czs cardiotoxicity?Gossypol (Gossypiumspp. - cottonseed oil meal)
What are 4 chemical agents which cz cardiotoxicities(1) Ionophores - (monensin, lasalocid, salinomycin, narasin, maduramycin, others)
(2) Antineoplastic agents - anthracyclines - (doxorubicin, daunorubicin)
(3) Antiviral agents - nucleoside reverse transcriptase inhibitors (AZT)
(4) Antimicrobials - furazolidone in birds
What are feed additives which are cardiotoxic?Ionophores - (monensin, lasalocid, salinomycin, narasin, maduramycin, others)
What are the antineoplastic agents which are cardiotoxic?Anthracyclines (doxorubicin, daunorubicin)
What are the antiviral drugs which are carditotoxic?Nucleoside Reverse Transcriptase Inhibitors (NRTIs) (AZT) (Zidovudine)
What is the antimicrobial agent that is cardiotoxic & in who?Furazolidone in birds
What should you know about catecholamines & the heart? Examples?Catecholamines can be CARDIOTOXIC
Ex: Isoproterenol, Epinephrine, Norepinephrine, etc
What minerals can be cardiotoxic & in who?NaCl in birds
What vitamins can be cardiotoxic?Vit D
What homones can be cardiotoxic?Growth hormone
Vit D poisoning can lead to?Endocardial fibrosis &/or mineralization
What is "Manchester wasting dz" & what czs it/ what’s the resulting problem? Aka?AKA enzootic (endemic) calcinosis. Extensive calcificationczd by plants. Some of the plants that can cz this are Cestrum diurnum, Trisetum flavescent, Solanum malacoxylon. Lleading to Endocardial fibrosis &/or mineralization
Endocardial fibrosis &/or mineralization → 5 possible czs?(1) Vit D poisoning
(2) "Manchester Wasting Dz", enzootic calcinosis (Cestrum diurnum, Trisetum flavescens, Solanum malacoxylon)
(3) Chronic cardiac dilation
(4) Cachexia (Johne's Dz)
(5) Chronic uremia
What specific lesion might you see w/ endocardial fibrosis &/or mineralization?"Jet lesions" associated w/ valvular lesions
Chronic cardiac dilation, chronic uremia & cachexia (Johne's Dz) can all lead to?Endocardial fibrosis &/or mineralization
What are the lesions of endocardial fibrosis &/or mineralization?Thick, rough, white areas on endocardium
4 VALVULAR degenerative dzs which fall under "valvular endocarditis" that the DOG is prone to? Czs? & histo?(1) Valvular endocardiosis
(2) Valvular fibrosis
(3) Mucoid or myxomatous valvular degeneration
(4) Chronic valvular Dz!
Usually due to AGE & maybe a genetic influence w/ breed disposition. Resulting in degradation of valve collagen
What are the gross lesions of valvular dz? (3)(Valvular endocardiosis, valvular fibrosis, mucoid or myxomatous valvular degeneration, chronic valvular Dz)
(1) Smooth, firm, thick (diffuse or nodular) valve cusps (usually AV & especially mitral, prolly cause only 2 flaps)
(2) Thick chordae tendineae (occasional rupture)
(3) Left atrial “jet lesions” (occasional rupture)
What are the histo lesions of the valvular endocarditis of dogs? (3)(Valvular endocardiosis, valvular fibrosis, mucoid or myxomatous valvular degeneration, chronic valvular dz)
(1) Thickening of valve cusps by proliferation of fibroblastic tissue & accumulation of acid mucopolysaccharides
(2) Focal myocardial necrosis & fibrosis
(3) +/- arteriosclerosis of intramyocardial arteries
What is the MOST COMMON CZ of CHF in OLD DOGS?VALVULAR ENDOCARDITIS (Valvular endocardiosis, valvular fibrosis, mucoid or myxomatous valvular degeneration, chronic valvular dz)
What do lesions of ruptured chordae tendineae look like?Torn chordae & mobile valve cusp


Question Answer
3 different types/locations of inflammation in the heart?(1) Pericarditis
(2) Endocarditis
(3) Myocarditis
2 kinds of pericarditis?(1) Fibrinous
(2) Suppurative
2 portals of entry to the pericardium?(1) Hematogenous dissemination
(2) Foreign body penetration from reticulum (cattle) aka hardware dz
What are the defense mechanisms of the pericardium?Immunological responses - both humoral & innate
FIBRINOUS pericarditis → What czs this?**Hematogenous** infxn in Streptococcosis, Pasteurellosis, Salmonellosis, Histophilussp. Infxn, blackleg, psittacosis, sporadic bovine encephalomyelitis
What are the LESIONS of FIBRINOUS pericarditis?Yellow sheets & strands of fibrinous pericardial surface ("bread & butter heart"). If chronic, there may be fibrous adhesions
What is bread & butter heart?Common name for fibrinous pericarditis - bc there are yellow sheets & strands of fibrin on pericardial surface
What are possible sequale of FIBRINOUS pericarditis?(1) Death from SEPTICEMIA
(2) Recovery w/ adhesions or resolution of exudate
What czs SUPPURATIVE pericarditis?**Traumatic Reticuloperitonitis** (FB penetration in cattle ("Hardware Dz") )
What are the lesions of SUPPURATIVE pericarditis?Distended pericardial sac containing yellow to white pus, thick fibrous pericardium, fetid odor, may find FB
What are the possible sequale of SUPPURATIVE pericarditis?(1) Death from septicemia
(2) Chronic cardiac failure from constrictive pericarditis
4 portals of entry into the ENDOcardium?(1) Hematogenous dissemination
(2) Parasitic migration
(3) Intravenous & intracardiac catheters(long-term placement)
(4) Uremia-induced vascular dmg & 2⁰ endocardial ulceration (dog, Lt atrium)
Uremia induced vascular dmg & 2⁰ endocardial ulceration, leading to endocarditis, often occurs in WHO & where specifically?Dogs, in the Lt atrium
What are the defense mechanisms of the endocardium? (2)(1) Constant blood flow through cardiac chambers
(2) Immunologic responses (humoral & innate)
4 main czs of endocarditis?(1) Hematogenous infxn → Streptococcosis, Erysipelas, Phycomycosis, Trueperella pyogenes infxn
(2) Strongylosis
(3) Uremia
(4) Trauma
What are some hematogenous agents which cz FIBRINOUS PERICARDITIS?Streptococcosis
Histophilus spp.
Sporadic Bovine Encephalomyelitis
What are some hematogenous agents which cz ENDOCARDITIS?Streptococcosis
Trueperella pyogenes
Explain the pathogenesis of endocarditisBacteremia & mechanical stress (exertion, cardiac anomalies) → valvular endothelial dmg → thrombosis & endocarditis → valvular dysfxn & septicemia
What are the gross lesions of endocarditis? (Acute, chronic & if uremia)Friable dry yellow "vegetations" on valve...if chronic, firm, irregular nodular masses on valves ("verrucae") & if uremic, LA endocardial ulceration
Uremia leading to endocarditis w/ ulceration would be where most likely?LA
What are verrucae & what do they indicate?Firm, irregular nodular masses on valves which indicate chronic endocarditis
What does endocarditis look like histologically?Masses of fibrin & bacteria adhered to base of granulation tissue
What are 4 possible sequale to endocarditis?(1) Cardiac failure from valvular dysfxn
(2) Death from bacteremia
(3) Septic embolism
(4) Recovery
Valvular Endocarditis vs Valvular Endocardiosis?Endocarditis: Inflammation of the endocardium. Could be due to infxn, parasites, uremia, or trauma
Endocardosis: Chronic fibrosis & nodular thickening of the free edges of the atrioventricular valves, w/ no known/specific cz (dogs - polygenetic trait)
2 portals of entry for the myocardium?(1) Hematogenous dissemination
(2) Embolic dissemination of infective material fragments from vegetative (friable yellow lesions) endocarditis lesions into coronary arterial tree
1 defense mechanism of the myocardium?Immunologic - humoral & innate
3 things to consider about the pathogenesis of myocarditis?(1) Hematogenous infxn
(2) Host factors such as age, sex, strain, nutritional status, ambient temperatures, various stresses
(3) Role of immune mediated dmg
5 types of myocarditis?Suppurative
What are some viral etiologies for myocarditis?**Canine parvovirus**
Encephalomyocarditis virus
Foot & Mouth dz
Canine Distemper
Newcastle dz
Avian Encephalomyelitis
Eastern & Western Equine Encephalomyelitis
What are some bacterial etiologies for myocarditis?**Blackleg**(clostridium)
Tyzzer's Dz
Actinobacillus equuli
Corynebacterium kutscheri
Staphylococcus spp.
Pseudomonas aeruginosa
Diplococcus pneumonia
Caseous lymphadenitis
(Mycotic: Histoplasmosis)
What are the protozoan etiologies for myocarditis** Toxoplasmosis

Trypanosomiasis (Chagas' Dz)
Theileriasis (East Coast Fever)
(Parasitic ones are cysticercosis, trichinosis)
What is the dz which is an IDIOPATHIC cz of myocarditis?*Eosinophilic myocarditis
3 possible expected outcomes of myocarditis?(1) Complete resolution
(2) Residual scars
(3) Progressive myocardial dmg w/ acute or chronic cardiac failure

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