Food Ani. Med- Cardiovascular and Hemolymphatics 1

wilsbach's version from 2016-04-22 17:08


Question Answer
what can be used as a marker for heart probs in rumis?cardiac troponin 1
what does cardiac troponin 1 tell you?if you see it, indicates myocardial damage
if you see lactate, what does it mean?poor perfusion
if mult systems affected, you should think about...which is showing the worst signs, which is the most danger to the animal?
hardware dz is aka?traumatic reticulopericarditis
do small rumis get traumatic reticulopericarditis?no
when is a common time for TRP to show up?dairy cattle around time of calving
aside from trauma from a wire or sthing, what is another common way beef cattle can get pericarditis?bacteremia from histophilus somni
ways to prevent TRP?prevent pica, place magnet into RETICULUM when 6mo calves let out ot graze, place magnet in feed wagons chute
which side of the heart fails first with pericarditis?right side-- fluid compresses this side in first bc weaker wall
CSs associated with pericarditis?tachypnea, dyspnea, orthopnea, expiratory grunt, exercise intolerance, peripheral edema, jug distension and pulses, congested MM, delayed CRT, weak peripheral pulses, muffled heart sounds that radiate broadly, splashy heart sounds, might get arrhythmia from myocarditis
tx for TRP?remove hardware, PERICARDIAL LAVAGE, tx infection with LONG TERM ABX (broad spectrum, def G- and anaerobes.) 5th rib resection and pericardial marsupialization, thoracotomy and pericardectomy
what should you keep in mind if you are trying to dx TRP via rads?wire might be gone by time you radiograph, but the infection it seeded is left behind
what changes might you see on ECG with pericarditis?might see small amplitude from pericardial effusion and distance, myocarditis might result in arrhythmias
what characterizes IDIOPATHIC pericarditis? tx? what might be associated with this?charaterized by HEMORRHAGIC pericardial effusion, can do pericardial drainage and lavage. can also consider dexamethasone IF CYTOLOGY AND CULTURE rule out infectious cause (better be damn sure its idiopathic before you put them on steroids or your classic TRP just got a whole lot worse) MIGHT be assocaied with lymphoma

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Question Answer
what IS going on with cor pulmonale?it is a PRIMARY LUNG dz which causes a SECONDARY HEART disease
explain the pathophys of cor pulmonalethere is alveolar hypoxia due to a primary lung condition--> pulmonary vasculature constriction (wiki says: constriction leads to redistribution of bloodflow to better-ventilated areas of the lung, which increases the total area involved in gaseous exchange. This improves ventilation/perfusion ratio and arterial oxygenation, but is less helpful in the case of long-term whole-body hypoxia)--> pulmonary hypertension--> functional outflow compromise of the R heart--> hypertrophy of the R ventricle until it dilates--> exceeds compensation capacity-->heart failure (in other words: high up in mountains--> alveolar hypoxia-->BVs are alveolus sense low O2 content-->vasoconstrict-->hypertension in lungs-->high pressure-->dams into heart-->heart hypertrophy-->heart dilation)
common inciting causes of cor pulmonale?conditions inducing alveolar hypoxia: HIGH ALTITUDE, airway obstruction, pneumonia (consolidation and atelectasis), pulm edema, lungworms, pulm thromboembolism secondary to abscesses
CSs of cor pulmonale?(basically anything to do with R heart failure) Brisket edema, jug vein distension, tachypnea progressing to dyspnea, tachycardia (CO=SVxHR and if the right heart is failing the HR will inc to try to compensate for the lack of output), SPLIT S2 (lub= AVs close. Dub= when SLs close (this is S2). well, the SLs close once all the blood is out of the ventricles-- but if the R heart is working against pulm hypertension, then it takes slightly longer for the blood to get out of the right heart so the aortic valve will close slightly before the pulmonary and hence you will hear "lub da-dub")
what will cor pulmonale look like on rads?pulmonary arteries will be dilated, R heart will be dilated
Two treatment options for cor pulmonale?IF they have a genetic predisposition-- cull. Otherwise just take them down the mountain
how common is afib in cattle?MOST COMMON ARRHYTHMIA IN CATTLE!
**afib is associated with what other dz? why? *****GI DZ (vagal tone stuff)
how would you describe afib?irregularly irregular arrhythmia with no p-waves (f-waves, f for fibrillation), no 4th heart sound (that is vibration of vent wall following atrial contraction). HR can be norm, inc or dec. Can be preceded by atrial premature contractions
which electrolyte abnormalities can be associated with afib?HYPOcalcemia, HYPOkalemia, HYPOchloremia
***what do you use to treat afib?Quinidine sulfate has poor bioavail in cows, so we need to use quinidine gluconate
how does hyperkalemia affect ECG?BRADYCARDIA, absent Ps, tented Ts, wide QRSs (At first inc repol because resting membrane potential less negative (resting -70 and threshold at 30 so closer to threshold)-->more excitable-->but then get less excitable after that. And atrial cells more sensitive to this so SA node slows)
who gets hyperK commonly, why?calves commonly get acidotic because of calf diarrhea, and then get hyperkalemic (exchange H into cell for K out of cell)
***what is the most common congenital heart defect in calves?VSD
CS of VSD, what is the murmur?low average daily gain, lethargy, dyspnea, CHF, loud pansystolic murmur with PMI at TRICUSPID VALVE (aka Right side, bc higher pressures on L push blood to hit R wall)
VSD is hereditary in who?limousin and herefords (so white limos with no barrier between the front and back are no good)
is R or L heart failure more common in cattle?R (usu 2* to sthing else)
****where do cattle get valvular endocarditis most commonly?TRICUSPID VALVE
pathophys of valvular endocarditis? what do the lesions look like?bacteremia (chronic infections)--> colonization--> fibrin--> CAULIFLOWER like lesions
which infectious agent is usually the reason there is tricuspid endocarditis?arcanobacterium pyogenes (this is trueperella pyogenes) >:( (think pus)
CSs of valvular endocarditis in cattle?(TRICUSPID) signs of infection + R heart failure
who has inherited cardiomyopathy?red holsteins and polled herefords
toxins which can cause cardiomyopathy? monensin (ionophore), gossypol (from toxo:used as protein additive in feeds, should be less than 100ppm), selenium deficiency (WMD), Cu deficiency (Cu works as coenzyme, can be from lack in diet or too high Mb, sulfates,zin, iron etc in diet)
what are ionophores used for?growth promoters
examples of ionophores?rumensin, monensin, nystatin
order of susceptibility of rumis to ionophores?Sheep > goats > cattle
MOA of ionophores?modify permeability of cell membranes and interfere with cation homeostasis, diff ionophores deal with diff ions. result in cell death. Affect skeletal and cardiac mm the most (FROM TOX: Monensin causes cellular alkalosis bc in NaKATPase.(Na in, K and H out, less H in cell=alkalotic). Salinomycin/narasin causes cellular acidosis bc cause large efflux of K out of cell, pushing some H into the cell, hence acidosis. all 3 also inc Ca++ATPase, which causes Ca to be pushed into cell and Na ion balance totally messed up. and more Ca-->mitochondria takes it up-->cant work-->no energy-->necrosis. and signals apoptosis. see more neurtophils in histo bc cells dead and theyre going there to clean it) (also think about Ca activating enzymes--> cell death)
what does the heart look like with ionophore tox?resemble selenium/vit E deficiency. pale streaks in heart and skele mm, chronic tox results in necrotic tissue being replaced by fibrous tissue. Heart becomes dilated (DCM), with evidence of acute cardiac failure or chronic CV insufficiency
what is enzootic lymphosarcoma? how common is it? what is happening?MOST COMMON NEOPLASM IN CATTLE, associated with BLV (bovine leukemia virus), which is a retrovirus. Affects lymphocytes (B-lymphocytes)
organs affected by enzootic lymphosarcoma?HAULS-R (1) Heart (r atrium) so see R heart failure, hear murmur (2) Abomasum (pylorus) (3) Uterus (4) Lymph nodes (5) spinal canal (6) retrobulbar space
2 ways to test for enzootic lymphosarcoma based on serology?(1) ADIG (individual animal) (2) ELISA (pooled sera/bulk milk, more sensitive)
major management way to dec transmission of enzootic lymphosarcoma?feeding BLV positive milk to BLV neg calves may dec risk of BLV exposure. Feeding colostrum from dam may be protective against within farm BLV transmission