Food Animal - Cardiac Disease Flashcards
List the causes of acquired valvular disease in cattle.
- Degenerative changes.
- Infection (bacterial or viral endocarditis or myocarditis).
- Inflammation.
- Trauma.
- Myocardial dz (cardiomyopathy).
- Neoplasia (esp lymphoma).
- Idiopathic.
Chronic bacterial infection can predispose to bacterial endocarditis. List three common chronic bacterial infections that have been linked with endocarditis in cattle.
- Foot abscesses.
- Rumenitis.
- Reticular abscesses.
What is the most common bacterial isolate from bacterial endocarditis lesions in cattle?
Trueperella pyogenes.
Which valve is most commonly affected in cattle with bacterial endocarditis?
Tricuspid valve.
List the clinical signs of valvular disease in cattle.
- Murmur: varies with valve affected; often quiet to no murmur in cattle with bacterial endocarditis.
- Cardiac enlargement –> greater area for auscultation +/- arrhythmias e.g. a fib.
- CHF: tachycardia, coughing, respiratory distress, jugular v distension, abnormal jugular pulsation, subcutaneous oedema, mammary v distension, crackles/moist lung sounds; wt loss, anorexia, fever, mastitis.
Describe echocardiographic findings in cattle with acquired valvular disease.
Regurgitant jet, increased chamber dimensions, valvular lesions.
Valvular insufficiency: mild jet 2/3 receiving chamber.
List potential CBC, MBA and urinalysis findings in cattle with bacterial endocarditis.
- CBC: anaemia, neutrophilia, hyperfibrinogenaemia.
- MBA: hyperglobulinaemia, inc liver enzymes.
- Urinalysis: pyuria or haematuria.
Describe the pathophysiology of congestive heart failure (CHF) in cases of acquired valvular disease in cattle.
Valvular incompetence –> volume overload of recipient chamber –> increased EDV –> compensatory dilation and increased ED pressure +/- hypertrophy –> decreased contractile ability –> CHF.
Describe the pathophysiology of bacterial endocarditis in cattle.
Localised infection –> bacterial endocarditis –> disseminated sepsis –> cull.
List the components of bacterial valvular vegetative lesions in cattle.
Blood cells, fibrin, necrotic tissue, bacteria.
Outline the treatment and prognosis for bacterial endocarditis lesions in cattle.
- Antibiotics (gram +ve), aspirin/LMWH to prevent platelet adhesion, furosemide if CHF, digoxin to improve contractility.
- Px is guarded to poor (they present with advanced dz).
Define High Mountain Disease (a.k.a. Brisket Dz) of cattle.
Hypoxic vasoconstriction from high altitude dwelling.
What factors can exacerbate the signs of HMD and what does this combination of factors lead to?
- Pneumonia, lungworms, prolonged exposure to cold temperatures, ingestion of locoweed.
- HMD + factors above –> cor pulmonale (effect of lung dysfunction on the heart).
Describe the pathophysiology of HMD in cattle.
High altitude (>6000ft) +/- respiratory dz +/- locoweed –> pulmonary a constriction in response to hypoxia –> pulmonary hypertension –> pressure overload on RV –> RV hypertrophy, dilation or failure.
List the latin name and toxic principal of Locoweed.
- Plant: different oxytropis and astragalus species.
- Toxin: swainsonine; causes myocardial damage.
List the clinical signs of Brisket Disease in cattle.
- Subcutaneous brisket oedema, oedema of ventral thorax, limbs, submandibular space.
- Lethargy, weakness, pulling eyes, diarrhoea, collapse, death, jugular v distension or pulsations, dyspnoea, tachypnoea.
- Auscultation: tachycardia, +/- gallop rhythm, +/- split S2, +/- murmur related to tricuspid or pulmonic regurg.
List four differential diagnoses for Brisket Disease in cattle.
- Bacterial endocarditis of the tricuspid valve.
- Cardiomyopathy.
- Lymphoma.
- Traumatic reticuloperitonitis-pericarditis.
Describe the epidemiology of HMD in cattle.
- Occurs in 0.5-5% native high-altitude cattle; higher % if lowland cattle moved to high altitudes.
- Mainly occurs in calves and yearlings.
- Complex inheritance with breeds/pedigrees resistant or susceptible.
Outline the treatment and prognosis for HMD in cattle.
- Remove from high altitude, treat primary dz process, InO2 +/- digoxin, furosemide.
- Px poor once CHF has developed; can potentially reverse for pulmonale.
Outline methods to prevent HMD in cattle.
Select cattle for breeding at high altitudes that are resistant to HMD, remove susceptible cattle to low altitudes, avoid locoweed, vaccinate against respiratory viruses, deworm to prevent lungworm.
Define myocarditis.
Inflammation of the myocardium.
Occurs secondary to bacteraemia, septicaemia, pericarditis, endocarditis.
List the infectious organisms capable of causing myocarditis in cattle.
- Bacterial: Clostridium chauvoei, Mycobacteria.
- Fungal: FMD.
- Parasitic: Toxoplasmosis, Cysticercosis, Sarcocystis.
Define cardiomyopathy.
Subacute or chronic disease of the ventricular myocardium without valvular disease, congenital abnormalities or pulmonary disease.
In what breed of cattle is hereditary Dilated Cardiomyopathy (DCM) reported?
Holstein-Friesian.
In what breed of cattle is a hereditary (non-DCM) cardiomyopathy reported?
Curly-coated Poll Hereford.
Which neoplasia may cause a cardiomyopathy through myocardial invasion in cattle?
Lymphoma or fibrosarcoma.
List toxins associated with the development of cardiomyopathies in large animals.
Monensin, lasolacid, salinomycin, cassia occidentalis (coffee senna), gossypol (cotton), phalaris, vitamin E/selenium deficiency, copper deficiency (primary or secondary to high sulphates), excessive molybdenum.
List the clinical signs associated with myocarditis in cattle,
- CSx depend on extent of disease, location of inflammation and systemic illness.
- +/- fever, cardiac arrhythmias (supraventricular or ventricular), gallop rhythm, murmur, signs of CHF.
List the clinical signs of DCM in cattle.
- Heart-related: peripheral oedema, jugular dilation/pulse, tachycardia, arrhythmias, murmurs, tachypnoea, pleural/pericardial effusion.
- Extra-cardiac: poor exercise tolerance, decreased milk production, increased liver enzymes, DA, diarrhoea, anorexia.
List differential diagnoses for cardiomyopathies in cattle.
Bacterial endocarditis, congenital heart defects, for pulmonale, nutritional myodegeneration, cardiac neoplasia, thoracic abscess, pericarditis, pleuritis, diaphragmatic hernia.
Outline diagnostic tests which should be performed in cattle with suspected myocarditis or cardiomyopathies.
- CBC/MBA: +/- neutrophilia, dec albumin, inc BUN, inc creatinine, inc GGT, inc SDH, inc TBili, inc CTnI.
- Echo/ECG: variable - WNL or changes consistent with DCM, CHF, arrhythmias.
- Urinalysis: haemoglobinuria is suggestive of monensin, gossypol, nutritional myodegeneration.
- Test serum for BLV, alpha-tocopherol, glutathione peroxidase and Cu; test whole blood for Se.
Describe the treatment and prognosis for cattle with myocarditis or cardiomyopathies.
- Myocarditis: tx underlying dz if recognised, control complications (arrhythmias, CHF, shock), Vit E if ionophore toxicity, corticosteroids may be beneficial.
- Px for myocarditis good if no CSx CHF, guarded if CHF.
- DCM: +ve inotrope (digoxin), diuretics (furosemide), vasodilators (ACE-I), rest.
Define pericarditis.
Inflammation of the pericardium, resulting in accumulation of fluid or exudate between the visceral and parietal pericardium.
List the causes of pericarditis in cattle.
- Traumatic reticuloperitonitis-pericarditis (TRP).
- Neoplasia.
- Idiopathic.
Describe typical cardiac auscultation findings in a cow with pericarditis.
Tachycardia, muffled heart sounds, absent lung sounds in the ventral thorax; ‘washing machine murmur’: splashing sounds attributed to gas and fluid accumulation in the pericardium secondary to anaerobic infection.
Describe the clinical signs seen in cattle with pericarditis.
- Non-specific: fever, inappetence, depression, weight loss.
- More specific: peripheral oedema, jugular distension and pulses, tachypnoea, dyspnoea, elbow adducted, expiratory grunt, reluctance to move.
How do you diagnose a case of pericarditis in large animals?
- CBC/MBA: variable findings dependant on underlying disease and chronicity.
- Elevated CTnI or myocardial CK/LDH.
- Rads: in TRP metallic FB and fluid and gas accumulation may be identified.
- Echo: confirms Dx –> fluid, fibrin, gas in pericardial sac.
- Fluid analysis following pericardiocentesis: TRP –> mixed bacteria, yellow, could odour, TP >3.5g/dL, WBC >2500/ul; idiopathic: hemorrhagic, sterile.
Describe the pathophysiology of pericarditis.
Fluid accumulates in the pericardial sac –> increased pericardial pressure –> increased end diastolic pressure -> impaired ventricular filling, increased atrial pressure, decreased venous return, decreased diastolic perfusion to myocardium –> decreased contractibility, SV, CO –> CHF.
Describe the treatment for TRP in cattle.
Px is poor; salvage procedures only: drain pericardium, perform rib resection at 5th intercostal space.
Describe the treatment of Idiopathic Haemorrhagic Pericarditis in cattle.
Drain pericardial sac.
Corticosteroids may result in resolution in some cases.
How common are cardiac neoplasias in large animals?
Uncommon. More common to see secondary involvement from adjacent structures i.e. lungs, pleura, LNs, diaphragm.
What is the most common cardiac neoplasia of cattle and where in the heart is it most commonly observed?
Lymphoma.
Right atrium.
List the clinical signs observed in cattle with cardiac neoplasia.
Non-specific and related to chronic disease; progress to cardiac signs related to involvement of pericardium or myocardium.
How is cardiac neoplasia diagnosed in cattle?
- CBC/Chem: non-sepcific changes.
- Test for BLV: only 1-5% BLV positive cattle develop lymphosarcoma.
- Echo.
- Definitive diagnosis via histopathology following necropsy.
What is the prognosis for cattle with cardiac neoplasia?
Hopeless.
