Cardiac Flashcards
Why does traumatic reticulopericarditis occur?
Pericardium and reticulum are anatomically closely located
Most common pericardial condition in cattle
Traumatic reticulo-pericarditis (TRP)/tyre wire disease
Pathogenesis of traumatic reticulopericarditis
Sharp linear metallic FB ingested
FB penetrates reticular wall, through diaphragm and into pericardial sac (can go elsewhere)
Wire not clean so bacteria tracks through
Effects of traumatic reticulopericarditis on cardiac function
Cardiac tamponade: reduced CO, forward failure
Progresses to CHF: backward cardiac failure (oedema)
History in TRP
Milk drop
Non-specific illness, appears to resolve and recur
Inappetance
Tachycardia (present at cardiac failure)
Early presenting signs of TRP
Pain (abducted elbows, wither test positve, arched back)
Rubbing/friction sound on auscultation
Tachycardia
Pyrexia
Heart sounds (can change daily: splashing, tinkling, muffled, clear)
Later presenting signs of TRP
Muffled heart sounds bilaterally
Difficult to palpate apex beat
Pyrexia
CHF signs (jugular distension, ventral oedema, tachycardia, dyspnoea, injected scleral vessels)
What are the likely (non-specific) findings in bloodwork for a cow with TRP?
Leukocytosis
Hyperfibrinogenaemia
Hyperglobulinaemia (increased TP)
Neutrophilia
Elevated liver enzymes
Diagnostic method of choice for TRP
Ultrasound
Ultrasound technique looking for TRP
ICS3-5 on both sides
Rectal scanner can be used
Ultrasound findings in TRP
Purulent fluid in pericardial sac (+/- fibrin)
Why is pericardiocentesis not performed in cows with suspected TRP in the UK?
Done in US to differentiate causes but this isn’t necessary in UK so (potentially fatal) risks not justified
Post mortem findings in TRP
Thickened pericardium
Fibrin (grey material)
Treatment of TRP in early stages
Magnet placed using bolus applicator
Amoxicillin/oxytetracycline (broad spectrum antibiotics)
Treatment of TRP in late stages
Prognosis poor to hopeless, euthanasia on welfare grounds
Prevention of TRP
Due diligence regarding silage and feed management
Do not use tyres to hold tarp on feed
Magnets (cheap, £2-4)
How does bacterial endocarditis occur?
Chronic bacterial infection elsewhere
Adhesion to endothelium, predilection sites of tricuspid and bicuspid valve
Bacteria that can cause bacterial endocarditis
Truperella pyogenes
Also staphs, streps and G -ves
At which intercostal space can you auscultate the pulmonary valve in a cow?
3rd ICS, left side
At which intercostal space can you auscultate the aortic valve in a cow?
4th ICS, left side
At which intercostal space can you auscultate the mitral valve in a cow?
5th ICS, left side
At which intercostal space can you auscultate the tricuspid valve in a cow?
3rd ICS, right side
What are the murmur grading systems in cows?
5 point or 6 point
Clinical signs of bacterial endocarditis
Murmur +/- palpable thrill
Persistent tachycardia
Ill thrift
Milk drop, may be episodic
What may you find on haematology of a cow with bacterial endocarditis that you don’t typically find with TRP?
Non-regenerative anaemia
(Other blood findings similar)
What does this echocardiography image show?
Enlarged valve (due to bacterial endocarditis)
How would you perform a blood culture for bacterial endocarditis? (Not commonly done)
Repeat samples, 3 different sites over 1 hour
What is found on post mortem of bacterial endocarditis?
Valve rough and irregular, reddened
Small abscesses elsewhere (liver, kidney)
What is this rare finding and would it cause a murmur?
Mural endocarditis, would present as a murmur
Treatment of bacterial endocarditis
Long term antibiotic therapy (3w, penicillin/amoxicillin)
Furosemide if CHF present
Analgesia
Prognosis of bacterial endocarditis
Guarded (return to normal HR/sounds is a good prognostic indicator, better if diagnosed and treated early)
What is usually recommended if CHF is found in a cow with bacterial endocarditis?
Euthanasia due to poor prognosis
Prevention of bacterial endocarditis
Keep cows healthy (associated with bacterial infection), no specific preventative measures
Is congenital cardiac disease in calves common or uncommon?
Uncommon, but virtually all defect types reported
Presenting signs of congenital cardiac disease
Murmurs
Poor growth
Increased RR/effort
Cough
Most common congenital cardiac abnormality in a cow?
Ventricular septal defect
Do cows normally have a single cardiac congenital defect?
No, usually multiple
What is the prognosis for multiple congenital cardiac abnormalities?
Poor
Murmur associated with ventricular septal defects in cows
Pansystolic (R > L)
Lower grade = larger defect (less turbulence)
Prognosis of ventricular septal defect in a cow
Reasonable if small defect and not in CHF
What is tetralogy of fallot?
VSD + pulmonary stenosis + RV hypertrophy + overriding aorta
Are atrial septal defects common or uncommon in cows?
Uncommon
What rare condition causes the heart beat to be visible in the neck region? What is the prognosis?
Ectopia cordis
Hopeless prognosis, euthanasia necessary
Effect of hyperkalaemia on the heart
Bradyarrhythmias
Causes of hyperkalaemia
Severe, acute diarrhoea (neonatal calves)
Urinary obstructions (older male calves, male sheep and goats)
What causes white muscle disease?
Vitamin E/selenium deficiency
What effect can white muscle disease have on the heart?
Myocardial damage can be focal, multifocal or diffuse
Top differential for dramatic and bilateral epistaxis
Caudal vena cava syndrome
Differentials for a cow with epistaxis
CVCS
Anticoagulant rodenticides
Coagulation disorders
Local trauma
Nasal obstruction (foreign body)
Ethmoid carcinomas
Nasal granulomas
Toxicities
Thrombocytopaenia (immune-mediated)
Congestive heart failure
Aspergillosis
Malignant catarrhal fever
Toxicities that cause epistaxis in cows
Ethylene glycol
Bracken
Broad categories (3) that cause thrombocytopaenia
Platelet consumption
Decreased platelet production
Platelet destruction
Conditions that commonly lead to platelet consumption in the cow
Sepsis
DIC
Conditions that commonly lead to decreased platelet production in the cow
Aplastic anaemia
Infiltration of marrow with neoplastic cells
Most common causes of immune mediated thrombocytopaenia
Drug treatment (penicillin)
Lymphosarcoma
Systemic bacterial infections
Does malignant catarrhal fever cause a true epistaxis?
No, sloughing and ulceration of nasal tissue
What is caudal vena cava thrombosis?
Occlusion of vein by ‘white’ thrombus (abscess adjacent to caudal vena cava that ruptures)
Infectious agents that most commonly causes caudal vena cava thrombosis
Fusobacterium necrophorum
Arcanobacter pyogenes
(Concomitant pathogens: Streptococci, Staphylococci and E. coli)
What is thrombosis of the cranial vena cava usually attributable to?
Thrombophlebitis of the jugular vein
Common clinical signs of caudal vena cava syndrome
Chronic weight loss
Poor condition
Intermittent fever
Respiratory signs
Less common signs of caudal vena cava thrombosis
Pulmonary haemorrhage
Ascites
Sudden death
Most important diagnostic finding in caudal vena cava syndrome
Dilation of caudal vena cava seen via ultrasonography (normally appears triangular but circular in CVCS)
Prognosis of caudal vena cava syndrome
Poor, no treatment
Causes of acute haemorrhage in cattle
Clotting disorders
Neoplasia
Injury/trauma
When is a blood transfusion indicated in a cow?
PCV <10%
Is cross matching required in cow blood transfusions?
No, unnecessary as transfusion reactions after a single administration of blood is rare and mild
Over what time should a blood transfusion be given to a cow?
30-60 minutes
Does bracken fern toxicity happen due to small or large amounts of bracken?
Large amounts ingested over several weeks (may die up to 6 weeks after ingestion)
What virus has strains which can cause thrombocytopaenia?
Acute BVDV (usually asymptomatic)
How can mycotoxins cause thrombocytopaenia?
Trichothecene mycotoxins produced by Fusarium fungi, readily colonise fodder and damp cereal crops stored in temperate climate
What is referred to as ‘bleeding calf syndrome’?
Bovine neonatal pancytopaenia (calves <1m, pyrexia, unexplained haemorrhage)
Which breed of cattle suffer from inherited bovine thrombopathia?
Simmental
Complex syndrome in which pathological intravascular coagulation occurs
Disseminated intravascular coagulation
How does multisystem organ failure occur in DIC?
Formation of multiple thrombi in microcirculation causes ischaemia
Why does bleeding occur in DIC?
Excessive consumption of platelets
What disease processes can DIC be secondary to?
Septic mastitis
Septic metritis
Clostridial infections
Abomasal displacement (particularly right sided displacement with torsion)
Causes of blood loss that can lead to anaemia in cow
Abomasal ulcers
Parasites
Trauma
Surgical procedures
Post partum period
Caudal vena cava syndrome
Most common parasite involved in blood loss/anaemia
F. hepatica (liver fluke)
Anaemia more common in sheep and rare in cattle, whole herd/flock likely to be afected
How do liver fluke cause anaemia in cows?
Hepatic haemorrhage (death more common than anaemia)
When can blood loss/anaemia occur in post partum period? What is the cause?
<10 days after calving
Phosphorous deficiency
Causes of haemolytic anaemia in cows
Babesiosis
Post-parturient haemoglobinuria
Mycoplasma wenyonii
Top clinical sign of all causes of haemolytic anaemia in cows
Haemoglobinuria
Treatment for babesiosis
Imidocarb dipropionate
(+/- blood transfusion and appropriate tick control)
What is the vector for babesiosis?
I. ricinus
Strains of babesia seen in the UK
B. divergens
B. major
Why is post parturient haemoglobinuria less common nowadays?
High quality nutrition (caused by phosphorous deficiency)
Treatment for Mycoplasma wenyonii
Oxytetracycline or macrolides
(+/- immunosuppressive doses of steroids and blood transfusion)
Prognosis of IMHA due to M. wenyonii
Guarded (poor treatment response and carriers)
Parasite of red blood cells that causes a regenerative IMHA
Mycoplasma wenyonii
Parasites that cause covert blood loss in sheep (chronic infection)
Haemonchus contortus (Barbers pole worm)
Treatment of Haemonchus contortus in sheep
Ivermectin
New paddock?
Differentials for haemolysis
Toxins (onions/brassica feeding, copper)
Parasitism of RBCs
IV injection of hyper/hypotonic solutions
Bacterial toxins
Water intoxication
Causes of water intoxication
Excess Na ingestion with adequate water intake
Normal Na ingestion with inadequate water intake
Consumption of high Na water
Administration of hypertonic oral electrolytes
Pathophysiology of water intoxication
Dehydration results in hypernatraemia
Hypernatraemia results in net movement of water extracellularly
Rapid reintroduction of water causes rapid movement back into intracellular compartments
Cerebral oedema and intravasular haemolysis
Clinical signs of water intoxication
Thirst
Somnolence
Hyperthermia
Tachycardia
Rumen stasis
Diarrhoea
Mucoid faeces
Nasal discharge
Convulsions
Found dead
Treatment of water intoxication
Restrict water intake (little and often)
Corticosteroids to reduce CNS oedema
Frusemide to support kidney function
IV fluid therapy at modest rate
Prevention of water intoxication
Maintain fresh, clean water intake
If salt-limited feeds are offered anticipate the changes in water intake associated with weather
Ensure appropriate oral electrolytes are used where appropriate
