3.1.3: Bacterial endocarditis and traumatic reticulopericarditis

Question 1

Effects of TRP on cardiac function

Answer 1

1. Cardiac tamponade
2. Reduced cardiac output -> forward failure
3. Progresses to congestive heart failure (backward failure) - this is when animal presents as clinical signs now apparent

Question 2

Early stage traumatic reticulopericarditis: clinical signs

Answer 2

• Pain: abducted elbows, withers positive, arched back
• Rubbing/friction/tinkling/splashing on auscultation as there is liquid pus
• Tachycardia
• Pyrexia ± associated BRD signs

Heart sounds may change daily in the acute stages! Hard to diagnose.

Question 3

Later stage traumatic reticulopericarditis: clinical signs

Answer 3

• Muffled heart sounds bilaterally: regular rhythm with splashing/squeaking/rubbing sounds
• Difficulty palpating apex beat; cardiac sounds obscured due to fibrin in pericardium
• ± Pyrexia
• Signs related to congestive heart failure: jugular distension, ventral oedema, tachycardia, dyspnoea, injected scleral vessels

Question 4

What clinical pathological findings might be expected with traumatic reticulopericarditis?

Answer 4

• Leukocytosis, hyperfibrinogenaemia, hyperglobulinaemia (elevated TP) -> inflammation
• Neutrophilia -> infection/inflammation
• Elevated liver enzymes -> hepatic congestion esp if congestive heart failure

Question 5

What is the diagnostic method of choice for traumatic reticulopericarditis? How would you carry this out?

Answer 5

Ultrasonography
* ICS 3-5 on both sides
* Rectal scanner can be used

Question 6

What would you expect to see on ultrasonography of a cow with TRP?

Answer 6

• Purulent fluid in the pericardial sac ± fibrin
• Fibrin provies the “snowstorm” appearance within the pericardium

Question 7

Describe these findings

Answer 7

“Snowstorm” appearance within the pericardium caused by purulent material and fibrin

This is consistent with traumatic reticulopericarditis

Question 8

True/false: congenital cardiac defects are more common in cattle than acquired cardiac disease.

Answer 8

False
Congenital cardiac defects are rare in cattle
Acquired disease e.g. TRP is more common

Question 9

True/false: pericardiocentesis can help differentiate the cause of pericarditis in the cow.

Answer 9

True but this is not really done in practice. Could be done in some hospitals.
* Useful for differentiating septic pericarditis from lymphoma and idiopathic haemorrhagic pericarditis (latter = not seen in UK, seen in US)

Question 9

True/false: pericardiocentesis can help differentiate the cause of pericarditis in the cow.

Answer 9

True but this is not really done in practice. Could be done in some hospitals.
* Useful for differentiating septic pericarditis from lymphoma and idiopathic haemorrhagic pericarditis (latter = not seen in UK, seen in US)

Question 10

Describe the PM findings shown here

Answer 10

• The pericardium is extremely thickened (normally it is transparent)
• Lots of grey-coloured fibrin has accumulated on the epicardium
• This is a chronic septic pericarditis/TRP

Question 11

Treatment and prognosis for early TRP

Answer 11

• Fair to reasonable prognosis if caught before there has been perforation/septic pericarditis
• Treatment: bolus with magnet, give broad spectrum antibiotics (i.e. amoxicillin, oxytetracycline)

Question 12

Treatment and prognosis for late TRP

Answer 12

• Poor to hopeless prognosis
• Euthanise on welfare grounds -> this animal goes for fallen stock

Question 13

Prevention of traumatic reticulopericarditis

Answer 13

• Due diligence regarding silage and other feed management
• Magnets costs £2/3-4 per head and are effective
• Can put more than one magnet in if need be

Question 14

Describe the pathophysiology of bacterial endocarditis in cattle

Answer 14

• There is a bacteraemia secondary to chronic bacterial infection elsewhere e.g. mastitis, metritis, pneumonia, lameness
• The bacteria circulate, reach the heart and adhere to the endothelium
• Particular predilection sites for bacteria to adhere: right and left AV valves

Question 15

Clinical signs of bacterial endocarditis

Answer 15

Ante-mortem diagnosis is challenging!
* Murmur ± palpable thrill
* Persistent tachycardia
* Ill thrift
* Milk drop (may be episodic)

Question 16

Clinical pathological findings for bacterial endocarditis

Answer 16

Findings usually non-specific so clin path rarely used.
* Leukocytosis/ hyperfibrinogenaemia/ hyperglobulinaemia (elevated TP) -> inflammation
* Neutrophilia -> infection/inflammation
* Non-regenerative anaemia -> chronic disease
* Elevated liver enzymes -> hepatic congestion if CHF

Question 17

Describe the post-mortem appearance of a normal healthy heart valve

Answer 17

Crisp/shiny, regular shape

Question 18

Describe the post-mortem appearance of a heart valve in a cow with endocarditis

Answer 18

Rough, irregular shape. This allows turbulence and therefore murmurs can be heard.

Question 19

What diagnostic techniques could be used to investigate endocarditis?

Answer 19

• Ultrasonography - can be challenging to get a good image. Would see fluffy appearance of the affected valve.
• Blood culture - not commonly performed as expensive, hard to access and need repeat samples.

Question 20

Describe these findings

Answer 20

• Valve has much large diameter than expected and “fluffy” appearance
• Consistent with bacterial endocarditis where bacterial have adhered to the right AV valve

Question 21

Treatment for bacterial endocarditis

Answer 21

• Long-term antibiotic therapy - minimum 3 weeks penicillin/amoxicillin
• Furosemide if CHF present
• Analgesia

Quite impractical and expensive. Hard to justify under responsible use of antimicrobials.

Question 22

Prognosis for a cow with bacterial endocarditis

Answer 22

• Guarded if caught early - this is hard to do!
• Return to normal heart rate and sounds is a good prognostic sign.
• If signs of CHF -> poor prognosis and should euthanise.
• Animal may be fit to travel a short, stress-free journey, OR if severe signs/brisket oedema, should go for fallen stock.

Question 23

Describe the incidence of congenital heart defects in cattle

Answer 23

• Uncommon
• About 0.2% of bovine heart affected

Question 24

Presenting signs of congenital heart defects in cattle

Answer 24

• Murmurs
• Poor growth
• Increased RR/effort
• Cough
  May have been treated for penumonia but not improved.
  Will have had signs since birth.

Question 25

What is the most common congenital cardiac defect in cattle?

Answer 25

Ventricular septal defect (VSD)

Question 26

Describe the pathophysiology and diagnosis of a VSD

Answer 26

• L –> R shunting
• Obvious pansystolic murmur (constant whoosh) louder on the R than L
• Small defects have higher grade murmurs due to turbulence so here murmur volume does not correlate to defect severity

Question 27

Describe the treatment and prognosis for VSD in cattle

Answer 27

• Cannot treat, can only deal with compensatory mechanisms/let them live their lives
• Prognosis is dependent on size of defect

Question 28

What is ectopic cordis and what should be done about it?

Answer 28

• Congenital defect where heart can be seen beating in the neck because it is outside the chest
• Requires euthanasia

Question 29

When might you see hyperkalaemia and what relevance does it have to the heart?

Answer 29

Hyperkalaemia causes bradyarrythmias
* Seen in neonatal calves with severe, acute diarrhoea
* Seen in older male goats and sheep with urinary obstruction

Question 30

What is white muscle disease?

Answer 30

• Vitamin E/selenium deficiency
• Results in myocardial damage which may be focal/multifocal/diffuse
• Cardiac signs are variable