3.1.3: Bacterial endocarditis and traumatic reticulopericarditis Flashcards
Effects of TRP on cardiac function
- Cardiac tamponade
- Reduced cardiac output -> forward failure
- Progresses to congestive heart failure (backward failure) - this is when animal presents as clinical signs now apparent
Early stage traumatic reticulopericarditis: clinical signs
- 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.
Later stage traumatic reticulopericarditis: clinical signs
- 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
What clinical pathological findings might be expected with traumatic reticulopericarditis?
- Leukocytosis, hyperfibrinogenaemia, hyperglobulinaemia (elevated TP) -> inflammation
- Neutrophilia -> infection/inflammation
- Elevated liver enzymes -> hepatic congestion esp if congestive heart failure
What is the diagnostic method of choice for traumatic reticulopericarditis? How would you carry this out?
Ultrasonography
* ICS 3-5 on both sides
* Rectal scanner can be used
What would you expect to see on ultrasonography of a cow with TRP?
- Purulent fluid in the pericardial sac ± fibrin
- Fibrin provies the “snowstorm” appearance within the pericardium
Describe these findings
“Snowstorm” appearance within the pericardium caused by purulent material and fibrin
This is consistent with traumatic reticulopericarditis
True/false: congenital cardiac defects are more common in cattle than acquired cardiac disease.
False
Congenital cardiac defects are rare in cattle
Acquired disease e.g. TRP is more common
True/false: pericardiocentesis can help differentiate the cause of pericarditis in the cow.
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)
True/false: pericardiocentesis can help differentiate the cause of pericarditis in the cow.
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)
Describe the PM findings shown here
- 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
Treatment and prognosis for early TRP
- 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)
Treatment and prognosis for late TRP
- Poor to hopeless prognosis
- Euthanise on welfare grounds -> this animal goes for fallen stock
Prevention of traumatic reticulopericarditis
- 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
Describe the pathophysiology of bacterial endocarditis in cattle
- 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
Clinical signs of bacterial endocarditis
Ante-mortem diagnosis is challenging!
* Murmur ± palpable thrill
* Persistent tachycardia
* Ill thrift
* Milk drop (may be episodic)
Clinical pathological findings for bacterial endocarditis
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
Describe the post-mortem appearance of a normal healthy heart valve
Crisp/shiny, regular shape
Describe the post-mortem appearance of a heart valve in a cow with endocarditis
Rough, irregular shape. This allows turbulence and therefore murmurs can be heard.
What diagnostic techniques could be used to investigate endocarditis?
- 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.
Describe these findings
- Valve has much large diameter than expected and “fluffy” appearance
- Consistent with bacterial endocarditis where bacterial have adhered to the right AV valve
Treatment for bacterial endocarditis
- 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.
Prognosis for a cow with bacterial endocarditis
- 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.
Describe the incidence of congenital heart defects in cattle
- Uncommon
- About 0.2% of bovine heart affected
Presenting signs of congenital heart defects in cattle
- Murmurs
- Poor growth
- Increased RR/effort
- Cough
May have been treated for penumonia but not improved.
Will have had signs since birth.
What is the most common congenital cardiac defect in cattle?
Ventricular septal defect (VSD)
Describe the pathophysiology and diagnosis of a VSD
- 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
Describe the treatment and prognosis for VSD in cattle
- Cannot treat, can only deal with compensatory mechanisms/let them live their lives
- Prognosis is dependent on size of defect
What is ectopic cordis and what should be done about it?
- Congenital defect where heart can be seen beating in the neck because it is outside the chest
- Requires euthanasia
When might you see hyperkalaemia and what relevance does it have to the heart?
Hyperkalaemia causes bradyarrythmias
* Seen in neonatal calves with severe, acute diarrhoea
* Seen in older male goats and sheep with urinary obstruction
What is white muscle disease?
- Vitamin E/selenium deficiency
- Results in myocardial damage which may be focal/multifocal/diffuse
- Cardiac signs are variable
