Heart disease in cattle and sheep Flashcards
Focus on bacterial endocarditis and traumatic reticulo-pericarditis (31 cards)
Cardiac dz in farmed spp
- Cardiovascular disease moderately common in cattle
- Rare in other ruminants
- Acquired > congenital
– Congenital defects ~0.2%
Types of pericarditis
- Traumatic reticulo-pericarditis (TRP)
- Other types of pericarditis are uncommon and rarely cause signs of cardiac disease
– Sepsis in calves
– Severe BRD in adult cattle
– May be seen on PME associated with ‘pulpy kidney’ (C.perfringens type D)
– Idiopathic haemorrhagic pericardial effusion (IHP) (not seen in UK)
Traumatic reticulo-pericarditis (TRP) overview
- Cattle
– Most common pericardial condition in cattle - Septic pericarditis (see lots of pus and fibrin)
– Rarely reported in other species
– Hard wire/Hardware disease (“wire”) - Pericardium and reticulum are anatomically closely located
TRP - aetiology and pathogenesis
- Sharp linear metallic FB ingested
– Typically wires from tyres used to weigh down silage cover
– Associated with clamp silage feeding - FB penetrates reticular wall -> into pericardial sac (through diaphragm)
– Not always cranial direction
(with reticular contraction the wire moves, typically in cranial direct, but can go in other directions -> get inflammation of whatever other organ has been penetrated)
TRP - effects on cardiac function
- Cardiac tamponade
- Reduced cardiac output
– Forward failure - Progresses to CHF
– Backward cardiac failure
– CS related to this (e.g. oedema)
Why does TRP cause cardiac tamponade?
- Pericardial sac filled with pus and fibrin
- Heart won’t be able to beat effectively
- Get cardiac tamponade
TRP - history
- Typically non-specific
- Milk drop
- Non-specific illness 1-2 weeks prior to exam that appeared to resolve before recurring
- Inappetance
TRP - Presenting signs: early stages
- Pain
– Abducted elbows
– Withers positive
– Arched back
– Firm palpation - Rubbing/friction sounds on auscultation (pus still liquidy - heart moving around in this fluid)
- Tachycardia
- Pyrexia +/- associated BRD signs
- In the early (acute) stages, heart sounds can change daily
TRP - Presenting signs: later stages
- Muffled heart sounds (bilateral)
– Regular rhythm
– Splashing, squeaking, rubbing sounds - Difficulty palpating apex beat
- +/- pyrexia
- Signs related to congestive heart failure
– Jugular distension, ventral oedema, tachycardia, dyspnoea, injected scleral vessels - In the later (chronic) stages, heart sounds tend to be consistent
TRP - Clinical pathological findings
Non-specific
- Inflammation: Leukocytosis, Hyperfibrinogenaemia, Hyperglobulinaemia (TP ^)
- Infection/inflammation: neutrophilia
- Hepatic congestion (if CHF): Elevated liver enzymes
TRP - US
- Method of choice
- ICS3 – ICS5 on both sides
- Rectal scanner can be used
- Purulent fluid in pericardial sac (+/- fibrin)
- Hepatic congestion
TRP - Alternative imaging
- Radiography
– Lateral thoracic views (standing)
– Gas-fluid interface
– Metal wire may be identified
– Not often available
TRP - Pericardiocentesis - use & risks
- Differentiate causes of pericarditis – NOT treatment
– Septic pericarditis
– Lymphoma (not in UK)
– Idiopathic haemorrhagic pericarditis (not in UK) - Potentially fatal risks
– Pneumothorax
– Cardiac puncture
– Contamination of pleural space
TRP - PM
- thickened reticular wall
- bruised pericardium (should be whitish colour)
- thickened pericardium
- potentially squished chambers
- lots of fibrin
TRP - Treatment and prognosis
Early stages (i.e. before fibrinous septic pericarditis has developed)
- Magnet
- Broad-spec antibiotics (e.g. amoxicillin, oxytetracycline)
Late stages (septic pericarditis has developed)
- Prognosis = poor to hopeless
- PTS on welfare grounds
- Pericardiotomy/percardiostomy and drainage are reported
– Poor outcomes
TRP - Prevention
- Due diligence regarding silage (and other feed) management
- Magnets
Bacterial endocarditis - Pathophysiology
Bacteraemia
- Chronic bacterial infection elsewhere (e.g. mastitis, metritis, pneumonia, lameness etc.)
- Truperella pyogenes
– Also staphs, streps and G-ves
- Adhesion to endothelium
– No prior endothelial damage (cf other species)
– Can occur on mural endocardium
- Predilection sites:
– Right AV (tricuspid) valve
– Left AV (mitral) valve
Bacterial endocarditis - Clinical signs
- Ante-mortem diagnosis = challenging
- Murmur +/- palpable thrill
- Persistent tachycardia
- Ill thrift
- Milk drop
- May be episodic (particularly if little thrombi are breaking away)
Bacterial endocarditis - Clinical pathological findings
Non-specific
- Inflammation: Leukocytosis, Hyperfibrinogenaemia, Hyperglobulinaemia (TP ^)
- Infection/inflammation: neutrophilia
- Chronic dz: non-regenerative anaemia
- Hepatic congestion (if CHF): Elevated liver enzymes
Bacterial endocarditis - Ancilliary investigations
- Ultrasonography (echocardiography)
– Can use rectal scanner
– Can be challenging to achieve good images - Blood culture
– Not commonly performed (not very practical)
– Repeat samples recommended (3 different sites over 1hr)
Bacterial endocarditis - Treatment
- Long-term antibiotic therapy
– Minimum 3 weeks
– Penicillin/amoxicillin are abs of choice - Furosemide if CHF present (furosemide only licensed cardiac product for cattle)
- Analgesia
Bacterial endocarditis - PM findings
- murial endocarditis: big lump of bacteria and pus on the inside of 1 of the heart chambers. with this you won’t hear such a big murmur as not a lot of turbulence created
- thickened valves, discoloured, possibly ruptured chordae tendinae
- haematogenous spread: very common in the liver and kidney, tiny abscesses and infarcts esp in organs with lots of capillaries
Bacterial endocarditis - Prognosis
- Guarded
– Return to normal heart sounds and rate = good prognostic sign
– Better if diagnosed and treated early - Signs of CHF = poor prognosis
Cardiac disease in calves
- Congenital cardiac disorders
- VSD
- Multiple defects
- ASD (uncommon)
- Ectopia cordis
