Equine Pericardial, Myocardial, & Vascular Diseases Flashcards
How does pericarditis manifest?
uncommon in horses —> often an emergency!!
What are the 3 most common infectious causes of pericarditis? Other causes?
- BACTERIAL: Actinobacillus spp., Streptococcus
- VIRAL
- FUNGAL
(commonly secondary to penumonia)
- immune-mediated
- traumatic
- neoplasia
What are the 2 most common risk factors that predispose horses to pericarditis?
- extension of pleural pneumonia in horses that have been transported, fever, and exposure to a large number of horses
- high prevalence in mare reproductive loss syndrome caused by Eastern Tent Caterpillar
What is the theory to Eastern Tent Caterpillars causing mare reproductive loss syndrome?
- ETC nests in trees
- ETC hatch in Feb-March and larvae migrate to find pupation site
- horses ingest ETC and their setae hairs break off and lodge in the stomach lining, which carries gut bacteria into tissue and bloodstream
- setae carry bacteria to immuno-sensitive areas, such as placental/fetal membranes and the heart
(late-term abortion storms)
What is the consequence to infectious pericarditis?
impaired cardiac filling causes cardiac tamponade and pericardial construction, which leads to right-sided CHF —> peripheral edema, bilateral jugular pulsation
What are the 3 forms of infectious pericarditis?
- effusive
- fibrinous (cows!)
- constrictive
What are the most common clinical signs associated with infectious pericarditis?
- respiratory distress: tachypnea, tachycardia
- fever
- colic, weight loss
- jugular distension and pulsation, weak pulse
- ventral edema, ascites
- pericardial friction rub, muffled heart sounds, pleural effusion
- cardiac tamponade
What are the 3 determinants to the severity of infectious pericarditis clinical signs?
- distensibility of pericardial sac
- rate of fluid accumulation
- amount of fluid accumulation
What 4 clinical pathology findings are seen in patients with infectious pericarditis?
- anemia
- hyperproteinemia
- hyperfibrinogenemia
- neutrophilic leukocytosis
What is the diagnostic modality of choice to diagnosing infectious pericarditis?
echocardiography —> shows amount and character of fluid and degree of cardiac compromise
Infectious pericarditis, fibrin accumulation:
What 3 things are seen on ECG in patients with pericarditis?
- small amplitude QRS
- sinus tachycardia
- PVC
What 2 things are seen on radiographs in patients with pericarditis? What can it not differentiate?
- globulus heart with effusion
- infiltrates and enlarged pulmonary vessels
doesn’t differential from other forms of cardiac enlargement
What is recommended for pericarditis treatment? What is prognosis like?
- stall rest
- drainage and lavage with ECG monitoring
- local and systemic antimicrobials
- NSAIDs
- steroids to decrease inflammation if idiopathic
guarded to fair due to lengthy, hard treatment course
What is the difference between right-sided and left-sided heart failure?
R = peripheral edema, ascites, jugular distension and pulsation
L = pulmonary edema, effusion, tachypnea, tachycardia
What is heard on auscultation in right-sided and left-sided heart failure?
R = splitting S2
L = crackles, prominent S3
What are the 4 most common etiologies of myocarditis?
- bacteria
- virus
- parasites
- thromboembolic
What are 4 consequences of myocarditis?
- decreased myocardial contractility and ventricular ejection fraction
- diastolic dysfunction with impaired ventricular filling
- mitral and tricuspid valve incompetency
- development of arrhythmias
What are the most common clinical signs of myocarditis?
- fever
- tachypnea
- arrhythmias
- signs of CHF
- myalgia, reluctance to move, exercise intolerance
- tachypnea, lethargy, depression
- ataxia, staggering, recumbency
- sudden death
What clinical pathology is seen in patients with myocarditis? What are 2 signs on ECGs?
increased cardiac enzyme, troponin I
- sinus tachycardia
- cardiac arrythmias
What treatments of myocarditis are recommended?
- supportive care: rest*
- corticosteroids*
- Digoxin
- Quinidine sulfate
- Lasix
(remove underlying cause!)
In what animals is the use of ionophores common?
- POULTRY: coccidiostat
- CATTLE: growth promoter
(TOXIC IN HORSES)
What are the 3 most common situations where horses come into contact with ionophores?
- got into cattle food
- accidental contamination of feed from a new feed mill
- recently acquired food from a new brand
What 3 ionophores commonly cause toxicity in horses?
- Monensin
- Salinomycin
- Lasalocid
What do the clinical signs of ionophore toxicity depend on? What is seen?
type, quantity, concentration, pre-existing health and BCS
- sudden death*
- fever, depression, lethargy
- exercise intolerance, lethargy
- colic, diarrhea, ilues, anorexia
- trembling, ataxia
- increased HR and RR
- polyuria and oliguria
- hypovolemia, hypotension, shock
What 4 changes in biochemistry is indicative of ionophore toxicity?
- increased PCV and total solids
- increased BUN and creatinine
- decreased phosphorus, increased unconjugated bilirubin
- increased cTroponin I (sensitive to cell damage)
What is the test of choice for diagnosing ionophore toxicity? What is seen?
echocardiography
- altered echogenicity and chamber sizes
- fractional shortening
How is ionophore toxicity treated? What is NOT used?
- remove all contaminated feed
- administer charcoal and mangesium sulfate adsorbent
- large dose of vitamin E
- control arrhythmias
- stall rest for 2 months
Digoxin - adds to monensin effect
Other than echocardiography, how is ionophore toxicity diagnosed?
- ECG: arrhythmia
- analyze feed, GI content, and soil
When is blister beetle toxicosis most common?
- horses fed cut and crimped alfalfa, which attract the beetles
- beetles most commonly found in the Midwest in middle to late summer
What causes blister beetle toxicosis?
cantharidin within the beetle is a vesicant and irritant to the GIT and urinary tract and can cause direct injury to the myocardium, hypocalcemia, and endotoxemia
What are the 6 most common clinical signs of blister beetle toxicosis?
- GIT mucous membrane irritation, colic
- hypocalcemia
- synchronous diaphragmatic flutter
- frequent urination, hematuria, and hemoglobinuria
- cardiac damage, shock
- neurologic signs, sudden death
How is blister beetle toxicosis diagnosed?
- clinical signs
- beetles found in hay or GI contents
- cantharidin in GI or urine
- CTnI, hypocalcenia
How is blister beetle toxicosis treated? What is avoided?
- pain relief
- evacuate GIT with activated charcoal, smectite, and magnesium sulfate
- establish diuresis with IV fluids and supplemental calcium or magnesium
- ulcer prophylaxis
- monitor calcium
mineral oil
What are the 2 most common etiologies of vasculitis?
- INFECTIOUS: virus, bacteria, parasites
- NON-INFECTIOUS: immune complexes, drug-induced
What are the 3 most common clinical signs associated with vasculitis?
- hyperemia, petechia, ecchymosis, ulcers
- well-demarcated areas of cutaneous edema
- ventral edema
What is an aneurysm? What causes its development?
vascular dilation/bulge with a high risk of rupture
weakening of medial elastic coat (primary or atherosclerotic)
What are the 4 most common etiologies of aneurysms?
- trauma
- sepsis
- parasite migration (Strongyle infection in mesenteric arteries)
- degenerative vascular disease, like artherosclerosis
What is thrombosis?
formation of a clot that obstructs blood flow, which develops from intimal disease or hypercoagulable state
What are the 5 most common etiologies of thrombosis? Secondary causes?
- trauma
- venous stasis
- needle/catheter penetration
- irritating solutions
- bacteria
SECONDARY - perivascular inflammation, dilated cardiac chambers (regurgitation, AF)
What is an embolism? 3 most common causes?
(foreign) material carried in the blood stream
- arterial or venous thrombus
- catheter fragments, foreign material
- endocarditis, thrombophlebitis
What is equine purpura hemorrhagica (EPH)? What are the 3 most common clinical signs?
vasculitis resulting from Strep (Strangles) infection
- hyperemia, petechia, ecchymosis, ulcers
- well-demarcated areas of cutaneous edema
- ventral edema
What is the pathophysiology of equine purpura hemorrhagica (EPH)? How is it diagnosed?
necrotizing arteritis in small dermal/subdermal arteries
history, clinical signs, SEM titers
What are 5 treatment options for equine purpura hemorrhagic (EPH)?
- corticosteroids
- antibiotics
- Furosemide
- hydrotherapy
- wraps
(decrease inflammation and swelling!)
What is thrombophlebitis? What are the 2 most common etiologies?
inflammation and thrombosis of veins
- IV catheterization or injection
- vessel injury, hypercoagulability, low flow
What are the most common clinical signs associated with thrombophlebitis? How is it diagnosed?
swelling and pain on palpation of vein with distension + fever, hyperfibrinogenemia, and neutrophilic leukocytosis —> HEAD SWELLING due to improper blood flow during exercise
- history, clinical signs
- ultrasound and Doppler
- culture catheter
How is thrombophlebitis treated?
topical ichthammol, DMSO, or NSAIDs
What is a highly thrombogenic catheter material? What 3 tend to avoid thrombophlebitis?
polypropylene (PE tubing, Medicut)
- teflon - Angiocath
- polyutethane - Mila
- Silastic* - Centrasil
What is aortoiliac thrombosis? What are 3 clinical signs?
thrombosis from migrating Strongylus vulgaris larvae
- intermittent hindlimb lameness (exercise)
- colic, sweating, trembling, pain, collapse, death
- cool limb due to decreased arterial pulse and saphenous vein filling
What is the pathophysiology of aortoiliac thrombosis?
larval migration damages endothelium, causing turbulence, thrombus formation, and compromised blood supply
How is aortoiliac thrombosis diagnosed and prevented?
rectal palpation, ultrasound, scintigraphy
parasite control
What is the most common result of aortic root rupture or aortopulmonary fistulation?
sudden death with massive hemorrhage in male stallions > 10 y/o or Friesians
What clinical signs are associated with aortic root rupture or aortopulmonary fistulation?
- distress, colic
- tachycardia, jugular distension and pulsation
- acute death
- bounding arterial pulses with loud and continuous murmur
What are the 2 ways aortic root rupture or aortopulmonary fistulation are diagnosed?
- ECG: ventricular tachycardia, abnormal rhythm
- ultrasound: ruputure in aortic root, aneurysmal dilation
What element in the anamnesis will guide you towards a diagnosis of ionophore toxicity?
a. alfalfa hay from Midwest is fed
b. there are beetles in the hay
c. new grain from feed mill was fed
d. horse was administered a milkshake (sodium bicarbonate)
C
How is vasculitis treated?
- diuretics
- hydrotherapy
- corticosteroids
- antimicrobials
An embolism corresponds to which of the following events?
a. vascular dilation
b. formation of a clot that obstructs blood flow
c. foreign material carried in the blood stream
d. vascular inflammation
C
