Lecture 20- Pericardial, myocardial, vascular

Pericardial disease definition

Inflammation of the pericardium

Pericarditis etiology

• Idiopathic

• bacterial (Actinobacillus, Strep)

• viral

• fungal

• secondary to pneumonia (50%)

• immune-mediated

• traumatic

• neoplasia

• MRLS-associated

MRLS/ETC pathophysiology

Ingestion of Eastern Tent Caterpillar setae → bacterial translocation → placental/fetal membrane inflammation → late-term abortion

Pericarditis pathophysiology

• Impaired cardiac filling

• cardiac tamponade → right CHF

• pericardial constriction

• effusive, fibrinous, constrictive forms

Pericarditis clinical signs

• Emergency presentation

• respiratory disease

• fever

• tachypnea

• tachycardia

• anorexia

• depression

• colic

• weight loss

• jugular distension/pulsation

• weak pulse

• ventral edema

• ascites

• friction rub

• muffled heart sounds

• pleural effusion

• cardiac tamponade

Determinants of tamponade

• Distensibility of pericardial sac

• rate of fluid accumulation

• amount of fluid accumulation

Pericarditis clinical pathology

• Anemia

• hyperproteinemia

• hyperfibrinogenemia

• neutrophilic leukocytosis

Pericarditis echocardiography

Diagnostic modality of choice → evaluates fluid amount/character and cardiac compromise

Pericarditis ECG

• Small amplitude QRS

• sinus tachycardia

• PVCs

Pericarditis radiographs

• Globular heart

• effusion

• pleural effusion

• pulmonary infiltrates

• enlarged pulmonary vessels

Pericardiocentesis diagnostics

• Cytology

• culture

• viral isolation

• troponin I if myocardial disease suspected

Pericarditis treatment

• Stall rest

• drainage/lavage

• antimicrobials (local + systemic)

• NSAIDs

• steroids if idiopathic

• prolonged treatment

Pericarditis prognosis

Guarded to fair

Myocardial disease definition

• Myocarditis = myocardial inflammation

• myocardial fibrosis = collagen deposition after ischemia/end-stage disease

Heart failure right vs left

Right: peripheral edema, ascites, jugular distension/pulsation, splitting S2

Left: pulmonary edema/effusion, crackles, tachypnea, tachycardia, prominent S3

Myocarditis etiology

• Bacterial

• viral

• parasitic

• thromboembolic

• other systemic disease

Myocarditis pathophysiology

• ↓ contractility

• ↓ ejection fraction

• diastolic dysfunction

• mitral/tricuspid incompetence

• arrhythmias

Myocarditis clinical signs

• Fever

• tachycardia

• arrhythmias

• CHF signs

• myalgia

• reluctance to move

• exercise intolerance

• tachypnea

• lethargy

• depression

• ataxia

• recumbency

• sudden death

Myocarditis diagnosis

• ↑ cardiac enzymes (troponin I)

• ECG (sinus tachycardia, arrhythmias)

• echo (normal or abnormal)

• post-exercise echo

Myocarditis treatment

• Remove underlying cause

• supportive care

• rest

• corticosteroids

• digoxin/quinidine/lasix (case-dependent)

Toxic myocardial injury causes

• Ionophore toxicity

• blister beetle toxicosis

• box elder

• endotoxemia

• rattlesnake venom

• white snakeroot

• Japanese yew

• oleander

Ionophore toxicity etiology

• Coccidiostat in poultry feed

• growth promoter in cattle

• accidental feed contamination

• horses uniquely sensitive

Ionophore toxicity clinical signs

• Sudden death

• fever

• depression

• lethargy

• sweating

• colic

• anorexia

• muscle weakness

• trembling

• ataxia

• diarrhea

• ileus

• ↑ HR/RR

• respiratory distress

• staggering

• polyuria→oliguria

• cardiac failure

• hypovolemia

• hypotension

• shock

Ionophore toxicity biochemistry

• ↑ PCV/TS

• ↑ BUN/creatinine

• ↓ phosphorus

• ↑ unconjugated bilirubin

• ↑ cardiac enzymes

• troponin I rises 18–48h post-ingestion

Ionophore toxicity echo

• Altered echogenicity

• chamber size changes

• fractional shortening prognosis:

  • 30–40% excellent

  • <20% poor

  • <10% fatal

Ionophore toxicity treatment

• Remove contaminated feed

• charcoal

• magnesium sulfate

• high-dose vitamin E

• control arrhythmias

• stall rest 2 months

• supportive care

• avoid digoxin

Blister beetle toxicosis etiology

• Ingestion of Epicauta spp.

• alfalfa cut/crimped

• Midwest

• summer

• cantharidin toxin

• GI/urinary irritation

• myocardial injury

• hypocalcemia

• endotoxemia

Blister beetle toxicosis clinical signs

• Mucous membrane irritation

• colic

• hypocalcemia

• frequent urination

• hematuria

• hemoglobinuria

• cardiac damage

• shock

• neurologic signs

• sudden death

Blister beetle toxicosis diagnosis

• Beetles in hay/GI

• cantharidin in GI/urine

• ↑ troponin I

• hypocalcemia

Blister beetle toxicosis treatment

• Pain relief

• GI evacuation

• charcoal/smectite/magnesium sulfate

• avoid mineral oil

• diuresis

• IV fluids

• Ca/Mg supplementation

• ulcer prophylaxis

• monitor Ca

Peripheral vascular disease types

• Vasculitis

• aneurysm

• embolism

• thrombosis

Vasculitis definition

Inflammation of blood vessels

Vasculitis etiology

• Infectious (virus, bacteria, parasites)

• non-infectious (immune complexes, drug-induced)

Vasculitis clinical signs

• Hyperemia

• petechiae

• ecchymosis

• ulcers

• cutaneous edema

• ventral/dependent edema

Aneurysm definition

• Vascular dilation/bulge

• risk of rupture

• weakening of medial elastic coat

Aneurysm etiology

• Trauma

• sepsis

• parasite migration

• degenerative vascular disease

• atherosclerosis

Thrombosis definition

Clot formation obstructing blood flow

Thrombosis etiology

• Trauma

• venous stasis

• catheter penetration

• irritating solutions

• bacteria

• perivascular inflammation

• dilated chambers (regurgitation, AF)

Embolism definition

Foreign material carried in bloodstream

Embolism etiology

• Thrombus

• catheter fragments

• foreign material

• air

• endocarditis

• thrombophlebitis

Purpura hemorrhagica definition

Immune-mediated vasculitis post-Strep infection (2–4 weeks)

Purpura clinical signs

• Hyperemia

• petechiae

• ecchymosis

• ulcers

• cutaneous edema

• ventral edema

Purpura pathophysiology

Necrotizing arteritis of small dermal/subdermal arteries

Purpura diagnosis

• History

• clinical signs

• SEM titers

Purpura treatment

• Corticosteroids

• antibiotics

• furosemide

• hydrotherapy

• wraps

Thrombophlebitis definition

Inflammation + thrombosis of vein

Thrombophlebitis etiology

• IV catheterization

• injection

• vessel injury

• hypercoagulability

• low flow

Thrombophlebitis clinical signs

• Swelling

• pain

• distension

• fever

• hyperfibrinogenemia

• neutrophilic leukocytosis

Thrombophlebitis diagnosis

• History

• clinical signs

• ultrasound + Doppler

• catheter culture

Thrombophlebitis treatment

• Topical therapy (ichthammol, DMSO, NSAIDs)

• monitor for head swelling

Catheter thrombogenicity ranking

Polypropylene > Teflon > Polyurethane > Silastic (least thrombogenic)

Aortoiliac thrombosis etiology

Migrating Strongylus vulgaris larvae

Aortoiliac thrombosis clinical signs

• Intermittent hindlimb lameness

• colic

• sweating

• trembling; pain

• collapse

• death

• cool limb

• ↓ arterial pulse

• ↓ saphenous vein filling

Aortoiliac thrombosis pathophysiology

Larval migration → endothelial damage → turbulence → thrombus → compromised blood supply

Aortoiliac thrombosis diagnosis

• Rectal palpation

• ultrasound

• scintigraphy

• parasite control

Aortic root rupture epidemiology

• Sudden death

• male horses >10 years

• Friesians predisposed

Aortic root rupture clinical signs

• Distress

• colic

• tachycardia

• jugular distension/pulsation

• acute death

• bounding pulses

• loud continuous murmur

Aortic root rupture diagnosis

• ECG: ventricular tachycardia

• U/S: rupture at aortic root

• aneurysmal dilation

• fistula formation (aorto-cardiac)