6. Myxomatous mitral valve diseases in dogs (occurrence, diagnosis, differential diagnosis, treatment) Flashcards

1
Q

MMVD INFO and pathogenesis?

A

The most common acquired cardiac disease in dogs

Older dogs>Younger dogs; Small breeds; Males>Females

King Charles Cavalier Spaniel; Dachshund; Poodle

Mitral valve > Tricuspid valve

Synonyms: Mitral valve disease; Valvular; Chronic valvular disease;

Endocardosis/endocardiosis; Degenerative valvular disease

Overview

PATHOGENESIS (BRIEF)

Controlled by 2 pathways: TGF-β & serotonin pathways

Chronic endocardiosis → Chronic valvular degeneration

Degeneration of the AV valve’s layers → Mitral valve prolapse

Mitral valve involvement → ↑Pulmonary pressure →

Cardiogenic pulmonary oedema

Tricuspid valve involvement → ↑Venous pressure →

Signs of Right-side heart failure

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2
Q

Pathophysiology, Compensatory mechanisms and pathological lesions?

A
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3
Q

Clinical signs of MMVD?

A

CLINICAL SIGNS

§ If signs of LS-HF are present: Pulmonary oedema;

Tachypnoea; Dyspnoea

§ If signs of RS-HF are present: Ascites; Jugular distension

& pulsation

§ Holosystolic/systolic murmur

§ Systolic click (3-heart-sound rhythm)

DIAGNOSIS

Physical exam

§ Systolic heart murmur (left apical)

§ Signs of LS-HF

§ Signs of RS-HF

Diagnostic imaging

Echocardiography: Gold standard – Diagnostic

§ Regurgitation of blood from the valves (see fig 5.3)

§ Atrial & ventricular dilation

§ Thickening of valves

§ Rupture of chordae tendineae

Radiography: Chamber enlargement (mainly LS); Lung oedema

ECG: Determination of any arrhythmias; May also indicate

LA/bilateral enlargements & LV dilation

§ Ventricular myocardial lesions & CHF →

Ventricular premature beat & sinus tachycardia

§ Left atrial enlargement →

Atrial arrhythmias (atrial premature complexes;

Atrial Fib.)

§ Left atrial & ventricular enlargement →

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4
Q

Grading of valvular diseases and treatment?

A
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5
Q

Endocarditis?

A

Endocarditis

Rare condition; Large breeds;

PATHOGENESIS

Caused by bacterial infection → Bacteraemia

Staphylococcus spp.; Streptococcus spp.; E. coli; Bartonella spp.

Predisposing factor: Aortic stenosis

Complications: CHF; Immune-mediated disease; Thromboembolism

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