Infective endocarditis Flashcards
Define infective endocarditis
Infection of intracardiac endocardial structures (mainly
heart valves)
Explain the aetiology/risk factors of infective endocarditis
Most common organisms causing infective endocarditis:
Streptococci (40%) - mainly a haemolytic S. viridans and S. bovis
Staphylococci (35%) - S. aureus and S. epidermidis
Enterococci (20%) - usually E. faecalis
Other organisms: Haemophilus Actinobacillus Cardiobacterium Coxiella burnetii Histoplasma (fungal)
Vegetations form when organisms deposit on the heart valves during a period of bacteraemia, made of platelets, fibrin and infective organisms. They destroy valve leaflets, invade the myocardium or aortic wall leading to
abscess cavities. Activation of the immune system can lead to the formation of immune complexes –> vasculitis, glomerulonephritis, arthritis
Risk Factors
Abnormal valves (e.g. congenital, calcification, rheumatic heart disease)
Prosthetic heart valves
Turbulent blood flow (e.g. patent ductus arteriosus)
Recent dental work/poor dental hygiene (source of
S. viridans)
Summarise the epidemiology of infective endocarditis
UK Incidence: 16-22/1 million per year
Recognise the presenting symptoms of infective endocarditis
Fever with sweats/chills/rigors NOTE: this might be relapsing and remitting Malaise Arthralgia Myalgia Confusion Skin lesions Ask about recent dental surgery or IV drug use
Recognise the signs of infective endocarditis on physical examination
Pyrexia
Tachycardia
Signs of anaemia
Clubbing
New regurgitant murmur or muffled heart sounds
(Frequency of heart murmurs: Mitral> Aortic > Tricuspid > Pulmonary)
Splenomegaly
Vasculitic Lesions - Roth spots on retina, Petechiae on pharyngeal and conjunctival mucosa, Janeway lesions (painless macules on the palms which blanch on pressure), Osler’s nodes (tender nodules on finger/toe
pads)
Splinter haemorrhage
Identify appropriate investigations for infective endocarditis
FBC- high neutrophils, normocytic anaemia, High ESR/CRP
U&Es
NOTE: a lot of patients with infective endocarditis tend to be rheumatoid factor positive
Urinalysis - Microscopic haematuria, Proteinuria
Blood Culture - Do microscopy and sensitivities as well
Echocardiography - Transthoracic or transoesophageal (produces better image)
Duke’s Classification - a method of diagnosing infective endocarditis based on the findings of the investigations and the symptoms/signs
Generate a management plan for infective endocarditis
Antibiotics for 4-6 weeks
On clinical suspicion= EMPIRICAL TREATMENT
Benzylpenicillin
Gentamicin
Streptococci- continue the same as above
Staphylococci - Flucloxacillin/vancomycin, Gentamicin
Enterococci - Ampicillin, Gentamicin
Culture Negative - Vancomycin, Gentamicin
SURGERY - urgent valve replacement may be needed if there is a poor response to antibiotics
Identify the possible complications of infective endocarditis
Valve incompetence Intracardiac fistulae or abscesses Aneurysm Heart failure Renal failure Glomerulonephritis Arterial emboli from the vegetations shooting to the brain, kidneys, lungs and spleen
Summarise the prognosis for patients with infective endocarditis
FATAL if untreated
15-30% mortality even WITH treatment
