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Y1 Cardiology > Endocarditis (Abnormalities) > Flashcards

Endocarditis (Abnormalities) Flashcards

1
Q

Bacteraemia (def)

A

The presence of viable bacteria in the circulating blood; may be transient following trauma such as dental or other iatrogenic manipulation or may be persistent or recurrent as a result of infection.

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2
Q

If bacteraemia/septicaemia is not treated properly, the patient may develop….

A

septic shock and death.

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3
Q

What do the two different colours of bottles stand for in a blood culture?

A

Aerobic and anaerobic.

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4
Q

Why are blood cultures used?

A

The results of the blood culture tailor the treatment- the faster the delivery of the antibiotic the better the outcome.
Therefore blood culture allows the right drug, at the right dose, at the right time and duration for every patient.
Clinical outcomes are improved where causative organisms found.
see antimicrobial stewardship.

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5
Q

What three questions would you ask yourself upon a positive culture result?

A

What is the usual habitat of this organism?
What diseases is this organism associated with?
What is the optimum antimicrobial management required?

See bacterial infections overview diagram.

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6
Q

Endocarditis (def)

A

infection of the endothelium of the heart valves (persistent bacteraemia)- two disease groups; acute and subacute.

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7
Q

Predisposing factors for Endocarditis

A

Heart valve abnormality - calcification/sclerosis in elderly, congenital HD, post rheumatic fever.
Prothetic heart valve
IV drug users
Intravascular lines

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8
Q

Pathogenesis of Endocarditis

A
  1. Heart valve damaged
  2. Turbulent blood flow over roughened endothelium
  3. Platelets/fibrin deposited
  4. Bacteria introduced- possibly transient e.g. dental treatment
  5. Organisms settle in fibrin/platelet thrombi and become microbial vegetation.

Infected vegetations are friable and can break off and become lodged in capillary bed - this can cause haemorrhage or abscess and can be fatal.

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9
Q

Which side of the heart is more commonly effected by Endocarditis?

A

Left side of heart i.e. mitral and aortic valves

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10
Q

What are the four most common causative organisms of endocarditis in native valves?

A
  1. Staphylococcus Aureus (38%)
  2. Viridans Streptococci (31%)
  3. Enterococcus sp (8%)
  4. Staph. Epidermis (6%)

Note - all gram positives.

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11
Q

What are the more unusual organisms that can cause endocarditis?

A

Atypical organisms- Bartonella, Coxiella Burnetti (Q-fever), Chlamydia, Legionella, Mycoplasma, Brucella
Gram negatives- HACEK (haemophilus spp., aggregatibacter spp. (aka actinobacillus), Cardiobacterium, Eikenella sp., Kingella sp.) and Non HACEK gram negatives.
Fungi

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12
Q

Does a ‘clear’ blood culture rule out endocarditis?

A

No- there are causes of endocarditis that will not grow on the regular blood culture.
If blood cultures negative, consider serology for “atypical” organisms. (see unusual causative organisms)

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13
Q

How many blood cultures are taken and why?

A

3 sets of blood cultures -very important since if all are positive there is good evidence of continuing bacteraemia. If only one set taken and is positive, it might be a contaminant.

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14
Q

Duke Criteria (major and minor)

A

Major Criteria
> Two separate blood cultures with microorganisms typical for infective endocarditis: Viridans Strep., Strep. Bovis, HACEK group, Staphylococcus Aureus, community acquired enterococci.
> Echocardiographic evidence of endocardial involvement: typical vascular lesions, vegetations, abscess, or new partial dehiscence of a prosthetic valve.
> New valvular regurgitations

Minor Criteria
>Predisposition: predisposing heart condition or IV drug use
>Temperature greater than 38c
>Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial heamorrhage, conjunctival haemorrhage, Janeway lesions
>Immunological phenomena: glomerulonephritis, Osler nodes, Roth spots, Rheumatoid factor
>Microbiological evidence: positive blood cultures but not meeting major criteria, or serological evidence of active infection with organism consistent with infective endocarditis.

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15
Q

How do staphylococcus organisms appear on gram film?

A

gram positive cocci arranged in clusters.

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16
Q

What is the most common coagulase negative Staphylococcus organism?

A

Staph. Epidermidis - often contaminant from the skin but can infect prosthetic material.

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17
Q

Skin contaminants in blood cultures

A 
Staph Epidermidis 
Corynebacterium sp (diphtheroids)
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18
Q

When would coagulase testing be important?

A

If plastic or metals involved i.e. prosthetics.

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19
Q

What is the most common coagulase positive Staph. organism?

A

Staph. Aureus

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20
Q

What is the mortality rate where Staph. Aureus + HF + periannular complication?

A

79%

21
Q

Temperature of blood cultures?

A

37oc

22
Q

What is the difference between acute and subacute endocarditis?

A

Acute- sudden, Subacute- grumbling.

23
Q

How does acute endocarditis present?

A

Acute Endocarditis presents as overwhelming sepsis and cardiac failure. This is usually due to aggressive virulent organisms such as Staph. Aureus.

24
Q

What are the signs and symptoms of subacute endocarditis?

A

Symptoms; fever, malaise, weight loss, tiredness and breathlessness.

Signs; fever, new or changing heart murmur, finger clubbing, splinter haemorrhages, splenomegaly, roth spots, janeway lesions, osler nodes, microscopic haematuria.

25
Q

What group of organisms is the most common cause of subacute endocarditis?

A

Viridans group streptococci.

Alpha haemolytic strep; 
Strep mitis 
Strep sanguinis 
Strep mutans 
Strep salivarius etc.

Subacute Endocarditis;
Normal oral commensals
No lancefield group

26
Q

What are Janeway Lesions?

A

Non-tender, small erythematous or haemorrhagic macular or nodular lesions on the palms or soles only a few millimeters in diameter that are indicative of infective endocarditis

27
Q

What are Roth’s Spots?

A

Retinal haemorrhages with white/pale centres, indicative of infective endocarditis.

28
Q

What are Ostler’s Nodes?

A

Painful, red, raised lesions found on the hands and feet. They are associated with a number of conditions, including infective endocarditis, and are caused by immune complex deposition.

29
Q

When does prosthetic valve endocarditis present?

A

Early or Late

Early- within 60 days,usually infected at the time of valve insertion and usually due to Staphylococcus Epidermidis or Staphylococcus Aureus.
Late- up to many years after the valve insertion, due to coincidental bacteraemia. There is a wide range of possible organisms that could be involved.

30
Q

How would Prosthetic Valve Endocarditis be treated?

A

Vancomycin + Gentamicin IV + Rifampicin PO 3-5 days after the others.

Often valve replacement required.

31
Q

What side of the heart does Endocarditis in PWID most commonly occur, and what is the most common causative organism?

A

Right side (think of direction of blood flow- tricuspid > pulmonary > mitral > aortic)

Staph. Aureus

32
Q

What is commonly the first presentation of endocarditis in PWID?

A

Multiple septic emboli - Staph. Aureus is very efficient at colonising and therefore original valve damage is often not present (normal valve in 75-93% of cases).

33
Q

How would native valve endocarditis be treated?

A

Amoxicillin and Gentamicin IV

34
Q

How would IV drug use endocarditis be treated?

A

Flucloxacillin IV

35
Q

Antibiotic therapy for Staph. Aureus?

A

Non MRSA - Flucloxacillin IV

MRSA - treat as per prosthetic valve

36
Q

Antibiotic therapy for Viridans Strep.?

A

Benzylpenicillin IV + gentamicin IV

SYNERGISTIC

37
Q

Antibiotic therapy for Enterococcus sp.?

A

Amoxicillin/ vancomycin + gentamicin IV

38
Q

Antibiotic therapy for Staph. Epidermidis?

A

Vancomycin + gentamicin IV + rifampicin PO

39
Q

Four categories of risk in endocarditis?

A

Patient characteristics
Clinical complications of IE
Microorganism
Echocardiographic findings

(see risk table in notes)

40
Q

OPAT in Endocarditis;

Use in 2 x phases?

A 
Critical phase- inpatient preferred, OPAT if oral strep, strp bovis, native valve and patient stable. 
Continuation phase (2 weeks +)- OPAT if medically stable, not for use if ech features, neurological signs or renal impairment.
41
Q

Myocarditis (def)

A

inflammation of the cardiac muscle

42
Q

What are the main causes of Myocarditis?

A

Viruses are the main cause-enteroviruses Coxsackie A and B and echovirus in particular, but other viruses form an extensive list of causes.

43
Q

What are the main signs and symptoms of myocarditis?

A

Symptoms- fever, chest pain, SOB and palpitations.

Signs- arrhythmia, cardiac failure.

44
Q

How would myocarditis be diagnosed?

A

Viral PCR, throat swab and stool for enteroviruses, and throat swab also for influenza.

45
Q

How would you treat Myocarditis?

A

Supportive treatment (as viral)

46
Q

Pericarditis (def)

A

inflammation of the pericardium (lining of the heart)

47
Q

What is the main feature of Pericarditis?

A

Chest pain

48
Q

What are the causes of pericarditis?

A

Viral
Bacterial causes rare e.g. post cardiothoracic surgery, rare secondary spread from endocarditis or pneumonia

see table in notes for specific examples.

49
Q

How is pericarditis treated?

A

Viral = supportive treatment

Bacterial (rare) = aspiration and antibiotics

Y1 Cardiology (9 decks)

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