Cardiac infections Flashcards
Define what is meant by a bacteraemia
The presence of bacteria in the bloodstream (bacteraemia) is a potentially life-threatening event - if not treated promptly the patient may develop septic shock and die.
When someone has a Implantable cardiac electronic devices (ICED) what are the 3 locations infection may occur ?
In either the Box (generator pocket), leads or Endocardium
How do generator pocket infections of a ICED usually present ?
Localized cellulitis, pain, swelling, discharge, wound breakdown.
What are often co-infections with a generator pocket infection of an ICED ?
Infective endocarditis (IE) or ICED lead infection (ICED-LI) frequently coexist
How may Infective endocarditis (IE) or ICED lead infection (ICED-LI) present alongside generator pocket infections & what is used to help diagnose these co-infections ?
- Non-specific signs and symptoms of systemic infection (including fevers, chills, night sweats, malaise and anorexia) may be the only clinical features of ICED-IE/ICED-LI.
- Dukes criteria used to help diagnose them
What is the initial investigations which should be done in someone with a suspected ICED infection ?
Not septic:
- 3 sets of blood cultures (≥ 6 hrs apart)
- Arrange Echo
- Arrange removal of entire system & temporary pacing if needed
- Empirical PO/IV Abx
If septic:
- 2 sets of blood cultures at different times within 1hr
- Commence empirical IV Abx’s following blood cultures within 1hr
- Urgent echo
- Prompt removal of entire system and temporary pacing if needed
What is the empirical Abx treatment for ICED infections ?
Teicoplanin IV (+ Gentamicin if high risk of infection)
Following initial investigations if there is echo evidence of lead or tricuspid valve vegetation/regurgitation how should the infection be treated?
ICED-infective endocarditis/ ICED-lead infection
Define what infective endocarditis (IE) is
This is infection of the endothelium of the heart valves
What are the risk factors for developing infective endocarditis ?
- Heart valve abnormality - calcification/sclerosis in elderly, congenital heart disease, post rheumatic fever
- Prosthetic heart valve
- IVDU
- Intravascular lines
- Others: recent piercings, dental prcedures etc
Describe the pathogenesis of infective endocarditis
- Heart valve damaged
- Turbulent blood flow over roughened endothelium
- Platelets / fibrin deposited
- Bacteraemia (may be very transient) e.g. from dental treatment
- Organisms settle in fibrin/platelet thrombi becoming a microbial vegetation
- Infected vegetations are friable and break off, becoming lodged in the next capillary bed they encounter causing abscesses or haemorrhage - may be fatal
Can infective endocarditis occur on normal healthy valves ?
Yes - upto 50% of cases do
What are the 4 common organisms which cause infective endocarditis ?
- Staphylococcus aureus
- Viridans group streptococci
- Enterococcus sp
- Staphylococcus epidermidis
What is the most common organism causing infective endocarditis ?
Staphylococcus aureus
In people with previously normal heart valves what is the most common heart valve to be affected by infective endocarditis ?
The mitral valve
In IVDU’s what is the most common heart valve to be affected by infective endocarditis ?
Tricuspid valve
What organism is particularly associated with infective endocarditis in IVDU’s ?
Staph.aureus
What organism is particularly associated with causing infective endocarditis in patients with poor dental hygeine/following a recent dental procedure ?
Streptococcus viridans
What are the 2 key investigations to be done in someone with suspected infective endocarditis ?
- 3 sets of blood cultures & TTE echocardiogram
- Blood cultures should be taken before any antibiotics
If blood cultures are negative in someone with suspected infective endocarditis what should be considered ?
Consider serology for “atypical” organisms
How is infective endocarditis diagnosed ?
Based on the modified dukes criteria (shown in pic)
- Definitive endocarditis = 2 major or 1 major & 3 minor or all 5 minor criteria
What are the 2 main ways in which infective endocarditis may present ?
- As acute IE
- Or as subacute IE
How does acute infective endocarditis present ?
- Presents as overwhelming sepsis and cardiac failure
- Usually due to aggressive (virulent) organisms such as Staphylococcus aureus
Who is acute IE more common in ?
People with previously normal heart valves (naive)
How does subacute IE present ?
Symptoms:
- Fever
- Malaise
- Weight loss
- Tiredness
- Breathlessness
Signs:
- Fever
- New or changing heart murmur
- Finger clubbing
- Splinter haemorrhages
- Splenomegaly
- Roth spots, Janeway lesions, Osler nodes
- Microscopic haematuria
Who is subacute IE more common in ?
People with abnormal heart valves
Fever + new murmur = what until proven otherwise ?
Infective endocarditis
What 2 clinical signs when seen together is pathognmoic of infecitve endocarditis ?
Janeway lesions + oslers nodes
What clinical sign of IE is shown here ?
- Janeway lesion = painless palmar or plantar macules
- Roth spots = boat shaped retinal haemorrhages with a pale centre
What clinical sign of IE is shown here ?
Oslers nodes = painful pulp infarcts in fingers or toes
What are the 2 presentations of prosthetic valve IE & the typical organisms causing the infection ?
- Early- usually infected at time of valve insertion and usually due to Staphylococcus epidermidis or Staphylococcus aureus
- Late - up to many years after valve insertion - due to co-incidental bacteraemia. Wide range of possible organisms
Go over the image of the potential embolic effects of IE
What is the empirical treatment of Native valve indolent (Subacute) infective endocarditis ?
IV Amox + Gent
What is the empirical treatment of Native valve severe sepsis (Acute) infective endocarditis ?
IV flucloxacillin
What is the empirical treatment of prosthetic valve endocarditis
- Vancomycin IV + Gentamicin IV
- Add in day 3 to 5 (delayed) rifampicin PO
- often valve replacement is required
What should be done if IE suspected but blood cultures are negative ?
Serology (blood & specific PCR)
Following blood culture results specific treatments are given for IE what is the specific treatment for staph. aureus IE ?
IV flucloxacillin
Following blood culture results specific treatments are given for IE what is the specific treatment for Strep.viridans ?
Benzylpenicillin iv & gentamicin iv
Following blood culture results specific treatments are given for IE what is the specific treatment for enterococcus sp. ?
Amoxicillin/ vancomycin & gentamicin IV
Following blood culture results specific treatments are given for IE what is the specific treatment for Staph.epidermis IE?
Vancomycin & gentamicin IV & rifampicin PO
What monitoring is requried for patients with IE, how long are they treated for and what is usually done if Abx Tx is failing ?
- IV antibiotics usually given for 4 - 6 weeks
- Monitor cardiac function, temperature and serum C-reactive protein (CRP)
- If failing on antibiotic therapy, consider referral for surgery early
Should prophylactic Abx’s be given to patients undergoing the following to prevent IE risk?
- dental procedures
- upper and lower gastrointestinal tract procedures
- genitourinary tract; this includes urological, gynaecological and obstetric procedures and childbirth
- upper and lower respiratory tract; this includes ear, nose and throat procedures and bronchoscopy
No
Define what myocarditis is
This is inflammation of the myocardium
What is myocarditis mainly caused by ?
Mainly caused by enteroviruses -Coxsackie A & B, echovirus, but other viruses possible
What are the signs/symptoms of myocarditis ?
- Symptoms -fever, chest pain, shortness of breath, palpitations
- Signs -arrhythmia, cardiac failure
How is myocarditis diagnosed ?
- By viral PCR.
- Throat swab and stool for enteroviruses. Throat swab for influenza
What is the treatment of myocarditis ?
Supportive
What is acute pericarditis ?
Inflammation of the pericardium
What are the clinical features of pericarditis ?
- chest pain: may be pleuritic. Is often relieved by sitting forwards
- other symptoms include non-productive cough, dyspnoea and flu-like symptoms
- pericardial rub
- tachypnoea
- tachycardia
What are the classical causes of pericarditis ?
- viral infections (Coxsackie)
- Post MI - dresslers syndrome
What are the ECG changes suggestive of pericarditis ?
- ‘saddle-shaped’ ST elevation
- PR depression: most specific ECG marker for pericarditis
- the changes in pericarditis are often global/widespread, as opposed to the ‘territories’ seen in ischaemic events
Alongisde an ECG what should all patients with suspected pericarditis be investigated with ?
TTE echo
What is the treatment of pericarditis ?
Supportive - NSAID’s + colchicine 1st line
What can acute pericarditis lead to ?
Constrictive pericarditis = scarring, thickening, and muscle tightening, or contracture due to long-term chronic inflammation of the pericardium
What are the features of constrictive pericarditis ?
- dyspnoea
- right heart failure: elevated JVP, ascites, oedema, hepatomegaly
- JVP shows prominent x and y descent
- pericardial knock - loud S3
- Kussmaul’s sign is positive
- Pericardial calcification on CXR
