Infections of the Heart Flashcards
What is infective endocarditis?
Infective endocarditis is infection of the endocardium, usually with bacteria (commonly, streptococci or staphylococci) or fungi.
How do you get infective endocarditis?
- Vegetation is a mixture of infected and inflammatory material on the heart wall.
What are the major diagnostic criteria for infective endocarditis?
- Blood cultures positive for IE.
- Imaging positive for IE.
What are the minor diagnostic criteria for infective endocarditis?
- Predisposition such as predisposing heart condition, or IVD use.
- Fever (>38°C).
- Vascular phenomena.
- Immunological phenomena.
- Microbiological evidence.
What are the criteria for dianosis of:
- Definite IE?
- Possible IE?
- Rejected IE?
What are the eponymous signs of infective endocarditis?
- Osler nodes are caused by immune complex deposition.
- Janeway lesions are caused by septic emboli which deposit bacteria, forming microabscesses. Organisms may be cultured from the lesions.
- Roth spots are seen upon fundoscopy.
- Probably represent embolic or immune complex deposition processes.
What is the mainstay of treatment for a patient with infective endocarditis?
- ABx therapy
- Most patients have relatively small vegetations, so the mainstay, rather than progressing straight to surgery, is ABx therapy.
- They don’t have torrential regurgitation but they do have chronic infection.
- Generally requires prolonged IV ABx. Must emphasise that they will be in hospital for a number of weeks.
- See slides for specific ABx.
Which patient characteristics carry a high risk of poor prognosis?
- Older age
- Prosthetic valve IE
- Diabetes Mellitus
- Comorbidity
- Frailty
- Immunosuppression
- Renal or pulmonary disease
What are the clinical complications of infective endocarditis which are associated with poor prognosis?
- Heart failure
- Renal failure
- >Moderate area of ischaemic stroke
- Brain haemorrhage
- Septic shock
Which causative microorganisms are associated with poor prognosis in infective endocarditis?
- Staphylococcus aureus
- Fungi
- Non-HACEK gram-negative bacilli
- The acronym HACEK refers to a group of fastidious gram-negative coccobacillary organisms.
- HACEK stands for Haemophilus species, Aggregatibacter species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species
What are the complications of infective endocarditis?
What are the indications for surgery in patients with infective endocarditis?
- Heart failure
- Uncontrolled infection
- Prevention of embolism
Describe the risk of embolism and neurological complication associated with infective endocarditis.
- Embolism is very frequent in infective endocarditis, complicating 20-50% of cases, but falling to 6-21% after initiation of ABx therapy.
- Risk of embolism is highest after the first 2 weeks of ABx therapy and is clearly related to the size and mobility of the vegetation, although other risk factors exist.
- The decision to operate early to prevent embolism is always difficult and specific for the individual patient.
- Governing factors include the size and mobility of the vegetation, previous embolism, type of microorganism and duration of ABx therapy.
Describe nonbacterial thrombotic endocarditis.
- A form of vegetative endocarditis most often encountered in debilitated patients, such as those with cancer or sepsis - hence the previously used term marantic endocarditis.
- Frequently occurs concomitantly with venous thromboses or PE.
- In a hypercoagulable state with systemic activation of blood coagulation.
- Underlying diseases:
- Cancer (particularly mucinous adenocarcinomas of the pancreas, GI tract or ovary).
- Promyelocytic leukaemia.
- Endocardial trauma (as from an indwelling venous catheter).
Summarise the presentation and management of infective endocarditis.
-
Presentation
- Fever
- Malaise
- Murmur
- Substrate = suspect
-
Investigation
- Baseline tests
- BCs
- Inflammatory markers
- Temperature
-
Management
- TTe then TOE
- Long-course IV ABxs; surgery if indicated
- Multidisciplinary management in speciality setting.
What is myocarditis?
- Inflammation of the myocardium which can affect the heart muscle and the heart’s electrical system, reducing the heart’s ability to pump and causing rapid or abnormal heart rhythms (arrhythmias).
- Characterised by damaged myocytes and the infiltration of inflammatory and immune cells.
Describe the pathogenesis of viral and inflammatory cardiomyopathy.
- Viral elimination healed inflammation is the most common cause.
What are infective the causes of myocarditis?
- RNA viruses
- Picornaviruses
- Orthomyxovirus
- DNA viruses
- Adenovirus
- Retrovirus
- Bacteria
- Legionella
- Brucella clostridium
- Spirocheta
- Reckettsia
- Fungi
- Protozoa
- Helmintic
What are non-infective the causes of myocarditis?
- Autoimmune diseases
- Drugs
- Hypersensitivity reactions (drugs)
- Hypersensitivity reactions (venoms)
- Systemic diseases
What are the outcomes for patients with myocarditis?
