Infective Endocarditis and Rheumatic Fever Flashcards
Definition of rheumatic fever and what does it affect
- Multisystem disease which occurs after a group A streptococcal infection
- Affects heart (50% of cases), skin, joints and CNS
- Inflammatory disease that develops 2-6 weeks after a streptococcal throat infection
Epidemiology of RF
- Often between 5-15 yo
- Most commonly in Iran
Aetiopathogenesis, incubation period and risk factors of RF
- Group A, B haemolytic streptococci
- Latent period of 2-6 weeks before onsent
- Streptococcal causes an exaggerated B lymphocyte response
- Type II Hypersensitivity
- Streptococcal antigens cross react with connective tissue (molecular mimicry)
- Bacterial sugar component shares antigenic homology with glycoproteins found in the connective tissue in the human heart valves
- Pathologic process causing vaculitis affecting the connective tissue
- Aschoff’s body is the pathologic lesion and consists of an aggregate of large cells with polymorphs and basophils around a vascular fibrinoid core
- Cardiac lesion characterised by a pancarditis with the endocardium being the most severely involved
-Risk factors include patients from low socio-economic groups, overcrowded conditions and HLA-DDR4 positive
Clinical Features of RF
According the the Duckett-Jones Criteria:
-Major Criteria:
Carditis (inflammation of any part of the heart- my, peri or end)
Polyarthritis (arthritis affecting many joints)
Erythema marginatum (red patch rash with a pale centre and a red outer area)
Subcutaneous nodule (nodule below the skin)
Chorea (involuntary movements)
-Minor Criteria: Fever Arthralgia (pain in a joint) Previous rheumatic fever Raised acute phase proteins such as CRP, ESR and Ferritin Prolonged P-R interval on the ECG
Diagnosis of RF
Using the Ducket-Jones Criteria, 2 major and 1 minor indicates a high probability of RF
Major:
- Carditis (inflammation of any part of the heart including myocardium, pericardium or endocardium)
- Polyarthritis (arthritis of multiple joints)
- Subcutaneous nodule
- Erythema marginatum (red patch rash with a pale centre but red surrounding it)
- Chorea (uncontrolled movements)
Minor:
- Lab Findings (CRP, ESR and Ferritin Levels)
- Increase PR interval
- Previous Rheumatic Fever
- Fever
- Arthralgia (pain in the joints)
Carditis definition, importance, clinical features
- Occurs in 50% of RF patients and lasts between 3-6 months
- Occurs 2 weeks after polyarthritis and involves all the cardiac tissue
- Pancarditis: inflammation of the entire heart
- May be asymptomatic or present with congestive cardiac failure
- Increasing breathlessness, palpatations which may be intermittent and/or chest pain
- Morbidity and mortality is associated with congestive cardiac failure
-Asymtpmatic cases usually only recognised after presentation of other clinical signs or cardiomegaly on CXR (abnormal enlargement of the heart)
Types of carditis and explanation of how RF affects each
-Myocarditis
Involves the myocardium (muscular tissue of the heart)
Clinical consequences are usually due to left and right ventricular involvement
Patients may present with left ventricular failure which may lead to right ventricular failure and subsequent congestive cardiac failure
-Endocarditis:
Inflammation of the inner heart lining and valves
Mitral Valve (Left atrium to left ventricle) most commonly affected. Either occurs alone or in association with the aortic valve failure (Left Ventricle to aorta)
When mitral and aortic valve disease occurs together the disease becomes fulminant and is associated with a high mortality rate
Valvulitis involves nodules on the mitral and aortic valves resulting in murmurs which may change
Mitral valve involvement results in Carey Coombs murmur which is a soft diastolic murmur which is a soft diastolic murmur
-Pericarditis
Inflammation of the cardiac pericardium
Presents with fluid in the pericardial space and may give rise to an intermittant percardial rub
Mitral Valve murmur name and type
- Carey Coombs Murmur
- Soft, Diastolic murmur
Polyarthritis significance, how long, clinical features
- Often first clinical manifestation after streptococcal sore throat
- 80-90% of patients
- Arthritis is migratory and lasts for 4-6 weeks
- Affects large joints such as knee, ankle, elbow hip and shoulder
- Onset of pain is sudden and associated with one or more joins
- Accompanies with swelling
- Pain may last for a week
Chorea, another name, how common and when, clinical features
- Syndenhams Chorea or St Vitus Dance
- 10% of patients
- Late clinical manifestation, often 5 months after other manifestations
- Involuntary movements of the face and limbs nut disappears during sleep
Subcutaneous nodules how common, clinical features and other types
- Rare
- Small that are non-tender, mobile and firm
- Occur over bony prominences eg. elbows
-Erythema nodosum may also occur over the shins
Larger than subcutaneous nodules and are painful
Appear as deep pink/red nodules and are tender on palpation
Erythema Marginatum how common, clinical features
- 65% of pts
- Invariably seen in association with carditis
- Rash is painless and non-pruritic
- Not a well defined boundary, with a fading centre
- Spreads over the trunk and limbs
Complications of RF
-Either a predisposition of infective endocarditis or endocarditis itself
Definition of infective endocarditis
- Infection of the endocardial surface of the heart
- Includes the inner lying and the valves
- Usually bacterial, occasionally fungal
- Morbidity and mortality (20-30%)
- Maybe an acute, fulminating infection, but more commonly runs an insidious course known as subacute bacterial endocarditis (SBE)
Aetiology of IE
-Endocarditis usually a consequence of 2 factors:
Abnormal cardiac endothelium facilitating bacterial adherence and growth
Presence of organisms in the blood
- Abnormal endothelium is usually a result of a valvular lesion, which creates non-laminar, turbulent flow, promoting fibrin and plately deposition
- Small thrombi allow organisms to adhere and grow
- Leads to characteristic infected vegetation
