Revision - Kawasaki Disease & Rheumatic Fever Flashcards
What is the diagnosis of Kawasaki disease based on?
The American Heart Association diagnostic criteria
What is the AHA diagnostic criteria for Kawasaki disease?
Presence of fever (usually ≥39°C) for at least 5 days, plus at least 4 out of 5 key features:
1) Mucositis: erythema and cracking of the lips, strawberry tongue and/or oral erythema
2) Conjunctivitis: bilateral conjunctivitis without exudate
3) Rash: maculopapular, erythroderma or erythema multiforme
4) Peripheral changes: erythema, oedema and/or desquamation of the hands and feet
5) Cervical lymphadenopathy
Location of lymphadenopathy in Kawasaki disease?
Cervical
What can happen to hands and feet in Kawasaki disease?
Red palms of the hands and the soles of the feet which later peel
Which phase of Kawasaki disease is the highest risk period for developing cardiac complications?
Subacute phase (2-4w from fever onset)
What investigation can be done to exclude Streptococcus infection?
Anti-streptolysin O titre (ASOT): to exclude group A streptococcal infection
Mx of Kawasaki disease?
High dose aspirin + IV immunoglobulins
Role of aspirin in Kawasaki disease?
Reduce risk of coronary artery aneurysms & thrombosis
How long is aspirin given for in Kawasaki disease?
High dose aspirin given until fever has resolved for 48h, then low dose given for approx 6 weeks
What is Reye’s syndrome?
A rare acute encephalopathy associated with liver failure.
Role of IVIG in Kawasaki disease?
Infusion within the first 10 days of illness can reduce the incidence of coronary artery aneurysms .
When should improvement be seen after intiating treatment in Kawasaki disease?
Within 36 hours.
Note - A second dose of IVIG may be given if an improvement is not seen.
What are some complications of Kawasaki disease?
1) Coronary artery aneurysms
2) Myocarditis/pericarditis
3) Arrhythmias
4) Valvular disease (e.g. mitral regurgitation)
5) Coronary artery thrombosis/myocardial infarction
6) Sudden cardiac death
What is the danger of a coronary artery aneurysm in Kawasaki disease?
Can rupture –> cardiac tamponade
What bacteria is implicated in rheumatic fever?
GAS
What is rheumatic fever?
A systemic inflammatory disorder that arises as a result of infection with GAS.
How soon after Strep infection can rheumatic fever develop?
2-6 weeks
How does initial Strep. pyogenes infection typically present?
1) Pharyngitis (sore throat)
or
2) Cellulitis
How is strep infection more likely to present in hot countries?
As skin infection instead of pharyngitis
What criteria is used for diagnosing rheumatic fever?
Jones criteria
What does the Jones criteria state about the diagnosis of rheumatic fever?
There must be evidence of recent GAS infection plus either;
- 2 major criteria
- 1 major criteria and 2 minor criteria
Give some evidence of a recent group A strep infection
1) Positive throat swab
2) Positive rapid streptococcal antigen test
3) Raised streptococcal antibody titre (ASO or DNAse)
4) Recent episode of scarlet fever
What are the 5 major criteria for rheumatic fever?
1) Polyarthritis (joint involvement)
2) Carditis & valvulitis (heart involvement)
3) Sydenham’s chorea (nervous system involvement)
4) Erythema marginatum (skin involvement)
5) SC nodules (skin involvement)
typical symptoms of rheumatic fever?
- fever
- joint pain
- rash
- chorea
- SOB
- nodules
How can rheumatic fever affect the joints?
Affects large joints - hot, swollen, painful joints.
‘Migratory polyarthritis’ - different joints become inflamed and improve at different times.
What is the most common symptom of rheumatic fever?
Polyarthritis (80%)
What may aspiration of synovial fluid in polyarthritis caused by rheumatic fever show?
Sterile inflammation with no organisms present
What is the most significant manifestation of rheumatic fever?
Carditis
What clinical features can carditis caused by rheumatic fever cause?
1) pericarditis
2) myocarditis
3) endocarditis
How can myocarditis present?
Congestive heart failure: SOB, orthopnoea, PND, cardiogenic shock
What is the most commonly affected valve in rheumatic fever?
Mitral valve
How does rheumatic fever typically affect valves?
In an attack of rheumatic fever, valve incompetence (i.e. regurgitation) is more likely to develop than valve stenosis.
Valve stenosis tends to develop as a feature of chronic disease many years later.
How soon after initial streptococcal infection does Sydenham’s chorea appear?
2-6m later
What is Sydenham’s chorea sometimes preceded by?
Emotional lability or behaviour which is out of character for the patient.
What are the 2 key skin findings in rheumatic fever?
1) SC nodules (only present with severe carditis)
2) Erythema marginatum rash –> look up pic!
Where are subcutaneous nodules typically found in rheumatic fever?
Extensor surfaces
What are the 4 minor criteria for rheumatic fever?
1) Raised ESR or CRP
2) Pyrexia (typically >39 degrees)
3) Polyarthralgia i.e. pain present in multiple joints (this is not included in the criteria if polyarthritis is already present)
4) Prolonged PR on ECG
5) History of rheumatic fever
Arthritis vs arthralgia?
Arthritis is an inflammatory condition that causes joint pain.
Arthralgia is joint pain.
Mneumonic for rememebering major criteria for rheumatic fever: JONES
J - joint arthritis
O - organ inflammation such as carditis
N - nodules
E - erythema marginatum rash
S - sydenham’s chorea
What 2 ECG findings may be present in rheumatic fever?
1) Prolonged PR
2) Tachycardia
N.B. may also be signs of pericarditis or myocarditis
Investigations in rheumatic fever?
1) ECG
2) Vital signs (fever)
3) Throat swabs for GAS
4) Rapid streptococcal antigen test (RAST)
5) Anti-streptococcal antibodies
6) Blood tests: FBC, ESR, CRP, troponin, rheumatoid factor, anti-CCP
What are the 2 most common antibody tests used for rheumatic fever?
1) anti-streptolysin (ASO)
2) anti-DNAse B
When may troponin be raised in rheumatic fever?
Myocarditis
Role of CXR in rheumatic fever?
Rule out HF
Management of rheumatic fever can be divided into acute management and prophylaxis.
What does acute management of rheumatic fever involve?
1st line –> supportive, bed rest
Abx –> single dose of IV benzylpenicillin followed by oral penicillin V (phenoxymethylpenicillin) for 10d
High dose aspirin
Steroids (if carditis expected)
What Abx are indicated in acute rheumatic fever?
Single stat IV dose of benzylpenicillin, followed by 10d oral penicillin V.
To kill GAS
Role of high dose aspirin or other NSAIDs in acute rheumatic fever?
To manage inflammation and reduce symptoms such as fever, joint pain, and swelling.
Importance of bed rest in rheumatic fever?
Rheumatic fever is one of the few conditions where bed rest is recommended as first-line treatment, even if the patient feels well.
This is even more important in cases of suspected active myocarditis (indicated by abnormalities seen on the echocardiogram and a raised ESR), where limitation of exercise is strongly advised.
Is bed rest recommended in myocarditis?
Yes
After the initial attack, the child should be followed up regularly and prophylactic treatment started to reduce the chance of any future attacks.
What is the current recommended first-line prophylactic treatment for rheumatic fever?
Benzathine penicillin G, given every 4 weeks as an IM injection.
What is the most common valve lesion in rheumatic fever overall?
Mitral regurgitation
What is the most common long-term cardiac complication of rheumatic fever?
Mitral stenosis
What 3 factors can trigger a relapse of rheumatic fever?
1) reinfection with GAS
2) pregnancy
3) COCP
Which medication can trigger a relapse of rheumatic fever?
COCP
What is the most common valvular abnormality in Kawasaki disease?
Mitral regurg
What 3 conditions can a strawberry tongue indicate?
1) Scarlet fever
2) Kawasaki disease
3) Toxic shock syndrome
