Diagnosis of ARF in children

Diagnosis of ARF in children

ARF: some basics
• 3-6% of any population susceptible
• Incidence and prevalence in females >males
• ARF/RHD can run in families
• Specific genetic markers have been identified
• There is no racial predisposition
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Risk factors

• Established clear link with poverty
• household overcrowding
• poor sanitation
• housing quality and appropriateness
• educational disadvantage
• Limited access to health services
• variability of health infrastructure and follow up
• Geographically remote
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GAS pharyngitis

Arthritis
Carditis
Chorea

Fever

Exaggerated immune response

Acute rheumatic fever – ARF

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ARF recurs - often many times

Valve damage is cumulative and silent
Rheumatic heart disease (RHD)
Cardiac failure, early death

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ARF progression
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Diagnosis and GAS
• Definite initial or recurrent ARF diagnosis requires:
• 2 major plus evidence GAS infection
• 1 major plus 2 minor plus evidence of GAS infection
• Throat swab
• ASOT
• Anti DNAse B
• No other probable diagnosis

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Major manifestations

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Major manifestations

High risk groups
Polyarthritis or aseptic mono-arthritis or polyarthralgia
Carditis (including subclinical evidence of rheumatic valvulitis on echocardiogram)
Chorea
Erythema marginatum
Subcutaneous nodules
Low Risk groups
Polyarthritis
Carditis
Erythema marginatum
Subcutaneous nodules
Chorea
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• Monoarthritis present in 17% of ARF presentations
• Migratory asymmetric polyarthritis
• Affects peripheral large joints
• Often intense pain – will not tolerate passive movement
• Limited duration: 2 days to 3 weeks
• Dramatic response to salicylates
• rapid response assists diagnosis

Arthritis

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Can a monarthritis be ARF?

• In high risk populations:
• aseptic monoarthritis can be a major manifestation
• monoarthritis often associated with carditis
• if joint aspirate sterile, prior to treatment for septic arthritis, investigate for ARF
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Polyarthralgia
• A major criteria ONLY in high risk populations:
• Multiple painful joints
• Can be migratory
• Unlike arthritis lacks:
• Effusions
• Heat
• Morning stiffness
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Carditis

• Can involve all layers of the heart
• Pericardium – can cause effusions
• Myocardium – affects heart function and conduction
• Endocardium – the classic valve lesions
• MR then AR most common lesions
• Right sided valves rarely involved
• Stenosis is a late finding


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Carditis: investigations

• Early echocardiography essential
• repeated at 2 to 6 weeks
• Chest x-ray
• Electrocardiogram
•

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Carditis: treatment

• Often requires inpatient bed rest and care if :
• moderate/severe carditis suspected by clinical findings
Consider steroids for severe carditis
If signs of heart failure or cardiomegaly
• consider diuretics and ACE inhibitors



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Sydenham’s chorea

• Rapid, uncoordinated jerking movements

• Primarily the face, feet and hands
• Female to male ratio of 2:1
• Occurs up to 6 months after acute infection
• Mostly children, 5 to 13 years
• “Milkmaids” sign
• Tongue fasciculations
• Emotional lability
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Erythema marginatum

• Rare finding
• reported in less than 2% Australian Aboriginals
• difficult to see on dark skin
• Presence of rash diagnostic of ARF
• Pale center and darker margins
• Blanch under pressure
• Circular snake like pattern
• Occurs on trunk and extremities
• Not itchy or painful



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Subcutaneous nodules

• Rare, only seen in 2% cases
• Highly specific of ARF
• Strongly associated with carditis
• Round firm and freely mobile
• 0.5 to 2.0 cm in diameter
• Appear 1 to 2 weeks after symptom onset
• Occur in crops of up to 12
• over elbows knees, wrists, ankles, achilles tendons, occiput, and posterior spinal processes

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Minor manifestations

High risk groups
Monoarthralgia
Fever
ESR≥30 mm/h or CRP ≥30 mg/L
ECG changes
Low Risk groups
Fever
ESR≥30 mm/h or CRP ≥30 mg/L
ECG changes
Polyarthralgia or aseptic monoarthritis
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Fever
• Temperature greater than 38C
• In the absence of fever documentation
• reliable history if anti-inflammatory therapy given
• already given
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ESR & CRP

• Repeat serology 10 to 14 days if not confirmatory
• To satisfy minor criteria:
• serum CRP ≥30mg/L
• ESR ≥30mm/hr
• Elevated WBC insensitive marker for ARF

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ECG
• If ARF suspected always ECG
• Check P-R interval
• Normal 0.16 sec if 3 to 12 years old
• If prolonged
• repeat ECG in 1 to 2 months
• If P-R interval returns to normal:
• ARF more likely

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Diagnosis: key investigations

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Differential diagnosis

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ARF diagnosis and management

• First requires diagnosis then secondary prophylaxis
• Inpatient assessment recommended
• Specialist review for ongoing management
• Bed rest
• NSAIDs
• Initial then follow up echocardiography
• Chest x-ray
• If heart failure: ACE inhibitors, diuretics
• Consider steroids for carditis



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Take home messages

• Incidence in Aboriginal Australians and Torres Strait Islander people amongst the highest in the world
• Predominantly affects children aged 5 to 15
• Largely affects disadvantaged populations
• High index of suspicion in high risk populations
• Diagnosis needs clinical criteria and investigation results
• Diagnosis often requires hospital admission
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