Rheumatic%20fever%20-%20acute Diagnosis
Diagnosis
- Diagnosis of acute rheumatic fever (ARF) is primarily based on clinical assessment
Classification
Definite ARF
- Initial episode of ARF with 2 major or 1 major and 2 minor manifestations with evidence of previous Group A streptococcus (GAS) infection
- Initial episode of ARF with 1 major and 2 minor manifestations with evidence of previous beta-hemolytic streptococcal (GAS) infection as 1 of the minor manifestations
- Strong clinical suspicion of ARF but with insufficient signs and symptoms
Evaluation
Diagnosis of Initial Attack of Rheumatic Fever (RF) Based on Revised Jones Criteria
- Generally, 2 major or 1 major and 2 minor criteria leads to the diagnosis of RF along with history of Group A streptococcus (GAS) infection
- Arthritis
- Most common and the earliest manifestation of acute rheumatic fever (ARF)
- Usually affects >1 joint, large joints (eg ankles, wrists, knees, elbows, or shoulders)
- Presents with swelling, heat, redness, severe pain, tenderness and limited movement
- Highly responsive to nonsteroidal anti-inflammatory drugs (NSAIDs)
- Presents as polyarthritis (asymmetrical and migratory) in low-risk populations
- Presents as either polyarthritis or monoarthritis in moderate- and high-risk populations
- Polyarthralgia may be considered only after other causes of arthralgia (viral, autoimmune) has been ruled out
- Carditis (inflammation of the heart)
- Sometimes accompanied by weakness and shortness of breath or chest pain
- May be clinical and/or subclinical
- Tachycardia, valvulitis, heart murmur of mitral and/or aortic regurgitation
- Pericarditis
- Friction rub, pericardial effusion, chest pain and electrocardiogram (ECG) changes
- Cardiomegaly on chest X-ray
- Signs of chronic HF: Gallop rhythm, distal heart sounds, cardiomegaly
- Sydenham’s chorea
- Neuropsychiatric disorder primarily involving jerky or uncoordinated movement of the limbs and face or more subtle movement difficulties (eg difficulty with handwriting)
- May also present with psychiatric signs (eg emotional lability, hyperactivity, separation anxiety, obsessions and compulsions)
- Often affects prepubertal girls 8-12 years old
- Subcutaneous nodules
- Hard, painless, nonpruritic, freely movable, small bumps under the skin
- Usually 0.5-2 cm in diameter and number from 1 to dozens with a mean of 3-4
- Nodules appear over the extensor surfaces of the elbows, knees, ankles, knuckles, scalp and spinous processes of the lumbar and thoracic vertebrae
- Tend to appear 2-4 weeks after onset of other symptoms and usually lasts 1-2 weeks
- Erythema marginatum
- Begins as 1-3 cm diameter, pink to red nonpruritic macules or papules that spread outward to form a serpiginous ring with erythematous raised margins and central clearing
- Located on the trunk and proximal limbs but never on the face
- Fever
- Common manifestation of ARF
- Usually >38.5°C (101.3°F) in low-risk populations, >38°C (100.4°F) in moderate- to high-risk populations and responds to antipyretics
- Arthralgia
- Pain in ≥1 joint without inflammation
- Polyarthralgia in low-risk populations; monoarthralgia in moderate- to high-risk populations
- May not be used as a criteria if arthritis is a major manifestation
- Pain in ≥1 joint without inflammation
- Blood test indicating inflammation
- Low-risk populations: Elevated C-reactive protein (CRP) of ≥3.0 mg/dL and/or erythrocyte sedimentation rate (ESR) of ≥60 mm in the 1st hour
- Moderate- to high-risk populations: CRP of ≥3.0 mg/dL and/or ESR of ≥30 mm/hour
- Prolonged P-R interval on ECG
- Should be done in all patients suspected to have ARF except if carditis is a major manifestation
- Upper limit of normal should be adjusted according to age
Careful diagnosis is warranted, there are ARF patients with insufficient history, clinical or laboratory findings
- Only has chorea as manifestation
- Patients who consult after months of RF and only have indolent carditis as manifestation
History
Previous Group A streptococcus (GAS) Infection
- History of an antecedent sore throat 1-5 weeks prior to onset is present in most patients
- Evidenced by streptococcal antibody tests
- Plasma Antistreptolysin O (ASO) titer
- 333 Todd units is considered elevated
- Antideoxyribonuclease B (anti-DNAse B) titer
- >240 Todd units is considered elevated
- Positive throat culture for GAS
- Plasma Antistreptolysin O (ASO) titer
Laboratory Tests
- Complete blood count (CBC)
- Chest radiograph (cardiomegaly, pulmonary congestion and other findings consistent with heart failure)
- Echocardiography with Doppler
- Recommended for patients with suspected or definite acute rheumatic fever (ARF) including chorea
- More sensitive and specific for diagnosing acute rheumatic conditions as compared to auscultation
- Recommended as confirmatory tool for carditis in the absence of murmurs (subclinical carditis)
- Electrocardiogram (ECG)
- Rapid antigen detection test (RADT)