Rheumatic%20fever%20-%20acute Diagnosis

• Diagnosis of acute rheumatic fever (ARF) is primarily based on clinical assessment

• 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

• 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

• 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 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

• 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)