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Questions and Answers
What is the primary purpose of prophylaxis against Group A Streptococcus infections?
Which of the following is NOT considered a major sign of rheumatic fever?
Which minor sign is associated with rheumatic fever?
How many M types of Group A Streptococcus are recognized?
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What percentage of healthy school children may show a prevalence of group A streptococci in throat cultures?
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What is the appropriate duration of secondary prophylaxis for patients without carditis after their last rheumatic fever attack?
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Which antibiotic is administered as a single intramuscular injection in the case of patients weighing over 27 kg for secondary prophylaxis?
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For how long should a patient with carditis but without cardiac sequela receive secondary prophylaxis?
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Which antibiotic is specifically indicated for secondary prophylactic use in patients who have rheumatic heart disease?
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What should be done for patients who have undergone cardiovascular surgery to prevent rheumatic fever recurrences?
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Which of the following criteria can support a diagnosis of acute rheumatic fever if evidence of recent streptococcal infection is present?
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Which of the following is considered a major manifestation of acute rheumatic fever?
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What is a common laboratory finding in low-risk populations suspected of acute rheumatic fever?
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Which of the following is NOT classified as a minor manifestation of acute rheumatic fever?
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What is the primary method of prophylaxis to prevent an initial attack of acute rheumatic fever?
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Which of the following acute phase reactants is indicative of inflammation in suspected acute rheumatic fever cases?
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Which of the following conditions may see an increased incidence of carditis among patients?
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Which of the following statements about the relationship between major and minor manifestations is true?
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Which of the following serological tests can support the diagnosis of a recent streptococcal infection?
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Study Notes
Secondary Prophylaxis
- Regular penicillin administration for patients who have had rheumatic fever to prevent further infection and recurrences.
- Benzathine penicillin doses: 600,000 units IM for < 27kg , 1,200,000 units IM for > 27 kg
- Phenoxymethyl penicillin/Amoxicilline doses: 3x 250 mg oral for children, 3x 500 mg oral for adults (10 days)
- Cephalexin doses: 50mg/kg/day:2 (10 days)
- Erythromycine doses: 30 mg/kg/day:2 (10 days)
Prophylaxis Duration
- Patients without carditis should receive prophylaxis for at least 5 years after their last attack, continuing until at least age 21.
- Patients with carditis during an acute attack, but without cardiac sequela, should receive secondary prophylaxis for 10 years or until they reach the age of 25.
- Patients with carditis and rheumatic heart disease should continue prophylaxis for their entire lifespan.
- Patients with chorea should receive prophylaxis until they reach age 21, regardless of whether carditis is present.
Secondary Prophylaxis and Infective Endocarditis
- Secondary prophylaxis for rheumatic fever should not be confused with antibiotic prophylaxis used for the prevention of infective endocarditis. Importantly, patients with rheumatic heart disease require both.
Recurrent Attacks
- Patients who have undergone cardiovascular surgery remain at risk for recurrences and require prophylaxis.
Sydenham's Chorea
- Affects 15-20% of patients.
- More common in prepubertal girls.
- Characterized by personality changes, emotional lability, purposeless involuntary jerky movements, motor weakness, and difficulty with fine motor skills (writing, buttoning clothes).
- The condition is usually self-limited, typically lasting 3 months.
- Features a long latent period.
- Incidious carditis is common.
Erythema Marginatum
- Affects 10% of patients.
- More common in patients with carditis.
- Characterized by serpiginous macular erythematous lesions with a pale center and pink borders.
- These lesions are usually found on the trunk and proximal portions of the extremities and are not pruritic.
Subcutaneous Nodules
- Affects 5-10% of patients.
- These nodules are typically 0.2-2cm in diameter, hard, mobile, painless, and non-pruritic.
- Common sites include the extensor surfaces of the extremities, scalp, and spine.
- More common in patients with carditis.
Clinical and Laboratory Manifestations of Rheumatic Fever
- Clinical findings: Arthralgia (Must not be considered in the presence of arthritis), Fever (> 38°C).
- Laboratory findings: Elevated acute phase reactants (ESR > 60mmHg, CRP), Prolonged PR interval (Must not be considered in the presence of carditis).
Diagnostic Criteria for Rheumatic Fever
Low Risk Populations
- Incidence of ARF < 2/100000, prevalence of RHD <1/1000.
- Laboratory findings: Elevated acute phase reactants (ESR > 60mm/hr, CRP>3mg/dl), Prolonged PR interval.
Moderate/High Risk Populations
- Incidence of ARF > 2/100000, prevalence of RHD >1/1000.
Major Manifestations
- Carditis: Clinical/echocardiographic diagnosis.
- Arthritis: Polyarthritis, monoarthritis or poliarthralgia.
- Chorea: Sydenham's Chorea.
- Erythema marginatum: Rash noted above.
- Subcutaneous nodules: Nodules noted above.
Minor Manifestations
- Clinical findings: Monoarthralgia, Fever (> 38°C)
- Laboratory findings: Elevated acute phase reactants (ESR > 30mm/hr, CRP>3mg/dl), Prolonged PR interval.
Supporting Evidence of Antecedent Group A Streptococcal Infection
- Positive throat culture or rapid streptococcal antigen test.
- Elevated or rising streptococcal antibody titers (ASO, Anti-DNAsB).
- History of scarlet fever (for high-risk populations).
Diagnostic Criteria for Rheumatic Fever
-
At least 2 major criteria
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1 major + 2 minor criteria.
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3 minor criteria.
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Each criteria should be supported by recent evidence of streptococcal infection. This will allow for a possible diagnosis.
Other Manifestations of Rheumatic Fever
- Nose bleeding
- Abdominal pain
- Rheumatic pneumonia
Prognosis of Rheumatic Fever
- Perfect outcome without cardiac involvement.
- Valvular heart disease in patients with carditis.
- Recurrent attacks worsen the prognosis.
- Recurrent attacks mostly occur within the first five years.
Conditions Mimicking Rheumatic Fever
- Juvenile rheumatoid arthritis.
- Immune complex disease.
- Other arthropathies (septic arthritis, toxic synovitis).
- Infective endocarditis.
- Henoch-Schonlein purpura.
- Sickle cell anemia.
- Acute leukemia.
- Systemic lupus erythematosus.
- Viral myocarditis.
- Functional murmurs.
- Mitral valve prolapse.
- Poliomyelitis.
- Acute appendicitis.
Primary Prophylaxis
- Treatment of upper respiratory tract infection due to group A streptococci to prevent an initial attack of acute rheumatic fever.
Group A Streptococci
- Gram-positive
- Prevalent in nature
- Arranged in chains when cultured
Streptococcal Classification
- Hemolytic properties: α, β, γ
- Polysaccharide antigen: A, B, C, D...
- Group A - Streptococcus pyogenes - Responsible for 90% of human streptococcal infections.
- M types: > 150
- Cell membrane protein, Virulence factor, Antigenic
- Nephritogenic (12, 49)
- Rheumatogenic (1, 3, 5, 6, 14, 18, 19, 24, 27, 29)
Cross-Reactivity Between Streptococcal and Mammalian Tissues
- Streptococcal component Mammalian tissue constituent
- Streptococcal hyaluronic acid Mammalian hyaluronic acid, protein polysaccharide
- Group A carbohydrate Glycoproteins of heart valves
- Protein cell wall Sarcolemma of cardiac and skeletal muscle
- Protein cell membrane Sarcolemma of cardiac and skeletal muscle
- Glycoprotein of cell membrane Glycoprotein of glomerular basement membrane
- Antigen of cell membrane Histocompatibility antigen
Streptococcal Antigens and Antibodies
- Hemolysins (Streptolysin O) Antistreptolysin
- Streptokinase Antistreptokinase
- Hyaluronidase Anti hyaluronidase
- Deoxyribonucleases ( A,B,C,D) Anti DNB
- Streptococcal esterase Anti streptococcal esterase
Prevalence and Attack Rates
- Prevalence of group A streptococci in throat cultures of healthy school children is between 10 to 50%.
- Elevated ASO titers may be found in 15 to 69% of healthy school children.
- Attack rate of ARF following a streptococcal pharyngitis is 0.3 to 3%.
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Description
This quiz covers the guidelines for administering prophylactic treatments for patients recovering from rheumatic fever. It details the dosages of various antibiotics, the duration of prophylaxis based on patient conditions, and considerations for specific age groups. Test your knowledge on the preventive measures to avoid recurrences of this condition.
