From the Guidelines
The treatment for pediatric patients with high Anti-Streptolysin O (ASO) titers primarily involves antibiotic therapy to eradicate Group A Streptococcus infection, with penicillin being the first-line treatment, specifically oral penicillin V at 250 mg (for children <27 kg) or 500 mg (for children ≥27 kg) twice daily for 10 days, as recommended by the American Heart Association 1. The goal of this treatment is to prevent complications such as acute rheumatic fever, which can lead to long-term cardiac damage if the streptococcal infection isn't adequately treated. Key considerations in selecting a treatment regimen include:
- Bacteriologic and clinical efficacy
- Ease of adherence to the recommended regimen
- Cost
- Spectrum of activity of the selected agent
- Potential side effects Alternative treatments for patients allergic to penicillin include:
- Azithromycin (12 mg/kg once daily, maximum 500 mg, for 5 days) 1
- Clindamycin (20 mg/kg per day divided in 3 doses, maximum 1.8 g/d, for 10 days) 1 It's crucial to note that elevated ASO titers alone don't necessarily require treatment - they indicate recent streptococcal infection but should be correlated with clinical symptoms. Treatment decisions should be based on active infection signs or complications like acute rheumatic fever or post-streptococcal glomerulonephritis. Following treatment, clinical follow-up is recommended, though repeat ASO testing isn't routinely needed as titers may remain elevated for months after infection resolution 1.
From the FDA Drug Label
NOTE: Penicillin by the intramuscular route is the usual drug of choice in the treatment of Streptococcus pyogenes infection and the prophylaxis of rheumatic fever. Pharyngitis/tonsillitis caused by Streptococcus pyogenes as an alternative to first-line therapy in individuals who cannot use first-line therapy.
The treatment for pediatric patients with high Anti-Streptolysin O (ASO) titers is penicillin by the intramuscular route, as it is the usual drug of choice in the treatment of Streptococcus pyogenes infection and the prophylaxis of rheumatic fever. Azithromycin can be used as an alternative to first-line therapy in individuals who cannot use first-line therapy 2.
From the Research
Treatment for Pediatric Patients with High Anti-Streptolysin O (ASO) Titers
- The treatment for pediatric patients with high ASO titers is primarily focused on managing the underlying group A streptococcal (GAS) infection, which can cause pharyngitis/tonsillitis 3, 4.
- Penicillin V for 10 days is the standard therapy for GAS pharyngitis, but it has drawbacks such as a lengthy dosing regimen and potential for bacteriologic treatment failures, particularly in children under 6 years old 3.
- Alternative treatments, such as azithromycin, have been shown to be effective in eradicating GAS and have the advantage of simpler and shorter dosing regimens compared to penicillin V 3, 4.
- A total dose of 60 mg/kg azithromycin, given either as 12 mg/kg once daily for 5 days or 20 mg/kg once daily for 3 days, provides the best rate of GAS eradication 3.
Interpretation of ASO Titers
- The interpretation of ASO titers can be influenced by factors such as age, geographical location, and recent infections 5, 6, 7.
- Normal values for ASO titers in children vary by age, with upper limits of normal (ULN) ranging from 239 IU to 400 IU in different studies 5, 6, 7.
- Elevated ASO titers can indicate a recent GAS infection, but it is essential to consider the clinical context and other diagnostic criteria when interpreting ASO titers 5, 6, 7.
Clinical Considerations
- The treatment of pediatric patients with high ASO titers should be guided by clinical judgment and consideration of the underlying infection and potential complications, such as acute rheumatic fever 3, 4, 5.
- Physicians should be aware of the normal values for ASO titers in their patient population and consider these values when interpreting test results 6, 7.