What is the treatment for tics following a streptococcal (Strep) infection?

Treatment for Tics Following Streptococcal Infection

For tics following streptococcal infection, the most effective treatment approach includes antibiotics to eradicate the infection (amoxicillin 500 mg twice daily for 10 days) combined with immunomodulatory therapies such as plasmapheresis for severe cases with suspected autoimmune etiology. 1, 2

Understanding Post-Streptococcal Tics

Post-streptococcal tics are often associated with PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections), where an autoimmune response triggered by Group A beta-hemolytic streptococcal infection affects the basal ganglia, resulting in neuropsychiatric symptoms including tics 2, 3.

Research indicates that:

• 53% of children with tic disorders experience sudden onset or worsening of symptoms
• Approximately 11% of children with tic disorders develop abrupt changes in tic behavior within 6 weeks after a streptococcal infection 4
• Elevated antibody titers against streptococcal M12 and M19 proteins have been found in patients with Tourette's syndrome, suggesting a streptococcus-induced autoimmune process 5

Treatment Algorithm

Step 1: Eradicate the Streptococcal Infection

First-line antibiotic therapy options:

• Amoxicillin: 500 mg twice daily for adults or 25 mg/kg twice daily (max 500 mg per dose) for children for 10 days 1
• Penicillin V: 500 mg twice daily for adults or 250 mg 2-3 times daily for children for 10 days 1

For penicillin-allergic patients:

• Clindamycin: 7 mg/kg three times daily (max 300 mg per dose) for 10 days 1
• Azithromycin: 12 mg/kg once daily (max 500 mg) for 5 days 1
• Clarithromycin: 7.5 mg/kg twice daily (max 250 mg per dose) for 10 days 1

Important: Complete the full course of antibiotics to ensure complete eradication of Group A Streptococcus and reduce the risk of treatment failure, which can be as high as 30% with penicillin 1, 6

Step 2: Immunomodulatory Therapy for Severe Cases

For patients with severe neuropsychiatric symptoms that persist after antibiotic treatment:

• Plasmapheresis: Shown to be effective in interrupting the autoimmune process in cases with severe symptoms 2
• Intravenous immunoglobulin (IVIG): Alternative immunomodulatory treatment 2

Step 3: Symptomatic Treatment

• NSAIDs or acetaminophen: For symptomatic relief
• Warm salt water gargles and throat lozenges: To alleviate throat symptoms 1

Clinical Pearls and Pitfalls

Diagnostic Considerations

• Use the Centor Criteria to assess likelihood of GAS infection (tonsillar exudates, tender anterior cervical lymph nodes, lack of cough, fever) 1
• Consider testing for antineuronal antibodies, particularly against D1R and lysoganglioside, which are elevated in patients with post-streptococcal tics 3

Treatment Pitfalls

1. Inadequate antibiotic duration: Failing to complete the full 10-day course (5 days for azithromycin) can lead to treatment failure and increased risk of neuropsychiatric complications 1, 6

2. Overlooking reexposure: Patients may be reexposed to Streptococcus-infected family members or peers, causing persistent or recurrent symptoms 6

3. Ignoring immunological aspects: In cases with clear autoimmune features, antibiotics alone may be insufficient, and immunomodulatory treatments should be considered 2, 3

4. Misdiagnosis: Not all tics are post-streptococcal; careful history and laboratory confirmation of recent streptococcal infection are essential 4

Special Considerations

• Patients with a history of rheumatic fever require continuous antimicrobial prophylaxis 1
• The presence of both tics and OCD symptoms may indicate more severe autoimmune involvement with higher activation of CaMKII activity in neuronal cells 3