What is the treatment for corioretinitis caused by toxoplasmosis in a child?

Treatment of Corioretinitis by Toxoplasmosis in Children

The first-line treatment for toxoplasmic chorioretinitis in children is a combination of pyrimethamine and sulfadiazine with leucovorin supplementation, continued for at least 4-6 weeks and until 1-2 weeks after resolution of clinical signs and symptoms. 1

Medication Regimen

First-line Treatment

• Pyrimethamine:

  • Initial dose: 2 mg/kg/day orally divided twice daily for first 2 days
  • Maintenance dose: 1 mg/kg/day daily 1
  • Duration: Continue for at least 4-6 weeks total 2

• Sulfadiazine:

  • Dosage: 100 mg/kg/day orally divided twice daily 1, 3
  • Note: Sulfadiazine is contraindicated in infants under 2 months of age except as adjunctive therapy with pyrimethamine for congenital toxoplasmosis 3

• Leucovorin (folinic acid):

  • Dosage: 10 mg three times weekly 1
  • Important: Folic acid should not be used as a substitute for folinic acid 2

Alternative Treatment Options

For children who cannot tolerate the first-line therapy:

• Trimethoprim-sulfamethoxazole (TMP-SMX):

  • Dosage: 5 mg/kg trimethoprim plus 25 mg/kg sulfamethoxazole orally twice daily 1
  • This was used successfully in a 10-year-old with toxoplasmic chorioretinitis 4

• Other alternatives (less evidence in children):

  • Pyrimethamine plus clindamycin (5.0-7.5 mg/kg orally 4 times daily) 2, 1
  • Pyrimethamine plus azithromycin (dosing based on weight) 2, 1

Treatment Duration

• Standard duration: 4-6 weeks total, continuing treatment for at least 1-2 weeks after resolution of clinical signs and symptoms 2, 1

  • Resolution typically occurs within 10-14 days but may take longer in some cases 2

• Extended duration:

  • French experience suggests courses up to 3 months in children with pyrimethamine/sulfadiazine 2
  • For severe cases (with abnormal neurological exam or active chorioretinitis), treatment for 12 months may be considered 1

Monitoring During Treatment

• Ophthalmologic follow-up: Every 2-3 weeks during active treatment to assess response and determine optimal treatment duration 2

• Laboratory monitoring:

  • Complete blood count weekly while on daily pyrimethamine and at least monthly while on less frequent dosing 1
  • Monitor for bone marrow suppression (leucopenia, thrombocytopenia) due to pyrimethamine

Prevention of Recurrence

Recurrences of toxoplasmic chorioretinitis are common, particularly during puberty 5. Consider:

• Prophylactic treatment:

  • Trimethoprim-sulfamethoxazole has shown a 75% decrease in recurrence risk in older patients 2
  • For adolescents with recurrences during puberty, some experts have tried azithromycin as suppressive therapy 2

• Home monitoring:

  • Teach parents/children to monitor for any signs of decreased visual acuity
  • Prompt referral to ophthalmologist if new symptoms occur 2

Special Considerations

• Corticosteroids:

  • Use with caution and only in conjunction with anti-parasitic therapy
  • Local corticosteroid injection without anti-parasitic coverage may trigger or exacerbate toxoplasmic chorioretinitis, leading to fulminant retinal necrosis 6

• Lesion location:

  • For lesions in vision-threatening areas, aggressive treatment is warranted
  • For peripheral lesions, some experts have tried shorter antimicrobial courses 2

Treatment Outcomes

With appropriate treatment, clinical improvement is typically observed within 2 weeks, although larger lesions (>2 disc diameters) may take longer to improve 7. Despite treatment, visual outcomes may be poor if there is significant retinal damage at presentation.

Early diagnosis and prompt treatment are crucial for improving visual outcomes in children with toxoplasmic chorioretinitis 8.