What are the latest management strategies for Congenital Sucrase-Isomaltase Deficiency (CSID)?

Management of Congenital Sucrase-Isomaltase Deficiency (CSID)

Enzyme replacement therapy with sacrosidase (Sucraid) is the first-line treatment for patients with Congenital Sucrase-Isomaltase Deficiency (CSID) and should be prescribed for all diagnosed patients aged 5 months and older to improve quality of life and reduce gastrointestinal symptoms. 1

Diagnosis

CSID is a rare genetic disorder characterized by deficiency of the brush-border sucrase-isomaltase enzyme complex, resulting in an inability to properly digest sucrose and starches. Diagnosis can be challenging but should be suspected in patients with:

• Chronic watery diarrhea
• Abdominal pain and bloating
• Symptoms worsening after ingestion of fruits, juices, grains, and starches 2
• Failure to thrive in infants and children
• Persistent GI symptoms despite treatment for other conditions 3

Diagnostic approaches include:

1. Disaccharidase assay of duodenal or jejunal mucosa obtained endoscopically (gold standard)
2. Sucrose hydrogen breath test (though impractical in young children)
3. Genetic testing for mutations in the SI gene (emerging alternative to endoscopic biopsies) 2, 4

Treatment Algorithm

1. Pharmacological Management

• Sacrosidase (Sucraid) oral solution: FDA-approved for treatment of sucrase deficiency in CSID for patients ≥5 months of age 1
  • Dosing: Based on weight
    • ≤15 kg: 1 mL per meal/snack

    • 15 kg: 2 mL per meal/snack 5

  • Administration: Take with water, milk, or infant formula (not fruit juice as acidity may reduce enzyme activity) 1
  • Timing: Administer with each meal or snack containing sucrose or starch

2. Dietary Management

• Dietary starch restriction: Since sacrosidase does not replace isomaltase, patients may still experience symptoms, especially if starch intake is high 1
• Consultation with dietitian: Recommended to ensure nutritional adequacy while managing carbohydrate intake
• Monitoring: For patients with diabetes mellitus, blood glucose should be monitored as sacrosidase enables absorption of glucose and fructose from sucrose hydrolysis 1

3. Follow-up and Monitoring

• Regular assessment of symptom control
• Growth monitoring in children
• Nutritional status evaluation
• Adjustment of sacrosidase dosing based on symptom control

Evidence for Treatment Efficacy

Clinical trials have demonstrated that sacrosidase is effective in:

• Significantly decreasing breath hydrogen excretion during sucrose breath tests
• Reducing the number of stools and improving stool consistency
• Decreasing symptoms of gas, abdominal cramps, and bloating 5

In a study of 28 children with CSID, higher concentrations of sacrosidase were associated with fewer stools, more formed stools, and fewer GI symptoms compared to lower concentrations or baseline periods with sucrose/starch-free diet 5.

Patient Experience and Quality of Life

A qualitative study of 43 patients (8 adults, 35 children/adolescents) with CSID found:

• Considerable improvement in symptoms and health-related quality of life after diagnosis and treatment with sacrosidase
• However, some symptoms persisted that continued to affect daily life, indicating potential unmet needs 6

Common Pitfalls and Caveats

1. Delayed diagnosis: Due to nonspecific symptoms, CSID may remain undiagnosed for years, leading to prolonged suffering and potential malnutrition 3

2. Incomplete symptom relief: Sacrosidase only addresses sucrase deficiency, not isomaltase deficiency, so dietary starch restriction may still be necessary 1

3. Administration errors: Mixing sacrosidase with fruit juice can reduce enzyme activity and effectiveness 1

4. Monitoring in special populations: Patients with diabetes require careful monitoring of blood glucose levels when starting sacrosidase 1

5. Limited awareness: Many clinicians are unfamiliar with CSID, leading to misdiagnosis as more common GI disorders 6

CSID management requires both enzyme replacement therapy and dietary modifications to effectively control symptoms and improve quality of life. Early diagnosis and appropriate treatment can significantly reduce morbidity and improve outcomes for affected individuals.