Blood Tests for a 4-Year-Old Boy with Pica and Speech Regression
For a 4-year-old boy presenting with pica (eating grass) and speech regression with autism, a complete blood count (CBC) with iron studies should be ordered as the primary investigation.
Primary Blood Tests Recommended
- Complete Blood Count (CBC) to assess for anemia 1
- Iron studies including:
- Serum iron
- Total iron binding capacity (TIBC)
- Ferritin
- Transferrin saturation 1
- Lead level testing (particularly important with pica behavior) 1
- Thyroid function tests (TSH and free T4) 2
Rationale for Testing
- Pica is strongly associated with iron deficiency anemia, which requires prompt identification and treatment 1
- Children with developmental issues, including speech regression, should undergo thyroid function testing as subclinical hypothyroidism can manifest as speech and language delays 2
- Lead poisoning is a significant concern in children with pica and can contribute to developmental issues 1
Additional Considerations
- Comprehensive audiologic evaluation should be considered given the speech regression, as hearing loss can contribute to speech delays 3
- For a 4-year-old, conventional screening audiometry can be performed with a fail criterion of >20 dB at frequencies of 500,1000,2000, and 4000 Hz 3
- Consider evaluation for autism-related genetic conditions that may present with pica:
- Though not first-line, genetic testing may be considered if initial workup is negative and symptoms persist 3
Management Approach
- Treat identified iron deficiency with appropriate iron replacement therapy 1
- Address any nutritional deficiencies identified through blood testing 1
- Consider behavioral interventions for pica, which have shown high effectiveness (Cohen's d = 1.80) 4
- Implement response-interruption and redirection (RIRD) with differential reinforcement of alternative behavior (DRA) if pica persists 5
Follow-up Recommendations
- Recheck CBC and iron studies after 4-6 weeks of iron therapy if deficiency is identified 1
- Monitor lead levels if initially elevated 1
- Re-examine at 3-6 month intervals until the condition resolves or additional intervention is needed 3
Common Pitfalls to Avoid
- Not considering iron deficiency as a primary cause of pica 1
- Overlooking potential hearing loss as a contributor to speech regression 3
- Failing to test for lead toxicity in a child with pica 1
- Attributing all symptoms solely to autism without investigating treatable medical causes 1
Remember that pica often self-remits in younger children but may require multidisciplinary management if persistent, especially in children with developmental disabilities 6.