Case 4: Thrombocytopenia and Hematochezia in an Infant

1. Alexandra Schaller, DO* 2. Angela Myers, MD† 3. Shakila Khan, MD‡ 4. Avni Joshi, MD§ 5. Vilmarie Rodriguez, MD¶ 6. George Maher, DO** 1. *Division of Pediatric Critical Care, University of Tennessee Health Sciences Center, Memphis, TN 2. †Department of Medical Genetics, University of California Irvine, Orange, CA 3. ‡Division of Pediatric Blood and Bone Marrow Transplantation, Mayo Clinic, Rochester, MN 4. §Division of Pediatric Allergy and Immunology, Mayo Clinic, Rochester, MN 5. ¶Division of Pediatric Hematology/Oncology, Mayo Clinic, Rochester, MN 6. **Division of Pediatric Hematology/Oncology, Sanford Children’s Hospital, Sioux Falls, SD A 6-week-old white boy presented to his primary care provider with complaints of bloody stools and petechiae and was found to be thrombocytopenic, with an initial platelet count of 25 × 103/μL (25 × 109/L). The complete blood cell (CBC) count was otherwise normal. The mother’s platelet phenotype was PLA1 positive, ruling out neonatal alloimmune thrombocytopenia. The infant’s primary care provider recommended a milk and soy protein-free diet for the mother (the infant was exclusively breastfed), reasoning that the hematochezia and thrombocytopenia may have been unrelated. After this maternal dietary intervention, the infant’s symptoms abated transiently. Hematochezia, petechiae, and thrombocytopenia recurred at age 4 months, at which time the platelet count was 19 × 103/μL (19 × 109/L), prompting further evaluation. Medical history revealed spontaneous vaginal delivery at 39 weeks' gestation, mild eczema, and intermittent nasal congestion. The …