Differential Diagnosis for Thrombocytopenia with Hematochezia in a 9-Month-Old Female with Normal Coagulation Profile
Single Most Likely Diagnosis
- Immune thrombocytopenic purpura (ITP): This condition is characterized by low platelet count due to immune-mediated destruction. Hematochezia (blood in stool) can occur due to thrombocytopenia, and a normal coagulation profile supports this diagnosis, as ITP primarily affects platelets, not the coagulation cascade.
Other Likely Diagnoses
- Infection-related thrombocytopenia: Certain infections, especially viral, can lead to thrombocytopenia. The presence of hematochezia could be due to the thrombocytopenia or the underlying infection itself.
- Allergic interstitial nephritis or other drug reactions: Although less common in infants, exposure to certain medications or substances can lead to thrombocytopenia and potentially gastrointestinal symptoms.
- Congenital infections (e.g., CMV, rubella): These can cause thrombocytopenia among other symptoms, and hematochezia could be a manifestation of gastrointestinal involvement.
Do Not Miss Diagnoses
- HUS (Hemolytic Uremic Syndrome): Although typically presents with a triad of hemolytic anemia, acute kidney injury, and thrombocytopenia, the thrombocytopenia and hematochezia could be initial or prominent features. It's crucial to consider this diagnosis due to its severe implications and need for prompt treatment.
- Abdominal trauma or child abuse: Though the coagulation profile is normal, trauma could lead to thrombocytopenia due to consumption, and hematochezia could result from direct injury to the gastrointestinal tract.
- Leukemia or lymphoma: These malignancies can cause thrombocytopenia and gastrointestinal symptoms, including hematochezia, due to infiltration or treatment effects.
Rare Diagnoses
- Congenital thrombocytopenias (e.g., Wiskott-Aldrich syndrome, Bernard-Soulier syndrome): These are rare genetic disorders that affect platelet production or function and could present with thrombocytopenia and bleeding manifestations like hematochezia.
- Kasabach-Merritt syndrome: A rare condition characterized by thrombocytopenia and coagulopathy due to a vascular tumor, which could potentially cause gastrointestinal bleeding.
- Thrombotic thrombocytopenic purpura (TTP): Extremely rare in infants, TTP is characterized by thrombocytopenia, microangiopathic hemolytic anemia, renal failure, and neurological symptoms. The presence of hematochezia could be part of the broader clinical picture.