Differential Diagnosis for Oliguria in a 2-year-old Girl
- Single most likely diagnosis
- Hemolytic Uremic Syndrome (HUS): This condition is characterized by the triad of hemolytic anemia, thrombocytopenia, and acute kidney injury, which aligns with the patient's laboratory findings (low hemoglobin, thrombocytopenia, elevated urea nitrogen, and creatinine). The recent history of bloody diarrhea, a common trigger for HUS, further supports this diagnosis.
- Other Likely diagnoses
- Acute Tubular Necrosis (ATN): The patient's history of bloody diarrhea and subsequent renal failure could also suggest ATN, possibly due to ischemia or toxins from the diarrhea. However, the presence of thrombocytopenia and hemolytic anemia points more towards HUS.
- Prerenal Acute Kidney Injury: This could be considered due to the patient's decreased urine output and elevated urea nitrogen. However, the absence of significant hypovolemia signs and the presence of other systemic findings make HUS more likely.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Thrombotic Thrombocytopenic Purpura (TTP): Although less common in children and not typically associated with diarrhea, TTP could present with similar laboratory findings. It's crucial to differentiate TTP from HUS due to the different treatment approaches.
- Sepsis: The patient's recent history of fever and bloody diarrhea could suggest a septic process leading to acute kidney injury. However, the resolution of fever and the specific pattern of laboratory abnormalities make this less likely.
- Rare diagnoses
- Vasculitis (e.g., Henoch-Schönlein Purpura): This could explain some of the patient's symptoms, including the rash and renal involvement. However, the specific combination of hemolytic anemia, thrombocytopenia, and acute kidney injury is more suggestive of HUS.
- Malignancy (e.g., Neuroblastoma): Although rare, certain malignancies could present with renal impairment and systemic symptoms. The absence of other suggestive findings (e.g., masses, specific tumor markers) makes this diagnosis less likely.