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, low platelet count, 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 recent illness and the presence of oliguria, elevated creatinine, and urea nitrogen could suggest ATN, possibly secondary to dehydration or toxins from the gastrointestinal infection.
- Prerenal Acute Kidney Injury: Although the patient has been drinking well, the history of recent diarrhea and possible dehydration could lead to prerenal causes of acute kidney injury, which might explain the oliguria.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Sepsis: Although the patient's fever has resolved, sepsis could lead to acute kidney injury and should be considered, especially given the recent history of infection.
- Meningococcemia: The presence of red spots (petechiae or purpura) and the acute onset of symptoms could suggest meningococcemia, a condition that requires immediate treatment.
- Rare diagnoses
- Thrombotic Thrombocytopenic Purpura (TTP): Although less common in children and typically presenting with a pentad of symptoms (thrombocytopenia, microangiopathic hemolytic anemia, renal failure, neurological symptoms, and fever), TTP could be considered given the thrombocytopenia and renal impairment.
- Vasculitis (e.g., Henoch-Schönlein Purpura): The combination of renal impairment, oliguria, and the presence of red spots could rarely suggest a vasculitic process, although the lack of other typical symptoms (such as joint pain or abdominal pain) makes this less likely.