Differential Diagnosis for Kidney Injury in a 6-year-old Boy
The patient presents with pallor, decreased energy, and laboratory results indicating anemia, thrombocytopenia, and acute kidney injury. The following differential diagnoses are considered:
Single most likely diagnosis
- Hemolytic Uremic Syndrome (HUS): This condition is characterized by the triad of hemolytic anemia, acute kidney injury, and thrombocytopenia. The patient's recent history of diarrhea, which could be caused by E. coli O157:H7, supports this diagnosis. The laboratory results showing low hemoglobin, low platelet count, and elevated creatinine levels are consistent with HUS.
Other Likely diagnoses
- Acute Poststreptococcal Glomerulonephritis (APSGN): Although the patient's sister had a sore throat, there is no direct evidence linking the patient's condition to a streptococcal infection. However, APSGN can cause acute kidney injury and is a consideration given the patient's age and the presence of a systolic murmur.
- Anemia of Chronic Disease: The patient's anemia could be contributing to his decreased energy and pallor. However, the acute kidney injury and thrombocytopenia suggest a more complex diagnosis.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Meningococcemia: This condition can cause acute kidney injury, thrombocytopenia, and anemia. Although the patient does not have a typical presentation of meningococcemia, such as a rash or severe headache, it is essential to consider this diagnosis due to its high mortality rate if left untreated.
- Sepsis: The patient's recent history of fever, emesis, and diarrhea could be indicative of a severe infection. Sepsis can cause acute kidney injury, and it is crucial to rule out this diagnosis due to its potential for high morbidity and mortality.
Rare diagnoses
- Thrombotic Thrombocytopenic Purpura (TTP): This condition is characterized by thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney injury. Although TTP is rare in children, it is essential to consider this diagnosis due to its potential for severe complications if left untreated.
- Vasculitis: Conditions such as Henoch-Schönlein purpura or systemic lupus erythematosus can cause acute kidney injury, anemia, and thrombocytopenia. However, these diagnoses are less likely given the patient's age and lack of other typical symptoms.