Differential Diagnosis for Kidney Injury in a 6-year-old Boy
The patient presents with pallor, decreased energy, and laboratory results indicating anemia (low hemoglobin), thrombocytopenia (low platelets), elevated leukocytes, and signs of kidney injury (elevated blood urea nitrogen and creatinine). The recent history of fever, emesis, diarrhea, and a sore throat in the sister suggests a possible infectious etiology.
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 gastrointestinal symptoms are consistent with a diarrheal illness caused by E. coli O157:H7, a common precipitant of HUS. The laboratory findings of low hemoglobin, low platelets, and elevated creatinine support this diagnosis.
Other Likely Diagnoses
- Poststreptococcal Glomerulonephritis: Given the sister's recent sore throat, this could be a consideration, especially if the patient had a streptococcal infection. However, the presence of hemolytic anemia and thrombocytopenia makes HUS more likely.
- IgA Vasculitis (Henoch-Schönlein Purpura): This condition can cause kidney injury and is often preceded by a gastrointestinal or respiratory infection. However, the lack of purpura, joint pain, or abdominal pain in the patient's presentation makes this less likely.
Do Not Miss Diagnoses
- Renal Vascular Occlusion: Although less common, conditions like renal vein thrombosis can cause acute kidney injury and must be considered, especially in the context of severe dehydration or nephrotic syndrome. The patient's recent illness could have led to dehydration, making this a possibility.
- Severe Sepsis: The patient's initial symptoms of fever, emesis, and diarrhea could have progressed to sepsis, leading to acute kidney injury. The elevated leukocytes and signs of kidney injury support this consideration.
Rare Diagnoses
- Thrombotic Thrombocytopenic Purpura (TTP): This is a rare condition characterized by thrombocytopenia, microangiopathic hemolytic anemia, renal failure, and neurological symptoms. It is less common in children and would be an unusual diagnosis without additional supporting symptoms.
- Vasculitis (e.g., ANCA-associated vasculitis): These conditions are rare in children and typically present with a combination of systemic symptoms, including renal involvement. The patient's presentation does not strongly suggest vasculitis, but it remains a consideration in the differential diagnosis of kidney injury.