From the Guidelines
The most likely renal finding associated with this 4-year-old girl's condition is acute kidney injury, specifically hemolytic uremic syndrome (HUS), characterized by elevated blood urea nitrogen and creatinine levels, oliguria or anuria, hematuria, and proteinuria. The clinical presentation of fever, abdominal pain, nausea, vomiting, diarrhea, petechiae, hepatomegaly, splenomegaly, low hemoglobin concentration, thrombocytopenia, and erythrocyte fragmentation is consistent with HUS, as described in the case definitions for infectious conditions under public health surveillance by the Centers for Disease Control and Prevention 1. Key features of HUS include:
- Acute onset of microangiopathic hemolytic anemia
- Renal injury
- Low platelet count
- Often follows an acute gastrointestinal illness, usually diarrheal The mechanism of HUS involves microangiopathic hemolytic anemia, where damaged endothelial cells in small vessels lead to platelet aggregation, fibrin deposition, and mechanical destruction of red blood cells, primarily affecting the kidneys and causing acute tubular necrosis and potentially acute renal failure. In children, HUS is most commonly associated with Shiga toxin-producing Escherichia coli (STEC) infection, which damages the intestinal epithelium and releases toxins that subsequently injure renal endothelial cells. Given the clinical picture and the typical presentation of HUS, acute kidney injury characterized by hemolytic uremic syndrome is the most likely renal finding associated with this patient's condition.
From the Research
Renal Findings Associated with Hemolytic Uremic Syndrome
The patient's condition, characterized by fever, abdominal pain, nausea, vomiting, diarrhea, petechiae, hepatomegaly, splenomegaly, low hemoglobin concentration, thrombocytopenia, and erythrocyte fragmentation, is suggestive of Hemolytic Uremic Syndrome (HUS). The renal findings most likely associated with this condition include:
- Acute kidney injury (AKI) requiring renal replacement therapy (RRT) 2
- Thrombotic microangiopathy of the glomerular microcirculation 3
- Renal failure, which is a defining clinical phenotype of HUS 3
Pathophysiology and Treatment
The pathophysiology of HUS involves microvascular thrombosis, endothelial injury, and systemic and intra-glomerular inflammation 4, 3. Treatment options include plasma manipulation, such as plasma exchange or infusion of fresh-frozen plasma 4, and immunomodulation using the selective cytopheretic device 5.
Clinical Presentation and Outcome
HUS can present with a range of symptoms, including acute kidney injury, microangiopathic anemia, and thrombocytopenia 3, 6. The outcome of HUS can vary, with some patients recovering fully, while others may develop chronic renal morbidity or progress to end-stage kidney disease 5, 3.
Key Findings
Key findings in HUS include: