A 14-year-old girl develops a rash, abdominal pain, and arthralgias. She is also experiencing some nausea, vomiting, and crampy abdominal pain. On examination, she has a palpable purpuric rash on her buttocks and lower legs, a tender abdomen, and no active joint inflammation. Her stools test positive for blood, and urinalysis reveals RBCs and RBC casts. Her renal function deteriorates rapidly over several days. A renal biopsy is performed.For the above patient with GN, select the most likely diagnosis on renal biopsy.
High-Yield Explanation
This is a case of Henoch-Schonlein purpura (HSP). Diffuse proliferative GN is characterized by acute nephritic syndrome: AKI over days to weeks, with hypertension, edema, oliguria, and active urine sediment. Less severe clinical presentation correlates with a more benign biopsy. The pattern of glomerular involvement is similar to IgA nephropathy.