An 8-year-old boy presents with headaches, dizziness, and malaise. He was seen for a severe sore throat 2 weeks ago. Physical examination reveals facial edema. The blood pressure is 180/110 mm Hg. A 24-hour urine collection demonstrates oliguria, and urinalysis shows hematuria. What finding on microscopic urinalysis indicates that hematuria in the patient is caused by a renal process, rather than bleeding from another site in the urinary tract?
Injury to the glomerular capillaries results in spillage of protein and blood cells into the urine. Hematuria is also seen in patients with bleeding from the lower urinary tract. However, RBC casts in the urine sediment originate from erythrocytes compacted during passage through the renal tubules and denote a renal origin of hematuria.Diagnosis: Postinfectious glomerulonephritis, nephritic syndrome
Blood clots
Hemoglobin crystals
Phagocytosed hemoglobin
Red blood cell casts
Kidney