Question: how does sickle cell cause renal failure?
Answer: The renal complications in sickle cell disease originate from the occluded vessels (vasa recta) in the renal medulla, given the low partial pressure of oxygen (10 to 35 mm Hg), acidosis, and high osmolarity, which predisposes to hemoglobin S tetramerization and subsequent sickling of the erythrocytes.