Renal Papillary Necrosis
Renal papillary necrosis is a condition in which the tips of the kidney’s pyramids—the renal papillae—become damaged and begin to break down. This damage reduces the kidney’s ability to concentrate urine and can lead to pain, infection, or blood in the urine. It is often associated with underlying conditions such as diabetes, severe infections, kidney stones, sickle cell disease, or long-term use of certain medications.
What is it?
Renal papillary necrosis occurs when the renal papillae—small structures that drain urine from the kidney’s filtering units—lose blood supply and begin to die. This may happen gradually or suddenly. Conditions such as diabetes, urinary obstruction, severe infections, analgesic overuse, or sickle cell disease are common contributors.
Imaging, especially CT, can show characteristic findings such as sloughed tissue, cavities where the papillae have broken down, or obstruction from debris. Ultrasound may show swelling but is less specific. Urine tests may reveal blood, infection, or tissue fragments shed from damaged papillae.
Important to Know
Early recognition and treatment of the underlying cause can help prevent further kidney damage. Severe cases may lead to obstruction, recurrent infections, or reduced kidney function. Avoiding medications that stress the kidneys—such as certain pain relievers—is important for prevention and recovery.
Red flag symptoms include fever with flank pain, inability to urinate, severe nausea or vomiting, passage of tissue fragments, or visible blood in the urine. These may indicate infection, obstruction, or significant papillary damage requiring urgent evaluation.