Renal papillary necrosis is a form of nephropathy

Nephropathy

Nephropathy refers to damage to or disease of the kidney. An older term for this is nephrosis.-Causes:Causes of nephropathy include administration of analgesics, xanthine oxidase deficiency, and long-term exposure to lead or its salts...

 involving the necrosis

Necrosis

Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

 of the renal papilla

Renal papilla

In the kidney, the renal papilla is the location where the medullary pyramids empty urine into the minor calyx. Histologically it is marked by medullary collecting ducts converging to form a duct of Bellini to channel the fluid. Transitional epithelium begins to be seen.-Role in disease:Some...

, which is supplied by the vasa recta

Vasa recta

In the blood supply of the kidney, the vasa recta renis form a series of straight capillaries in the medulla...

.

Causes

Analgesic nephropathy is a cause of renal papillary necrosis. The damage is cumulative and most patients of renal papillary necrosis would have ingested at least 20 kg of analgesics in the past. The risk is higher for phenacetin

Phenacetin

Phenacetin is an analgesic, once widely used; its use has declined because of its adverse effects.-History:Phenacetin was introduced in 1887, and was used principally as an analgesic, and was one of the first synthetic fever reducers to go on the market...

 and acetaminophen (paracetamol) compared to aspirin

Aspirin

Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...

 and other NSAIDs. Combination analgesic products, such as Goody's, also have a high risk of causing papillary necrosis.

It can be an outcome of chronic analgesic nephritis, with persistent use or abuse of phenacetin

Phenacetin

Phenacetin is an analgesic, once widely used; its use has declined because of its adverse effects.-History:Phenacetin was introduced in 1887, and was used principally as an analgesic, and was one of the first synthetic fever reducers to go on the market...

 or its derivatives (such as Acetaminophen). This is less common since phenacetin is no longer available over the counter. But is more common when patient's taken combination analgesic products for an extended period of time.

It is also caused by diabetes mellitus

Diabetes mellitus

Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...

 and vaso-occlusive sickle cell crisises, in which it is related to renal infection or vascular disease.

It can also occur as a result of acute pyelonephritis

Pyelonephritis

Pyelonephritis is an ascending urinary tract infection that has reached the pyelum or pelvis of the kidney. It is a form of nephritis that is also referred to as pyelitis...

 or sickle cell disease.