Renal papillary necrosis is a form of nephropathy involving the necrosis of the

renal papilla The renal medulla is the innermost part of the kidney. The renal medulla is split up into a number of sections, known as the renal pyramids. Blood enters into the kidney via the renal artery, which then splits up to form the segmental arteries whi ...

. Lesions that characterize renal papillary necrosis come from an impairment of the blood supply and from subsequent

ischemic Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems w ...

necrosis that is diffuse.

Signs and symptoms

Symptoms (and signs) consistent with renal papillary necrosis are:

Causes

In terms of cause, almost any condition that involves ischemia can lead to renal papillary necrosis. A

mnemonic A mnemonic ( ) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding. Mnemonics make use of elaborative encoding, retrieval cues, and imag ...

for the causes of renal papillary necrosis is POSTCARDS:

pyelonephritis Pyelonephritis is inflammation of the kidney, typically due to a bacterial infection. Symptoms most often include fever and flank tenderness. Other symptoms may include nausea, burning with urination, and frequent urination. Complications may ...

, obstruction of the urogenital tract,

sickle cell disease Sickle cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as sickle cell anaemia. It results in an abnormality in the oxygen-carrying protein haemoglobin found in red b ...

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, i ...

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue rep ...

of the liver, analgesia/ alcohol use disorder, renal vein thrombosis,

diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

, and systemic

vasculitis Vasculitis is a group of disorders that destroy blood vessels by inflammation. Both arteries and veins are affected. Lymphangitis (inflammation of lymphatic vessels) is sometimes considered a type of vasculitis. Vasculitis is primarily caused ...

. Often, a patient with renal papillary necrosis will have numerous conditions acting synergistically to bring about the disease. Analgesic nephropathy is a common cause of renal papillary necrosis. The risk is higher for phenacetin (which was withdrawn from market in the United States) and paracetamol (acetaminophen) compared to

aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...

and other

NSAID Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of ...

Pathophysiology

This condition is due to ischemia of the renal papillae, the portion of the kidney that collects urine from the

nephron The nephron is the minute or microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and a cup-shaped structure ...

. The papillae are vulnerable to ischemia as they are supplied by small caliber arteries which are liable to obstruction. All of the underlying causes of papillary necrosis cause diminished flow through these arteries, either through direct mechanical obstruction (sickle cell), obstruction secondary to inflammation ( vasculitides), or vasoconstriction (NSAIDs). Papillary necrosis is more likely to develop when multiple of these underlying factors are present. Ultimately, necrosis of the papillae results in sloughing into the lumen, causing hematuria. If the degree of necrosis is substantial post-renal failure may occur, though this is uncommon.

Diagnosis

Individuals with renal papillary necrosis due to excess use of analgesic have an elevated risk of

epithelial Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercell ...

tumors, hence a urine cytology exam is useful. In terms of imaging this condition can be identified by retrograde pyelography (RGP). The diagnosis of renal papillary necrosis is therefore done via:

Treatment

Treatment of renal papillary necrosis is supportive, any obstruction (urethral) can be dealt with via stenting. This condition is not linked to a higher possibility of

kidney failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

. Control of infection is important, thus antimicrobial treatment is begun, so as to avert surgery (should the infection not respond).

References

External links

{{Medicine Kidney diseases