Renal Papillary Necrosis

Introduction

Von Friedrick described renal papillary necrosis in the year 1877. It is one of the complications of diabetes mellitus, where there is acute destruction of the renal papilla and an absence of suppuration in the affected area. It is a worrisome complication but is rare. Renal papillary necrosis can occur as a sequel of obstructive uropathy (a condition when urine cannot drain through the urinary tract) in nondiabetic cases.

What Is Renal Papillary Necrosis?

Renal papillary necrosis is a kidney disorder in which one or all renal papillae are destroyed. The renal pyramid has an apex called the renal papilla, where the openings of the collecting ducts enter the kidney, and the urine flows into the ureters. It most frequently affects individuals over the age of 60 and is more prevalent in women and those assigned female at birth.

What Are the Synonyms of Renal Papillary Necrosis?

The synonyms involve:

• Necrotizing pyelonephritis.

• Papillitis renis necroticans.

• Gunther's disease (also called congenital erythropoietic porphyria affects skin, teeth, bones, the hematopoietic system, and bones).

• Diphtheria of the papilla.

• Papillitis necroticans.

What Is the Pathogenesis of Renal Papillary Necrosis?

In the absence of urinary tract obstruction, the lesions of renal papillary necrosis are rarely seen in cases of nondiabetic patients. The most accepted concept is ischemia of the medullary portion of the medulla, which is an ischemic infarct. The characteristics of the lesion are similar to that of an infarct (a condition in which tissue dies due to obstruction of blood supply caused by a blood clot or narrowing of a blood vessel). The demerit of this theory is that there is no evidence of obstructed blood flow to the papilla. In studies conducted, authors have suggested that it may be due to the coalescence of abscesses at the base of the medulla, and some say it is due to arteriosclerosis of the blood vessels supplying the medulla. Increased hydrostatic pressure, which leads to extrinsic pressure in the tubules caused by obstruction, may also be one of the reasons.

What Are the Causes?

Causes involve:

• Analgesic Nephropathy: This condition involves damage to the internal structures of the kidney caused by long-term usage of pain medications (analgesics). They involve counter drugs such as Phenacetin and Acetaminophen and NSAIDs such as Ibuprofen and Aspirin.

• Sickle Cell Nephropathy: Sickling of red blood cells in the small blood vessels leading to kidney complications.

• Diabetes mellitus, accompanied by urinary tract infections.

• Prolonged usage of NSAID (Nonsteroidal anti-inflammatory drugs).

• Pyelonephritis: Infection in the kidneys.

• Kidney transplant rejection.

• Urinary tract blockage.

What Are the Symptoms?

The symptoms include:

• Flank Pain: The pains present on one side of the body between the upper abdomen and the back.

• Presence of blood (hematuria) or dark and cloudy urine.

• Presence of tissue pieces in the urine.

• The patient may sometimes have chills along with fever.

• Dysuria: Pain while passing urine.

• Urgency: Strong, irresistible urge to pass urine; the patient is often not able to hold the urine.

• Increased frequency of passing urine.

• Urinary Hesitancy: Difficulty in maintaining a continuous urine stream.

• Urinary Incontinence: Leaky urine caused by loss of bladder control.

• Passing urine in large volumes.

• Increased frequency of passing urine at night.

• Azotemia: Increased levels of urea and nitrogen compounds in the blood.

• Albuminuria: The presence of high levels of albumin in the urine.

• Individuals have elevated white blood cell count.

• Stupor: A state of unconsciousness.

What Are the Diagnostic Tests Done for Renal Papillary Necrosis?

On examination, the affected flank area may be tender, and the patient may have a history of frequent urinary tract infections. The patient may also show signs of kidney failure or blocked urine flow.

The doctor may advise the following tests:

• Ultrasound.

• Computed tomography (CT).

• Blood test.

• Urine test.

Structural changes increase the size of the minor calyces, which are cavities in the kidney where urine is collected. The papilla may slough, producing negative shadows in the large calyces or pelvis. A retrograde urogram can detect all these findings. However, the program may fail to detect initial cases in which no sloughing has occurred and may appear normal.

What Laboratory Tests Are Used to Diagnose Renal Papillary Necrosis?

Kidney function tests aid in diagnosing this condition and include:

• Blood Urea Nitrogen (BUN): Measures nitrogen levels in the blood, with higher levels indicating improper kidney filtration.

• Creatinine: Reflects muscle wear and tear, cleared by kidneys; elevated levels suggest filtration issues.

• Estimated Glomerular Filtration Rate (eGFR): A calculation based on protein, creatinine, age, sex, size, and race, estimating kidney filtration efficiency.

• Urinalysis: Examines urine through visual, microscopic, and chemical tests to detect blood, red and white blood cells, and fragmented renal papillae.

• Urine Protein-Creatinine Ratio: Identifies blood protein levels indicative of kidney damage.

What Are the Complications of Renal Papillary Necrosis?

• Infection of the kidney (pyelonephritis).

• Renal Calculi: Formation of kidney stones.

• Cancer of the kidneys.

When to Seek Help?

Contact a health care professional immediately if there is blood in urine and other symptoms such as fever or chills, painful urination, or pain in the back, particularly between hips and ribs.

What Is the Prognosis of Renal Papillary Necrosis?

The prognosis solely depends on the condition causing the disease. If symptomatic relief is provided and the cause is eliminated, then the person with renal papillary necrosis can recover. However, not all cases see complete recovery and may lead to kidney failure, which will require a kidney transplant or dialysis.

What Is the Possible Treatment for Renal Papillary Necrosis?

The treatment for renal papillary necrosis is more of a symptomatic approach, where the doctor will try to ease the symptoms and try to eliminate the cause.

Analgesic Neuropathy:

In cases of analgesic nephropathy, which is caused due to over-the-counter pain medications, the doctor will advise the patient to stop those medications.

Sickle Cell Neuropathy:

In cases of sickle cell nephropathy, proteinuria managed by a low-protein diet should be avoided. Medications that help manage sickle cell nephropathy involve angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) to help reduce proteinuria. Hydroxyurea is an analgesic that helps decrease the complications caused by sickle cell nephropathy. It helps reduce lactate dehydrogenase and reticulocytes. Erythropoietin-stimulating agents are used to treat anemia and hypoxia.

How Can Renal Papillary Necrosis Be Prevented?

Preventing renal papillary necrosis involves maintaining good overall health and using NSAIDs or other over-the-counter medications according to the manufacturer’s or healthcare provider’s instructions.

For individuals with diabetes, sickle cell disease, or other conditions that can lead to renal papillary necrosis, it is important to follow the care instructions provided by healthcare providers and attend regular check-ups. Routine laboratory tests are necessary to monitor kidney function and detect any changes early.

Conclusion

Renal papillary necrosis is a disorder of the kidney in which one or all renal papillae are destroyed. The renal pyramid has an apex called the renal papilla, where the openings of the collecting ducts enter the kidney, and the urine flows into the ureters. Von Friedrick described this disease in the year 1877. Renal papillary necrosis is caused by analgesic nephropathy, sickle cell neuropathy, diabetes mellitus, pyelonephritis, and urinary tract blockage. The treatment modalities for renal papillary necrosis are more of a symptomatic approach, where the doctor tries to ease the symptoms and eliminate the cause.