Introduction

Renal papillary necrosis (RPN) is a condition in which the renal papillae, found deep within the kidney, break down and die, leading to pain, blood in the urine, and possibly long-term kidney problems.¹ Conditions such as diabetes, urinary tract infections, and kidney stones increase the risk of developing RPN. Research shows that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen connects to the development of RPN.² 

In this article, we will discuss RPN in more detail. We will look into its causes, diagnosis, pain management for people living with the condition, and how pain medications themselves may actually contribute to the condition. 

Understanding Papillary Necrosis 

What Do Your Kidneys Do?

The kidneys are responsible for more than you think. They act as the body’s filtration system. Blood enters the kidney, and waste products, extra fluid, and other substances your body does not need are filtered out through the urine. As urine is formed, it flows through tubes in the kidney and collects at the renal papillae. The renal papillae guide the urine into the center of the kidney before it moves into the bladder. 

That is not all the kidneys do. They are also responsible for:³ 

• Balancing fluids and electrolytes
• Supporting the production of red blood cells
• Regulating blood pressure 
• Strengthening bones

What Is Papillary Necrosis?

Papillary necrosis happens when the renal papillae begin to break down. These tissues guide urine from the center of the kidney towards the bladder.⁴ When these become damaged, the kidney’s ability to filter and remove waste from the blood can be impacted.⁵ 

This often causes symptoms such as blood in the urine or pain in the sides and back. In some cases, fragments of damaged tissue can break away, potentially causing blockages or infections, therefore, proper management, ongoing damage may contribute to declining kidney function over time.⁶

Some individuals face a higher risk, mainly those with long-standing diabetes, a history of heavy painkiller use, or recurring kidney infections.² Fortunately, detection through imaging or urine tests can help detect problems early and reduce the risk of serious complications. Treatment usually focuses on managing the root cause and protecting the kidneys remaining function. 

What Can Lead to Papillary Necrosis? 

Common Medical Causes 

Some health problems make papillary necrosis more likely, especially those that affect blood flow or put extra strain on the kidneys. Here are a few of the main ones:

Diabetes

Consistently high blood sugar levels can harm the small blood vessels in the kidneys, resulting in a reduction in oxygen and nutrient supply to the papillae causing them to break down or degenerate.^7,10 

Urinary Tract Blockage (e.g. Kidney Stones)

Blockages can lead to urine backing up, increasing the pressure in the kidneys, which, over time, can damage the papillae resulting in their damage or death.^7,10  

Infections  

Repeated kidney infections cause irritation and can interfere with normal blood flow which increases the risk of tissue death.^7,10  

Sickle Cell Disease 

In sickle cell disease, red blood cells clump together and block small blood vessels reducing oxygen supply.^7,10  

The Role of Painkillers 

NSAIDs, like ibuprofen and naproxen, are very commonly used to manage pain and help to reduce inflammation. However, long-term or heavy use of these medications can affect your kidneys. 

NSAIDs work by blocking substances called prostaglandins. Prostaglandins work to keep blood flowing to your kidneys.⁸ When prostaglandins are blocked by NSAIDs, blood flow to the kidneys, and therefore, to the renal papillae is reduced, meaningless oxygen reaches the kidney tissue. Over time, the lack of oxygen can result in damage or even tissue death in the renal papillae.⁹

Symptoms and Diagnosis 

What Does Papillary Necrosis Feel Like? 

The symptoms of papillary necrosis can start quietly, but as the condition progresses, you can develop several noticeable symptoms: 

Flank or lower back pain 

These can feel like a sharp or cramping pain resulting from degenerating kidney tissue, inflammation, or from papilla fragments blocking the urinary tract, leading to episodes of renal colic.¹²

Blood in the urine

You may notice your urine looks pink, red, or brown, or tiny amounts of blood may be seen under a microscope.¹¹ 

Changes in urination 

You may experience burning, urgency, frequency, or feel like you cannot empty your bladder fully.¹¹

Fever or chills

You may experience this if there is an infection present, especially when papillary debris causes a blockage or urinary stasis.¹¹

How Is It Diagnosed?

Diagnosing RPN involves a combination of imaging and lab tests to check kidney function and confirm the diagnosis.

Urine Tests

Urine tests show changes to the urine, suggesting kidney injury, like an increase in certain enzymes. They may also show blood or fragmented pieces of renal papillae in the urine. 

However, urine tests alone cannot diagnose RPN. They only inform your doctors if your kidneys might be affected.¹³ 

Blood Tests

Blood tests look at waste products like urea and creatinine in your blood to see how well your kidneys are doing their job. If these levels are high, it can suggest your kidneys are not filtering as they should.¹³

Imaging

Ultrasounds and CT scans allow medical professionals to take a close look at your kidneys from the inside. CT scans show clearer images, helping doctors to see any tissue damage. MRI scans can also be used to see changes linked to papillary necrosis.¹³ 

Pain and Papillary Necrosis: A Complicated Relationship

What Causes the Pain?

As the renal papillae degenerate, it leads to inflammation and swelling in the kidney. This can cause pressure to build up inside the kidney, resulting in pain. Additionally, parts of the damaged tissue can break off and block the tubes carrying the urine, causing pain similar to how kidney stones would, which is also known as renal colic. 

Managing Pain Safely

Certain painkillers, especially NSAIDs (like ibuprofen and naproxen), have been linked to causing RPN. 

NSAIDs reduce the production of prostaglandins, which normally help to maintain healthy blood flow to the kidneys. When this blood flow drops, it can lead to damage and potential necrosis.^8,10 

In view of this, pain management in RPN should be approached with caution. There is not one clear answer, but several treatment options exist. In milder cases, basic steps such as staying hydrated may help.

One study found that increasing your intake of water could help to flush out the breakdown products of the papillae, which can ease your symptoms and reduce irritation in the kidneys therefore alleviating your pain.¹⁰

When pain medication is required, your doctor may look into alternatives depending on your condition. Paracetamol use in the context of kidney injury, when used properly, may be less harmful compared to NSAIDs. However, paracetamol also poses risks when overused.⁸

Sometimes, stronger pain relief may be needed, but always with close supervision from your doctors. The key for effective pain management in RPN is a tailored approach taking into account your symptoms, kidney function, and overall health.^8,10

Living With or Recovering From Papillary Necrosis

What Happens After Diagnosis?

The management of RPN is dependent on the underlying cause, if known. If NSAIDs or other pain medications are contributing, a medical professional may advise you to stop taking them.¹⁰ 

Your kidney function will be monitored regularly with blood tests to check how well they are working.⁷ 

It is also important to manage other health conditions that may have caused or worsened RPN, like keeping your diabetes under control.²

Protecting Your Kidney Health

Make sure you are drinking plenty of fluids to help flush your kidneys and lower the chance of further damage or pain.¹⁴ 

It is also best to avoid taking painkillers you do not really need, especially NSAIDs, as they can harm your kidneys further.¹⁴ 

Regular follow-ups and blood tests are essential in monitoring the condition so your doctor can spot changes early and adjust your treatment as required.⁷

Summary

Renal papillary necrosis is an uncommon condition affecting the kidney that needs careful attention. Managing pain is tricky because while some medications can help, others might make things worse if not used properly.

 It is essential to avoid overusing particular painkillers, like NSAIDs, where possible. It is crucial to see your healthcare provider regularly and talk honestly about your symptoms and treatments to keep your kidneys safe and improve your overall health. 

FAQs

Are kidney infections the same as papillary necrosis? 

No, they are different. However, infections can sometimes increase the chance of developing papillary necrosis or make it worse.

What kind of pain does papillary necrosis cause?

RPN usually causes a sharp or aching pain in the side or lower back, which is a result of tissue damage and potential ureteral obstruction

Which painkillers are safest if you have kidney problems?

Paracetamol is generally safer than NSAIDs, but it is important to check with your medical professional before taking anything.