“Renal parenchymal disease” is a general term for any condition that harms the kidneys’ working parts and affects how they function. Renal parenchymal diseases can develop suddenly or slowly over time, and they vary widely — some cases are more serious than others. This article covers how these conditions develop, common symptoms, and what to expect.

What Is the Renal Parenchyma?

The renal parenchyma is the working part of the kidney and has two main parts — the renal cortex and the renal medulla. Both can be affected by renal parenchymal disease.

Renal Cortex

The renal cortex is the outer layer of the kidney. It contains about 1 million nephrons, which filter the blood. Each nephron includes glomeruli (tiny blood vessels) and renal tubules (small tubes). Blood passes through the glomeruli first, and the tubules reabsorb water, nutrients, and minerals the body needs.

The renal cortex also produces certain substances, such as:

• Erythropoietin (a hormone that helps the body produce red blood cells)
• Renin (an enzyme that helps control blood pressure)
• 1-alpha-hydroxylase (an enzyme that activates vitamin D for bone health)

Renal Medulla

In the renal medulla — the inner portion of each kidney — renal tubules continue to absorb water, nutrients, and electrolytes. Any waste that remains after the filtration process collects in the medulla and later leaves the body as urine.

How Does Renal Parenchymal Disease Develop?

Renal parenchymal disease can result from conditions that damage the kidneys or even as a complication of certain medications.

Medical Conditions That Can Lead to Renal Parenchymal Disease

Conditions that overwork or damage the kidneys can lead to chronic (long-term) renal parenchymal disease. Common causes include:

• Hypertension (high blood pressure — one of the most common causes)
• Diabetes (another leading cause)
• Kidney cancer
• Polycystic kidney disease (a type that can be inherited from parents)
• Sickle cell anemia
• Autoimmune diseases (such as lupus nephritis)

Acute (short-term) renal parenchymal disease may result from:

• Infections
• Kidney stones
• Severe dehydration
• Serious allergic reactions
• Pulmonary embolism (a blood clot in the lungs)

Harmful Effects of Medications

Certain medications can also trigger kidney damage. For example, taking nonsteroidal anti-inflammatory drugs (NSAIDs) too often can lead to acute renal parenchymal disease.

Although medications like ACE inhibitors and angiotensin receptor blockers (ARBs) are commonly used to treat kidney disease, they can sometimes harm the kidneys — especially when combined with other drugs.

Risk Factors for Renal Parenchymal Disease

Anyone can develop renal parenchymal disease, but you may be at higher risk if you:

• Take NSAIDs too often
• Are over age 60
• Have a family history of renal parenchymal disease
• Live with a chronic condition like diabetes or heart disease

What Are the Symptoms of Renal Parenchymal Disease?

In the early stages, renal parenchymal disease often causes no symptoms. As kidney function gets worse, you may notice symptoms such as:

• Fatigue
• Blood in the urine
• Foamy urine (from protein leaking into the urine)
• Frequent urination, especially at night
• Loss of appetite
• Dry or itchy skin
• Swelling around the eyes, hands, feet, ankles, or belly

When To Seek Emergency Care

In some cases, kidney function can suddenly worsen and become an emergency. Get medical care right away if you have:

• Frequent muscle cramps
• Hiccups that don’t stop
• Trouble concentrating
• Severe fatigue
• Changes in urination (peeing too much or too little)
• Dizziness

What Are Possible Complications of Renal Parenchymal Disease?

Over time, the damage to the renal parenchyma can lead to health problems throughout the body. As your kidneys lose the ability to filter blood, you may develop complications such as:

• Anemia — Low red blood cell count
• Hyperkalemia — Too much potassium in the blood
• Hyperphosphatemia — High phosphate levels in the blood
• Metabolic acidosis — Excess acid in the blood
• Gout — Painful buildup of uric acid in the joints
• Osteoporosis — Weak bones that break more easily
• A weakened immune system, leading to more infections

Working with your doctor or a nephrologist (kidney doctor) can help prevent or manage these complications.

How Is Renal Parenchymal Disease Treated?

Healthcare providers treat renal parenchymal disease based on the underlying cause and severity of kidney damage.

Dietary and Lifestyle Changes

Healthy habits can help protect your kidneys. Your doctor or a dietitian can guide you in creating a kidney-friendly eating plan.

People with renal parenchymal disease often need to limit foods that are high in potassium, sodium (salt), and phosphorus. These minerals can build up in the blood when kidneys aren’t working well. You may also need to cut back on protein.

Your doctor might also recommend:

• Getting regular exercise
• Avoiding smoking and tobacco
• Keeping blood pressure and sugar levels in healthy ranges to prevent further damage

Medications

Depending on the cause of your renal parenchymal disease, your doctor may prescribe corticosteroids to reduce inflammation and slow kidney damage, especially in the glomeruli. Other immunosuppressants may be used if an autoimmune disease is causing kidney damage.

Dialysis

If your kidneys stop working, you may need dialysis, a treatment that filters waste and fluid from your blood. People with chronic kidney failure usually need lifelong dialysis unless they receive a transplant.

Kidney Transplant

Some people with advanced disease may need a kidney transplant. This surgery replaces a damaged kidney with a healthy one from a donor, either living or deceased. After a kidney transplant, you’ll need to take immunosuppressant medications to prevent your body from rejecting the new kidney.

What Is the Life Expectancy With Renal Parenchymal Disease?

Life expectancy with renal parenchymal disease depends on how severe the condition is and how well it’s managed. Working closely with a nephrologist to slow kidney damage can help you live longer and feel better. If renal parenchymal disease leads to kidney failure and isn’t treated, it can be life-threatening.

The average life expectancy of a person on dialysis for kidney failure is five to 10 years. With a successful kidney transplant and good overall health, life expectancy may reach 20 to 30 years.

Talk With Your Doctor

Treating renal parenchymal disease as early as possible can help slow kidney damage, prevent complications, and delay or prevent kidney failure. If you notice symptoms, tell your doctor right away.

If you live with a medical condition like high blood pressure or diabetes, keep up with regular checkups. Although renal parenchymal disease isn’t always preventable, managing your overall health can lead to early detection and better kidney health over time.

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