What Is Myeloma Kidney Failure? A Comprehensive Guide

What Is Kidney Failure or Renal Impairment in Multiple Myeloma?

The kidneys are crucial for filtering waste from the blood, regulating fluid balance, and producing hormones. When the kidneys are unable to perform these functions at full capacity, it's called renal impairment or kidney failure. In the context of multiple myeloma, when this kidney dysfunction occurs, it is referred to as myeloma kidney failure, kidney disease multiple myeloma, myeloma kidney renal failure, or even just myeloma kidney.

Renal impairment is a key component of the IMWG's CRAB diagnostic criteria for active myeloma, defined as creatinine clearance below 40 mL per minute or serum creatinine above 2 mg/dL due to myeloma. Recognizing the signs and understanding the progression of myeloma kidney failure is vital for everyone involved in the patient's care.

How Does Myeloma Damage the Kidneys? 

In multiple myeloma, the primary cause of myeloma kidney damage often stems from the toxic effects of abnormal proteins called monoclonal light chains. These proteins, produced by myeloma cells, can harm the delicate filtering units (glomeruli) and small tubes (renal tubules) within the kidneys. In simple terms, myeloma cells make faulty protein pieces (monoclonal light chains) that can build up and damage the tiny filters and tubes in the kidneys by clogging them, making it harder for the kidneys to clean blood properly.

As noted in the IMF Patient Handbook, these light chains can build up to the point of blocking kidney tubules, causing reduced kidney function.

Cast Nephropathy

Cast nephropathy myeloma is the predominant type of kidney impairment affecting patients with MM. The condition arises when free light chains 'clog' the renal tubules, forming blockages (casts). These obstructions negatively impact the kidney's filtering functions, resulting in inflammation and kidney dysfunction.

Other Factors Contributing to Kidney Issues in Myeloma

While monoclonal light chains are the main culprit, other factors can contribute to or worsen myeloma kidney failure.

These additional factors include:

• Existing health conditions: Diabetes, arterial disease, and complications from infections
• Lifestyle factors: Including smoking and obesity
• Hypercalcemia: High blood calcium levels resulting from bone breakdown caused by myeloma
• Dehydration: Insufficient fluid intake
• Nephrotoxic drugs: Certain antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and some myeloma therapies that are processed by the kidneys
• Contrast agents: Used in imaging studies, like gadolinium, can negatively impact kidney function
   

Factors that can increase the risk of developing myeloma kidney disease include advancing age, the development or worsening of other medical problems, a high multiple myeloma disease burden, and cumulative toxicity from prior treatments.

Monitoring Kidney Health: Essential Tests for Myeloma Patients

Regular monitoring is crucial for detecting and managing myeloma kidney damage. At diagnosis and during disease assessment, your healthcare team will typically order the following tests:

• Serum creatinine: A blood test measuring kidney function.
• Electrolytes: Blood tests that check the balance of essential minerals in your body.
• Serum free light chain assay (Freelite test): A blood test measuring the levels of free light chains, which are often implicated in renal failure myeloma.
• Urine protein electrophoresis (UPEP) from a 24-hour urine collection: This test helps identify and quantify abnormal proteins in the urine. It may be routinely conducted.

Treating Kidney Failure in Multiple Myeloma

Effectively treating the underlying multiple myeloma is often the best way to reverse myeloma kidney damage. In some cases, kidney impairment can improve, even for patients who experience kidney failure or require dialysis. However, long-term kidney failure may not always be reversible.

• Dialysis: For patients requiring dialysis, anti-myeloma therapy combined with high-cutoff hemodialysis membranes can help remove free light chains and potentially reverse renal impairment myeloma. If high-cutoff hemodialysis is unavailable, plasma exchange may be considered.
• Myeloma therapies for kidney impairment: Velcade® (bortezomib) based regimens are a standard of care for patients with myeloma and renal impairment. These can be safely combined with several other anti-myeloma agents to control the disease. Other proteasome inhibitors like Kyprolis® (carfilzomib) or Ninlaro® (ixazomib) may also be used.
• Dose adjustments: Medications like Revlimid® (lenalidomide), which are excreted by the kidneys, require dose adjustments based on the degree of myeloma kidney damage to ensure safety and efficacy.

Supportive Care and Management for Kidney Health

Patients with suspected myeloma kidney failure should receive crucial supportive care.

This includes:

• Hydration: Intravenous (IV) fluids are often administered to maintain hydration.
• Rapid treatment for hypercalcemia: Swift management of high calcium levels.
• Bone-modifying agents: Clinical trials indicate that XGEVA® (denosumab) may be safer than Zometa (zoledronic acid) for treating myeloma-related hypercalcemia in patients with severe renal impairment myeloma (creatinine clearance < 30 mL per minute). American Society of Clinical Oncology (ASCO) guidelines indicate that XGEVA® may be preferable to bisphosphonates in patients with kidney damage.

What Patients Can Do

Proactive steps for patients with myeloma kidney disease:

• Communicate with your team: Report any new or worsening symptoms to your healthcare provider immediately.
• Adhere to treatment: Follow your prescribed myeloma treatment plan diligently, as treating the myeloma often improves kidney function.
• Stay hydrated: Discuss appropriate fluid intake with your doctor.
• Manage other conditions: Work with your care team to manage conditions like diabetes or high blood pressure.
• Review medications: Consult your doctor or pharmacist before taking any new medications, including over-the-counter drugs or supplements.
• Dietary considerations: Ask your doctor or a renal dietitian if any dietary adjustments are recommended.
• Seek specialist care: Your doctor may recommend consulting a nephrologist for specialized management.

Finding Support and Staying Informed

The International Myeloma Foundation (IMF) is dedicated to empowering patients, care partners, and healthcare professionals by providing education, support, and advocacy worldwide.

We encourage you to utilize our resources for additional information or reach out to us at 1-800-452-CURE (2873).