Common Symptoms of Light Chain Multiple Myeloma
Common symptoms of Light Chain Multiple Myeloma are often referred to by the acronym CRAB:
| C – Calcium elevation: High calcium levels in the blood (hypercalcemia) can be a result of bone destruction and lead to symptoms such as excessive thirst, frequent urination, nausea, confusion, and constipation. |
| R – Renal (kidney) dysfunction: The abnormal light chain proteins can clog the kidneys, leading to kidney damage or failure. Symptoms include weakness, shortness of breath, and leg swelling. |
| A – Anemia: The overgrowth of cancerous plasma cells in the bone marrow can crowd out healthy blood cells, including red blood cells. Anemia can cause fatigue, weakness, dizziness, and shortness of breath. |
| B – Bone lesions: The myeloma cells can damage bones, leading to bone pain (especially in the spine, ribs, and hips), bone weakness, and an increased risk of fractures. |
Light Chain Multiple Myeloma (LCMM) is a rare subtype of multiple myeloma, a cancer of the plasma cells in the bone marrow. Unlike typical multiple myeloma, LCMM is marked by the overproduction of free light chains, which are small parts of antibodies that circulate in the bloodstream and can harm organs, especially the kidneys. Recognizing symptoms early is essential for timely diagnosis and treatment.
This guide covers the most common symptoms of LCMM, how they develop, and why getting medical help early can save lives.
📌 Table of Contents
- What Is Light Chain Multiple Myeloma?
- Why Symptoms Can Be Difficult to Detect
- Common General Symptoms
- Kidney-Related Symptoms
- Bone and Skeletal Symptoms
- Blood and Immune System Symptoms
- Nervous System Involvement
- Symptoms Related to Light Chain Deposition Disease (LCDD)
- Amyloidosis-Related Symptoms
- Rare and Advanced Symptoms
- How Symptoms Vary by Patient
- When to See a Doctor
- Final Thoughts
1. What Is Light Chain Multiple Myeloma?
Light Chain Multiple Myeloma (LCMM) is a type of multiple myeloma where plasma cells produce only light chains, not the full immunoglobulin antibody. These free light chains—either kappa or lambda—are filtered through the kidneys. If produced in excess, they can overwhelm the kidneys, causing renal failure, bone lesions, anemia, and other health issues.
2. Why Symptoms Can Be Difficult to Detect
One reason LCMM is diagnosed late is that its early symptoms are nonspecific and can look like more common issues. Symptoms such as fatigue, back pain, and mild kidney problems might not raise concerns right away. Additionally:
3. Common General Symptoms
Let’s look at general symptoms that are shared with other types of multiple myeloma and often appear in the early or mid-stages of LCMM:
🟣 Fatigue
Fatigue is one of the first and most common symptoms, caused by:
- Anemia (low red blood cell count)
- Poor oxygen delivery to tissues
- Chronic inflammation
- Kidney issues (leading to toxin buildup)
- Patients often describe it as persistent tiredness that doesn’t get better with rest.
🟣 Weakness
Muscle weakness in the body can result from:
- Anemia
- Low calcium or electrolyte imbalances
- Protein-energy malnutrition
- Steroid use in treatment
4. Kidney-Related Symptoms
Since light chains are mostly cleared by the kidneys, they can cause serious renal damage, which may be the first and only noticeable sign of LCMM.
🟡 Decreased Urine Output
As light chains block kidney tubules (cast nephropathy), patients may notice:
- Reduced urination
- Foamy urine (a sign of proteinuria)
- Trouble emptying the bladder
🟡 Swelling in Legs and Ankles
This is due to fluid retention from kidney problems.
🟡 High Creatinine and Urea
Blood tests may show:
- Elevated creatinine
- High blood urea nitrogen (BUN)
- Abnormal electrolyte levels (especially potassium and calcium)
🟡 Nausea and Loss of Appetite
As waste products build up, gastrointestinal symptoms may arise.
🟡 Confusion or Drowsiness
Uremia (toxic waste in the blood) can disrupt brain function, leading to mental clouding or changes in consciousness.
5. Bone and Skeletal Symptoms
Plasma cells in LCMM invade bone marrow and create osteolytic lesions, causing issues in the bones.
🔵 Bone Pain
- Most common in the lower back, ribs, hips, and skull
- Worsens with physical activity
- Can be dull or sharp
- Sometimes misdiagnosed as arthritis or injury
🔵 Pathologic Fractures
Even minor injuries can cause:
- Spine compression fractures
- Hip and femur breaks
- Loss of height or hunched posture
🔵 Hypercalcemia (High Calcium)
Damage to bones releases calcium into the bloodstream, leading to:
- Nausea and vomiting
- Excessive thirst and urination
- Constipation
- Confusion or tiredness
6. Blood and Immune System Symptoms
🔴 Anemia
The most common blood-related symptom:
- Happens due to overcrowding in the bone marrow
- Causes fatigue, dizziness, and shortness of breath
- Often found by low hemoglobin in lab tests
🔴 Frequent Infections
- Plasma cells make non-functional antibodies, weakening the immune system
- Increases the risk of pneumonia, urinary tract infections, sepsis
- Patients may experience regular fevers, cough, or general malaise
🔴 Easy Bruising or Bleeding
This occurs due to low platelet counts or problems with clotting.
7. Nervous System Involvement
Nerve damage can happen from:
- Amyloid deposits
- Calcium imbalances
- Compression from bone lesions
🟢 Peripheral Neuropathy
- Tingling, numbness, or burning feeling in hands and feet
- Difficulty balancing or coordinating
- Often worsens with chemotherapy (like bortezomib)
🟢 Confusion or Cognitive Changes
Caused by:
- Uremia
- Hypercalcemia
- Amyloidosis
- Side effects of medications
8. Symptoms Related to Light Chain Deposition Disease (LCDD)
In some LCMM patients, light chains build up in organs such as the heart, liver, or kidneys, resulting in Light Chain Deposition Disease (LCDD). Symptoms include:
- High blood pressure
- Foamy or bloody urine
- Heart rhythm issues
- Swelling
- Liver enlargement
9. Amyloidosis-Related Symptoms
If light chains misfold into amyloid proteins, it can cause AL amyloidosis, which shares features with LCMM but presents distinct symptoms:
💠Cardiac Involvement
- Restrictive cardiomyopathy
- Shortness of breath
- Irregular heartbeat
- Low blood pressure when standing (orthostatic hypotension)
💠Gastrointestinal Symptoms
- Diarrhea or constipation
- Feeling full quickly
- Unexplained weight loss
💠Skin and Joint Issues
- Easy bruising
- Purple patches around the eyes (raccoon eyes)
- Joint stiffness
10. Rare and Advanced Symptoms
In the late stages or aggressive forms of LCMM, you may also see:
âš« Myeloma Kidney (Cast Nephropathy)
Severe kidney damage from light chain buildup—may need dialysis.
âš« Bone Marrow Failure
Extremely low levels of red cells, white cells, and platelets, leading to pancytopenia.
âš« Plasma Cell Leukemia
A rare and fast-moving form where plasma cells enter the bloodstream—usually with serious systemic symptoms.
11. How Symptoms Vary by Patient
Not all patients will have the same symptoms. Factors that affect symptom presentation include:
- Extent of kidney involvement
- Presence of amyloidosis or LCDD
- Stage at diagnosis
- Overall health and other health issues
Some may have silent kidney damage, while others may first show fractures or severe infections. This variety makes early screening even more important.
12. When to See a Doctor
You should seek medical help if you experience:
- Ongoing fatigue or unexplained weakness
- Bone pain or fractures from minor injuries
- Sudden swelling in legs or face
- Reduced urine output or foamy urine
- Frequent infections or prolonged fevers
- Numbness or tingling in hands and feet
- Unexplained weight loss
- A hematologist or oncologist can run blood tests, urine tests, imaging, and biopsies to confirm diagnosis and find the best treatment options.
13. Final Thoughts
Light Chain Multiple Myeloma is a serious but treatable condition. Knowing its early warning signs—especially fatigue, kidney issues, bone pain, and frequent infections—can lead to quicker diagnosis and better results. If caught early, modern treatments like proteasome inhibitors, stem cell transplants, and supportive kidney therapies can greatly extend life expectancy and enhance quality of life.