If you or a loved one is living with multiple myeloma, you might worry about the cancer spreading. In some cases, people with the condition may experience symptoms that suggest problems with their central nervous system (CNS), which includes the brain and spinal cord. Could symptoms like confusion or cognitive decline be related to multiple myeloma?

Although it’s rare for multiple myeloma to reach the brain, the condition can affect cognitive functions such as thinking, memory, and problem-solving. It can also influence your ability to perceive sensations like touch, temperature, and pain. Additionally, multiple myeloma can affect your mood due to physical symptoms, treatment side effects, uncertainty, isolation, and changes in your daily life.

Keep reading to learn more about how multiple myeloma can affect the brain and nerves.

Can Multiple Myeloma Cells Spread to the Brain?

Multiple myeloma can spread to the brain, but it’s very rare. About 0.7 percent of people diagnosed with the condition develop problems due to multiple myeloma cells invading the brain. People with multiple myeloma typically experience headaches, dizziness, and vision issues. Occasionally, they may have signs and symptoms similar to those of a stroke.

You may have been told that multiple myeloma is causing lesions on your skull. Although the condition commonly spreads to the skull, it’s still unlikely to affect your brain directly.

However, you should always talk to your oncologist or someone on your health care team if you notice new or worsening symptoms. Identifying the cause of these symptoms is crucial for improving your quality of life and overall well-being, whether or not they’re related to multiple myeloma.

Ways Multiple Myeloma Can Affect the Central Nervous System

Most people with multiple myeloma won’t develop tumors in their brains, but there are other ways your blood cancer might be causing cognitive or neurological symptoms.

Potential neurological or cognitive symptoms of multiple myeloma include:

• Muscle weakness
• Numbness
• Dizziness
• Confusion
• Slurred speech
• Difficulty moving one side of the body
• Prickling sensation
• Depression
• Anxiety
• Cognitive decline

Multiple Myeloma in the Spine

If you experience numbness or muscle weakness without another cause, you may have multiple myeloma in your spine. The condition can create destructive spots in your bones, known as lytic lesions. These spots can make your spine bones so weak that they may collapse onto each other, sometimes causing pressure on the spinal cord, a condition called spinal cord compression.

In some rare cases, the excessively high numbers of plasma cells seen in multiple myeloma can come together and create a mass on the spinal cord, which is called a plasmacytoma. Pressure on nerves of the spine can cause back pain and paresthesia (altered sensation in the hands and feet).

If you notice these symptoms, get emergency medical treatment right away because severe cases can result in permanent paralysis.

Multiple Myeloma, Multiple Myeloma Treatments, and the Nerves

Multiple myeloma and its treatments can both affect the nerves. These effects on the nerves can lead to various symptoms, including tingling, numbness, and weakness in different parts of the body.

In multiple myeloma, your body may produce abnormal antibodies (immune proteins) that cause nerve damage, resulting in numbness or weakness. You may also experience a prickling sensation or a feeling of “pins and needles.” These sensations are referred to as peripheral neuropathy.

Neuropathy may range from mild to severe. One member of MyMyelomaTeam said, “Today is a good day! Only numb feet from neuropathy, but no pain.”

If you’re experiencing peripheral neuropathy, your oncology team may be able to help you manage these uncomfortable symptoms.

Multiple myeloma tumors can also put pressure directly on nerves, causing similar symptoms. One team member described this, saying, “About six weeks ago, my right lower lip and chin became numb. My oncologist called last week to say I have bone lesions on both sides of my mandible, skull, upper spine, and sternum.”

Treatment for multiple myeloma can affect nerve health as well. Lenalidomide (Revlimid) is known to worsen peripheral neuropathy as a side effect. Additionally, certain drugs are believed to be potential causes of neuropathy in some people, including:

• Bortezomib (Velcade)
• Ixazomib (Ninlaro)
• Pomalidomide (Pomalyst)
• Thalidomide (Thalomid)

Hyperviscosity in the Blood

Because multiple myeloma causes abnormalities in the way your plasma cells produce antibodies, you can sometimes end up with more immune proteins in your blood than your body can handle. This can cause hyperviscosity — thicker-than-normal blood. With hyperviscosity, your body has to work harder than usual to move blood around your body. Blood that’s too thick with abnormal proteins can cause a shortage of blood in your brain or other parts of your CNS.

People who develop hyperviscosity develop symptoms similar to those of having a stroke, such as slurred speech or trouble moving one side of their bodies. They may also become dizzy or confused. If you or your loved one has symptoms like this, it’s time to see a doctor as soon as possible. A process called plasmapheresis can remove the proteins from the blood and should help temporarily.

Multiple Myeloma and Mental Health

Multiple myeloma can cause mental health issues like depression and anxiety. Worrying about cancer can worsen make depression and anxiety. One member said, “I’m feeling depressed. I have to go in for a bone marrow test and PET scan. I’m worried my cancer is coming back.”

Another noted, “I’m feeling a little anxious about the results of next week’s blood draw.”

Pain (including bone pain) from multiple myeloma or associated treatments is also a risk factor for both depression and anxiety.

It’s important to treat depression and anxiety. When someone with cancer faces mental health challenges, they may be less likely to stick with their treatment. There are many ways to treat depression and anxiety and improve your quality of life with multiple myeloma.

Cognitive Problems and Multiple Myeloma

People with some forms of cancer, including multiple myeloma, commonly experience a decline in cognitive functions. Researchers don’t know whether this decline is caused by the cancer itself, cancer treatment, or if it occurs alongside the cancer in older people because they’re more likely to experience cognitive decline anyway. The longer someone lives with multiple myeloma, the more likely they are to experience this decline.

Cognitive skills include:

• Paying attention
• Planning
• Multitasking
• Remembering short-term information
• Following instructions

If you notice symptoms of cognitive decline in yourself or your loved one, talk to a doctor soon. There may be treatments available or ways to counteract the negative effects. They’ll know where to direct you and how to help you get the most out of any treatment you decide to try.

Keep Your Doctor in the Loop

If you experience any of the symptoms mentioned above or any other new or worsening symptoms you think might be related to multiple myeloma, talk to your doctor right away. Your quality of life is important, and your medical team can help.

Talk With Others Who Understand

On MyMyelomaTeam — the online social network for people with multiple myeloma and their loved ones — more than 20,000 members come together to ask questions, give advice, and share their stories with others who understand life with multiple myeloma.

Are you wondering if multiple myeloma can affect the brain? Share your experience in the comments below, or start a conversation by posting on your Activities page.