Cancer, Paraneoplastic Syndromes

Certain cancers can cause unusual problems in the nervous system. This happens when the body's immune system, which normally fights cancer, mistakenly attacks healthy parts of the brain, spinal cord, nerves, or muscles. These problems are called paraneoplastic syndromes.

They aren't just limited to the nervous system. These syndromes can also affect other parts of the body, like the hormone-producing glands, skin, blood, and joints.

The effects on the nervous system depend on which part is attacked. This can lead to difficulties with movement, balance, how you feel things, your memory, thinking, and even sleep.

In some cases, treatment for the cancer and the immune system can help reverse the damage. However, sometimes the damage is permanent.

Treating the cancer and other therapies can help stop further damage and improve symptoms, making it easier to live with the condition.

Paraneoplastic syndromes of the nervous system are a group of conditions that affect the nervous system and can develop quickly, sometimes within days or weeks. These symptoms often appear before a cancer is diagnosed. The symptoms depend on which part of the nervous system is affected.

Common symptoms include:

• Movement problems: Difficulty walking, maintaining balance, loss of muscle coordination or tone, and weakness. This can include problems with fine motor skills like picking up small objects.
• Swallowing and speech issues: Difficulty swallowing, slurred speech, or stuttering.
• Cognitive problems: Memory loss, trouble thinking clearly, and confusion.
• Vision changes: Problems with vision, such as double vision or other changes.
• Sleep disturbances: Difficulty sleeping.
• Neurological events: Seizures, hallucinations, and uncontrolled movements.

Different Types of Paraneoplastic Syndromes:

These syndromes affect different parts of the brain and nervous system, leading to various symptoms.

• Cerebellar Degeneration (Cerebellar Ataxia): This affects the part of the brain that controls balance and muscle coordination. Symptoms include trouble walking, loss of coordination in arms and legs, problems with posture, dizziness, nausea, uncontrolled eye movements, double vision, and difficulty speaking or swallowing.

• Limbic Encephalitis: This affects an area of the brain involved in emotions, behavior, and memory. Symptoms might include mood swings, personality changes, memory loss, seizures, hallucinations, and drowsiness.

• Encephalomyelitis: This involves inflammation of the brain and spinal cord, leading to a wide range of symptoms depending on the area affected.

• Opsoclonus-Myoclonus: This condition causes rapid, uncontrolled eye movements and muscle jerks in the arms, legs, and torso, often due to problems with the cerebellum.

• Stiff Person Syndrome: This causes severe, worsening muscle stiffness, mainly in the spine and legs, along with painful muscle spasms.

• Myelopathy: This involves damage to the spinal cord. Symptoms vary based on the location of the damage, and may include changes in bladder and bowel control, and weakness or numbness in parts of the body. Neck injuries can result in serious arm and leg problems.

• Lambert-Eaton Myasthenic Syndrome (LEMS): This syndrome affects the communication between nerves and muscles, causing muscle weakness, especially in the legs and pelvis. Other symptoms include fatigue, difficulty swallowing and talking, eye movement problems, double vision, dry mouth, and erectile dysfunction. LEMS is often linked to lung cancer.

• Myasthenia Gravis: Similar to LEMS, this condition also disrupts nerve-muscle communication. It causes weakness and rapid fatigue of voluntary muscles, including those in the face, eyes, arms, and legs, as well as the muscles used for chewing, swallowing, speaking, and breathing. In paraneoplastic cases, it's often associated with a thymus gland cancer (thymoma).

• Neuromyotonia (Isaacs' Syndrome): This condition involves overly active nerve impulses that cause muscle twitching, rippling (looking like a "bag of worms"), worsening stiffness, cramps, slowed movements, and other muscle problems.

• Peripheral Neuropathy: This happens when the nerves that carry messages to and from the brain and spinal cord are damaged. This damage can cause pain and changes in sensation in any part of the body.

It's important to note that these are just examples, and the specific symptoms and combination of symptoms can vary greatly depending on the individual. If you experience any of these symptoms, it's crucial to see a doctor for proper diagnosis and treatment.

Paraneoplastic syndromes affect the nervous system, often mimicking other health problems. These symptoms can be similar to those of cancer itself, its side effects, or even some cancer treatments. Examples include issues like muscle weakness, numbness, or problems with vision or balance.

If you're experiencing any of these nervous system symptoms, it's crucial to see a doctor right away. Early detection is key. Prompt diagnosis and treatment can help manage the cancer and prevent further harm to your nervous system.

Paraneoplastic neurological syndromes aren't directly caused by cancer itself, or by the cancer spreading to other parts of the body. They're also not due to other problems like infections or side effects of cancer treatment. Instead, these syndromes happen alongside cancer because of how the body's immune system reacts.

Scientists think these syndromes happen because the body's immune system, which is designed to fight cancer, mistakenly attacks healthy nerve cells. The immune system's weapons, such as antibodies and special white blood cells called T cells, are usually trained to target cancer cells. But in these syndromes, these same immune system components mistakenly attack healthy nerve cells in the brain and spinal cord, along with other parts of the nervous system.

Some cancers can be linked to problems in the nervous system. This is called a paraneoplastic syndrome. While any cancer could be involved, it's more common with cancers of the lungs, ovaries, breasts, testes, or lymph nodes (part of the lymphatic system). In simpler terms, these particular cancers are more likely to cause these nervous system problems.

Diagnosing Paraneoplastic Neurological Disorders

Paraneoplastic neurological disorders happen when cancer affects the nervous system. To figure out if this is the case, doctors will likely use a combination of tests. These tests help them understand what's happening and rule out other possible causes.

Physical Exams and Neurological Assessments:

Your doctor, or a neurologist (a doctor specializing in the nervous system), will perform a thorough physical exam. This includes checking your:

• Reflexes: The automatic responses your muscles have.
• Muscle strength: How much force your muscles can exert.
• Muscle tone: The firmness or stiffness of your muscles.
• Senses: Touch, vision, and hearing are assessed.
• Coordination and balance: Your ability to move and maintain your posture.
• Mood and memory: Your mental state.

Laboratory Tests:

• Blood tests: These are used to look for specific antibodies (proteins produced by the immune system) that are often linked to paraneoplastic disorders. Blood tests can also check for infections, hormone imbalances, or problems with how your body processes nutrients (metabolic issues).
• Spinal tap (lumbar puncture): A small amount of cerebrospinal fluid (CSF), the liquid that cushions the brain and spinal cord, is collected. A doctor or nurse inserts a needle into your lower back. This test can also reveal antibodies related to paraneoplastic disorders, sometimes even when blood tests don't show them. If the antibodies are found in both the CSF and blood, it strongly suggests a link to cancer.

Imaging Tests:

Doctors may use different imaging techniques to look for tumors or other issues:

• CT (Computed Tomography): This is a type of X-ray that creates detailed cross-sectional images of your body.
• MRI (Magnetic Resonance Imaging): This uses magnetic fields and radio waves to create detailed images of organs and tissues.
• PET (Positron Emission Tomography): This method uses radioactive substances to create images that can show how tissues are working and can help detect tumors. PET scans are especially useful for finding tumors and detecting changes in the brain related to seizures.
• PET/CT: Combining PET and CT scans can increase the chances of finding smaller cancers, which are sometimes present in people with paraneoplastic neurological disorders.

What if no tumor is found?

If tests don't show a tumor or other cause, it's possible the tumor is still too small to be detected, or the immune system's reaction to the tumor might be masking its presence. In these cases, your doctor might recommend regular follow-up tests (every 3 to 6 months) to monitor for changes and potential tumor development.

Managing Paraneoplastic Syndromes in Cancer Patients

When you have cancer, your healthcare provider might prescribe medicines in addition to cancer treatments like chemotherapy. These extra medications aim to prevent your immune system from harming your nervous system. This is important because some cancers can trigger a reaction where the immune system mistakenly attacks healthy nerves and muscles. This reaction is called a paraneoplastic syndrome.

Different medicines can help, depending on the specific type of paraneoplastic syndrome and its symptoms:

• Anti-seizure medications: If the syndrome causes electrical problems in your brain, these medicines can help control seizures.
• Medications to improve nerve-muscle communication: These medicines can improve symptoms if the syndrome affects how your nerves and muscles talk to each other. Some medicines help your nerves release the chemical messengers that tell your muscles what to do. Other medicines, like pyridostigmine (sometimes called Mestinon), prevent the breakdown of these important chemical messengers.

Besides medicines, there are other treatments:

• Plasmapheresis: This procedure uses a special machine to separate the liquid part of your blood (plasma) from your blood cells. The plasma contains antibodies that are attacking your nerves. The machine removes the harmful plasma and replaces it with healthy fluids. Your red blood cells, white blood cells, and platelets are returned to you.
• Intravenous immunoglobulin (IVIg): This treatment uses antibodies from healthy blood donors. High doses of these antibodies help your body get rid of the harmful antibodies attacking your nerves.

Important Note: Some cancer treatments, called immune checkpoint inhibitors, can make paraneoplastic syndromes worse. These treatments help your immune system fight the cancer, but they can also make the immune system attack your nervous system more aggressively. So, if you have a paraneoplastic syndrome, it's crucial to discuss these treatments with your doctor.

Managing the Effects of the Syndrome:

If a paraneoplastic syndrome has caused problems like weakness or trouble speaking, these therapies can help:

• Physical therapy: Specific exercises can help you regain strength and movement.
• Speech therapy: A speech therapist can help you improve your ability to speak and swallow if the syndrome affects these functions.

Support and Education:

Learning about your condition and coping with its challenges can be very helpful. Your healthcare team can provide information and support. Talking with your doctor about any questions or concerns is essential. Knowing more about your condition can help you make informed choices about your care.

Support groups can connect you with others who understand what you're going through. These groups can be helpful in person or online.