To diagnose paraneoplastic syndrome of the nervous system, you may need a physical exam and blood tests. You also may need imaging tests or a spinal tap, also known as a lumbar puncture.

Because paraneoplastic syndromes of the nervous system are associated with cancer, you may need certain cancer screening tests based on your age.

Clinical exam

Your healthcare professional or a neurologist conducts a general physical and a neurological exam. You're asked questions and your healthcare professional conducts simple tests in the office to judge your:

  • Reflexes.
  • Muscle strength.
  • Muscle tone.
  • Sense of touch.
  • Vision and hearing.
  • Coordination.
  • Balance.
  • Mood.
  • Memory.

Laboratory tests

Laboratory tests may include:

  • Blood tests. You may have blood drawn for a number of tests, including tests to pinpoint antibodies commonly associated with paraneoplastic syndromes of the nervous system. Other tests may help diagnose an infection, a hormone condition or a condition in processing nutrients, known as a metabolic condition.
  • Spinal tap, also known as a lumbar puncture. During a spinal tap, a sample of cerebrospinal fluid (CSF) is taken. CSF cushions your brain and spinal cord. A neurologist or specially trained nurse inserts a needle into your lower spine to remove a small amount of CSF for analysis.

    Sometimes paraneoplastic antibodies are found in CSF but they can't be seen in your blood. If these antibodies are found in both your CSF and blood, it provides strong evidence that a paraneoplastic syndrome is causing the symptoms.

Imaging tests

Imaging tests are used to find a tumor or other causes of your symptoms. One or more of the following tests may be used:

  • Computerized tomography (CT) is a specialized X-ray technology that produces thin, cross-sectional images of tissues.
  • Magnetic resonance imaging (MRI) uses a magnetic field and radio waves to create detailed cross-sectional or 3D images of your body's tissue.
  • Positron emission tomography (PET) uses radioactive compounds injected into your bloodstream to produce cross-sectional or 3D images of the body. PET scans can be used to identify tumors, measure metabolism in tissues, show blood flow and locate brain changes related to seizures.
  • PET plus CT, a combination of PET and CT, may help find small cancers. Small cancers are common in people who have paraneoplastic neurological disorders.

If tests don't find a cancerous tumor or another cause of your symptoms, you might have a tumor that is still too small to find. The tumor may be causing a powerful response from the immune system that is keeping it very small. Your healthcare professional likely will recommend that you have follow-up tests every 3 to 6 months until a cause is found.


Treatment of paraneoplastic syndromes of the nervous system involves treating the cancer. Sometimes treatment also involves suppressing the immune response that's causing your symptoms. Your treatment depends on the type of paraneoplastic syndrome you have. It may include the following options.


In addition to cancer treatments, such as chemotherapy, your healthcare professional may prescribe one or more medicines. These medicines can help stop your immune system from damaging your nervous system:

  • Corticosteroids, such as prednisone, inhibit inflammation. These medicines can have serious long-term side effects. Corticosteroids may lead to type 2 diabetes, high blood pressure, high cholesterol and weakened bones, known as osteoporosis. The medicine also can cause other conditions.
  • Immunosuppressants slow the production of disease-fighting white blood cells. Side effects include an increased risk of infections. These medicines include azathioprine (Imuran, Azasan), mycophenolate (CellCept), rituximab (Rituxan, Riabni, others) and cyclophosphamide (Cytoxan). They also include methotrexate (Trexall, Xatmep, others), cyclosporine (Gengraf, Neoral, others), and tacrolimus (Astagraf XL, Envarsus XR, others). Newer medicines include eculizumab (Soliris), ravulizumab (Ultomiris) and efgartigimod (Vyvgart).

Depending on the type of paraneoplastic syndrome and symptoms, other medicines may include:

  • Anti-seizure medicines, which may help control seizures associated with syndromes that cause electrical instability in the brain.
  • Medicines to enhance nerve-to-muscle transmission. These medicines may improve symptoms of syndromes that affect muscle function. Some medicines enhance the release of a chemical messenger that transmits a signal from nerve cells to muscles. Other drugs, such as pyridostigmine (Mestinon, Regonol), prevent the breakdown of these chemical messengers.

Other medical treatments

Other treatments that may improve symptoms include:

  • Plasmapheresis. This process separates the fluid part of the blood, called plasma, from your blood cells with a device known as a blood cell separator. The plasma, which contains the antibodies causing symptoms, is discarded and replaced with other fluids. Your red and white blood cells, along with your platelets, are returned to your body.
  • Intravenous immunoglobulin (IVIg). Immunoglobulin contains healthy antibodies from blood donors. High doses of immunoglobulin speed up the destruction of the damaging antibodies in your blood.

If you have a paraneoplastic neurologic syndrome, it's generally recommended that you don't use certain cancer medicines called immune checkpoint inhibitors. These treatments activate the immune system to fight cancer. While this can help destroy the cancer, it also can lead to worsening of the immune attack on the nervous system.

Other therapies

Other therapies may be helpful if a paraneoplastic syndrome has caused disability:

  • Physical therapy. Specific exercises may help you regain some lost muscle function.
  • Speech therapy. A speech therapist can help you relearn the necessary muscle control if you are having trouble speaking or swallowing.

Coping and support

Many people with cancer benefit from education and resources designed to improve coping skills. If you have questions or would like guidance, talk with a member of your healthcare team. The more you know about your condition, the better you're able to participate in decisions about your care.

Support groups can put you in touch with others who have faced the same challenges you're facing. If you can't find an appropriate support group where you live, you might find one on the internet.

Preparing for your appointment

Most people with paraneoplastic syndromes of the nervous system experience symptoms before being diagnosed with cancer.

Therefore, you're likely to start by seeing your healthcare professional about your symptoms. You may be referred to a specialist in nervous system disorders, known as a neurologist, or a cancer specialist, known as an oncologist.

What you can do

  • Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
  • Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
  • Write down key personal information, including any major stresses or recent life changes.
  • Make a list of all medicines, vitamins or supplements that you're taking.
  • Consider taking a family member or friend along. Sometimes it can be hard to remember all the information provided during an appointment. Someone who comes with you may remember something that you missed or forgot.
  • Write down questions to ask your healthcare professional.
  • Bring your images on a disc to hand to your healthcare professional at the appointment.

Your time with your healthcare professional may be limited. Preparing a list of questions can help you make the most of your time together. List your questions from most important to least important in case time runs out. Some basic questions to ask include:

  • What's the most likely cause of my symptoms?
  • What diagnostic tests will you order? Do I need to prepare for these tests?
  • Which specialists will I need to see?
  • How soon am I likely to complete the tests and get results?
  • What are you looking for in the tests?
  • What conditions are you trying to rule out?

What to expect from your doctor

Your healthcare professional may ask the following questions:

  • Have you had any muscle weakness or lack of coordination?
  • Have you had any different or involuntary muscle movements?
  • Have you had any trouble with your vision?
  • Do you have trouble chewing, swallowing or speaking?
  • Do you have any trouble breathing?
  • Have you had any seizures? How long have they lasted?
  • Have you experienced dizziness or nausea?
  • Do you have trouble sleeping, or have your sleep patterns changed?
  • Is it hard to perform everyday tasks with your hands?
  • Have you had any numbness or tingling in your limbs?
  • Have you had a significant change in mood?
  • Have you been seeing or hearing things that others are not aware of?
  • Have you had any memory problems?
  • When did your symptoms begin?
  • Have your symptoms become worse?
  • Have you been diagnosed with cancer?
  • What medicines do you take, including medicines you take without a prescription and dietary supplements? What are the daily dosages?
  • Have any close relatives had cancer? If so, what types of cancer?
  • Have you ever smoked?
  • Do you or does anyone in your family have some form of autoimmune disease?
Feb. 20, 2024
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