Nerve damage

Nervous system problems can develop after some types of cancer or cancer treatment. Sometimes nervous system problems happen as a late effect of treatments for cancer during childhood.

The nervous system is made up of the central nervous system (CNS) and the peripheral nervous system (PNS).

The central nervous system is made up of the brain and spinal cord. It controls thoughts, emotions and many actions of the body. It is also responsible for coordination and interprets information from the senses, such as sight, hearing and smell.

The peripheral nervous system is made up of the parts of the nervous system outside the brain and spinal cord. It includes the cranial nerves, spinal nerves and peripheral nerves.

• The cranial nerves connect the brain to parts of the head, neck and upper body. They are involved in movement and touch sensation of the head and neck, as well as vision, hearing, taste and smell.
• The spinal and peripheral nerves send messages from the spinal cord to other parts of the body. They also send sensory signals back to the spinal cord and brain. These nerves are involved in movement, sensation and control of involuntary functions, such as heart rate and breathing.

Some types of cancer can cause nervous system problems. Certain types of chemotherapy, radiation therapy and surgery can also cause nervous system problems.

Brain and spinal cord tumours can cause nervous system problems as the tumours grow larger. Non-Hodgkin lymphoma in the central nervous system can also cause nervous system problems.

Chemotherapy drugs can damage the central nervous system and the peripheral nervous system. Nervous system damage is often related to the dose of the drug. Damage to the central nervous system is more likely to occur after radiation therapy to the brain or when chemotherapy drugs are injected into the cerebrospinal fluid (CSF).

Chemotherapy drugs that can damage the nervous system include:

• vinblastine
• vincristine (Oncovin)
• cisplatin
• docetaxel (Taxotere)
• paclitaxel (Taxol)
• etoposide (Vepesid, VP-16)
• cytarabine (Cytosar)
• ifosfamide (Ifex)
• methotrexate

Radiation therapy to the brain or spinal cord can damage the central nervous system. Radiation to the head and neck or the whole body can cause peripheral nerve damage.

Surgery to remove a tumour from the brain or spinal cord can damage the nervous system.

Other drugs can cause nervous system problems. These drugs include anticonvulsants, opioid pain medicines and some medicines that prevent vomiting.

Nervous system damage can develop months or years after treatment. Some problems are temporary but may take months to go away. Others last a long time or become permanent.

Damage to the nervous system can cause problems with:

• vision
• hearing
• balance and walking
• coordination
• thinking, speaking and memory

Symptoms of nervous system changes depend on the nerves that are damaged.

Damage to the central nervous system can include these symptoms:

• unsteadiness when walking
• problems with muscle control and balance
• an overall lack of strength
• confusion
• agitation
• changes in behaviour
• cognitive problems
• dizziness
• seizures

Damage to the peripheral nerves can include these symptoms:

• numbness, tingling (pins and needles) or a burning sensation in the hands or feet
• the inability to feel something hot or cold, such as heat from a stove
• muscle weakness (trouble walking, doing up buttons or opening jars)
• changes in reflexes
• constipation
• the inability to urinate
• incontinence
• erectile dysfunction

Damage to the cranial nerves can include these symptoms:

• ringing in the ears (tinnitus) or hearing loss (especially for high-frequency sounds)
• blurred vision, double vision or loss of vision
• jerky eye movements
• weakness of the face, tongue, neck or shoulder
• slurred speech
• difficulty understanding speech or expressing yourself
• difficulty swallowing
• changes in taste or smell

If you develop a new symptom or if symptoms get worse or don’t go away, report them to your doctor or healthcare team without waiting for your next scheduled appointment.

Your doctor will do a neurological exam to assess your nervous system. A neurological exam checks your reflexes, balance, coordination, memory and language skills. A hearing test and a vision test may also be done.

Nervous system problems can make it difficult to manage your usual daily activities. There are ways to try to prevent or manage nervous system problems.

You can help prevent falls by:

• using non-skid rugs or moving rugs out of your pathway
• adding extra lighting in the house
• installing handrails on the walls and in the bathroom
• using a rubber bath mat in the tub or shower
• wearing sturdy shoes
• getting up slowly, especially if you feel dizzy

Be careful with sharp, hot, cold or other dangerous objects if your fingers are numb. Ask someone to check the water temperature or check it with your elbow to make sure it’s not too hot.

Wear shoes both indoors and outdoors to protect your feet. If you have peripheral nerve damage, check your hands, arms, feet and legs every day for cuts and scratches.

Ask your doctor about pain medicines and other methods to help relieve pain. They may prescribe pain medicine and suggest acupuncture, massage, yoga or other practices to help lower your pain.

Therapists can help you regain your strength, physical function and independence. They include:

• an occupational therapist to help with motor skills needed for daily activities
• a physical therapist to help improve strength, balance, coordination and walking
• a speech therapist to help improve speech and swallowing problems
• a neuropsychologist to help with cognitive problems

Ask for help and let people help you if a task is too difficult for you to manage. Give yourself more time to do things.

All people who are treated for cancer need regular follow-up. The healthcare team will develop a follow-up plan based on the type of cancer, how it was treated and your needs.

Make sure you tell your doctor all the treatments you received. If you are at risk for nervous system problems, your doctor will ask you about your symptoms and how you are coping. You may have a physical exam and a neurological exam.

Find out more about peripheral nerve damage (peripheral neuropathy) and cognitive problems.