Peripheral Neuropathy After Chemotherapy

Chemotherapy-induced peripheral neuropathy is a type of nerve damage that sometimes occurs as a side effect of chemotherapy. Symptoms include pain, numbness, or tingling in the hands or feet. As nerve damage increases, the muscles in the feet or hands may become weak. Children may walk differently because they are unable to lift the front of the foot, a condition known as “foot drop”. Peripheral neuropathy usually improves after chemotherapy ends as nerves are able to heal. However, symptoms may not completely go away, and new symptoms can sometimes develop as late effects of therapy.

There are ways to manage peripheral neuropathy. A doctor may prescribe medicine to help with pain. Physical therapy and occupational therapy can also help patients address physical limitations due to pain, loss of sensation, and muscle weakness.

Symptoms of peripheral neuropathy

Specific symptoms of peripheral neuropathy depend on the type and severity of nerve damage. Symptoms may include:

Sensory symptoms

• Numbness (loss of sensation), tingling, or burning sensation, usually in the hands or feet
• Mouth or jaw pain
• Sensitivity to touch or temperature
• Sharp, sudden, shooting pain

Motor symptoms

• Loss of balance or coordination
• Change in gait or manner of walking that can cause tripping or falling
• Poor reflexes
• Muscle weakness and loss of muscle (making legs look thinner), especially in arms and legs
• Muscle cramps
• Problems with fine motor skills such as writing, tying shoes, or buttoning clothes

Autonomic symptoms

• Constipation or trouble urinating
• Decrease in sweating
• Change in blood pressure

Problems tend to start in the ends of nerves, farthest away from the spinal cord. This is why the hands and feet tend to be most affected. Similarly, weakness tends to occur in legs before arms.

Causes of peripheral neuropathy

Peripheral nerves carry signals from the brain to different parts of the body and back again. These signals can have different functions including motor (movement), sensory (pain, touch), or autonomic (blood pressure, temperature).

Chemotherapy medicines can harm these nerves. Drugs that pose the highest risk in childhood cancer include:

• Vincristine
• Vinblastine
• Cisplatin
• Carboplatin
• Bortezomib
• Thalidomide

Higher doses and combinations of medicines can increase the likelihood of neuropathy. Younger children may be especially susceptible because their nervous systems are still developing. Radiation therapy and medical conditions such as diabetes can also cause nerve damage and increase the risk of peripheral neuropathy with chemotherapy.

Assessment of peripheral neuropathy

In general, assessment of peripheral neuropathy considers:

• Type of symptoms (sensory, motor, autonomic, or combination)
• Severity of symptoms (pain, how much the symptoms affect daily life)
• Change in symptoms over time (whether the symptoms get worse or remain stable)

Patients with symptoms of peripheral neuropathy may be referred to a neurologist for additional screening. A neurological exam includes tests that measure reflexes, sensations, and nerve signals (conduction). Based on this information, doctors may use a rating scale to assign a grade, or measure of severity, to nerve damage.

A physical therapist may also perform an exam to assess:

• Muscle strength
• Range of motion of joints
• Position or alignment of feet and ankles while sitting and standing
• Balance
• Walking without shoes to see gait and foot position
• Ability to sense touch and vibration
• Reflexes

Information from the patient, family, and care team members helps decide next steps.

Prevention and treatment of chemotherapy-induced peripheral neuropathy

Doctors plan chemotherapy and supportive care to reduce risk for nerve damage as much as possible while still effectively treating the cancer. Researchers are studying drugs and interventions that might be used to help protect nerves from toxic effects of chemotherapy. When possible, doctors try to limit the dose of medication, plan to have rest breaks, or avoid combinations of therapies that increase risk of neuropathy.

Current treatment of peripheral neuropathy centers on management of symptoms. Strategies may include:

• Pain management – Different types of medication may be tried for nerve pain including antidepressants, anticonvulsants such as gabapentin, and analgesics such as opioid pain relievers or lidocaine.
• Rehabilitation support – Physical therapy and occupational therapy offer treatments and support interventions for patients. Specific treatments include:
  • Exercises to improve strength, range of motion, and balance
  • Assistive devices to help with walking including walkers, crutches, or canes
  • Orthotics such as arch or ankle supports to align joints and improve function
  • Assistive devices to help with daily activities such as tools to help with writing, buttoning clothes, or brushing teeth
  • Mild electrical stimulation to stimulate weakened muscles (needs doctor approval, as it may not be appropriate for patients during cancer treatment)
  • Home exercises and family education
• Complementary therapies – Patients may find help from mind-body therapies such as massage, acupuncture, biofeedback, and relaxation techniques. Families should talk to their care team before trying any new therapy to make sure it is safe.
• Adjustment of chemotherapy – In the case of severe peripheral neuropathy, the care team may recommend changes to the chemotherapy plan to reduce exposure to the drug. These decisions must be balanced against risks to overall patient health.

Long-term effects of chemotherapy-induced peripheral neuropathy

Muscle weakness, changes in gait, and poor joint alignment can lead to long-term health problems for pediatric cancer survivors. When joints and muscles don’t work properly, the knees, hips, and spine may become damaged over time. This causes pain and loss of function and can increase risk of falls. Pain and reduced mobility can affect work and family life. Peripheral neuropathy often leads to low levels of physical activity, which contributes to other health problems.

For survivors of childhood cancer, management of peripheral neuropathy and regular monitoring of symptoms is important for lifelong health and quality of life.

Tips for families

• Wear shoes that are supportive but not too tight. Look for rubber soles, and avoid shoes that make it easier to slip or fall.
• Use recommended orthotics as prescribed by a health care professional. Splints and other artificial devices can improve function and mobility, helping children maintain activity and independence and preventing falls. Children may resist at first, but they will be able to move and play more normally. Check the fit regularly to protect against sores or blisters.
• Protect hands and feet from injury. Loss of sensation can make it easier to get cuts or burns in everyday activities. It is also important to check regularly for blisters, scrapes, and cuts. Avoid walking barefoot.
• Check water temperature before washing hands or bathing. Loss of sensation can increase risk of burns when water is too hot.
• Watch for problems in hot weather. Some patients may have more symptoms in the heat or have decreased sweating.
• Be mindful in dimly lit areas and uneven surfaces (i.e. grass, gravel, etc.) to help reduce trips and falls.