What are neurological symptoms? What may contribute to neurological symptoms?
Neurological side effects and symptoms affect or interfere with the function of the brain or nerves. Symptoms are often grouped into central nervous system (CNS) effects on the brain and spinal cord and peripheral effects on any other nerves. Both cancer itself and cancer treatments can cause neurological symptoms and side effects.
Cancer’s direct effects include compression to the brain, spine, or peripheral nerves from tumor growth. Fractures in vertebrae in the spine or swelling caused by cancer can also cause compression and pressure on nerves. Tumors within the brain or pressure from swelling can cause seizures.1Giglio P, Gilbert MR. Neurologic complications of cancer and its treatment. Current Oncology Reports. 2010 Jan;12(1):50-9.
Paraneoplastic syndromes are another neurological effect of cancer. “Paraneoplastic syndromes are a group of rare disorders that are triggered by an abnormal immune system response to a cancerous tumor known as a ‘neoplasm.’ Paraneoplastic syndromes are thought to happen when cancer-fighting antibodies or white blood cells (known as T cells) mistakenly attack normal cells in the nervous system.”2Paraneoplastic Syndromes. National Institute of Neurological Disorders and Stroke. April 25, 2022. Viewed May 4, 2022.
The most common side effects of cancer treatments are injury to the brain, spine, and peripheral nerves from radiation and peripheral neuropathy from chemotherapy.3Giglio P, Gilbert MR. Neurologic complications of cancer and its treatment. Current Oncology Reports. 2010 Jan;12(1):50-9. Surgery can also damage nerves.4Cancer.Net. Nervous System Side Effects. American Society of Clinical Oncology. February 2018. Viewed May 4, 2022. Chemotherapy-induced peripheral neuropathy is the most researched neurological effect with regard to complementary therapies.
What are the signs of neurological symptoms?
Neurological effects can be seen in a range of symptoms.5Overview of Nervous System Disorders. Johns Hopkins Medicine. Viewed May 4, 2022; Cancer.Net. Nervous System Side Effects. American Society of Clinical Oncology. February 2018. Viewed May 4, 2022.
Changes in sensation or physical function
Loss of feeling or tingling
Loss of sight or blurred or double vision
Lack of coordination
Tremors and seizures
Hearing loss and/or a ringing in the ears (tinnitus)
Changes in taste and smell
Weakness or loss of muscle strength
Loss of urinary control (incontinence)
Impaired mental ability
Language impairment (expression or comprehension)
Persistent or sudden onset of a headache
A headache that changes or is different
Back pain which radiates to the feet, toes, or other parts of the body
Burning or “electrical shock” sensation radiating from the back or other areas
See our Pain handbook for information about managing pain.
What may contribute to neurological symptoms?
In addition to cancer, these conditions can also increase your risk of neurological symptoms:6Cancer.Net. Nervous System Side Effects. American Society of Clinical Oncology. February 2018. Viewed May 4, 2022.
Infections causing swelling or inflammation of the brain, spinal cord, or inner ear
Infections, such as Lyme disease, shingles, Epstein-Barr virus, hepatitis B and C, and HIV
Diabetes, especially if your sugar levels are poorly controlled
Kidney, liver or thyroid disorders
Human immunodeficiency virus (HIV)
Autoimmune diseases, such as rheumatoid arthritis and lupus
Vitamin deficiencies, particularly B vitamins
Managing these conditions if you have them, or reducing your risk of them, could help you avoid their additional burden on your nervous system.
Medications and therapies
Cancer treatments and some medications used during cancer treatment or for other conditions may trigger neurological symptoms. Check the inserts with any prescription medications you use or ask your pharmacist if you have concerns.
Complementary therapies that we have reviewed that may trigger neurological symptoms:
Other medications that may trigger or contribute to neurological symptoms:
Risk factors for neurological symptoms
These situations increase your risk of neurological symptoms such as peripheral neuropathydamage to the peripheral nerves outside the brain and spinal cord:7Peripheral neuropathy. Mayo Clinic. Viewed May 4, 2022; Seretny M, Currie GL et al. Incidence, prevalence, and predictors of chemotherapy-induced peripheral neuropathy: a systematic review and meta-analysis. Pain. 2014 Dec;155(12):2461-2470.
Exposure to toxic substances such as heavy metals—especially lead and mercury—or organophosphorus compounds common in pesticides
Repetitive motion, such as those performed for certain jobs
Family history of neuropathy