Nervous System Side Effects

21.03.2024

NERVOUS SYSTEM (NEUROLOGICAL) SIDE EFFECTS IN CANCER TREATMENT

Cancer treatment, especially chemotherapy, radiotherapy and some targeted treatments, can affect the nervous system and cause various side effects. One of the most common side effects is peripheral neuropathy, in which patients experience symptoms such as numbness, tingling and pain in the hands and feet. Symptoms such as changes in cognitive function, memory problems, difficulty concentrating, and mental fogginess, sometimes referred to as “chemo brain,” reflect the cognitive effects of treatment. Additionally, treatment-related headaches, sleep disorders, hearing loss, and rarely epilepsy and seizures may also occur. These side effects vary depending on the type, dosage, and duration of treatment, as well as the patient's general health and pre-existing health conditions. Management of nervous system side effects may include drug therapies, lifestyle changes, and supportive therapies and is important for maintaining patients' quality of life. Patients sharing these side effects with their doctors and being in constant communication with doctors for early intervention can increase the success of the treatment and reduce the impact of side effects.

Image 1: Many different neurological diseases can occur due to the effects of drugs used during cancer treatment.

Drugs that can cause neurological side effects in cancer treatment include:

Vinka Alkaloidleri (Vinkristin, Vinblastine):It may cause neuropathy.

Platinum-Based Drugs (Cisplatin, Oxaliplatin): It may cause peripheral neuropathy.

Taxanlar (Paclitaxel, Doxetaxel): It can cause neuropathy and other neurological effects.

Immunotherapies (Nivolumab, Pembrolizumab): May cause neurological side effects.

BRAF Inhibitors (Vemurafenib, Dabrafenib): May cause headaches and neurological symptoms.

While these drugs target cancer cells, they can also affect the nervous system and cause various neurological side effects.

WHAT ARE THE TYPES OF SIDE EFFECTS?

Neurological side effects seen in cancer treatment may vary depending on the type of treatment and the individual characteristics of the patient.

Peripheral Neuropathy: Peripheral neuropathy is a condition that occurs as a result of damage or dysfunction of peripheral nerves (nerves in parts of your body outside the brain and spinal cord). This condition can cause a variety of symptoms and usually affects the extremities of the body, such as the hands and feet.

Reasons: Some chemotherapy drugs can damage nerve cells.

Symptoms: Numbness, tingling, pain, weakness; It is usually seen on the hands and feet.

Treatments:

Medications: Medications such as gabapentin and pregabalin can be used for neuropathic pain.

Physical Therapy: Can be applied to improve nerve functions and increase muscle strength.

Vitamin Supplements: B vitamins in particular may be helpful in managing neuropathy.

Adjusting Drug Dosage: It may be necessary to reduce the dosage of drugs that cause neuropathy.

Image 2: Neurological findings that occur during the cancer treatment process are related to the damage of nerves.

Cognitive Disorders: Cognitive disorders refer to problems that occur in an individual's mental functions such as thinking, remembering, learning, concentrating and decision-making. These disorders manifest as decreased or impaired cognitive functions and are often characterized by symptoms such as memory loss, attention deficit, difficulties in problem-solving abilities, and confusion. Cognitive impairments can be caused by age-related conditions (for example, Alzheimer's disease), traumatic brain injury, neurological diseases, side effects of certain medications, or temporary factors such as stress and fatigue. Diagnosis and treatment of such disorders are usually made through neurological and psychological evaluations and vary depending on the underlying causes.

Causes: Chemotherapy and radiotherapy can affect brain functions.

Symptoms: Difficulty concentrating, memory problems, difficulty making decisions.

Treatments:

Cognitive Therapy: Can be applied to improve memory and concentration.

Exercise and Healthy Lifestyle: Supports overall brain health.

Medication: Appropriate medications to improve sleep patterns and reduce anxiety.

Headache and Migraine: Headache is pain felt in any part of the head and can occur in many different ways. Headaches are usually temporary and can be caused by stress, fatigue, eyestrain, infections such as sinusitis, health problems such as high blood pressure, or consuming certain foods and beverages. Migraine is a type of moderate to severe headache that is felt as a pulse, usually on one side of the head. Additional symptoms such as sensitivity to light and sound, nausea and vomiting may occur during migraine attacks. Some types of migraines begin with visual or sensory changes called auras. Although the causes of migraine are not fully known, genetic factors and environmental triggers play an important role. Headaches and migraines are common health problems that can affect quality of life, and their treatments vary depending on the person's condition and the severity of the pain.

Causes: Treatment-related stress, hormonal changes or medication side effects.

Symptoms: Severe or persistent headaches.

Treatments:

Painkillers: Can be used to relieve headaches.

Anti-Migraine Medications: Can be used to treat chronic migraines.

Relaxation Techniques: Meditation and yoga can be done for stress management

Insomnia and Sleep Disorders: It is a condition of having difficulty falling asleep or staying asleep. Insomnia can be temporary (acute) or long-term (chronic). Stress, anxiety, hormonal changes, lifestyle habits and some health problems can lead to this condition.

Causes: It may be due to treatment-related stress, anxiety, pain or hormonal changes.

Symptoms: Difficulty falling asleep, interrupted sleep may occur.

Treatments:

Sleep Hygiene: It may be necessary to improve the sleep environment and organize the sleep routine.

Melatonin or Other Sleep Medicines: Can be used to treat insomnia.

Relaxation and Relaxation Techniques: Stress-reducing activities may be beneficial.

Sudden Emotional Changes: Sudden emotional changes can be defined as rapid and unexpected changes in a person's emotional state, behavior, or thought processes. These changes may include emotional fluctuations, sudden irritability, depression, agitation, fear or anxiety. It may also include cognitive changes, such as personality changes, irrational thinking, or difficulties making decisions.

Causes: Treatments affecting the central nervous system may be due to the location of the tumors.

Symptoms: Sudden emotional fluctuations, irritability and depression may occur.

Treatments:

Psychological Support: Therapy or counseling services may be helpful.

Antidepressants and Anti-Anxiety Medications: Can be used with physician evaluation to balance emotional fluctuations.

Social Support: Support groups and family support can be helpful.

Image 3: Neurology consultation may be requested because neurological side effects during cancer treatment are serious and persistent.

Hearing Loss and Tinnitus: Hearing loss is the inability to hear sounds correctly and includes a decrease in the perception of sound volume and tone height. It may develop suddenly or gradually for various reasons and may be temporary or permanent. The most common causes include aging, long-term noise exposure, side effects of some medications and head trauma. Tinnitus is when a person hears sounds such as ringing, whistling, or rustling in their ears or head without any real external sound. Often associated with hearing loss, tinnitus can be temporary or permanent and varies depending on the underlying causes. Hearing loss and tinnitus can significantly impact quality of life, and therefore individuals experiencing these conditions are recommended to seek medical attention.

Causes: It may be due to the effects of some chemotherapy drugs and radiotherapy on the auditory nerves.

Symptoms: Hearing difficulty and tinnitus.

Treatments:

Hearing Tests and Devices: Can be used to assess and manage hearing loss.

Adjusting Drug Dosage: The dosage of treatments that cause hearing loss may need to be reviewed.

Epilepsy and Seizures: Epilepsy is a neurological disorder characterized by recurrent seizures due to abnormal electrical activity in the brain. This abnormal activity can lead to various types of seizures, including loss of control, muscle spasms, loss of consciousness, abnormal sensations, and behavioral changes.

Causes: Brain tumors may occur due to treatments that affect the nervous system.

Symptoms: Muscle spasms, loss of consciousness and loss of control may occur.

Treatments:

Antiepileptic Drugs: Can be used to control seizures.

Lifestyle Changes: Care should be taken to reduce seizure triggers.

Surgical Intervention or Radiotherapy: May be useful for seizures due to brain tumors.

Motor Function Disorders: Motor dysfunctions describe problems with movement control and coordination. These disorders can present with a variety of symptoms, including muscle weakness, loss of muscle control, tremors, muscle spasms, and involuntary changes in movements. Neurological disorders, brain damage, spinal cord injuries, nervous system diseases and some genetic conditions are among the common causes of motor dysfunction.

Causes: Brain or spinal cord tumors may occur due to the effect of the treatment on motor nerves.

Symptoms: Muscle weakness and loss of coordination may occur.

Treatments:

Physiotherapy and Rehabilitation: Can be done to improve motor skills and coordination.

Corticosteroids and Anti-Inflammatory Medications: Can be used to reduce inflammation and increase mobility.

Treatment of these side effects usually requires a multidisciplinary approach and should be planned according to the needs of the patient individual. It is important for patients to report these side effects to their doctors and to stay in constant communication with doctors for early intervention. Management of neurological side effects during and after cancer treatment can significantly impact a patient's overall health and quality of life. Therefore, constant medical supervision and appropriate supportive treatments are required during the treatment process.