Dizziness is a broad term that describes a range of sensations. Lightheadedness refers to the feeling of being faint or woozy, often signaling that the brain is not receiving sufficient blood flow. Vertigo, by contrast, is the distinct sensation that you or your surroundings are spinning or moving, which typically points to an issue with the balance system in the inner ear or the brain. Dizziness is a frequently reported symptom among patients with cancer. The causes are numerous, ranging from the direct presence of a tumor to systemic side effects of treatment, all of which need careful evaluation.
Dizziness Caused by Tumor Location and Paraneoplastic Syndromes
The physical location of a tumor can directly interfere with the neurological structures responsible for balance and spatial orientation. Tumors that develop in the cerebellum, which controls coordination and posture, often lead to unsteadiness and a feeling of imbalance. Similarly, cancers affecting the brainstem or the vestibular nerve can cause true vertigo, where the world feels as if it is spinning. The resulting dizziness is a direct consequence of physical pressure or structural damage to the central nervous system.
Paraneoplastic Syndromes
A rarer cause is a group of conditions known as paraneoplastic syndromes of the nervous system. These syndromes occur when the body’s immune response to the cancer mistakenly attacks healthy nerve cells. For example, paraneoplastic cerebellar degeneration involves the immune system destroying cells in the cerebellum, leading to a rapid onset of severe dizziness, trouble walking, and a lack of coordination. Symptoms of these immune-mediated syndromes can sometimes appear even before the underlying cancer is diagnosed.
Dizziness Triggered by Cancer Treatments
Interventions designed to treat cancer can induce dizziness by causing damage to the delicate balance mechanisms of the inner ear, a process known as ototoxicity. Certain chemotherapy agents, particularly platinum-based drugs like cisplatin, harm the sensory hair cells within the inner ear’s vestibular apparatus. This damage impairs the body’s ability to sense movement and maintain balance, resulting in chronic dizziness and vertigo that can persist long after treatment concludes.
Radiation therapy directed at the head and neck area also carries a risk of affecting the vestibular system. If the radiation field includes the inner ear, it can cause inflammation or direct damage. High doses of radiation can lead to permanent sensorineural damage or cause temporary conditions such as serous otitis media, where fluid builds up in the middle ear. This damage disrupts the signals sent to the brain, manifesting as balance problems and dizziness.
Systemic Conditions and Supportive Care Medications
For many patients, the most common causes of dizziness are systemic issues often exacerbated by the cancer experience. Anemia, characterized by a low red blood cell count, is a frequent culprit, as it reduces the amount of oxygen delivered to the brain. Whether caused by the cancer itself or by chemotherapy, anemia causes lightheadedness and a general feeling of weakness.
Dehydration and electrolyte imbalances are also highly prevalent, often stemming from poor oral intake, persistent nausea, vomiting, or diarrhea related to treatment. A lack of body fluid can cause a sudden drop in blood pressure, known as orthostatic hypotension, when a person moves from sitting or lying down to standing. This sudden drop causes lightheadedness and a risk of fainting. Severe wasting, or cachexia, can also contribute to this problem by reducing muscle mass and overall physical reserve.
Furthermore, many supportive care medications used to manage symptoms can inadvertently cause or worsen dizziness. Pain medications, such as opioids, or anti-nausea drugs can affect the central nervous system or influence blood pressure. Drugs used to manage other conditions, like high blood pressure, may also contribute to orthostatic hypotension, making it harder for the body to maintain stable blood pressure during position changes.
Managing Dizziness and When to Seek Medical Attention
Managing dizziness starts with simple, practical adjustments and addressing the underlying systemic causes. Patients should move slowly when changing position, particularly when getting out of bed, to allow the circulatory system time to adjust and prevent orthostatic drops in blood pressure. Maintaining adequate hydration by consistently drinking fluids is a fundamental step in preventing lightheadedness due to volume depletion. For balance issues resulting from inner ear damage, specialized physical therapy called vestibular rehabilitation may help the brain compensate for the impaired signals.
While many causes of dizziness are manageable, certain symptoms require immediate medical evaluation to rule out a serious neurological event. Promptly contact a healthcare provider if dizziness is accompanied by any of the following red flags:
- Severe, sudden headache.
- Loss of consciousness.
- New changes in vision.
- Slurred speech or confusion.
- Seizures.
- Sudden loss of feeling or movement in the arms or legs.
These associated symptoms can signal a serious issue, such as a tumor pressing on a sensitive brain area or brain metastasis, requiring urgent intervention.