Lightheadedness, a sensation of faintness, dizziness, or unsteadiness, is a common symptom with various causes. While many everyday situations can cause this feeling, it can also be associated with cancer. Understanding this connection involves exploring both the direct effects of the disease and the indirect impacts of cancer treatments and medications.
Direct Ways Cancer Can Cause Lightheadedness
Cancer can directly lead to lightheadedness through several physiological mechanisms. One common cause is anemia, a condition where the body lacks sufficient healthy red blood cells. Certain cancers, like leukemia and lymphoma, can affect bone marrow, which produces red blood cells. Tumors, especially in the gastrointestinal tract, can also cause chronic internal bleeding, leading to iron-deficiency anemia. Low red blood cell counts reduce oxygen delivery to the brain and other tissues, causing fatigue, shortness of breath, and lightheadedness.
Electrolyte imbalances also contribute to lightheadedness. For instance, hypercalcemia, an abnormally high level of calcium in the blood, can occur with advanced cancers, especially those spread to bones or producing parathyroid hormone-like substances. Its symptoms include fatigue, weakness, confusion, and drowsiness, which can manifest as lightheadedness. Conversely, hyponatremia, low blood sodium, is common in cancer patients, particularly with small-cell lung cancer, often due to the Syndrome of Inappropriate Antidiuretic Hormone (SIADH). SIADH causes water retention, diluting sodium and leading to neurological symptoms like confusion and lethargy that contribute to lightheadedness.
Advanced cancer can also contribute to lightheadedness through dehydration and malnutrition. The disease process may cause poor appetite, nausea, vomiting, or diarrhea, reducing fluid and nutrient intake. Dehydration can drop blood pressure, leading to dizziness and lightheadedness, while malnutrition weakens the body. In specific cases, a tumor’s physical presence can directly impact neurological function. For example, a brain tumor can increase skull pressure or disrupt balance-related brain regions, causing dizziness or unsteadiness.
Lightheadedness from Cancer Treatment and Medications
Cancer treatments and the medications used to manage their side effects frequently cause lightheadedness. Chemotherapy, a common treatment, can induce nausea, vomiting, and fatigue. Persistent nausea and vomiting can lead to dehydration, which in turn causes a drop in blood pressure and lightheadedness. The fatigue experienced during chemotherapy also contributes to weakness and unsteadiness.
Radiation therapy, particularly when administered to the abdomen or head and neck, can also cause nausea, vomiting, and diarrhea, increasing dehydration risk. This fluid loss can manifest as lightheadedness. Radiation can also cause fatigue, which exacerbates dizziness and unsteadiness.
Newer cancer therapies, such as immunotherapy and targeted therapies, can also cause lightheadedness. Immunotherapy, which boosts the body’s immune system to fight cancer, can cause flu-like symptoms like fatigue, fever, and chills, inducing dizziness. Targeted therapies, designed to attack cancer cell vulnerabilities, can also cause fatigue, nausea, and vomiting, contributing to lightheadedness. Some targeted therapies can also affect blood pressure, leading to dizziness.
Medications for cancer-related pain or other symptoms can also cause lightheadedness. Opioid pain relievers, for instance, are known to cause drowsiness, dizziness, and orthostatic hypotension—a sudden blood pressure drop when standing. Anti-nausea drugs, while helpful, can have side effects like drowsiness or dizziness. Other supportive medications, including those for blood pressure management, can also inadvertently cause lightheadedness.
When to Seek Medical Attention for Lightheadedness
Experiencing lightheadedness, especially for cancer patients, warrants careful attention and communication with the healthcare team. If lightheadedness becomes persistent, severe, or interferes with daily activities, it is important to seek medical advice. Frequent or worsening dizziness episodes should prompt discussion with a doctor to determine the cause and management.
Certain accompanying symptoms alongside lightheadedness signal a need for immediate medical evaluation. These include fainting, chest pain, shortness of breath, sudden confusion, vision changes, or new neurological symptoms like weakness or numbness. These symptoms could indicate a more serious condition requiring prompt intervention.
Openly discussing all symptoms with the healthcare team is important for cancer patients. Lightheadedness can be a treatable medication side effect, a symptom of a correctable imbalance, or an indication of disease progression. Providing a complete picture of symptoms allows medical professionals to adjust treatment plans, manage side effects effectively, and ensure the best care.