Blood pressure is the force of blood pushing against the walls of your arteries as your heart pumps blood. It is measured with two numbers: systolic (when the heart beats) and diastolic (when the heart rests between beats). Low blood pressure, also known as hypotension, occurs when these forces are abnormally low, generally considered below 90/60 mmHg for adults. When blood pressure drops, the body’s organs, including the brain and heart, may not receive adequate blood flow, potentially leading to symptoms like dizziness or lightheadedness.
The Relationship Between Cancer and Low Blood Pressure
Low blood pressure can manifest in individuals with cancer, often as an indirect consequence of the disease or its treatments. While some healthy individuals may have naturally lower blood pressure without symptoms, a significant drop can indicate an underlying issue, particularly in cancer patients. The complex interplay between the disease, its complications, and therapies can disrupt the body’s normal blood pressure regulation.
Cancer patients often experience orthostatic hypotension, a specific type of low blood pressure that occurs when standing up. This indicates that the body’s ability to maintain stable blood pressure in response to positional changes can be compromised.
How Cancer-Related Factors Can Lead to Low Blood Pressure
Several aspects of cancer progression and its complications can directly contribute to low blood pressure.
Infections
Severe infections, particularly sepsis, are a significant cause of hypotension in cancer patients. Sepsis is a life-threatening response where the body’s immune system overreacts to an infection, causing widespread inflammation that can lead to dangerously low blood pressure and organ dysfunction. Cancer patients are at an increased risk for sepsis due to weakened immune systems from the disease itself or prior treatments.
Blood Loss and Dehydration
Significant internal or external bleeding from tumors can lead to a drop in blood pressure by reducing total circulating blood volume. Dehydration is another common factor, often resulting from symptoms like vomiting, diarrhea, or reduced fluid intake. When the body lacks sufficient fluids, blood volume decreases, directly affecting blood pressure.
Malnutrition and Fluid Shifts
Malnutrition and substantial weight loss can impair the body’s ability to maintain healthy blood pressure. Fluid shifts within the body, such as fluid accumulation in the abdomen (ascites), can reduce effective circulating blood volume, leading to hypotension. Paraneoplastic syndromes, conditions caused by the immune system’s response to a tumor, can affect the nervous system’s control over blood pressure, leading to autonomic dysfunction and hypotension.
Low Blood Pressure as a Complication of Cancer Treatment
Cancer treatments can frequently induce low blood pressure through various mechanisms.
Chemotherapy
Chemotherapy can cause side effects like severe nausea and vomiting, leading to dehydration and subsequent drops in blood pressure. Certain chemotherapy drugs may also directly affect the heart’s pumping ability or cause a reduction in red blood cells (anemia), leading to symptoms like fatigue and dizziness due to lower oxygen delivery.
Radiation and Surgery
Radiation therapy, depending on the treated area, can affect fluid balance or impact heart function, indirectly contributing to hypotension. Surgical procedures for cancer carry risks such as blood loss, which directly lowers blood pressure. Anesthesia used during surgery can also temporarily reduce blood pressure by relaxing blood vessels. Post-operative fluid shifts as the body recovers can further influence blood pressure stability.
Targeted Therapies, Immunotherapies, and Pain Medications
Targeted therapies and immunotherapies can have cardiovascular side effects. Immunotherapies may trigger an exaggerated immune response known as cytokine release syndrome (CRS). This systemic inflammatory reaction involves a rapid release of signaling proteins that can cause widespread blood vessel dilation and fluid leakage, leading to a significant drop in blood pressure. Pain medications, especially opioids, can also contribute to low blood pressure by affecting the central nervous system and causing vasodilation.
Addressing Low Blood Pressure in Cancer Care
Managing low blood pressure in cancer patients involves careful monitoring and tailored interventions to address the underlying causes.
Hydration and Nutrition
Regular blood pressure checks are standard practice, with healthcare teams assessing for symptoms such as dizziness, lightheadedness, or fainting. Ensuring adequate hydration is a primary focus; patients are encouraged to drink sufficient fluids. Oral rehydration solutions or intravenous fluids may be administered to replenish lost fluids and electrolytes, particularly with vomiting or diarrhea.
Nutritional support is also important, as malnutrition can exacerbate hypotension. Patients are encouraged to consume small, frequent meals and maintain a balanced diet. Dietary adjustments, such as a modest increase in salt intake, may be considered under medical guidance.
Medication and Positional Changes
Medication adjustments are common, especially if existing blood pressure-lowering drugs are contributing to hypotension. The healthcare team may modify dosages or consider alternative medications. Patients are advised to change positions slowly, particularly when moving from lying or sitting to standing, to mitigate orthostatic drops in blood pressure. It is important for patients and caregivers to promptly report symptoms of low blood pressure, such as persistent dizziness, confusion, or weakness, to their medical team, as these can indicate a need for immediate attention.