Kidney disease can lead to a low red blood cell count, a condition known as anemia. The kidneys are two bean-shaped organs that filter waste products and excess fluid from the blood, which are then excreted as urine. Red blood cells are produced in the bone marrow and transport oxygen from the lungs to all the body’s tissues and organs.
How Kidney Disease Affects Red Blood Cells
The connection between kidney disease and a low red blood cell count stems from the kidneys’ role in producing erythropoietin (EPO). This hormone signals the bone marrow to produce red blood cells. When kidneys are damaged due to chronic kidney disease (CKD), they produce less EPO. This reduction in EPO means the bone marrow receives fewer signals to create new red blood cells, leading to a decrease in their overall count.
A diminished supply of red blood cells results in less oxygen being delivered throughout the body to organs and tissues. This specific type of anemia is commonly referred to as “anemia of chronic kidney disease.” Beyond reduced EPO production, other factors can contribute to anemia in CKD, including iron deficiency, inflammation, and a shortened lifespan of existing red blood cells. The severity of anemia often increases as kidney disease progresses and more kidney function is lost.
Signs and Symptoms of Anemia
Anemia resulting from kidney disease can manifest through various signs and symptoms, which often develop gradually. One of the most frequently reported symptoms is persistent fatigue or unusual tiredness that does not improve with rest. Individuals may also experience general weakness and a lack of energy for daily activities.
Physical indicators can include unusually pale skin, a result of a lower number of red blood cells. Shortness of breath, even with minimal exertion, can occur because the blood is not carrying enough oxygen to meet the body’s demands. Other common symptoms involve dizziness, headaches, and trouble concentrating.
Some people might notice cold hands and feet due to insufficient oxygen delivery to the extremities. In more severe cases, anemia can lead to chest pain or an unusually fast or irregular heartbeat, as the heart works harder to pump oxygen-depleted blood throughout the body.
Diagnosing and Treating the Condition
Diagnosing anemia related to kidney disease involves a combination of medical history review, a physical examination, and specific blood tests. Healthcare professionals typically perform a complete blood count (CBC), which measures the number, size, and health of red blood cells, including hemoglobin and hematocrit levels. Hemoglobin is the protein within red blood cells that carries oxygen, and its level helps determine the severity of anemia. Kidney function tests, such as creatinine and glomerular filtration rate (GFR), also help assess the stage of kidney disease. Doctors may also check for levels of iron, vitamin B12, and folate, as deficiencies in these nutrients can contribute to anemia.
Treatment for anemia of chronic kidney disease focuses on addressing the underlying causes and improving red blood cell count. Iron supplementation is a common approach, often administered orally as pills or intravenously (IV) for better absorption, especially in later stages of CKD or for those on dialysis. Iron is crucial for the body to produce healthy red blood cells.
Erythropoiesis-stimulating agents (ESAs), such as synthetic EPO, are another primary treatment option. These injectable medications mimic the natural EPO hormone, stimulating the bone marrow to produce more red blood cells. ESAs can help improve symptoms and reduce the need for blood transfusions.
In some instances of severe anemia, particularly when other treatments are insufficient or there is acute blood loss, blood transfusions may be used to quickly increase red blood cell levels and alleviate symptoms. Alongside these specific treatments, managing the progression of the underlying kidney disease is also an important aspect of overall care.