Renal anemia is renal anemia that can be attributed to disturbances in erythropoiesis (red blood cell synthesis) caused by renal insufficiency. The extent of renal anemia is conditioned by the severity of the underlying renal insufficiency. Renal anemia is usually well treatable with medication.
What is renal anemia?
Renal anemia is anemia caused by renal insufficiency (underactive kidneys) and is due to a lack of red cells in the blood. The reduced quantity of erythrocytes, which ensure the transport of oxygen in the blood via hemoglobin (red blood pigment), leads to an undersupply of oxygen to the body and causes the symptoms typical of renal anemia, such as pallor, rapid signs of fatigue and shortness of breath. The likelihood of developing renal anemia increases as renal insufficiency progresses. In advanced renal failure (need for dialysis, needed kidney transplant), renal anemia is found in most cases.
Causes
Renal anemia is caused by chronic renal insufficiency, which in turn can have a variety of causes. For example, long-standing diabetes, excessive painkiller use, and inflammatory diseases of the kidneys can cause renal insufficiency and, even in its early stages, renal anemia. Healthy kidneys produce over four-fifths of their requirement of erythropoietin, a hormone that stimulates erythropoiesis (red cell synthesis) in the bone marrow. In renal insufficiency, this hormone is produced in insufficient quantities, so that too few erythrocytes are synthesized and renal anemia develops. Decreased red cell longevity and impaired iron uptake by hemoglobin can also be attributed to renal insufficiency and thus cause renal anemia.
Symptoms, complaints, and signs
Anemia triggered by renal insufficiency results in the typical symptoms of anemia. Due to the reduced supply of oxygen, performance is reduced, and patients feel tired and fatigued. Dizziness and headaches may occur. Skin and mucous membranes are pale, with a color similar to latte. Shortness of breath (dyspnea) occurs during physical exertion. Initially, breathing difficulties improve at rest, but in advanced stages of anemia they persist even at rest. The tongue looks red and slippery, which is called lacquer tongue by medical professionals. In addition to the symptoms caused by anemia, other complaints arise due to kidney dysfunction. Blood pressure increases, the ability to concentrate decreases, and states of confusion are possible. The digestive tract is also affected, resulting in diarrhea, abdominal pain, nausea and vomiting. Affected individuals often lose weight due to loss of appetite. The skin shows so-called uremic changes such as dryness, scaling and itching. The latter can be so severe that patients scratch their skin. It is not uncommon for these scratch marks to become infected. Damage to the kidneys can lead to menstrual disorders and impotence. In some cases, sensory disturbances, calf cramps and bone pain occur. Increased heartbeat, palpitations and arrhythmias are also possible.
Diagnosis and course
Renal anemia is diagnosed by blood count analysis, which includes determination of blood cell count, hemoglobin, and hematocrit (total percentage of blood cells in the blood). If the value of red blood cells with normal hemoglobin and/or the hematocrit value is reduced, renal anemia can be assumed. In the early stages of renal anemia, no symptoms are often detectable at rest, while signs of fatigue as well as weakness and shortness of breath may appear quickly due to exertion. In advanced renal anemia, these symptoms are also observable at rest. Furthermore, renal anemia is accompanied by an increased cardiac output, since the organism tries to compensate for the lack of oxygen by increasing the cardiac output. Since renal anemia is caused by renal insufficiency, the symptoms characteristic of renal damage (skin pallor, jaundice, gastrointestinal complaints, etc.) aredepending on the extent and stage of the kidney disease. In the long term, untreated renal anemia leads to a decrease in physical and mental performance and a shortened life expectancy.
Complications
Renal anemia often leads to complications, but these always depend on the type and severity of the underlying disease. For example, diabetics, among others, are at greatest risk for early onset of severe renal anemia. However, when mild renal damage is present, the anemia is mild and shows few symptoms. In severe cases, fatigue, loss of performance, mental decline with confusion, shortness of breath, and increased pulse occur. In addition, high blood pressure, bone pain, and gastrointestinal distress may occur. Overall, there is a high risk of serious cardiovascular disease. This is all the more true the later therapy for renal anemia begins in patients not yet requiring dialysis. In addition, the number of hospitalizations and, of course, the treatment costs increase. Overall, untreated renal anemia has a negative effect on physical and mental performance. It also leads to a drastic reduction in life expectancy. The reduction in the patient’s quality of life also weighs heavily. Due to the chronic complaints, the affected persons may also suffer from mental illnesses. In particular, the risk of developing depression is increased. Since the hormone erythropoietin (EPO) is lacking in renal anemia, it must be supplied as part of the therapy. Although the risks of this therapy are low, it can initially lead to an increase in blood pressure and a slight increase in the risk of thrombosis.
When should you see a doctor?
This condition should always be treated by a physician. In the worst case, this can lead to the death of the affected person if left untreated. As a rule, this disease can be treated relatively well with the help of medication. First and foremost, a doctor should be consulted if the patient suffers from impaired oxygen uptake. This often results in severe fatigue and dizziness. Severe headaches that are permanent may also indicate the disease. In most cases, the skin of the affected person also appears very pale and there is shortness of breath. Furthermore, severe digestive problems or a loss of appetite also point to the disease. The patient’s skin is reddened and itching occurs. If these symptoms occur over a longer period of time and make the life of the patient more difficult, a doctor should be consulted in any case. As a rule, the disease can be treated well, so that the life expectancy of the affected person is not reduced. However, a complete cure is usually not achieved, so that the patient is dependent on lifelong treatment.
Treatment and therapy
Renal anemia is treated with medication. If renal anemia is due to erythropoietin deficiency, which is the usual case, genetically synthesized erythropoietin is injected to eliminate the existing hormone deficiency (EPO therapy or erythropoietin replacement). Erythropoietin substitution compensates for the hormone deficiency and stimulates blood formation, which is why additional iron intake may be necessary. An adequate amount of iron is an essential prerequisite for erythropoiesis. The increased iron requirement can be ensured by an appropriate diet plan as well as by additional iron supplements. Since iron absorption in the gastrointestinal tract by tablets (peroral iron therapy) is only possible to a limited extent and in many cases may result in digestive disorders and nausea, intravenous administration (parenteral iron therapy) is recommended in renal anemia. Erythropoietin substitution avoids blood transfusions and the risks associated with them (viral diseases, exaggerated immune system reactions, inhibition of the body’s own erythrocyte formation). In patients who are not yet on dialysis, the risk of cardiovascular disease is minimized. In the case of kidney transplantation, an improvement in renal anemia is usually observed, since with the new kidney the cause of renal anemia has been eliminated and sufficient erythropoietin can be produced.
Prevention
Because renal anemia is caused by renal insufficiency, preventive measures aim to avoid renal damage. These include a healthy diet and early treatment of diseases that can cause renal insufficiency (diabetes mellitus, inflammatory kidney disease) and thus renal anemia. Regular blood level checks in chronic renal insufficiency contribute to early diagnosis and resolution of renal anemia.
Follow-up
The follow-up of renal anemia depends on its cause. In any case, regular testing of blood values is necessary in order to be able to react immediately if necessary. The physician determines the rotation in this regard. If the kidney is the cause, this is best done by a nephrologist. The control can be necessary monthly or in case of manifestation also in larger intervals. Especially in the case of renal insufficiency, it can be assumed that renal anemia will recur. It is then important to check for at least the following blood values: Hemoglobin and GFR (urine output of the kidneys). Once the GFR drops below 15 ml/min, renal failure occurs. Hemoglobin (Hb) should not drop below 11 g/dL. Hemoglobin is the iron-containing and therefore red blood pigment responsible for transporting oxygen in the blood. Iron levels can be increased by iron tablets or an injection. As soon as the hemoglobin level drops again, erythropoietin (EPO) must be administered again, the effect of which is delayed by several weeks. EPO is the hormone that stimulates the bone marrow to produce blood. Since blood pressure can rise during this process, it must also be checked and recorded daily during follow-up. Based on documentation of blood pressure values, the physician can decide whether therapy with blood pressure-lowering agents is necessary.
What you can do yourself
Patients suffering from renal anemia can positively influence the success of treatment by changing their diet. Since anemia is accompanied by a lack of iron, the intake of iron-containing foods is necessary. This is particularly the case if those affected do not tolerate corresponding medications (such as tablets) well. Foods containing iron include, above all, meat, whole grain products and legumes. It is advisable to ensure a sufficient supply of vitamin C (e.g. by drinking a glass of orange juice) when eating these foods, as this facilitates the absorption of iron in the body. A healthy amount of exercise can also have a positive effect on the body, depending on the stage of renal anemia. Relaxation exercises and exercise lead to a better body feeling and can also alleviate concomitant diseases, such as cardiovascular problems. Contact and exchange with like-minded people in a self-help group can also have a very positive effect on patients and their well-being. However, a visit to the doctor is indispensable. Because the symptoms of renal anemia can only be treated permanently with medication. Thus, those affected should have their blood values checked regularly in order to be able to intervene at an early stage in the event of any deterioration.
