Introduction
Red blood cells are profuse in blood cells. Healthy and mature red blood cells carry oxygen to your body's tissues with the help of a protein called hemoglobin. Red blood cells want iron to make hemoglobin (the bone marrow produces stem cells that become immature red blood cells, with the help of hemoglobin and iron, they become mature red blood cells).
However, when sideroblastic anemia develops, the body cannot use iron. Without iron, red blood cells do not have enough hemoglobin to carry oxygen throughout the body. On the other hand, unused iron accumulates in the bone marrow, forming abnormal cells. Immature red blood cells have a nucleus or center surrounded by an iron ring.
What Is Sideroblastic Anemia?
Sideroblastic anemia (SA) is a less common blood disorder that affects the way the body makes red blood cells. If one has sideroblastic anemia, they may have anemia due to a lack of red blood cells and anemia due to too much iron in the body because the body does not use the iron in the red blood cells.
People may be born with what health experts call congenital helminthic anemia (ICA). But more often, people develop or acquire sideroblastic anemia because of a related blood disorder, taking certain drugs, or overexposure to certain minerals.
Who Is Affected by Sideroblastic Anemia?
Congenital or hereditary sideroblastic anemia (CSA) can affect infants, children, or young adults. Acquired CSA often affects people with myelodysplastic syndrome.
How Does This Condition Affect My Body?
People with sideroblastic anemia usually have symptoms of anemia, such as extreme fatigue or shortness of breath, for no reason. They may also have macrocytic and microcytic anemia.
Megaloblastic anemia occurs when red blood cells are higher than normal. Microcytic anemia occurs when there are fewer red blood cells than normal.
What Causes Sideroblastic Anemia?
There are two forms of sideroblastic anemia.
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The first inheritance results from mutations in genes involved in heme synthesis, iron and sulfur cluster biosynthesis, or mitochondrial metabolism.
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People can be born with sideroblastic anemia (SA congenital) and develop the disease as a result of a related disease, a mutation in a gene involved in heme (iron) synthesis, or exposure to certain metals, minerals, or drugs.
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Sideroblastic anemia is known to cause microcytic anemia and megaloblastic anemia, depending on the type of mutation.
What Are the Various Congenital Forms of Sideroblastic Anemia?
There are three different types of congenital sideroblastic anemia. Namely,
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X-Linked Sideroblastic Anemia: This is the most commonly reported form of congenital anemia. It develops when the gene that forms a specific enzyme ALAS2 mutates, creating a hemoglobin shortage.
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Autosomal Recessive Sideroblastic Anemia (ARCSA): This is the second most commonly reported form of sideroblastic anemia. ARCSA affects infants and young children and is a serious and life-threatening condition that happens when there is excessive iron in the blood.
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Maternal: Maternal congenital sideroblastic anemia (MRCSA) represents about 20 % of all CSA cases. It occurs when the MT-ATP6 gene mutates, affecting the mitochondrial function.
Congenital SA occurs when certain genes are mutated or changed, affecting the ability of red blood cells to function.
What Are the Acquired Forms of Sideroblastic Anemia?
There are two distinct types of acquired sideroblastic anemia: primary and secondary. Primary SA refers to SA associated with myelodysplastic syndromes. Secondary SA refers to SA that can occur after significant exposure to certain metals, chemicals, and drugs. Substances that can cause secondary sideroblastic anemia include,
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Alcohol: Alcohol use disorders are the most common cause of acquired sideroblastic anemia.
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Heavy Metal Poisoning: Includes lead and arsenic poisoning.
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Vitamin B Deficiency: Vitamin B aids in the production of heme, which becomes hemoglobin, which helps carry oxygen; hence deficiency leads to anemia.
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Copper Deficiency: Copper helps produce enzymes that protect against iron overload.
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Zinc Overdose: Too much zinc affects the way your body uses iron and absorbs copper. People get excessive zinc from supplements.
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Drugs: Some antibiotics, chemotherapy, hormones, and drugs that remove copper from the body can cause secondary acquired sideroblastic anemia. Health care providers treat this form of AS by evaluating drugs and ruling out drugs that appear to cause AS.
What Are Sideroblastic Anemia Symptoms?
As with many forms of anemia, symptoms of iron blasts are;
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Fatigue: Feeling tired enough to cope with daily activities.
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Shortness of Breath: A feeling of being unable to breathe.
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Palpitations: A feeling that the heart is beating abnormally fast.
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Headache: The feeling of throbbing pain in a particular area or the whole head.
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Discomfort: Unable to feel comfortable or relax at resting time.
People with X-linked sideroblastic anemia may have additional symptoms due to a lack of hemoglobin in the body and an excess of iron. These symptoms include;
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Hepatomegaly (Enlarged Liver): The liver controls many important functions of the body.
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Enlarged Spleen: The spleen is a fist-sized organ in the upper abdomen. If your spleen is larger than normal, it causes dull pain in your upper abdomen.
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Bronze Skin: If too much iron accumulates in the body, the skin may turn bronze or brown.
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Uncontrolled Diabetes: Systemic iron overload could contribute to abnormal glucose metabolism (type 2 diabetes).
How Do Healthcare Providers Diagnose Sideroblastic Anemia?
Doctors look for rings when looking at bone marrow stem cells under a microscope. Iron rings are a signal that cells are storing iron, not using it. Infants and young children who are born with sideroblastic anemia may have life-threatening medical illnesses stemming from iron overload.
Because people can inherit sideroblastic anemia, health care providers first evaluate the person's condition to confirm or rule out acquired sideroblastic anemia. If acquired SA is ruled out, your provider will do additional tests to determine what kind of congenital helminthic anemia you have. Tests that help to diagnose are-
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Complete Blood Cell Count (CBC): CBC results show the size and shape of your blood cells, the number of new blood cells your body is making, and the number of mature and immature red blood cells.
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Peripheral Blood Smear: This is a test your donor uses to look for blood cells. Unlike some blood tests, which use a machine to analyze your blood, your provider does the test by looking at your blood cells under a microscope.
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Iron Study: This test shows your iron levels.
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Bone Marrow Aspiration: A procedure in which a sample of the fluid portion of the bone marrow is taken.
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Bone Marrow Biopsy: In this test, the provider takes a small sample of bone marrow to test for bone marrow cells.
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Genetic Testing: Genetic testing can help identify or rule out certain genetic conditions. Genetic testing can also help people understand how likely they are to pass SA to their biological children.
How Is Sideroblastic Anemia Treated and Managed?
The treatment for sideroblastic anemia depends on the severity of the condition. For patients with a mild or asymptomatic condition, physicians can follow up in the outpatient clinic.
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For patients diagnosed with X-linked sideroblastic anemia, vitamin B6 and reducing the amount of iron in the bloodstream can help.
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For people who do not respond to pyridoxine, blood transfusion is indicated if they have severe anemia.
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For patients who need a chronic transfusion, iron chelation can be considered to prevent iron overload. Typically it is recommended to start Deferoxamine or oral chelators when serum ferritin is more than 1000 ng/L.
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Iron overload, if left unnoticed, could result in the unresponsiveness of pyridoxine. Therefore it is recommended that patients with normal hemoglobin levels after pyridoxine should get phlebotomy as a treatment for iron overload.
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Treatment for iron overload is required as studies have shown an improvement in anemia when iron overload is treated.
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For people with syndromic congenital sideroblastic anemia, diabetes mellitus can develop, and in such patients, strict glycemic control should be recommended.
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In case of secondary acquired sideroblastic anemia caused by known drugs or toxins, such drugs should be discontinued and avoided. Since it is acquired, the condition will improve after the withdrawal of the drug.
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Replacement of copper is required in a patient with copper deficiency via nutrition.
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Aspirin therapy is recommended for patients with MDS/MPN-RS-T if the patient has an additional JAK2V617F mutation.
How To Prevent This?
In many cases, sideroblastic anemia occurs when certain genes are mutated, causing a congenital form of sideroblastic anemia that cannot be prevented but is treatable. People with X-linked CSA and mild symptoms can ask the healthcare provider about genetic testing.
However, you can do the following to prevent some forms of acquired CSA. These steps include:
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Avoid accidental lead or arsenic poisoning.
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If you are taking zinc supplements to treat a cold, ask your healthcare provider about the appropriate dosage.
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Limit your alcohol intake. Alcohol abuse can lead to sideroblastic anemia. Try to reduce your daily alcohol intake. For assistance, contact your ISP for program recommendations.
What Is the Prognosis for People With Sideroblastic Anemia?
If you have congenital X-linked sideroblastic anemia, your health care provider may treat your condition with vitamin B6 and iron-lowering drugs. In X-linked sideroblastic anemia, proper replacement of Pyridoxine and management of iron overload will improve the prognosis.
How To Take Care of Oneself?
Most people with sideroblastic anemia need to constantly monitor their iron levels to prevent further iron overload. If you develop sideroblastic anemia, ask your healthcare provider what you can do to avoid new cases of AS.
What Is the Differential Diagnosis for Sideroblastic Anemia?
The differential diagnosis of sideroblastic anemia includes clonal and non-clonal disorders. Clonal disorders include myelodysplastic syndromes. Non-clonal disorders include congenital and secondary acquired disorders such as copper deficiency, zinc overload, lead poisoning, and isoniazid use.
Conclusion
Sideroblastic anemia is a less common blood disorder that can have serious medical complications. But infants born with this condition pose life-threatening medical illnesses.
