Iron-Deficiency Anemia in Children With Congenital Heart Diseases

Introduction

Iron is an important micronutrient that plays a vital role in cell growth, differentiation, and the formation of hemoglobin, myoglobin, and various oxygen-carrier enzymes. Iron deficiency is the most common nutritional disorder in the world. According to the World Health Organization (WHO), iron deficiency anemia can have a negative impact, especially on women of reproductive age and school-going children. Iron deficiency in infancy, with or without anemia, is known to be associated with social and behavioral problems in adolescence. It also reduces their physical performance and affects psycho-motor development. According to research, the prevalence of iron deficiency anemia is found to be high in children with congenital heart disease.

What Are Congenital Heart Diseases in Children?

Congenital heart diseases are defects that are present at birth and affect the structure and functioning of the heart. It can range from mild (a small hole in the heart) to severe (poorly developed or missing parts of the heart). Approximately one in four babies born with defects in the heart can have a critical congenital heart defect (critical CHD) that may require surgery or other treatments during the first year of life. However, few congenital heart defects can be simple and may not require any treatment. Serious congenital heart diseases are associated with symptoms such as cyanosis, rapid breathing, shortness of breath, fainting, and swelling in the hands, legs, and feet. Some of the common congenital heart diseases in children include:

• Atrial septal defect (ASD) (a hole in the heart wall that divides the upper chambers of the heart).

• Ventricular septal defect (VSD) (a hole in the heart wall that divides the heart's lower chambers).

• Patent ductus arteriosus (a persistent opening between the major blood vessels that skips blood circulation to the lungs)

• Coarctation of the aorta (narrowing of the aorta).

• Atrioventricular canal defect (holes in between the chambers of the heart).

• Pulmonary valve stenosis (narrowing the pulmonary valve, which reduces blood flow to the lungs).

How Is Iron Deficiency Anemia in Children Associated With Congenital Heart Diseases?

Poor nutritional practices and early weaning are known to be associated with micronutrient deficiencies and malnutrition in children. Iron deficiency anemia is the most common form of anemia in young children. The risk for anemia is higher after six months in children as they are introduced to complementary foods and prone to being exposed to contaminants and infections. In children or infants with congenital heart disease (CHD), iron deficiency anemia can exacerbate left ventricular dysfunction (weak pumping of the heart) and heart failure. This causes hypoxia (reduced oxygen) in the tissues and increases the blood viscosity due to increased red blood cell mass.

Studies conducted on children between the ages of two weeks and 13.5 years with congenital heart disease (VSD) assessed the prevalence of anemia and risk factors associated with iron deficiency (ID) or iron deficiency anemia (IDA). The result was found to be 26.9 percent and 20.2 percent, respectively, for ID and IDA in children below five years of age with congenital heart disease. It was also understood that early weaning, a history of recent illness, and less consumption of red meat were associated with iron deficiency or iron deficiency anemia in children with CHD, and cyanotic congenital heart disease (CCHD) was considered a risk factor for iron deficiency, and iron deficiency anemia more than cyanotic congenital heart disease. It is explained by the physiological response of a rise in erythropoietin (EPO) (a hormone responsible for stimulating RBC production), causing an increase in the production of red blood cells (RBCs) and resulting in iron deficiency due to increased demand. These children mostly exhibit symptoms such as anorexia (loss of appetite), irritability, poor weight gain, and dyspnea (difficulty breathing).

How Can Iron Deficiency Anemia Be Managed in Children With Congenital Heart Diseases?

It is important to accurately diagnose iron deficiency in children and manage it appropriately to avoid future complications. Diagnosing IDA in children with congenital heart disease usually involves expensive resources and is constrained to certain environments. Another important factor is that hemoglobin, red blood cell count, and hematocrit values are mostly unreliable in diagnosing iron deficiency anemia in children with CHD.

However, studies have suggested that the determination of red blood cell distribution width (RDW), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) values can help diagnose iron deficiency in children with cyanotic congenital heart disease. The median values of MCH and MCV were significantly reduced and showed the presence of microcytic cells, thus indicating iron deficiency anemia.

The management of iron deficiency anemia in children with congenital heart disease depends on the hemoglobin status and severity of the condition. It includes oral iron supplements, intravenous iron therapy, and blood transfusion as treatment options. According to iron supplementation guidelines, it is recommended that iron-sufficient children with a hematocrit below 60 percent should be given low-dose iron supplements, which is up to 3 mg/kg (milligram per kilogram) Ferrous sulfate three times a day for four weeks to prevent iron deficiency later in life. Routine screening of children with congenital heart disease must be emphasized, and early management must be considered. Iron treatment for about three months was also observed to increase the hemoglobin and hematocrit levels in children with CCHD without increasing the blood viscosity. It also reduced the clinical symptoms.

Conclusion

Congenital heart disease is a spectrum of heart diseases present at birth and affecting the heart’s structure and major blood vessels. Patients with CHD mostly have low oxygen saturation in the blood due to inappropriate intracardiac communication. The requirement for increased circulating hemoglobin in cyanotic children creates severe stress on iron production and dietary supply, causing iron deficiency anemia. These patients are at a high risk of blood viscosity and tissue hypoxia, resulting in hyper-cyanotic attacks and thromboembolism in children, especially those below four years of age. However, early diagnosis, appropriate intervention, and management of the condition are highly necessary for children with iron deficiency anemia and congenital heart disease.