From the Guidelines
Iron deficiency anemia without evident blood loss is typically caused by poor dietary intake, malabsorption of dietary iron, or increased iron requirements, and can be due to various underlying pathological abnormalities, including gastrointestinal pathologies, as stated in the 2021 British Society of Gastroenterology guidelines 1. The causes of iron deficiency anemia (IDA) without evident blood loss can be multifaceted, including:
- Poor dietary intake of iron
- Malabsorption of dietary iron, which can be due to various conditions such as celiac disease, as discussed in the 2024 AGA clinical practice update on management of iron deficiency anemia 1
- Increased iron requirements, such as during pregnancy or rapid growth periods
- Underlying gastrointestinal pathologies, which can be present in approximately a third of men and postmenopausal women presenting with IDA, as noted in the 2021 British Society of Gastroenterology guidelines 1 It is essential to investigate the underlying cause of IDA, as it can be a sign of an underlying pathological abnormality, and optimal management requires iron replacement therapy (IRT) in combination with appropriate investigation, as stated in the 2021 British Society of Gastroenterology guidelines 1. In patients with celiac disease, iron deficiency anemia can occur due to epithelial cell injury and subsequent duodenal villous atrophy, disrupting normal absorption, and improvement in iron status can occur in parallel with normalization of the histologic abnormalities in the small bowel, as discussed in the 2024 AGA clinical practice update on management of iron deficiency anemia 1. Therefore, it is crucial to address the underlying cause of IDA, and treatment should involve oral iron supplementation, with alternative formulations and intravenous iron formulations considered if necessary, as well as lifestyle modifications, such as consuming iron-rich foods, to prevent recurrence and improve quality of life, as supported by the 2021 British Society of Gastroenterology guidelines 1 and the 2024 AGA clinical practice update on management of iron deficiency anemia 1.
From the Research
Causes of Iron Deficiency Anemia (IDA) without Evident Blood Loss
- Atrophic gastritis, either autoimmune or due to Helicobacter pylori infection, may contribute to IDA 2
- Celiac disease, chronic inflammation, and bariatric surgery can lead to iron malabsorption, resulting in IDA 3
- Chronic kidney disease (CKD) is a common cause of IDA, with both absolute and functional iron deficiency occurring in CKD patients 4
- Disorders affecting iron absorption, such as inflammatory bowel disease, can also lead to IDA 5
- Increased demand for iron, such as during pregnancy, can cause IDA 2, 6
- Insufficient dietary intake of iron can lead to IDA, particularly in individuals with restricted diets or poor nutrition 2, 6
- Rare genetic disorders, such as TMPRSS6 mutations, can cause iron-refractory iron deficiency anemia 2
Associated Conditions
- Chronic heart failure and chronic inflammatory disorders can be associated with IDA, and diagnosis may incorporate transferrin saturation in these cases 2
- CKD patients with IDA are at increased risk of morbidity and mortality, with the association between anemia and mortality related to the severity of anemia 4
- IDA can occur in patients with cancer, and iron supplementation is often necessary to manage anemia in these patients 5