Management of Iron Deficiency Anemia Kristine Jimenez, MD, Stefanie Kulnigg-Dabsch, MD, and Christoph Gasche, MD Dr Jimenez is a fellow in gastroenterology, Abstract: Anemia affects one-fourth of the world’s population, Dr Kulnigg-Dabsch is a specialist in internal and iron deficiency is the predominant cause. Anemia is asso- medicine, and Dr Gasche is a specialist in ciated with chronic fatigue, impaired cognitive function, and internal medicine, gastroenterology, and diminished well-being. Patients with iron deficiency anemia of hepatology and is an associate professor at the Medical University of Vienna in Vienna, unknown etiology are frequently referred to a gastroenterologist Austria. Dr Gasche is also the founder and because in the majority of cases the condition has a gastrointesti- head of Loha for Life, Centre of Excellence nal origin. Proper management improves quality of life, alleviates for Iron Deficiency in Vienna, Austria. the symptoms of iron deficiency, and reduces the need for blood transfusions. Treatment options include oral and intravenous iron Address correspondence to: therapy; however, the efficacy of oral iron is limited in certain Dr Christoph Gasche Division of Gastroenterology and Hepatology gastrointestinal conditions, such as inflammatory bowel disease, Medical University of Vienna celiac disease, and autoimmune gastritis. This article provides a Währinger Gürtel 18-20 critical summary of the diagnosis and treatment of iron deficiency 1090 Vienna anemia. In addition, it includes a management algorithm that can Austria help the clinician determine which patients are in need of further Tel: +43-1-40400-47640 gastrointestinal evaluation. This facilitates the identification and Fax: +43-1-40400-47350 E-mail: [email protected] treatment of the underlying condition and avoids the unnecessary use of invasive methods and their associated risks. nemia affects one-fourth of the world’s population, accounting for 8.8% of the total global burden of disease.1,2 Iron deficiency is the predominant cause of anemia across countries and in Aboth sexes, with women more commonly afflicted.1,2 The prevalence of anemia increases with age3 and in the hospital setting. Anemia decreases the capacity for work and increases health care costs.4,5 Iron deficiency is also associated with restless legs syndrome (RLS), diminished qual- ity of life, fatigue, impaired cognitive function, and infertility, all of which may occur in the absence of anemia and may be reversed with iron therapy.6-21 Gastrointestinal conditions, such as celiac disease and inflammatory bowel disease (IBD), as well as chronic kidney disease (CKD), cancer, and chronic heart failure (CHF) increase the risk for anemia and iron deficiency,22-30 and iron deficiency may influence clini- cal outcome. In CHF, iron deficiency is associated with an increased Keywords risk of mortality, regardless of the hemoglobin (Hb) level.29,30 Iron Anemia of chronic disease, intravenous iron, iron deficiency anemia, iron replacement therapy, oral deficiency is also associated with reactive thrombocytosis, potentially 31-38 iron, hemoglobin increasing the risk for thromboembolic events. Gastroenterology & Hepatology Volume 11, Issue 4 April 2015 241 JIMENEZ ET AL Diagnosed IDAa Iron replacement b Heavy uterine Age ≥50 years Noninvasive tests Ob/Gyn bleeding or family history of GI disease or GI symptoms or male (Hb <13.0 g/dL) or female (Hb <10.0 g/dL) Positive Negative Inappropriate Check response to Appropriate iron replacement (at 4-8 weeks) Consider EGD and/or IV iron Follow-up after colonoscopy 3-6 months Figure. A proposed algorithm for the management of iron deficiency anemia (IDA). a Endurance athletes and pregnant women should be treated without further diagnostic testing. b Celiac serology, anti–parietal cell antibody, Helicobacter pylori (stool), and fecal occult blood test. EGD, esophagogastroduodenoscopy; GI, gastrointestinal; Hb, hemoglobin; IV, intravenous; Ob/Gyn, obstetrics/gynecology. Patients with iron deficiency anemia of uncertain cytes, macrophages, or hepatocytes. Erythropoiesis is iron etiology are usually referred to a gastroenterologist restricted; anemia develops despite adequate iron stores, because gastrointestinal conditions are the most common and erythrocytes may appear normocytic or microcytic.45 causes,39-43 with only menstrual blood loss in premeno- This is the basis of anemia of chronic disease (ACD), in pausal women a more frequent cause. This article concurs which inflammation leads to the overexpression of hep- with most of the recommendations of the British Society cidin, blocking the absorption of iron by enterocytes and of Gastroenterology44; however, we propose an alterna- its release from macrophages and hepatocytes.45,46 Thus, tive, streamlined management algorithm (Figure). oral iron is ineffective, and intravenous iron is preferred. In certain patients (eg, those with IBD), the combina- Pathophysiology tion of iron deficiency and inflammation may result in significant anemia, which must be considered during Anemia resulting from iron-restricted erythropoiesis management and therapy. occurs through several mechanisms. In pure iron defi- ciency, depleted iron stores are due to an imbalance Diagnosis between iron uptake and utilization. Anemia may not be present initially because of iron recycling from erythro- The World Health Organization defines anemia as a level cyte turnover. However, iron deficiency alone is associated of Hb below 13.0 g/dL in male adults, below 12.0 g/dL with fatigue and RLS, so patients may be symptomatic in female adults who are not pregnant, and below 11.0 without anemia.16-18 The persistence of a negative balance g/dL in pregnant women.47 Hb levels may vary across age leads to microcytic and hypochromic anemia. Adequate and race,48 so care must be taken, particularly in the inter- iron repletion and management of the cause of iron defi- pretation of borderline values. Furthermore, smokers and ciency (Table 1) lead to resolution. inhabitants of higher altitudes may have higher baseline Functional iron deficiency, in contrast, is due to Hb levels,49,50 and participation in endurance sports may impaired iron release into the circulation from entero- alter Hb levels.51 242 Gastroenterology & Hepatology Volume 11, Issue 4 April 2015 MANAGEMENT OF IRON DEFICIENCY ANEMIA Table 1. Causes of Iron Deficiency the use of thiopurine medications (eg, azathioprine in IBD) Diminished Uptake can lead to a combination of iron deficiency anemia and Malabsorption macrocytosis, with resultant normocytic anemia. In this • Celiac disease situation, a wide red cell distribution width aids identifica- 52 • Duodenal resection/gastric bypass surgery tion of the iron deficiency component. The platelet and • Inflammatory bowel disease (ileal-jejunal disease and/or leukocyte counts help to rule out pancytopenia. Thalas- anemia of chronic disease) semia traits also present with microcytic, hypochromic • Helicobacter pylori gastritis anemia and should be considered in populations in which • Autoimmune gastritis these traits are highly prevalent. Further parameters to diag- Dietary causes nose iron deficiency are the transferrin saturation (TfS), • Malnutrition which reflects the iron available for erythropoiesis, and the • High intake of phytates, polyphenols serum level of ferritin, an iron storage protein.53,54 A TfS Increased Demand below 20% and a ferritin level lower than 30 ng/mL are indicative of iron deficiency. However, ferritin is an acute • Pregnancy, lactation phase protein that increases during inflammation. Inflam- • Childhood matory parameters such as C-reactive protein help identify • Erythropoiesis-stimulating agents (in chronic kidney these situations. Different cutoff values are used in the pres- disease, chemotherapy-induced anemia) ence of inflammatory comorbidities—such as IBD (<100 Enhanced Loss ng/mL),53,54 CKD (<500 ng/mL plus TfS <30%),55 Gynecologic causes and CHF (<100 ng/mL or <100-299 ng/mL plus TfS • Meno(metro)rrhagia (myoma, endometriosis, bleeding <20%)56—to diagnose iron deficiency. If the diagnosis disorders) remains unclear, the soluble transferrin receptor (sTfR) • Uterine cancer and sTfR/log ferritin index (<1) can be used to distinguish Gastrointestinal causes between iron deficiency anemia and ACD because the 57-59 • Malignancy sTfR is elevated only in iron deficiency anemia. • Upper gastrointestinal blood loss – Gastric/duodenal ulcer Management of Iron Deficiency Anemia – Variceal bleeding – Esophagitis, erosive gastritis There is clear evidence to support prompt treatment in all – Mallory-Weiss syndrome patients with iron deficiency anemia because it is known – Angiodysplasia, vascular ectasia that treatment improves quality of life and physical condi- – Dieulafoy lesions tion as well as alleviates fatigue and cognitive deficits.8-20 – Rare: Meckel diverticula, Cameron lesions Although clear evidence is lacking, iron deficiency without • Lower gastrointestinal blood loss anemia is associated with RLS and chronic fatigue, and – Diverticulosis/diverticulitis treatment alleviates these symptoms.7,14-18 In CHF, iron – Hemorrhoids, anal fissures, rectal ulcers – Angiodysplasia replacement therapy has been shown to be beneficial, even 8,12-14 – Inflammatory bowel disease when anemia is not present. Thus, the decision to treat – Infectious colitis iron deficiency in a patient without manifest anemia must 53,54 Other causes be made on an individual basis. The treatment of iron • Surgery,