Iron Deficiency in IBD:
An Interview with Tauseef Ali, MD

Dr Tauseef Ali is a Clinical Assistant Professor of Medicine at the University of Oklahoma in the section of Digestive Disease and Nutrition. He is the chief of Gastroenterology Section at Saint Anthony Hospital and the director of Inflammatory Bowel Disease Program and Research Center.


Continue Reading

Tauseef Ali MD, FACP, FACG, AGAF
@ibdtweets

 

What might account for the patient’s current complaints?

The most likely scenario is iron deficiency anemia, which is one of the most common extraintestinal manifestations in IBD. For this reason, we routinely screen for IDA in all of our patients who have active disease. At the early stages of IDA, patients may not be symptomatic, so regular screening must take place to ensure early detection and treatment. Certainly, typical symptoms of IDA such as fatigue, weakness, headaches, and irritability should immediately prompt further investigation. It is important to bear in mind that some of the symptoms of IDA can be similar to the symptoms of active disease, and sometimes can be confused with the side effects of the drugs the patient is taking, so an accurate diagnosis is essential, and IDA should always be included in the differential diagnosis.

What is the definition of anemia?

According to the World Health Organization (WHO), anemia is defined as hemoglobin levels <13g/dL (hematocrit <39%) in males; <12g/dL (hematocrit <36%) in nonpregnant females; and <11g/dL (hematocrit <33%) in pregnant females.1 Severe IDA is defined as hemoglobin levels <10g/dL.

Are there different types of anemia associated with IBD?

The two most common causes of anemia in IBD are anemia of chronic disease (ACD) and IDA. Patients with IDA and concomitant ACD generally have more severe anemia than those with ACD alone.

What are the pathological mechanisms that underlie IDA?

There are several mechanisms at work. One is that in IBD, patients frequently have acute or intermittently bloody stools, so they are losing iron from the loss of blood. Another is reduced iron absorption. In the case of Crohn’s disease, for example, inflammation in the duodenum, where iron is usually absorbed, blocks its absorption. Micronutrient deficiency due to inadequate intake of foods rich in iron and vitamin B12 is also implicated, since reduced appetite, nausea, diarrhea and vomiting affect the amount and types of food that the patient can eat. Myelosuppression can be a side effect of IBD medications, and medications such as omeprazole can interfere with iron absorption.

The impact of inflammation goes beyond its localized duodenal effects with resulting impaired absorption. Active inflammation itself causes the liver to overproduce hepcidin, an enzyme that interferes with iron absorption by trapping iron in the intestinal cells and preventing it from entering the bloodstream.2

Causes of IDA can be found in Table 1.

What type of diagnostic workup should the patient have?

IDA should be screened for by measuring hemoglobin, serum ferritin, and C-reactive protein (CRP). This should be done at least every 2 to 3 months for outpatients with active disease and once every 6 to 12 months for patients in remission or with mild disease.

For patients who meet WHO criteria for anemia, a further workup should be initiated to determine its cause. (Table 2)

It is important to keep in mind that the levels of serum ferritin in active inflammation are different from those in patients with quiescent IBD without biochemical or clinical evidence of inflammation. Ordinarily, iron deficiency is defined as serum ferritin <30ng/mL or transferrin saturation (TSAT) <16%. In the presence of active IBD with inflammation, as evidenced by elevated CRP, the serum ferritin cutoff level is higher (<100ng/mL).

Mr W’s Laboratory Findings

  • Hgb 10.3g/dL
  • Ferritin 40ng/mL
  • CRP 8mg/dL