Case 1: Recurrent iron-deficiency anemia in a teenager

A 16-year-old girl was referred by her paediatrician for evaluation of persistent microcytic anemia. Two years previously, she presented to her local hospital complaining of fatigue and weakness. At that point, her hemoglobin level was 46 g/L, with a low mean corpuscular volume and decreased iron and ferritin levels. She had no evidence of gastrointestinal bleeding and was otherwise healthy. Furthermore, she reported a regular menstruation cycle without increase in blood loss. She received a blood transfusion and was started on iron supplements, to which she had a good response as her hemoglobin level rose up to 129 g/L. Her clinical symptoms also resolved and iron supplementation was discontinued one year later. However, on follow-up, her hemoglobin level dropped to 85 g/L. Again, her iron stores were considerably low. A hemoglobin electrophoresis was normal. She still had no history of overt bleeding, but one of three fecal occult blood tests was positive. She was then evaluated in our centre.

The physical examination was unremarkable apart from a small hemangioma of the tongue. Both upper endoscopy and colonoscopy showed no source of bleeding. A small bowel follow-through was normal.

Further investigations revealed the diagnosis.

CASE 1 DIAGNOSIS: SMALL BOWEL HEMANGIOMA

Given the positive fecal occult blood test, we elected to proceed with a videocapsule endoscopy to better assess the small intestine. Capsule endoscopy showed a bluish subepithelial mass in the mid-jejunum. To better evaluate the lesion, the patient then underwent single-balloon enteroscopy. This procedure showed a 2.5 cm-wide purple-red polypoid lesion of the mid-jejunum (Figure 1). Because the patient had a small hemangioma of the tongue, a small bowel hemangioma was suspected. No biopsy was attempted during single-ballon enteroscopy. A paediatric surgeon resected the affected segment of small bowel. Pathological examination confirmed a 3.0 cm x 1.8 cm capillary hemangioma. The recovery was uneventful.

Figure 1).

Single-balloon enteroscopy showing the polypoid lesion of the mid-jejunum

Hemangiomas are classified as benign vascular tumours. There are three types of intestinal hemangiomas: cavernous, capillary and mixed. The small intestine is the most common site of gastrointestinal hemangiomas, with the jejunum the most likely affected segment. Hemangiomas account for 7% to 10% of the benign tumours of the small bowel (1). These tumours may manifest as solitary or multiple lesions. Multiple lesions are typically associated with cutaneous vascular lesions or syndromes. Most patients present with either acute or chronic symptoms of gastrointestinal bleeding, including chronic microcytic anemia. Small bowel obstructions or intussusceptions have been reported as primary manifestations of large hemangiomas.

Microcytic anemia is a relatively common hematological condition in children. The differential diagnosis is quite broad and includes iron and copper deficiencies, anemia of chronic disease, sideroblastic anemia, lead poisoning and thalassemia. In iron-deficiency anemia, iron studies usually show decreased ferritin and serum iron levels, an elevated serum transferrin level and a high total iron binding capacity. Unless there is clear history of low dietary intake of iron, the clinician should initiate evaluation for a source of bleeding or a malabsorptive process. Beyond infancy, dietary iron deficiency is rare. Therefore, it should be regarded as a manifestation of an underlying disorder and not as a diagnosis. Malabsorptive conditions such as celiac disease and inflammatory bowel disease should be considered. As well, chronic occult blood loss should be investigated (esophagitis, peptic ulcer, vascular malformation). In girls, a careful history on menstrual blood loss should be taken. If investigations demonstrate occult gastrointestinal bleeding, this should prompt the clinician to find the source. When standard investigations, such as an upper endoscopy and a colonoscopy, fail to demonstrate a source, further evaluation for occult gastrointestinal bleeding is indicated. A small bowel follow-through is a useful tool; however, it may miss small lesions. Wireless capsule endoscopy is a noninvasive procedure that enables the visualization of the entire small bowel. As it progresses in the small bowel, several images of the mucosa are captured. The capsule may be either swallowed or inserted in the duodenum using an endoscope. It is limited by the fact that it does not permit tissue sampling or therapeutic intervention. There has been considerable literature regarding its safe use in paediatric patients (2). Another way to explore the small bowel is by using enteroscopy. This endoscopic procedure is also known as push-and-pull enteroscopy, and enables visualization and therapy of the entire small bowel. The endoscope is covered by an overtube that is also fitted with a balloon (commonly a double-balloon system). Serial inflation and deflation of balloons allow pleating of bowel on the back of the overtube and forward advancement of the enteroscope into a new segment of bowel. Recent studies have reported its safety and efficacy in paediatric patients.

In summary, recurrent or persistent iron-deficiency anemia must be investigated thoroughly. Occult gastrointestinal bleeding needs to be excluded.

CLINICAL PEARLS

• Iron-deficiency anemia in children needs to be investigated to identify a cause because dietary iron deficiency is rare beyond infancy.

• Occult gastrointestinal bleeding in children needs to be investigated with appropriate tests, including imaging of the entire gastrointestinal tract if no source is initially found.

• Vascular lesions of the small bowel, such as hemangioma, represent a rare but possible cause of recurrent or persistent iron-deficiency anemia in children.