Gut 1993; 34: 1297-1299 1297 Gut Gut: first published as 10.1136/gut.34.10.1297 on 1 October 1993. Downloaded from Leading article A perspective on iron deficiency anaemia Patients with suspected iron deficiency anaemia account for In the absence of an obvious bleeding point, it is impossible some four per cent of the patients referred to our gastro- to be certain that bleeding originates from the angiodysplasia enterology clinic. The first step in the investigation of these until the rest ofthe gastrointestinal tract has been examined. patients is to confirm the presence of iron deficiency. The An upper gastrointestinal endoscopy should be performed to next is to find out if the deficiency is a result of gastro- exclude other abnormalities. Hereditary haemorrhagic intestinal blood loss or malabsorption. Menorrhagia is the telangiectasia often presents with iron deficiency anaemia major non-gastrointestinal cause of blood loss while dietary although it can be usually diagnosed on clinical examination. deficiency may be the sole cause or a contributing factor to Anal lesions and haemorrhoids usually cause frank bleed- the anaemia. ing rather than anaemia while bleeding from diverticulosis is Microcytosis is also seen in patients with anaemia of usually acute and massive. Anaemic patients with these chronic disease, the thalassaemia syndromes and, rarely, lesions require full investigation as they are unlikely to be the sideroblastic anaemia. A low serum ferritin or low serum iron cause ofthe anaemia even iffrank rectal bleeding is present.9 with raised total iron binding capacity is usually sufficient to Diverticulosis may complicate investigation of these confirm iron deficiency.' Occasionally these may be mislead- patients, particularly ifthe colon is being assessed by barium http://gut.bmj.com/ ing. For example, inflammatory conditions such as inflam- enema examination as the diverticula may conceal the matory bowel disease or rheumatoid arthritis may lead to a presence of adenomata or malignancy.'"1' Crohn's disease is spuriously high ferritin or low total iron binding capacity often associated with iron deficiency anaemia. Ulcerative even in the presence of iron deficiency. In cases of doubt a colitis may present with anaemia when bowel symptoms are bone marrow aspirate, which is the best guide to body iron mild or ignored. Faecal occult blood studies have also stores, should be examined.' uncovered previously unrecognised cases of ulcerative colitis."1 Low rectal or anal malignancy may be seen. on September 29, 2021 by guest. Protected copyright. Therefore sigmoidoscopy should be mandatory as part ofthe Colonic causes investigation ofpatients with iron deficiency anaemia. In the Western world, the most important cause of iron deficiency anaemia secondary to gastrointestinal blood loss is carcinoma of the colon. Different series have estimated it Upper gastrointestinal causes accounts for 4-13% ofoutpatients34 and 16% ofinpatients.' It Oesophagogastroduodenoscopy in patients with anaemia is important not to miss this diagnosis because the disease is often yields abnormal findings but it is not always clear if potentially fatal but can be cured ifresected at an early stage. these abnormalities are the cause of the anaemia. A study of Most tumours presenting with iron deficiency anaemia are elderly hospital inpatients with iron deficiency anaemia found on the right side of the colon. Although carcinoma of found a high incidence (16%) of dual pathology when both the colon is usually considered a disease oflate middle age or the upper and lower gastrointestinal tracts were examined.5 elderly patients, it can occur in younger patients, particularly Although the incidence of dual pathology may be less in if associated with ulcerative colitis or a polyposis syndrome. hospital outpatients populations (9-14%),' '3 it is recom- Sporadic cases are seen in patients in their 20s or early 30s.6 In mended that the lower gastrointestinal tract should be an adult population it cannot be excluded on the grounds examined in all patients presenting with anaemia, regardless of age alone. Bleeding adenomata can present with iron ofupper gastrointestinal endoscopy findings, except in those deficiency anaemia and should be resected. found to have malignancy ofthe upper gastrointestinal tract.4 Patients who are anti-coagulated and patients taking non- Peptic ulceration may cause chronic gastrointestinal blood steroidal anti-inflammatory drugs (NSAIDs) frequently loss as well as an acute bleed. It is commonly asymptomatic in become anaemic due to increased gastrointestinal blood loss. anaemic patients.'4 NSAIDs may unmask an ulcer by causing This anaemia is usually related to the presence of a lesion in bleeding. As NSAIDs may cause bleeding, however, the gastrointestinal tract, rather than to the drug itself.78 throughout the gastrointestinal tract, unless the ulcer has These patients should, therefore, be fully investigated to stigmata of bleeding, the possibility of lesions elsewhere exclude the possibility of colonic cancer, in addition to cannot be excluded. Studies with radiolabelled red cells and stopping the drugs (where possible). leucocytes suggest that, in 70% of patients with rheumatoid Angiodysplasia is commonly found in elderly patients with arthritis, NSAIDs are associated with inflammation and chronic gastrointestinal bleeding leading to iron deficiency. blood loss from the small intestine, especially in the region of 1298 Sayer, Long the terminal ileum.'5 NSAIDs may also trigger or exacerbate Although few patients under investigation for iron defici- bleeding from vascular lesions in the intestine as well as ency anaemia will be found to have bleeding from the small malignant lesions. Antral ectasia (watermelon stomach) and intestine, these lesions can be difficult to find and therefore a carcinoma of the stomach'6 have presented in this way. disproportionate amount of time is spent in investigating Gut: first published as 10.1136/gut.34.10.1297 on 1 October 1993. Downloaded from Severe erosive oesophagitis may be a cause of iron deficiency these patients. Barium studies including small bowel enema anaemia but hiatus hernia alone seems unlikely to cause iron are rarely helpful in this group of patients,423 although deficiency anaemia. occasionally they may be useful in younger patients who are found to have Crohn's disease or a Meckel's diverticulum. Distal small bowel lesions may also be shown by reflux at Small intestinal causes barium enema or by entering the terminal ileum at colono- Bleeding from the small bowel may occur either from scopy. mucosal lesions or intramural lesions. Enteroscopy has In a young patient with a negative gastroscopy and large identified three different types of mucosal lesion: red spot bowel study, a small bowel enema may be useful to exclude lesions with intact villi overlying them, erosions with Crohn's disease. If there is suspicion of a Meckel's diverti- damaged villi and discrete edges, and ulceration in which the culum an isotope scan may be helpful but it is important to thickness of the mucosa has been breached.'7 Mural lesions remember that this investigation carries a significant propor- include leiomyomata, carcinomata, small bowel lymphoma, tion of false negatives.24 In older patients the small bowel secondary tumour deposits, and lipomata. Superior enema is rarely helpful and the next investigation should be mesenteric angiography may also show these lesions and enteroscopy or mesenteric angiography.23 For patients who angiodysplasia. are bleeding acutely technetium-labelled red cell isotope scans or technetium-labelled sulphur colloid scans may provide additional information but when the rate ofbleeding Malabsorption is slow, as in most patients with iron deficiency anaemia, Inability to absorb iron also leads to anaemia. Iron deficiency these investigations are not helpful.26 may thus be found in postgastrectomy patients or patients For a few patients who experience severe or recurrent with untreated coeliac disease. Most studies of patients gastrointestinal bleeding of unknown origin, diagnostic presenting with anaemia find 2-3% of the population have laparotomy still has a place.27 The diagnostic yield at villous atrophy.3'8 It is important to remember that coeliac laparotomy can be improved by combining it with preopera- disease can present at any age and that iron deficiency tive or peroperative angiography to identify the bleeding anaemia may be the only presenting symptom. 19 segment of bowel and with on table endoscopy to find the lesion.2" Recommended plan ofinvestigation A recent study suggests that symptoms are an unreliable Outcome guide to the cause ofanaemia in patients with gastrointestinal Initial investigations including colonoscopy or sigmoido- blood loss.3 Relevant aspects of the history include drug scopy and barium enema and upper gastrointestinal endo- http://gut.bmj.com/ ingestion, particularly NSAIDs or anti-coagulants, a history scopy with duodenal biopsy will establish a cause for the of previous abdominal surgery such as gastrectomy, or of anaemia in 80% ofpatients. Enteroscopy has identified small radiotherapy, or a family history of bowel cancer or colonic intestinal lesions in a further 30-40% ofpatients in whom the polyps. Dietary iron intake should be assessed. Although this first line investigations were normal. Where there is a is rarely the sole cause of the iron deficiency, in one study it possibility that the anaemia may be exacerbated by drugs