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Second capsule endoscopy for patients with severe iron deficiency anemia
Second capsule endoscopy for patients with severe iron deficiency anemia Simon Bar-Meir, MD, Rami Eliakim, MD, Moshe Nadler, MD, Olga Barkay, MD Zvi Fireman, MD, Eitan Scapa, MD, Yehuda Chowers, MD, Eytan Bardan, MD Haifa, Tel-Aviv, Haedera, and Zrifin, Israel
Background: Patients with iron deficiency anemia are subjected to multiple endoscopic and radiologic examinations of the GI tract. If negative, some of the examinations are repeated, occasionally with positive findings. The diagnostic yield of a second capsule endoscopy in such patients is unknown. The aim of the current study was to assess the diagnostic yield of a second capsule endoscopy in patients with significant iron deficiency anemia and a previous negative evaluation. Methods: Twenty patients with iron deficiency anemia (Hb < 10 g/dL) were enrolled. All had at least one normal evaluation of the GI tract, including capsule endoscopy. A second capsule endoscopy examination was offered to all patients. Results: The time between the first and the second capsule endoscopy ranged from 2 months to 1 year. Depending on the nature of an abnormality and its relevance to blood loss, the findings were classified as positive, suspicious, clinically irrelevant, or negative. In 7 patients, the second capsule endoscopy disclosed findings that were classified as either positive or suspicious findings, including arteriovenous malformations (2), flat polypoid lesion (1), edematous inflamed mucosa (1), erosions (1), and hemorrhagic gastritis (1). Lesions were located in the small intestine (5), the stomach (1), and the cecum (1). Based on the findings of the second capsule endoscopy, therapy was changed in two patients (10%). Conclusions: A second capsule endoscopy should be considered for patients with severe iron deficiency anemia and negative initial evaluation. (Gastrointest Endosc 2004;60:711-3.)
The management of patients with GI bleeding of obscure origin is a challenge. Such patients may present with either overt (melena or maroon stools) or occult (iron deficiency anemia) bleeding. By definition, repeated upper and lower endoscopy and barium contrast radiography of the small bowel are unrevealing in patients with obscure GI bleeding. The small intestine is thought to be the site of bleeding in most of these patients. With the incorporation of capsule endoscopy into the evaluation of patients with obscure GI bleeding, a bleeding site reportedly is detected in two thirds of cases,1-3 80% of Received May 7, 2004. For revision July 1, 2004. Accepted July 16, 2004. Current affiliations: Department of Gastroenterology, Chaim Sheba Medical Center, Tel Hashomer, Israel, Department of Gastroenterology, Rambam Medical Center, Haifa, Israel, Department of Gastroenterology, Soraski Medical Center, Tel-Aviv, Israel, Department of Gastroenterology, Hillel Yaffe Medical Center, Haedera, Israel, Department of Gastroenterology, Assaf Harofe Medical Center, Zrifin, Israel, Sackler Medical School, Tel Aviv University, Tel Aviv, Israel, Rapport Medical School, Technion, Israel. Reprint requests: Simon Bar-Meir, MD, Department of Gastroenterology, Chaim Sheba Medical Center, Tel-Hashomer 52621, Israel. Copyright Ó 2004 by the American Society for Gastrointestinal Endoscopy 0016-5107/$30.00 PII: S0016-5107(04)02051-6 VOLUME 60, NO. 5, 2004
which are arteriovenous malformations in patients older than 60 years.4 For patients under the age of 50 years, the most common cause of such bleeding is a small intestinal tumor.4 However, despite capsule endoscopy, an etiology for iron deficiency anemia is not established in many cases. The present study assessed the diagnostic yield of a second capsule endoscopy in patients with iron deficiency anemia in whom a first capsule study did not reveal the site of bleeding. PATIENTS AND METHODS Patients with significant iron deficiency anemia (Hb < 10 g/dL) were enrolled in the study. All patients had undergone upper and lower GI endoscopy, barium contrast radiography of the small bowel, abdominal CT, and push enteroscopy at least once, with negative results. Scintigraphy for Meckel’s diverticulum was obtained in 11 patients and was normal. The first capsule endoscopy (performed in all patients) did not detect any abnormality. Review of the history and the physical examination was non-contributory. A second capsule endoscopy was offered to all patients. Each of the two capsule studies was evaluated by two independent observers who used software provided by the capsule endoscope manufacturer (RAPID; Given Imaging Co., Yokneam, Israel). Findings on the second capsule endoscopy were defined as positive, if the detected abnormality seemed to be the cause for blood loss; suspicious, if the lesion could potentially be the site of GASTROINTESTINAL ENDOSCOPY
711
S Bar-Meir, R Eliakim, M Nadler, et al.
Second capsule endoscopy for patients with severe iron deficiency anemia
Table 1. Findings on second capsule endoscopy Findings No. patients
Positive
Suspicious
Clinically irrelevant
Normal
4
3
3
10
bleeding; clinically irrelevant, if the lesion seemed not to be the source of bleeding; and normal. The study was approved by the ethics committee of our hospital, and written informed consent was obtained from all patients.
RESULTS Twenty patients (13 men, 7 women; mean age 50 years, range 21-78 years) were enrolled. The Hb level in all patients was less than 10 g/dL, the lowest value being 4.5 g/dL. Bleeding was occult in 13 patients and was overt in 7. The latter manifested as melena in 5 patients and passage of bright red blood per rectum in two. The findings of the second capsule endoscopy are shown in Table 1. The capsule endoscopy findings were classified as positive for a source of bleeding in 4 patients and were suggestive (suspicious) in 7 patients. The abnormalities identified and their location are shown in Table 2. Thus, the second capsule endoscopy detected a clinically relevant abnormality in 35% of patients. Based on the presence or the absence of findings on the second capsule endoscopy, a therapeutic procedure was performed in 3 patients. One patient underwent another colonoscopy that confirmed the presence of a flat polypoid lesion in the cecum, and right hemicolectomy was performed. The lesion proved to be a villous adenoma with moderate dysplasia. Another patient with a normal second capsule endoscopy had band ligation of hemorrhoids. Bleeding recurred in a third patient 1 week after the second capsule study with normal findings. He underwent surgery with intra-operative enteroscopy at which 30 cm of terminal ileum were resected because of the presence of clots. No abnormality was detected in the resection specimen. At interoperative enteroscopy, minute arteriovenous malformations also were treated by argon plasma coagulation. All patients were followed for at least 1 year. Fourteen were taking supplemental iron; Hb levels in these patients ranged from 11 to 15 g/dL. One patient with erosive gastritis was treated with omeprazole with normalization of the Hb level. The anemia resolved spontaneously in another 3 patients in whom the second capsule study was normal. The Hb level also normalized for the patient who had hemorrhoid ligation and the patient who underwent right hemicolectomy. The patient in whom 712
GASTROINTESTINAL ENDOSCOPY
the terminal ileum was resected continued to bleed and died 4 months later of sepsis unrelated to the bleeding episodes. DISCUSSION A second capsule endoscopy examination detected abnormalities of potential clinical relevance in 35% of patients with significant iron deficiency anemia. The abnormalities seemed to be the definite cause for the anemia in 20% and a possible cause in another 15% of patients. In 3 patients, the findings were within reach of conventional endoscopic examinations. In all of these patients, the findings were confirmed endoscopically. In patients with iron deficiency anemia, lesions may be missed at standard upper endoscopy and later identified by enteroscopy. From 20% to 30% of such lesions are within the range of examination possible withastandard upper endoscope.5 Similarly, the present study found abnormalities that were missed by both standard and capsule endoscopy examinations. Landil et al.6 and Schilling et al.7 found that bleeding recurred in 28% to 31% of patients with iron deficiency anemia of obscure origin. Thus, a site of bleeding may be overlooked despite extensive diagnostic evaluation. Lewis and Waye8 performed push and Sonde enteroscopy in 504 patients with obscure GI bleeding. These studies yielded positive findings in 42% of patients, including angioectasias in 80% and small intestinal tumors in 10%. The high risk of recurrent bleeding and the types of abnormalities that cause bleeding justify a concerted effort to identify the source of bleeding. However, the economic burden of such investigation is significant. The costs of diagnosis and treatment for a patient with obscure GI bleeding is on average $33,630 and includes the cost of upper and lower endoscopy, enteroscopy, radiologic studies, and hospitalization with blood transfusions.9 Moreover, negative studies result in repeated examinations. In the study of Foutch et al.10 of 39 patients with obscure GI bleeding, a total of 316 diagnostic procedures were performed, an average of 8.1 examinations per patient. All patients in the present study underwent extensive evaluation, including capsule endoscopy, without identification of a source of bleeding. Nevertheless, patients with clinically significant iron deficiency anemia usually undergo repeated diagnostic procedures. Because most of the lesions in these patients are located in the small intestine, a second capsule endoscopy should be considered. Barium contrast radiography of the small bowel, the alternative examination, reveals lesions in only 5% of patients with obscure GI bleeding.11-13 In contrast, VOLUME 60, NO. 5, 2004
Second capsule endoscopy for patients with severe iron deficiency anemia
S Bar-Meir, R Eliakim, M Nadler, et al.
Table 2. Patients with positive findings on second capsule endoscopy Patient/pathology 1 2 3 4 5 6 7
Finding
Location
Therapeutic intervention
Anemia status
Flat polypoid lesions Gastritis, erosions, small gastric ulcer AV malformation AV malformation Edematous elevated mucosa with loss of villi Edematous mucosa with erosions Erosions
Cecum Stomach Small bowel Small bowel Small bowel Small bowel Small bowel
Right hemicolectomy PPI therapy Iron therapy Iron therapy Iron therapy None Iron therapy Hemorrhoid ligation
Resolved Resolved Resolved Resolved Persists Resolved Persists
PPI, Proton pump inhibitor; AV, anteriovenous.
a second capsule endoscopy revealed either a definite or suspected source of bleeding in 35% of patients in the present study. The number of patients in the current study is relatively small, and further studies with larger numbers of patients are warranted. Until such data are available, it is our belief that a second capsule endoscopy should be considered for patients with significant iron deficiency anemia and a negative evaluation that included capsule endoscopy. DISCLOSURE STATEMENT Two of the authors (Z.F., E.S.) serve on the advisory board of Given Imaging Co. REFERENCES 1. Scapa E, Jacob H, Lewkowicz S, Migdal M, Gat D, Gluckhovski A, et al. Initial experience of wireless-capsule endoscopy for evaluating occult gastrointestinal bleeding and suspected small bowel pathology. Am J Gastroenterol 2002; 97:2776-9. 2. Van Gossum A, Hittlet A, Schmit A, Francois E, Deviere J. A prospective study of push and wireless-capsule enteroscopy in patients with obscure digestive bleeding. Acta Gastroenterol Belg 2003;66:199-205. 3. Ell C, Remke S, May A, Helou L, Henrich R, Mayer G. The first prospective controlled trail comparing wireless capsule endoscopy with push enteroscopy in chronic gastrointestinal bleeding. Endoscopy 2002;34:685-9.
VOLUME 60, NO. 5, 2004
4. Lewis B, Goldfarb N. Review article: the advent of capsule endoscopy—a not-so-futuristic approach to obscure gastrointestinal bleeding. Aliment Pharmacol Ther 2003;17:1085-96. 5. Zaman A, Katon RM. Push enteroscopy for obscure gastrointestinal bleeding yields a high incidence of proximal lesions within the reach of a standard endoscope. Gastrointest Endosc 1998;47:372-6. 6. Landi B, Cellier C, Gandric M, Demont H, Guimbaud R, Cuillerier E, et al. Long-term outcome of patients with gastrointestinal bleeding of obscure origin explored by push enteroscopy. Endoscopy 2002;34:355-9. 7. Schilling D, Grieger G, Weidmann E, Adamek HE, Benz C, Riemann JF. Long-term follow-up of patients with iron deficiency anemia after a close endoscopic examination of the upper and lower gastrointestinal tract. Z Gastroenterol 2000;38:827-31. 8. Lewis B, Waye J. small bowel enteroscopy for obscure gastrointestinal bleeding. Gastrointest Endosc 1991;37:A277. 9. Goldfarb N, Phillips A, Conn M, Lewis B, Nash D. Economic and health outcomes of capsule endoscopy. Dis Manag 2002; 5:123-35. 10. Foutch PG, Sawyer R, Sanowski R. Push-enteroscopy for diagnosis of patients with gastrointestinal bleeding of obscure origin. Gastrointest Endosc 1990;36:337-41. 11. Bowden TA. Endoscopy of the small intestine. Surg Clin North Am 1989;69:1237-47. 12. Rabe FE, Becker GJ, Begozzi MJ, Miller RE. Efficacy study of the small bowel examination. Radiology 1981;140:47-50. 13. Gordon SR, Smith RE, Power GC. The role of endoscopy in the evaluation of iron deficiency anemia in patients over the age of 50. Am J Gastroenterol 1994;89:1963-7.
GASTROINTESTINAL ENDOSCOPY
713
Background: Patients with iron deficiency anemia are subjected to multiple endoscopic and radiologic examinations of the GI tract. If negative, some of the examinations are repeated, occasionally with positive findings. The diagnostic yield of a second capsule endoscopy in such patients is unknown. The aim of the current study was to assess the diagnostic yield of a second capsule endoscopy in patients with significant iron deficiency anemia and a previous negative evaluation. Methods: Twenty patients with iron deficiency anemia (Hb < 10 g/dL) were enrolled. All had at least one normal evaluation of the GI tract, including capsule endoscopy. A second capsule endoscopy examination was offered to all patients. Results: The time between the first and the second capsule endoscopy ranged from 2 months to 1 year. Depending on the nature of an abnormality and its relevance to blood loss, the findings were classified as positive, suspicious, clinically irrelevant, or negative. In 7 patients, the second capsule endoscopy disclosed findings that were classified as either positive or suspicious findings, including arteriovenous malformations (2), flat polypoid lesion (1), edematous inflamed mucosa (1), erosions (1), and hemorrhagic gastritis (1). Lesions were located in the small intestine (5), the stomach (1), and the cecum (1). Based on the findings of the second capsule endoscopy, therapy was changed in two patients (10%). Conclusions: A second capsule endoscopy should be considered for patients with severe iron deficiency anemia and negative initial evaluation. (Gastrointest Endosc 2004;60:711-3.)
The management of patients with GI bleeding of obscure origin is a challenge. Such patients may present with either overt (melena or maroon stools) or occult (iron deficiency anemia) bleeding. By definition, repeated upper and lower endoscopy and barium contrast radiography of the small bowel are unrevealing in patients with obscure GI bleeding. The small intestine is thought to be the site of bleeding in most of these patients. With the incorporation of capsule endoscopy into the evaluation of patients with obscure GI bleeding, a bleeding site reportedly is detected in two thirds of cases,1-3 80% of Received May 7, 2004. For revision July 1, 2004. Accepted July 16, 2004. Current affiliations: Department of Gastroenterology, Chaim Sheba Medical Center, Tel Hashomer, Israel, Department of Gastroenterology, Rambam Medical Center, Haifa, Israel, Department of Gastroenterology, Soraski Medical Center, Tel-Aviv, Israel, Department of Gastroenterology, Hillel Yaffe Medical Center, Haedera, Israel, Department of Gastroenterology, Assaf Harofe Medical Center, Zrifin, Israel, Sackler Medical School, Tel Aviv University, Tel Aviv, Israel, Rapport Medical School, Technion, Israel. Reprint requests: Simon Bar-Meir, MD, Department of Gastroenterology, Chaim Sheba Medical Center, Tel-Hashomer 52621, Israel. Copyright Ó 2004 by the American Society for Gastrointestinal Endoscopy 0016-5107/$30.00 PII: S0016-5107(04)02051-6 VOLUME 60, NO. 5, 2004
which are arteriovenous malformations in patients older than 60 years.4 For patients under the age of 50 years, the most common cause of such bleeding is a small intestinal tumor.4 However, despite capsule endoscopy, an etiology for iron deficiency anemia is not established in many cases. The present study assessed the diagnostic yield of a second capsule endoscopy in patients with iron deficiency anemia in whom a first capsule study did not reveal the site of bleeding. PATIENTS AND METHODS Patients with significant iron deficiency anemia (Hb < 10 g/dL) were enrolled in the study. All patients had undergone upper and lower GI endoscopy, barium contrast radiography of the small bowel, abdominal CT, and push enteroscopy at least once, with negative results. Scintigraphy for Meckel’s diverticulum was obtained in 11 patients and was normal. The first capsule endoscopy (performed in all patients) did not detect any abnormality. Review of the history and the physical examination was non-contributory. A second capsule endoscopy was offered to all patients. Each of the two capsule studies was evaluated by two independent observers who used software provided by the capsule endoscope manufacturer (RAPID; Given Imaging Co., Yokneam, Israel). Findings on the second capsule endoscopy were defined as positive, if the detected abnormality seemed to be the cause for blood loss; suspicious, if the lesion could potentially be the site of GASTROINTESTINAL ENDOSCOPY
711
S Bar-Meir, R Eliakim, M Nadler, et al.
Second capsule endoscopy for patients with severe iron deficiency anemia
Table 1. Findings on second capsule endoscopy Findings No. patients
Positive
Suspicious
Clinically irrelevant
Normal
4
3
3
10
bleeding; clinically irrelevant, if the lesion seemed not to be the source of bleeding; and normal. The study was approved by the ethics committee of our hospital, and written informed consent was obtained from all patients.
RESULTS Twenty patients (13 men, 7 women; mean age 50 years, range 21-78 years) were enrolled. The Hb level in all patients was less than 10 g/dL, the lowest value being 4.5 g/dL. Bleeding was occult in 13 patients and was overt in 7. The latter manifested as melena in 5 patients and passage of bright red blood per rectum in two. The findings of the second capsule endoscopy are shown in Table 1. The capsule endoscopy findings were classified as positive for a source of bleeding in 4 patients and were suggestive (suspicious) in 7 patients. The abnormalities identified and their location are shown in Table 2. Thus, the second capsule endoscopy detected a clinically relevant abnormality in 35% of patients. Based on the presence or the absence of findings on the second capsule endoscopy, a therapeutic procedure was performed in 3 patients. One patient underwent another colonoscopy that confirmed the presence of a flat polypoid lesion in the cecum, and right hemicolectomy was performed. The lesion proved to be a villous adenoma with moderate dysplasia. Another patient with a normal second capsule endoscopy had band ligation of hemorrhoids. Bleeding recurred in a third patient 1 week after the second capsule study with normal findings. He underwent surgery with intra-operative enteroscopy at which 30 cm of terminal ileum were resected because of the presence of clots. No abnormality was detected in the resection specimen. At interoperative enteroscopy, minute arteriovenous malformations also were treated by argon plasma coagulation. All patients were followed for at least 1 year. Fourteen were taking supplemental iron; Hb levels in these patients ranged from 11 to 15 g/dL. One patient with erosive gastritis was treated with omeprazole with normalization of the Hb level. The anemia resolved spontaneously in another 3 patients in whom the second capsule study was normal. The Hb level also normalized for the patient who had hemorrhoid ligation and the patient who underwent right hemicolectomy. The patient in whom 712
GASTROINTESTINAL ENDOSCOPY
the terminal ileum was resected continued to bleed and died 4 months later of sepsis unrelated to the bleeding episodes. DISCUSSION A second capsule endoscopy examination detected abnormalities of potential clinical relevance in 35% of patients with significant iron deficiency anemia. The abnormalities seemed to be the definite cause for the anemia in 20% and a possible cause in another 15% of patients. In 3 patients, the findings were within reach of conventional endoscopic examinations. In all of these patients, the findings were confirmed endoscopically. In patients with iron deficiency anemia, lesions may be missed at standard upper endoscopy and later identified by enteroscopy. From 20% to 30% of such lesions are within the range of examination possible withastandard upper endoscope.5 Similarly, the present study found abnormalities that were missed by both standard and capsule endoscopy examinations. Landil et al.6 and Schilling et al.7 found that bleeding recurred in 28% to 31% of patients with iron deficiency anemia of obscure origin. Thus, a site of bleeding may be overlooked despite extensive diagnostic evaluation. Lewis and Waye8 performed push and Sonde enteroscopy in 504 patients with obscure GI bleeding. These studies yielded positive findings in 42% of patients, including angioectasias in 80% and small intestinal tumors in 10%. The high risk of recurrent bleeding and the types of abnormalities that cause bleeding justify a concerted effort to identify the source of bleeding. However, the economic burden of such investigation is significant. The costs of diagnosis and treatment for a patient with obscure GI bleeding is on average $33,630 and includes the cost of upper and lower endoscopy, enteroscopy, radiologic studies, and hospitalization with blood transfusions.9 Moreover, negative studies result in repeated examinations. In the study of Foutch et al.10 of 39 patients with obscure GI bleeding, a total of 316 diagnostic procedures were performed, an average of 8.1 examinations per patient. All patients in the present study underwent extensive evaluation, including capsule endoscopy, without identification of a source of bleeding. Nevertheless, patients with clinically significant iron deficiency anemia usually undergo repeated diagnostic procedures. Because most of the lesions in these patients are located in the small intestine, a second capsule endoscopy should be considered. Barium contrast radiography of the small bowel, the alternative examination, reveals lesions in only 5% of patients with obscure GI bleeding.11-13 In contrast, VOLUME 60, NO. 5, 2004
Second capsule endoscopy for patients with severe iron deficiency anemia
S Bar-Meir, R Eliakim, M Nadler, et al.
Table 2. Patients with positive findings on second capsule endoscopy Patient/pathology 1 2 3 4 5 6 7
Finding
Location
Therapeutic intervention
Anemia status
Flat polypoid lesions Gastritis, erosions, small gastric ulcer AV malformation AV malformation Edematous elevated mucosa with loss of villi Edematous mucosa with erosions Erosions
Cecum Stomach Small bowel Small bowel Small bowel Small bowel Small bowel
Right hemicolectomy PPI therapy Iron therapy Iron therapy Iron therapy None Iron therapy Hemorrhoid ligation
Resolved Resolved Resolved Resolved Persists Resolved Persists
PPI, Proton pump inhibitor; AV, anteriovenous.
a second capsule endoscopy revealed either a definite or suspected source of bleeding in 35% of patients in the present study. The number of patients in the current study is relatively small, and further studies with larger numbers of patients are warranted. Until such data are available, it is our belief that a second capsule endoscopy should be considered for patients with significant iron deficiency anemia and a negative evaluation that included capsule endoscopy. DISCLOSURE STATEMENT Two of the authors (Z.F., E.S.) serve on the advisory board of Given Imaging Co. REFERENCES 1. Scapa E, Jacob H, Lewkowicz S, Migdal M, Gat D, Gluckhovski A, et al. Initial experience of wireless-capsule endoscopy for evaluating occult gastrointestinal bleeding and suspected small bowel pathology. Am J Gastroenterol 2002; 97:2776-9. 2. Van Gossum A, Hittlet A, Schmit A, Francois E, Deviere J. A prospective study of push and wireless-capsule enteroscopy in patients with obscure digestive bleeding. Acta Gastroenterol Belg 2003;66:199-205. 3. Ell C, Remke S, May A, Helou L, Henrich R, Mayer G. The first prospective controlled trail comparing wireless capsule endoscopy with push enteroscopy in chronic gastrointestinal bleeding. Endoscopy 2002;34:685-9.
VOLUME 60, NO. 5, 2004
4. Lewis B, Goldfarb N. Review article: the advent of capsule endoscopy—a not-so-futuristic approach to obscure gastrointestinal bleeding. Aliment Pharmacol Ther 2003;17:1085-96. 5. Zaman A, Katon RM. Push enteroscopy for obscure gastrointestinal bleeding yields a high incidence of proximal lesions within the reach of a standard endoscope. Gastrointest Endosc 1998;47:372-6. 6. Landi B, Cellier C, Gandric M, Demont H, Guimbaud R, Cuillerier E, et al. Long-term outcome of patients with gastrointestinal bleeding of obscure origin explored by push enteroscopy. Endoscopy 2002;34:355-9. 7. Schilling D, Grieger G, Weidmann E, Adamek HE, Benz C, Riemann JF. Long-term follow-up of patients with iron deficiency anemia after a close endoscopic examination of the upper and lower gastrointestinal tract. Z Gastroenterol 2000;38:827-31. 8. Lewis B, Waye J. small bowel enteroscopy for obscure gastrointestinal bleeding. Gastrointest Endosc 1991;37:A277. 9. Goldfarb N, Phillips A, Conn M, Lewis B, Nash D. Economic and health outcomes of capsule endoscopy. Dis Manag 2002; 5:123-35. 10. Foutch PG, Sawyer R, Sanowski R. Push-enteroscopy for diagnosis of patients with gastrointestinal bleeding of obscure origin. Gastrointest Endosc 1990;36:337-41. 11. Bowden TA. Endoscopy of the small intestine. Surg Clin North Am 1989;69:1237-47. 12. Rabe FE, Becker GJ, Begozzi MJ, Miller RE. Efficacy study of the small bowel examination. Radiology 1981;140:47-50. 13. Gordon SR, Smith RE, Power GC. The role of endoscopy in the evaluation of iron deficiency anemia in patients over the age of 50. Am J Gastroenterol 1994;89:1963-7.
GASTROINTESTINAL ENDOSCOPY
713