GI Evaluation of Iron Deficiency Anemia

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GI EvaluationofIron Deficiency Anemia

• January 9, 2006

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Basic Iron Principles

• Iron absorption occurs primarily in the duodenum
  and upper jejunum
• inorganic iron salts exists in either ferrous
  (Fe) or ferric (Fe)
• iron is coupled to transferrin in the epithelial
  cells

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Basic Iron Principles

• Plasma membrane receptors recognize transferrin
  -- internalization of the protein and release of
  the iron
• Excess iron is stored in the body as ferritin or
  hemosiderin

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Causes of Iron Deficiency

• Inc iron utilization
• postnatal growth spurt
• adolescent growth spurt
• Physiologic iron loss
• menstruation
• pregnancy

• Pathologic iron loss
• GI bleeding
• GU bleeding
• Decreased iron intake
• Cereal rich, meat poor
• food fads
• malabsorption

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Introduction

• Iron deficiency anemia (IDA) occurs in 2-5
  of adult men and postmenopausal women
• IDA is common cause of referral to GI
• blood loss from the GI tract is the most common
  cause of IDA in adult men and postmenopausal women

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Iron Deficiency Anemia

• 2/3 of patients with IDA will have a significant
  gastrointestinal tract lesion detected with
  colonoscopy and esophagogastroduodenoscopy
• 10-15 with malignancy

Rockey and Cello, NEJM 1993 Kepczyk, Dig Dis Sci
1995 McIntyre A, Gut 1993
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Definition

• Anemia
• Hgb lt 10-11.5 in women
• Hgb lt 12.5-13.8 in men
• Iron deficiency
• microcytosis (MCV less than lower limits nl)
• low ferritin
• low transferrin sat

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Definition

• Microcytosis is characteristic of IDA but may
  also occur with other conditions
• thalassemia
• AOCD
• serum ferritin
• most powerful test for IDA (Guyatt et al. J of
  Gen Int Med, 1992)
• Ferritin lt12 ug/dl is diagnostic

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Rockey and Cello

• NEJM 1992, 3291691-1695
• prospective study of 100 patients with IDA
• Patients Men and women with IDA (Hgblt12.5 in
  men and lt10.6 in women TSIlt45ug, transferrin
  sat lt10 , ferritin lt10 - 20 ug/l) or absent iron
  stores of BM bx
• Methods 1. Detailed clinical hx 2. NSAID use
  3. FOBT 4. Colonoscopy and EGD ( some pts had
  small bowel enteroclysis)

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Rockey and Cello

• Significant colon findings
• cancinoma
• AVMs (gt5)
• active colitis
• colonic ulcers (gt2 cm)

• Significant EGD findings
• esophagitis
• duodenal or gastric ulcer
• carcinoma
• adenomatous polyps
• AVMs

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Results

• 62/100 pts had significant lesions
• colonoscopy - 25 pts had significant findings
• 11 colon cancers
• EGD - 36 pts had significant findings
• 19 patients with peptic ulcerations
• 1 gastric cancer
• 6 esophagitis

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Results continued

• 38 patients had negative colonoscopy and EGD and
  26 underwent SB radiographs
• no lesion found on radiographs
• 30/36 on iron therapy had resolved IDA (20 mos)
• Site-specific symptoms were significantly
  associated with site specific lesions

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Further Evaluation

• SB visualization
• medically refractory anemia
• transfusion dependent
• visible blood loss
• Other sources
• example GU blood loss

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Investigation

• History
• dietary hx, presence of upper or lower GI
  symptoms, menstrual history, NSAID use.
  Anticoagulants, family hx of hematologic disorder
• Examination
• hyperpigmentation around mouth
• telangectasia

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Investigation

• GI Evaluation - should occur in all patients with
  confirmed IDA
• endoscopy
• colonoscopy
• small bowel evaluation
• small bowel x-rays
• push enteroscopy
• capsule endoscopy

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Small Bowel Pathology

• Push Enteroscopy - 60-120 cm beyond LT
• Ceruvattath L and Wilcox M
• Aim characterize yield and clinical effect of
  push enteroscopy
• Design retrospective (1/1995-12/2000)
• 126 patients (45 GI bleeding and 25 IDA)
• 89 identified lesions (47 within reach of EGD
  scope)
• Results 35 normal, 19 AVMs

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M2A Capsule
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Small Bowel Pathology

• Capsule Endoscopy
• Costamagna et al. Gastro 2002123999-1005
• Aim prospectively compare SB radiographs to
  Capsule endoscopy
• 22 patients with suspected small bowel disease
• SB x-rays abnormal in 3 patients
• M2A capsule abnormal in 17 patients
• obscure GI bleeding diagnostic yield (5 vs 31
  plt0.05) in favor of capsule endoscopy

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Gastrointestinal diseases presenting with ID

• Common
• NSAID use
• Colon cancer/ polyp
• Gastric cancer
• Angiodysplasia
• IBD

• Uncommon
• Esophagitis
• SB tumors
• Hookworm
• Malabsorption
• Celiac disease
• Gastric bypass
• Bacterial overgrowth
• lymphangiectasia

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Ulcer
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Colon Cancer
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Colon Polyp
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Inflammatory Bowel Disease
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Hookworm
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Small Bowel Pathology

• Celiac Sprue
• anemia is the frequent presenting feature
• Ransford et al. J of Clinical Gastr 2002
• 484 pts with microcytic, hypochromic vs 498
  non-anemic controls
• IgA EmA assay, if pos EGD with biopsy
• 1/44 anemia patients dx with CS compared to 1/498
  non-anemic patients (plt0.01)

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Celiac Sprue
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Misc

• Gastric bypass surgery
• H. pylori infection (Dubois 2005, AJG)
• Occult blood loss secondary to chronic erosive
  gastritis
• Decreased iron absorption
• Hypochlorhydria or achlorhydria
• Increased iron uptake by bacteria

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Approach to IDA (Ioannou 2002, AJM)
Measure Serum Ferritin
Ferritingt100
Ferritin46-100
Ferritinlt45
Consider empiric Iron supplementation Or BM
biopsy
Consider other Causes of anemia
Colonoscopy EGD
Absent iron store
Adequate iron stores
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Therapy

• Treat the underlying cause
• Iron therapy
• ferrous sulfate 200mg tid
• vitamin C 500 mg daily (aid iron absorption)
• parenteral iron ( if oral iron not tolerated)
• Hgb inc 3 g/dl after 3-4 weeks
• continue iron therapy for 3 mos after correction
  of anemia