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  • A 62-year-old man is brought to the emergency room for blood in his stool this afternoon. He denies any prior episodes, straining, trauma, colon cancer, or alcohol abuse. His medical history is significant for stage 3 chronic renal failure. A physical examination yields hemoccult positive stool.
  • Clinical definition
    • describes small vascular malformations frequently found in the gastrointestinal (GI) tract
      • most common vascular anomaly within the GI tract and a common cause of unexplained GI bleeding and anemia  
    • lesions are composed of ectatic, dilated, thin-walled vessels lined by endothelium alone or endothelium with small amounts of smooth muscle
      • small arteriovenous communications may be present  
    • often multiple lesions that frequently involve the cecum or ascending colon
  • Epidemiology
    • demographics
      • most often seen in patients older than 60 years of age
  • Pathogenesis
    • pathogenesis of the condition is not well understood though its development is probably related to age and strain on the bowel wall
    • degenerative lesion that is probably a result from the venous obstruction secondary to the chronic and intermittent contraction of the colon
      • obstruction of the submucosal veins at the level of muscularis propria leads to dilation and tortuosity of the draining areas
      • precapillary sphincters become incompetent, which allows for the formation of arteriovenous malformations
  • Associated conditions
    • end-stage renal disease
    • von Willebrand disease
    • aortic stenosis
  • Symptoms
    • hematochezia
    • melena
    • fatigue
    • hematemesis
      • if present in the upper GI tract
    • shortness of breath
    • weakness
    • dizziness
  • Physical exam
    • pallor
    • hemoccult positive stool
    • tachycardia
  • Diagnostic testing
    • diagnostic approach
      • diagnosis is primarily based on endoscopy done for the evaluation of gastrointestinal bleeding
    • imaging
      • endoscopy
        • preferred method
        • options include upper endoscopy, colonoscopy, wireless video capsule endoscopy, and deep small bowel enteroscopy
          • a combination of the methods may be necessary
        • characteristic appearance of small (5-10mm), flat, cherry-red lesions with a fern-like pattern 
      • computed tomography (CT) angiography
        • may be especially useful in detecting angiodysplasias with an active hemorrhage
      • angiography
        • indicated in patients with negative endoscopic/CT angiography results and high clinical suspicion
        • allows for treatment
    • studies
      • laboratory studies
        • CBC and iron studies for evaluation of possible anemia
      • intaoperative enteroscopy
        • indicated in patients with significant bleeding but negative evaluation
  • Diverticulosis 
    • differentiating factors
      • will be visible on endoscopic studies of the colon
  • Colon/rectal cancer 
    • differentiating factors
      • may complain of symptoms (e.g., stool changes) and will be present on colonoscopy
  • Treatment is dependent on the level bleeding, if the lesion is not actively bleeding or is discovered incidentally on screening colonoscopy, no treatment is needed
  • First-line
    • endoscopic treatment with cautery or argon plasma coagulation (APC)  
    • supportive care
      • IV fluids
      • blood transfusion if severe anemia
  • Second-line
    • angiography and embolization with particles
    • antifibrinolytics (e.g., tranexamic acid or aminocaproic acid)
      • indicated in patients with bleeding from multiple or inaccessible sites
    • estrogen
      • used in patients with end-stage renal disease and von Willebrand disease
    • other drugs such as thalidomide or octreotide
  • Third-line
    • surgery
      • indicated in patients not responsive to either endoscopic or medical treatment
      • resection of the affected part of the bowel
  • Anemia
  • Bleeding/hemorrhage
  • Exsanguination

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Questions (2)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

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