Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (162 page)

   Neoplasms Caused by Primary Diseases of the Small Intestine

   Biopsy of lesions confirms the diagnosis.

   Laboratory findings due to complications (e.g., hemorrhage, obstruction, intussusception, malabsorption).

   Laboratory findings due to underlying conditions (e.g., Peutz-Jeghers syndrome, carcinoid syndrome).

LOWER GASTROINTESTINAL BLEEDING (ADULT), ACUTE

   Overview

   Lower GI bleeding is usually defined by bleeding originating from below the ligament of Treitz.

   If the initial assessment does not clearly distinguish between upper and lower sources of GI bleeding, evaluation of the upper tract should be pursued, as this is the more common site of massive GI bleeding.

   Differential Diagnosis of Lower Gastrointestinal Bleeding (Table
5-5
)

   Angiodysplasia: In elderly patients, angiodysplasia is diagnosed with proportional greater frequency. Angiodysplasia is not visualized by barium enema. The bleeding tends to be self-limited, frequently arising from the right colon.

   Benign anorectal pathology: In younger patients (<35 years of age), benign anorectal pathology (e.g., hemorrhoidal bleeding) is the most common etiology.

   Diverticulosis: Less than 33% of patients with diverticulosis develop significant bleeding. The bleeding is typically painless and occurs in the absence of diverticulitis. Although diverticula are more commonly located on the left side of the colon, right-sided lesions account for a significant portion of diverticular bleeding.

   Colon cancer polyps account for 19% of patients with lower gastrointestinal blood loss in patients older than 50 years of age.

   Coagulopathy usually causes bleeding in patients with a comorbid GI condition. Therefore, a patient with coagulopathy always requires further evaluation.