ch13 clinical indications: small intestine

giardiasis

is a common infection of the lumen of the small intestine that is caused by the flagellate protozoan (Giardia lamblia). It is often spread by contaminated food and water. It can also spread via person-to-person contact. Symptoms of giardiasis include nonspecific gastrointestinal discomfort, mild to profuse diarrhea, nausea, anorexia, and weight loss. The presence of this organism usually affects the duodenum and jejunum with spasms, irritability, and increased secretions. A small bowel series typically demonstrates giardiasis as dilation of the intestine, with thickening of the circular folds. Laboratory analysis of a stool specimen can confirm the presence of the giardia organism

Carcinoid tumors

Most common tumors of the small bowel, have a benign appearance, although they have the potential to become malignant. These small lesions tend to grow submucosally and frequently are missed radiographically.

Ileus

an obstruction of the small intestine. Two types have been identified: adynamic, or paralytic and mechanical.

Sprue and malabsorption syndromes

conditions in which the gastrointestinal tract is unable to process and absorb certain nutrients. Sprue consists of a group of intestinal malabsorption diseases that involve inability to absorb certain proteins and dietary fat. The malabsorption may be due to an intraluminal (digestive) defect, a mucosal abnormality, or a lymphatic obstruction. Malabsorption syndrome is often experienced by patients with lactose and sucrose sensitivities. Deficiency syndromes may result from excessive loss of vitamins, electrolytes, iron, or calcium. During a small bowel series, the mucosa may appear thickened as a result of constant irritation.

Adynamic or paralytic

ileus is due to the cessation of peristalsis. Without these involuntary, wavelike contractions, the bowel is flaccid and is unable to propel its content forward. Causes for adynamic ileus include infection, such as peritonitis or appendicitis; use of certain drugs; postsurgical complications,. Adynamic ileus usually involves the entire GI tract. Usually no fluids levels are demonstrated on the erect abdomen projection. However, the intestine is distended with a thin bowel wall.

enteritis

inflammation o the intestine, primarily of the small intestine. It may be caused by bacterial or protozoan organisms and other environmental factors. When the stomach is also involved, the condition is known as GASTROENTERITIS. Chronic irritation may cause the lumen of the intestine to become thickened, irregular, and narrowed.

Meckel diverticulum

is a common birth defect caused by the persistence of the yolk sac (umbilical vesicle)resulting in a saclike outpouching of the intestine wall. This outpouching is seen in the ileum of the small bowel. It may measure 10-12cm in diameter and is usually 50-100cm proximal to the ileocecal valve. Meckel diverticulum is found incidentally in approx. 3% of adults. The condition does not typically cause symptoms unless inflammation (diverticulitis) or bowel obstruction develops. Pain may mimic acute appendicitis. Surgical removal is often recommended to prevent possible diverliculitis, obstruction, or blood loss. Meckel diverticulitis is rarely seen on barium studies of the small bowel because of rapid emptying during a barium study. It is diagnosed with a radionuclide (nuc/med) scan

Regional enteritis (segmental enteritis or Crohn disease)

is a form of inflammatory bowel disease of unknown origin, involving any part of the gastrointestinal tract but commonly involving the terminal ileum. This condition leads to scarring and thickening of the bowel wall. This scarring produces the "cobblestone" appearance visible during a small bowel series, or enteroclysis. Radiographically, these lesions resemble gastric erosions or ulcers seen in barium studies as minor variations in barium coating. In advanced cases segments of the intestine become narrowed as the result of chronic spasm, producing the "string-sign" evident during a small bowel series. Regional enteritis frequently leads to intestinal obstruction, fistula, and abscess formation. This disorder also has a high rate of recurrence after treatment.

celiac disease

is a form of sprue or malabsorption disease that affects the proximal small bowel, especially the proximal duodenum. It commonly involves the insoluble protein (gluten) found in cereal grains.

Mechanical obstruction

is a physical blockage of the bowel that may be caused by tumors, adhesions, or hernia. The loops of intestine proximal to the site of obstruction are markedly dilated with gas. The dilation produces the radiographic sign commonly called the "circular staircase" or "herringbone" pattern, which is evident on an erect abdomen projection.

Whipple disease

is a rare disorder of the proximal small bowel whose cause is unknown. Symptoms include dilation of the intestine, edema, malabsorption, deposits of fat in the bowel wall and mesenteric nodules. Whipple diseae is best diagosed with a small bowel series, which shows distorted loops of small intestine.

neoplasm

is a term that means "new growth" This growth may be benign or malignant (cancerous). Common benign tumors of the small intestine include ADENOMAS and LEIOMYOMAS. Most benign tumors are found in the jejunum and ileum.

Lymphoma and adenocarcinoma

malignant tumors of the small intestine. lymphomas are demonstrated during a small bowel series as the "stacked coin" sign caused by thickening, coarsening, and possible hemorrhage of the mucosal wall. Other segments of the intestine may become narrowed and ulcerative. Adenocarcinomas produce short and sharp "napkin-ring" defects within the lumen and may lead complete obstruction. These radiographic signs of neoplasm are demonstrated during a BE procedure. The most frequent sites for adenocarcinoma are the duodenum and the proximal jejunum. The small bowel series, or enteroclysis, may demonstrate stricture or blockage caused by the neoplasm. CT of the abdomen may further ascertain the location and size of the tumor.