Chapter 13 Lower GI System (Connor)

The two strict contraindications for the barium enema are:

1. Possible perforated hollow viscus 2. Possible large bowel obstruction

Two strict contraindications to contrast media studies of the intestinal tract are known:

1. Presurgical patients and patients suspected to have a perforated hollow viscus (intestine or organ) 2. Patients with a possible large bowel obstruction

The two flexures of the colon are:

1. Right colic (Hepatic) flexure 2. Left colic (Splenic) flexure

Enteroclysis is indicated for patients with clinical histories of:

1. Small bowel ileus 2. Regional enteritis (Crohn's disease) 3. Malabsorption syndrome

The cecum, transverse colon, and sigmoid colon are more ____________ than other aspects of the large intestine.

Anterior

The rectum presents two _________________.

Anteroposterior curves

The anal canal terminates as an opening to the exterior, the _______.

Anus

Obstruction of the opening into the appendix caused by a small fecal mass may lead to narrowing of the blood vessels that feed it. The result is an inflamed appendix, or ______________.

Appendicitis

Common clinical indications for barium enema include:

Colitis Ulcerative colitis Diverticulum Diverticula Intussusception Neoplasms Adenocarcinoma Polyps Volvulus Cecal volvulus

The three most common enema tips are:

1. Plastic disposable 2. Rectal retention 3. Air-contrast retention

The four sections of the colon are:

1. Ascending colon 2. Transverse colon 3. Descending colon 4. Sigmoid colon

The large intestine consists of four major parts:

1. Cecum 2. Colon 3. Rectum 4. Anal canal

Four primary digestive functions are accomplished largely by the small and large intestines:

1. Digestion (Chemical and mechanical) 2. Absorption 3. Reabsorption of water, inorganic salts, vtakitamin K, and amino acids 4. Elimination (Defecation)

Certain conditions contraindicate the use of very effective cathartics or purgatives needed to cleanse the large bowel thoroughly. These conditions include:

1. Gross bleeding 2. Severe diarrhea 3. Obstruction 4. Inflammatory conditions such as appendicitis

In the large intestine, digestive movements continue as:

1. Peristalsis 2. Haustral churning 3. Mass peristalsis 4. Defecation

Digestive movements throughout the length of the small bowel consists of:

1. Peristalsis 2. Rhythmic segmentation

Three characteristics readily differentiate the large intestine from the small intestine:

1. The internal diameter of the large intestine is usually greater than the diameter of the small bowel. 2. The presence of multiple haustra in the large intestine. 3. The large relative positions; the large intestine extends around the periphery of the abdominal cavity, whereas the small intestine is more centrally located.

Four methods are used to study the small intestine radiographically:

1. Upper GI - small bowel combination 2. Small bowel - only series 3. Enteroclysis 4. Intubation method

The large intestine is about __________ long and about ______________ in diameter.

1.5 m (5 feet) 2.5 inches (6 cm)

A standard mixture used for single-contrast barium enemas is between _______ and ________ weight-to-volume (w/v).

15% 25%

In the routine small bowel series, regular barium sulfate ordinarily reaches the large intestine within _____________, but this time varies greatly among patients.

2 or 3 hours

Barium sulfate enters the stomach and reaches the ileocecal valve _____________ after ingestion.

2 to 3 hours

The jejunum's inner diameter is approximately ___________.

2.5 cm

Mass peristalsis tends to move the entire large bowel contents into the sigmoid colon and rectum, usually once every _____________.

24 hours

The diameter of the small intestine varies from ___________ at the proximal aspect to about _________ at the distal end.

3.8 cm (1.5 inches) 2.5 cm (1 inch)

During life, with good muscle tone, the actual length of the small intestine is shorter, measuring __________________.

4.5 to 5.5 m (15 to 18 feet)

Feces consists normally of _____________ and ____________, such as food residues, digestive secretions, and bacteria.

65% water 35% solid matter

If the entire small intestine were removed from the body, separated from its mesenteric attachment, uncoilled, and stretched out, it would average ______________ in length.

7 m (23 feet)

The thicker barium used for double-contrast barium enemas has a weight-to-volume concentration between ________ and _________ or greater.

75% 95%

In the average ambulatory adult, a large collection of gas in the small intestine is considered ______________.

Abnormal

___________________ accounts for about 50% of all emergency abdominal surgeries and is 1.5 times more common in men than in women.

Acute appendicitis

Malignant tumor of the small intestine. Produce short and sharp "napkin-ring" defects within the lumen, which may lead to complete obstruction. The most frequent sites for this are the duodenum and the proximal jejunum.

Adenocarcinoma

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

Adynamic (Paralytic) ileus

The distal rectum contains the _____________, which ends at the anus.

Anal canal

The final 2.5 to 4 cm (1 to 1.5 inches) of large intestine is constricted to form the ___________.

Anal canal

One of the most typical forms of colon cancer, may form an "apple-core" or "napkin-ring" appearance as the tumor grows and infiltrates the bowel walls. It frequently results in large bowel obstruction.

Annular carcinoma (Adenocarcinoma)

The last stage of digestion occurs in the large intestine through _______________, which converts the remaining proteins into amino acids.

Bacterial action

The radiographic procedure designed to study the large intestine is most commonly termed a _______________.

Barium enema

An inflammatory condition of the large intestine that may be caused by many factors, including bacterial infection, diet, stress, and other environmental conditions. The intestinal mucosa may appear rigid and thick and lack haustral markings along the involved segment. Because of chronic inflammation and spasm, the intestinal wall has a "saw-tooth" or jagged appearance.

Colitis

The 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.

Carcinoid tumors

Describes the ascending colon and the cecum as having a long mesentery, which makes them more susceptible to a volvulus.

Cecal volvulus

At the proximal end of the large intestine is the ___________, a large blind pouch located inferior to the level of the ileocecal valve.

Cecum

The ___________, the widest portion of the large intestine, is fairly free to move about in the RLQ.

Cecum

Radiographs generally are taken every half-hour for 2 hours followed by radiographs every hour thereafter until barium reaches the _____________ or ________________ for the small bowel-only series.

Cecum Ascending colon

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.

Celiac disease

An outpouching of the mucosal wall that may result from herniation of the inner wall of the colon. Although this is a relatively benign condition, it may become widespread throughout the colon, specifically the sigmoid colon. It is most common among adults older than 40 years of age.

Diverticulum

_____________ is a so-called bowel movement, or emptying of the rectum.

Defecation

The C-shaped duodenum is fairly fixed in position immediately ________ to the stomach and is recognized easily on radiographs.

Distal

Appear as small, barium-filled, circular defects that project outward from the colon wall during a barium enema. The double-contrast barium enema provides an excellent view of the intestinal mucosa, revealing this.

Diverticula

The colon consists of _______ sections and ________ flexures and does not include the __________ and ___________.

Four Two Cecum Rectum

The primary function of the large intestine is the _________________.

Elimination of feces (defecation)

Describes inflammation of the intestine, primarily of the small intestine. May be caused by bacterial or protozoan organisms and other environmental factors. Chronic irritation may cause the lumen of the intestine to become thickened, irregular, and narrowed.

Enteritis

Common clinical indications for a small bowel series include:

Enteritis Regional enteritis (segmental enteritis or Crohn's disease) Giardiasis Ileus (Adynamic or paralytic) Mechanical obstruction Meckel's diverticulum Neoplasm Carcinoid tumors Lymphoma Adenocarcinoma Sprue and malabsorption syndromes Celiac disease Whipple's disease

Describes the injection of a nutrient or medicinal liquid into the bowel. Refers to a study wherein the patient is intubated under fluroscopic control.

Enteroclysis

A by-product of bacterial action is the release of hydrogen, carbon dioxide, and methane gas. These gases, called __________, help to break down remaining proteins to amino acids.

Flatus

A common infection of the lumen of the small intestine that is caused by the flagellate protozoan. It is often spread by contaminated food and water. It can also be spread via person-to-person contact. Symptoms 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 this as dilation of the intestine, with thickening of the circular folds. Laboratory analysis of a stool specimen can confirm the presence of this condition.

Giardiasis

Most of the large intestine except the rectum possesses _____________.

Haustra

The terminal ileum joins the large intestine at the ___________________ in the RLQ.

Ileocecal value (sphincter or fold)

A second function of the ________________ is to prevent reflux, or a backward flow of intestine contents, into the ileum.

Ileocecal valve

The ________________ acts as a sphincter to prevent the contents of the ileum from passing too quickly into the cecum.

Ileocecal valve

The large intestine begins in the RLQ, just lateral to the __________________.

Ileocecal valve

The most distal part of the small intestine, the ileum, joins the cecum at the ___________________.

Ileocecal valve

Radiographs are obtained at specific intervals throughout the small bowel series until the barium sulfate column passes through the ______________ and progresses into the ________________.

Ileocecal valve Ascending colon

The ___________ makes up the distal three-fifths of the remaining aspect of the small intestine and is the longest portion of the small intestine.

Ileum

The ____________ is located primarily in the RUQ, RLQ, and LLQ.

Ileum

The internal lining of the ____________ appears on a radiograph as smoother, with fewer indentations and a less "feathery" appearance.

Ileum

An obstruction of the small intestine. Two types have been identified.

Ileus

The initial direction of the rectum along the sacrum is __________ and ___________. However, in the region of the rectal ampulla, the direction changes to ___________ and ___________.

Inferior Posterior Inferior Anterior

A telescoping or invagination of one part of the intestine into another. It is most common in infants younger than 2 years of age but can occur in adults. A barium enema or an air/gas enema may play a therapeutic role in re-expanding the involved bowel. Radiographically, progression of the barium through the colon terminates at a "mushroom-shaped" dilation. Very little barium/gas, if any, passes beyond this area. The dilation marks the point of obstruction. This must be resolved quickly so that it does not lead to obstruction and necrosis of the bowel. If the condition recurs, surgery may be necessary.

Intussusception

The _______________ is located primarily to the left of the midline in the LUQ and LLQ, making up about two-fifths of the remaining aspect of the small intestine.

Jejunum

The mucosal folds of the distal duodenum are found in the ____________ as well.

Jejunum

The distribution of air and barium is influenced most often by the location of each portion of the _______________ in relation to the _______________.

Large intestine Peritoneum

Malignant tumor of the small intestine. Demonstrated during a small bowel series as the "stacked coin" sign. This sign is caused by thickening, coarsening, and possible hemorrhage of the mucosal wall. Other segments of the intestine may become narrowed and ulcerative.

Lymphoma

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. This dilation produces the radiographic sign commonly called the "circular staircase" or "herringbone" pattern, which is evident on an erect or decubitus abdomen projection. Air-fluid levels usually are present.

Mechanical obstruction

A common birth defect caused by the persistence of the yolk sac (umbilical vesicle) resulting in a saclike outpouching of the intestinal wall. This outpouching is seen in the ileum of the small bowel. It may measure 10 to 12 cm in diameter and is usually 50 to 100 cm proximal to the ileocecal valve. Usually found incidentally in approximately 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 diverticulitis, obstruction, or blood loss. Rarely seen on barium studies of the small bowel because of rapid emptying during a barium study. It is best diagnosed with a radionuclide (nuclear medicine) scan.

Meckel's diverticulum

Growth that 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.

Neoplasm

Are common in the large intestine. Although benign tumors do occur, carcinoma of the large intestine is a leading cause of death among both men and women. Most carcinomas of the large intestine occur in the rectum and sigmoid colon. These cancerous tumors often encircle the lumen of the colon, producing an irregular channel through it. The radiographic appearance of these tumors, as demonstrated during a barium enema, has led to the use of descriptive terms such as "apple-core" or "napkin-ring" lesions. Both benign and malignant tumors may begin as polyps.

Neoplasms

During a routine upper GI series, the patient generally should ingest __________________ of barium sulfate mixture.

One full cup or 8 oz.

______________ describes wavelike contractions that propel food from the stomach through the small and large intestines and eventually expel it from the body.

Peristalsis

The jejunum contains numerous mucosal folds, ________________, which increase the surface area to aid with absorption of nutrients. These numerous mucosal folds produce the "feathery appearance of the jejunum".

Plicae circulares (Valvulae connventes)

Saclike projections similar to diverticula except that they project inward into the lumen rather than outward, as do diverticula. Similar to diverticula, they can be inflamed and may be a source of bleeding. In this case, they may have to be surgically removed. Barium enema, endoscopy, and CT colonography are the most effective modalities used to demonstrate neoplasms in the large intestine.

Polyps

The appendix usually is attached to the ________________ aspect of the cecum and commonly extends ___________ the pelvis.

Posteromedial Toward

The ____________ position allows abdominal compression to separate the various loops of bowel, creating a higher degree of visibility.

Prone

When a patient is __________, barium rises to fill the structures that are most anterior.

Prone

The duodenum is located primarily in the __________.

RUQ

The _________________ is a dilated portion of the rectum located anterior to the coccyx.

Rectal ampulla

________________, sometimes called _____________, are used on patients who have relaxed anal sphincters or who cannot for whatever reason retain the contrast material.

Rectal disposable retention tips Retention catheters

The ____________ extends from the sigmoid colon to the anus.

Rectum

The final segment of the large intestine is the __________.

Rectum

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 enterocylsis. 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 smal bowel series. Frequently leads to intestinal obstruction, fistula, and abscess formation. This disorder also has a high rate of recurrence after treatment.

Regional enteritis (segmental enteritis or Crohn's disease)

________________ describes localized contractions in areas or regions that contain food.

Rhythmic segmentation

The large intestine begins in the ________________ with its connection to the small intestine.

Right lower quadrant (RLQ)

If the large intestine contained both air and barium sulfate, the air would tend to _________ and the barium would tend to _________ because of gravity.

Rise Sink

_______________, ____________, and ____________ are the most common forms of negative-contrast media used.

Room air Nitrogen Carbon dioxide

The rectum begins at the level of __________ and is about __________ long.

S3 (Third sacral segment) 4.5 inches (12 cm)

Most __________ and approximately _______________ are reabsorbed in the small intestine.

Salts 95% of water

It is important to review the patient's chart to determine whether the patient has had a recent _____________ or a ______________ before undergoing the barium enema.

Sigmoidoscopy Colonoscopy

A thin mixture of barium sulfate is used for most _______________.

Small bowel series

Radiographic examination specifically of the small intestine is called a ____________________.

Small bowel series (SBS)

Most digestion and absorption take place within the _______________.

Small intestine

At the point of the ileocecal valve (sphincter), the inner lumen of the ileum is nearly ___________.

Smooth

Conditions in which the gastrointestinal tract is unable to process and absorb certain nutrients. Consists of a group of intestinal malabsorption diseases that involve an inability to absorb certain proteins and dietary fat. Malabsorption may be due to an intraluminal (digestive) defect, a mucosal abnormality, or a lymphatic obstruction. Often experienced by patients with lactose and sucrose sensitivities. 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.

Sprue and malabsorption syndromes

The purpose of the small bowel series are to:

Study the form and function of the three components of the small bowel and to detect any abnormal conditions

When a person is ____________, air rises to fill the structures that are most anterior -- that is, the transverse colon and loops of the sigmoid colon. The barium sinks to fill primarily the ____________ and ____________ colon and aspects of the _____________ colon.

Supine Ascending Descending Sigmoid

The muscular portion of the intestinal wall contains three external bands of longitudinal muscle fibers of the large bowel that form three bands of muscle called ______________, which tend to pull the large intestine into pouches. Each of these pouches or sacculations, is termed a ___________.

Taeniae coli Haustra

Although it is longer than the jejunum, the ileum possesses a ___________ wall and has __________ mucosal folds (plicae circulares).

Thinner Fewer

The ______________ colon has a wide range of motion.

Transverse

For the small bowel-only series, the patient generally ingests _______________ of barium, and the time is noted.

Two cups (16 oz.)

A severe form of colitis that is most common among young adults. It is a chronic condition that often leads to development of coinlike ulcers within the mucosal wall. Along with Crohn's disease, it is one of the most common forms of inflammatory bowel disesase. These ulcers may be seen during a barium enema as multiple ring-shaped filling defects that create a "cobblestone" appearance along the mucosa. Patients with long-term bouts of this may develop "stovepipe" colon, in which haustral markings and flexures are absent.

Ulcerative colitis

The __________________ is attached to the cecum.

Vermiform appendix

The _________________ is a long (2 to 20 cm), narrow, worm-shaped tube that extends from the cecum.

Vermiform appendix (appendix)

The internal lining of the second and third (descending and horizontal) portions of the duodenum is gathered into tight circular folds formed by the mucosa of the small intestine, which contains numerous small, finger-like projections termed _________, resulting in a "feathery" appearance when filled with barium.

Vili

A twisting of a portion of the intestine on its own mesentery, leading to a mechanical type of obstruction. Blood supply to the twisted portion is compromised, leading to obstruction and localized death of tissue. May be found in portions of the jejunum or ileum. This can also occur in the cecum and sigmoid colon. More likely to occur in men than in women and is most common in adults 20 to 50 years old. The classic sign is a "beak" sign -- a tapered narrowing at site as demonstrated during a barium enema. Produces an air-fluid level, which is well demonstrated on an erect abdomen projection.

Volvulus

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. Best diagnosed with a small bowel series, which shows distorted loops of small intestine.

Whipple's disease