Pathology of the Digestive System

Presentation by Rowell Angeles

The large intestine is a long tube-like structure that stores and eliminates waste material. During normal lower intestinal function, the waste material (stool or feces) is slowly pushed along the large intestine to the rectum by the muscular bands in the colon. As a person ages, this continuous pressure can cause a bulging pocket of tissue or sac (called a diverticulum) that pushes out from the colon wall. More than one sac is called diverticula. Diverticula can occur throughout the large intestine, but are most commonly found near the end of the left intestine (called the sigmoid colon). The condition of having diverticula in the large intestine is called diverticulosis.

When a diverticulum ruptures or becomes infected, this condition is called diverticulitis. Diverticulitis develops when a mass of hardened waste matter (called a fecalith) forms in the pouch and reduces the blood supply to the thin walls of the pouch (by means of pressure against the wall), making them susceptible to infection by the bacteria of the colon.

Diverticulosis

Diverticulosis is rare before the age of 40, but the likelihood of developing this condition increases with passing decades. It is estimated that 30 percent of all people over the age of 45 have diverticulosis; at the age of 60, 50 percent of all people will develop this condition; and by the age of 85, 65 percent of all people will have diverticulosis.

Researchers believe that diverticulosis may be age related, genetically based and most importantly, caused by not enough fiber in the diet. A diet low in fiber can lead to small, hard stools that are difficult to pass and require more pressure to push them through the large intestine. Over time, these vigorous contractions in the large intestine push the inner intestinal lining outward, causing diverticula.

Causes and Risk Factors

Most people with diverticulosis have few or no symptoms. Doctors refer to diverticulosis with no symptoms as asymptomatic diverticulosis. For people who experience symptoms, the condition is called symptomatic diverticulosis. Symptomatic diverticulosis is categorized into three types - painful diverticulosis, inflammatory diverticulitis (inflamed and infected diverticula) and bleeding diverticulosis (the blood vessel in the wall of the diverticulum ruptures).

Symptoms of painful diverticulosis are: abdominal pain (usually located in

the lower left abdomen) that subsides after a bowel movement or passing gas

constipation, followed by bouts of diarrhea

bloating

Symptoms of inflammatory diverticulitis are: abdominal pain constipation fever bloating vomiting

Symptoms of bleeding diverticulosis are: sudden, mild cramps urge to have a bowel movement bright red blood clots and maroon-

colored stool If sufficient blood is lost in a short

amount of time, the person may experience:

increased thirst dizziness rapid heart beat fainting

Symptoms

Diverticulosis is often unsuspected and discovered by an x-ray or intestinal examination performed for an unrelated reason. The doctor may see the diverticula through a flexible tube (a colonoscope) that is inserted through the anus. Through this scope, the diverticula may be seen as dark passages leading out of the normal colon wall.

The doctor also may do a barium enema (an x-ray that reveals outpouchings in the walls of the colon). If rectal bleeding occurs, the doctor may take a special x-ray (an angiography). In this procedure, dye is injected into an artery that goes to the colon so that the site of the bleeding problem can be located.

Diagnosis

If the patient has diverticulosis with no symptoms, no treatment is needed. Some doctors advise eating a special high fiber diet, consisting of fresh vegetables, fresh fruits, whole-grain breads, cereals and bran.

Additionally, adding a fiber supplement (such as Metamucil or Hydrocil) to the diet, and avoiding certain foods with small seeds, such as strawberries, raspberries, whole cranberries and nuts is helpful in treating diverticulosis.

Patients experiencing bloating or abdominal pain may benefit from anti-

spasmodic drugs, such as Librax, Bentyl, Donnotal and Levsin.

If this condition turns into diverticulitis, bedrest, antibiotics or hospitalization may be needed. The vast majority of patients will recover from diverticulitis without surgery. Sometimes, patients need surgery to drain an abscess that has resulted from a ruptured diverticulum and to remove that portion of the colon. Surgery is reserved for patients with very severe or multiple attacks. In such cases, the involved segment of colon can be removed and the colon can then be rejoined.

Treatment

A hiatal hernia is an anatomical abnormality in which part of the stomach protrudes through the diaphragm and up into the chest. Although hiatal hernias are present in approximately 15% of the population, they are associated with symptoms in only a minority of those afflicted.

Normally, the esophagus or food tube passes down through the chest, crosses the diaphragm, and enters the abdomen through a hole in the diaphragm called the esophageal hiatus. Just below the diaphragm, the esophagus joins the stomach. In individuals with hiatal hernias, the opening of the esophageal hiatus (hiatal opening) is larger than normal, and a portion of the upper stomach slips up or passes (herniates) through the hiatus and into the chest. Although hiatal hernias are occasionally seen in infants where they probably have been present from birth, most hiatal hernias in adults are believed to have developed over many years.

Hiatal Hernia

It is thought that hiatal hernias are caused by a larger-than-normal esophageal hiatus, the opening in the diaphragm through which the esophagus passes from the chest into the abdomen; as a result of the large opening, part of the stomach "slips" into the chest. Other potentially contributing factors include:

A permanent shortening of the esophagus (perhaps caused by inflammation and scarring from the reflux or regurgitation of stomach acid) which pulls the stomach up.

An abnormally loose attachment of the esophagus to the diaphragm which allows the esophagus and stomach to slip upwards.

Causes

The vast majority of hiatal hernias are of the sliding type, and most of them are not associated with symptoms. The larger the hernia, the more likely it is to cause symptoms. When sliding hiatal hernias produce symptoms, they almost always are those of gastroesophageal reflux disease (GERD) or its complications. This occurs because the formation of the hernia often interferes with the barrier (lower esophageal sphincter) which prevents acid from refluxing from the stomach into the esophagus. Additionally, it is known that patients with GERD are much more likely to have a hiatal hernia than individuals not afflicted by GERD. Thus, it is clear that hiatal hernias contribute to GERD. However, it is not clear if hiatal hernias alone can result in GERD. Since GERD may occur in the absence of a hiatal hernia, factors other than the presence of a hernia can cause GERD.

Symptoms of uncomplicated GERD include: heartburn regurgitation nausea

Symptoms

Hiatal hernias are diagnosed incidentally when an upper gastrointestinal x-ray or endoscopy is done during testing to determine the cause of upper gastrointestinal symptoms such as upper abdominal pain. On both the x-ray and endoscopy, the hiatal hernia appears as a separate "sac" lying between what is clearly the esophagus and what is clearly the stomach. This sac is delineated by the lower esophageal sphincter above and the diaphragm below. The hernia may only be visible during swallows.

Diagnosis

Treatment of large para-esophageal hernias causing symptoms requires surgery. During surgery, the stomach is pulled down into the abdomen, the esophageal hiatus is made smaller, and the esophagus is attached firmly to the diaphragm. This procedure restores the normal anatomy.

Since sliding hiatal hernias rarely cause problems themselves but rather contribute to acid reflux, the treatment for patients with hiatal hernias is usually the same as for the associated GERD. If the GERD is severe, complicated, or unresponsive to reasonable doses of medications, surgery often is performed. At the time of surgery, the hiatal hernia is eliminated in a manner similar to the repair of para-esophageal hernias. However, in addition, part of the upper stomach is wrapped around the lower sphincter to augment the pressure at the sphincter and further prevent acid reflux.

Treatment

A peptic ulcer is a hole in the gut lining of the stomach, duodenum, or esophagus. A peptic ulcer of the stomach is called a gastric ulcer; of the duodenum, a duodenal ulcer; and of the esophagus, an esophageal ulcer. An ulcer occurs when the lining of these organs is corroded by the acidic digestive juices which are secreted by the stomach cells. Peptic ulcer disease is common, affecting millions of Americans yearly. The medical cost of treating peptic ulcer and its complications runs in the billions of dollars annually. Recent medical advances have increased our understanding of ulcer formation. Improved and expanded treatment options are now available.

Peptic Ulcer

For many years, excess acid was believed to be the major cause of ulcer disease. Accordingly, treatment emphasis was on neutralizing and inhibiting the secretion of stomach acid. While acid is still considered significant in ulcer formation, the leading cause of ulcer disease is currently believed to be infection of the stomach by a bacteria called "Helicobacter pyloricus" (H. pylori). Another major cause of ulcers is the chronic use of anti-inflammatory medications, commonly referred to as NSAIDs (nonsteroidal anti-inflammatory drugs), including aspirin. Cigarette smoking is also an important cause of ulcer formation and ulcer treatment failure.

H. pylori bacteria is very common, infecting more than a billion people worldwide. It is estimated that half of the United States population older than age 60 has been infected with H. pylori. Infection usually persists for many years, leading to ulcer disease in 10 % to 15% of those infected. H. pylori is found in more than 80% of patients with gastric and duodenal ulcers. While the mechanism of how H. pylori causes ulcers is not well understood, elimination of this bacteria by antibiotics has clearly been shown to heal ulcers and prevent ulcer recurrence.

Causes

NSAIDs are medications for arthritis and other painful inflammatory conditions in the body. Aspirin, ibuprofen (Motrin), naproxen (Naprosyn), and etodolac (Lodine) are a few of the examples of this class of medications. Prostaglandins are substances which are important in helping the gut linings resist corrosive acid damage. NSAIDs cause ulcers by interfering with prostaglandins in the stomach.

Cigarette smoking not only causes ulcer formation, but also increases the risk of ulcer complications such as ulcer bleeding, stomach obstruction and perforation. Cigarette smoking is also a leading cause of ulcer medication treatment failure.

Contrary to popular belief, alcohol, coffee, colas, spicy foods, and caffeine have no proven role in ulcer formation. Similarly, there is no conclusive evidence to suggest that life stresses or personality types contribute to ulcer disease.

Causes

Symptoms of ulcer disease are variable. Many ulcer patients experience minimal indigestion or no discomfort at all. Some report upper abdominal burning or hunger pain one to three hours after meals and in the middle of the night. These pain symptoms are often promptly relieved by food or antacids. The pain of ulcer disease correlates poorly with the presence or severity of active ulceration. Some patients have persistent pain even after an ulcer is completely healed by medication. Others experience no pain at all, even though ulcers return. Ulcers often come and go spontaneously without the individual ever knowing, unless a serious complication (like bleeding or perforation) occurs.

Symptoms

The diagnosis of an ulcer is made by either a barium upper GI x-ray or an upper endoscopy (EGD-esophagogastroduodenoscopy) The barium upper GI x-ray is easy to perform and involves no risk or discomfort. Barium is a chalky substance administered orally. Barium is visible on x- ray, and outlines the stomach on x-ray film. However, barium x-rays are less accurate and may not detect ulcers up to 20% of the time.

An upper endoscopy is more accurate, but involves sedation of the patient and the insertion of a flexible tube through the mouth to inspect the stomach, esophagus, and duodenum. Upper endoscopy has the added advantage of having the capability of removing small tissue samples (biopsies) to test for H. pylori infection. Biopsies can also be examined under a microscope to exclude cancer. While virtually all duodenal ulcers are benign, gastric ulcers can occasionally be cancerous. Therefore, biopsies are often performed on gastric ulcers to exclude cancer.

Diagnosis

The goal of ulcer treatment is to relieve pain and to prevent ulcer complications, such as bleeding, obstruction, and perforation. The first step in treatment involves the reduction of risk factors (NSAIDs and cigarettes). The next step is medications.

Antacids neutralize existing acid in the stomach. Antacids such as Maalox, Mylanta, and Amphojel are safe and effective treatments. However, the neutralizing action of these agents is short-lived, and frequent dosages are required. Magnesium containing antacids, such as Maalox and Mylanta, can cause diarrhea, while aluminum agents like Amphojel can cause constipation. Ulcers frequently return when antacids are discontinued.

Studies have shown that a protein in the stomach called histamine stimulates gastric acid secretion. Histamine antagonists (H2 blockers) are drugs designed to block the action of histamine on gastric cells, hence reducing acid output. Examples of H2 blockers are cimetidine (Tagamet), ranitidine (Zantac), nizatidine (Axid), and famotidine (Pepcid). While H2 blockers are effective in ulcer healing, they have limited role in eradicating H. pylori without antibiotics. Therefore, ulcers frequently return when H2 blockers are stopped. Generally, these drugs are well tolerated and have few side effects even with long term use. In rare instances, patients report headache, confusion, lethargy, or hallucinations. Chronic use of cimetidine may rarely cause impotence or breast swelling. Both cimetidine and ranitidine can interfere with body's ability to handle alcohol. Patients on these drugs who drink alcohol may have elevated blood alcohol levels. These drugs may also interfere with the liver's handling of other medications like Dilantin, Coumadin, and theophylline. Frequent monitoring and adjustments of the dosages of these medications may be needed.

Treatment

Proton-pump inhibitors such as omeprazole (Prilosec), lansoprazole (Prevacid), pantoprazole (Protonix), esomeprazole (Nexium), and rabeprazole (Aciphex) are more potent than H2 blockers in suppressing acid secretion. Different proton-pump inhibitors are very similar in action and there is no evidence that one is more effective than another in healing ulcers. While proton-pump inhibitors are comparable to H2 blockers in effectiveness in treating gastric and duodenal ulcers, it is superior to H2 blockers in treating esophageal ulcers. Esophageal ulcers are more sensitive than gastric and duodenal ulcers to minute amounts of acid. Therefore, more complete acid suppression accomplished by proton-pump inhibitors are important for esophageal ulcer healing. Proton-pump inhibitors are well tolerated. Side effects are uncommon; they include headache, diarrhea, constipation, nausea and rash. Interestingly, proton-pump inhibitors do not have any effect on a person's ability to digest and absorb nutrients. Proton-pump inhibitors have also been found to be safe when used long term, without serious adverse health effects reported.

Sucralfate (Carafate) and misoprostol (Cytotec) are agents that strengthen the gut lining against attacks by acid digestive juices. Carafate coats the ulcer surface and promotes healing. The medication has very few side effects. The most common side effect is constipation and the interference with the absorption of other medications. Cytotec is a prostaglandin-like substance commonly used to counteract the ulcer effects of NSAIDs. Studies suggest that Cytotec may protect the stomach from ulceration in those who take NSAIDs on a chronic basis. Diarrhea is a common side effect. Cytotec can cause miscarriages when given to pregnant women, and should be avoided by women of childbearing age.

Treatment

Many people harbor H. pylori in their stomachs without ever having pain or ulcers. It is not completely clear whether these patients should be treated with antibiotics. More studies are needed to answer this question. Patients with documented ulcer disease and H. pylori infection should be treated with antibiotic combinations. H. pylori can be very difficult to completely eradicate. Treatment requires a combination of several antibiotics, sometimes in combination with a proton-pump inhibitor, H2 blockers or Pepto-Bismol. Commonly used antibiotics are tetracycline, amoxicillin, metronidazole (Flagyl), clarithromycin (Biaxin), and levofloxacin (Levaquin). Eradication of H. pylori prevents the return of ulcers (a major problem with all other ulcer treatment options). Elimination of this bacteria may also decrease the risk of developing gastric cancer in the future. Treatment with antibiotics carries the risk of allergic reactions, diarrhea, and sometimes severe antibiotic-induced colitis (inflammation of the colon).

There is no conclusive evidence that dietary restrictions and bland diets play a role in ulcer healing. No proven relationship exists between peptic ulcer disease and the intake of coffee and alcohol. However, since coffee stimulates gastric acid secretion, and alcohol can cause gastritis, moderation in alcohol and coffee consumption is often recommended.

Treatment

Intestinal malrotation is a birth defect involving a malformation of the intestinal tract. Intestinal malrotation is an abnormality that occurs while a fetus is forming in its mother's uterus.

As a fetus is growing in its mother's uterus before birth, different organ systems are developing and maturing. The digestive tract starts off as a straight tube from the stomach to the rectum. Initially, it is located in the fetus' abdomen, but, for a while, part of the intestine moves

into the umbilical cord. At about the 10th week of pregnancy, the intestine leaves the umbilical cord and goes

back into the abdomen. After returning to the abdomen, the intestine makes two turns, and is no longer a

straight tube.

Malrotation occurs when the intestine does not make these turns as it should.

In addition, intestinal malrotation causes the cecum (the end of the small intestine) to develop abnormally. The cecum is normally located in the lower right side of the abdomen. With malrotation, the cecum and the appendix (which is attached to the cecum) stay in the upper right side of the abdomen. Bands of tissue called Ladd's bands form between the cecum and the intestinal wall and can create a blockage in the duodenum (the beginning of the small intestine).

A volvulus is a problem that can occur after birth as a result of intestinal malrotation. The intestine becomes twisted, causing an intestinal blockage. This twisting can also cut off the blood flow to the intestine, and the intestine can be damaged.

Intestinal Malrotation

Intestinal Malrotation

The following are the most common symptoms of malrotation and volvulus. However, each individual may experience symptoms differently. When the intestine becomes twisted, or obstructed by Ladd's bands, the symptoms may include:

vomiting bile (green digestive fluid) drawing up the legs abdominal pain abdominal distention (the abdomen becomes swollen) rapid heart rate rapid breathing bloody stools

The symptoms of malrotation and volvulus may resemble other conditions or medical problems. Consult your child's physician for diagnosis.

Symptoms

In addition to a physical examination and medical history, diagnostic procedures for malrotation and volvulus may include various imaging studies (tests that show pictures of the inside of the body). These are performed to evaluate the position of the intestine, and whether it is twisted or blocked. These tests may include:

abdominal x-ray - a diagnostic test which may show intestinal obstructions.

barium swallow / upper GI test - a procedure performed to examine the intestine for abnormalities. A fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray) is swallowed. An x-ray of the abdomen may show an abnormal location for the small intestine, obstructions (blockages), and other problems.

barium enema - a procedure performed to examine the intestine for abnormalities. A fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray) is given into the rectum as an enema. An x-ray of the abdomen may show that the large intestine is not in the normal location.

Diagnosis

Specific treatment for malrotation and volvulus will be determined by your child's physician based on the following: the extent of the problem your child's age, overall health, and medical history the opinion of the surgeon and other physicians involved in your

child's care expectations for the course of the problem your opinion and preference Malrotation of the intestines is not usually evident until the intestine becomes twisted (volvulus) or obstructed by Ladd's bands and symptoms are present. A volvulus is considered a life-threatening problem, because the intestine can die when it is twisted and does not have adequate blood supply.Children may be started on IV (intravenous) fluids to prevent dehydration and antibiotics to prevent infection. A tube called a nasogastric (or NG) tube may be guided from the nose, through the throat and esophagus, to the stomach to prevent gas buildup in the stomach.

Treatment

A volvulus is usually surgically repaired as soon as possible. The intestine is untwisted and checked for damage. Ideally, the circulation to the intestine will be restored after it is unwound, and it will turn pink.

If the intestine is healthy, it is replaced in the abdomen. Since the appendix is located in a different area than usual, it would be difficult to diagnose appendicitis in the future; therefore, an appendectomy (surgical removal of the appendix) is also usually performed.

If the blood supply to the intestine is in question, the intestine may be untwisted and placed back into the abdomen. Another operation will be done in 24 to 48 hours to check the health of the intestine. If it appears the intestine has been damaged, the injured section may be removed.

If the injured section of intestine is large, a significant amount of intestine may be removed. In this case, the parts of the intestine that remain after the damaged section is removed cannot be attached to each other surgically. A colostomy may be done so that the digestive process can continue. With a colostomy, the two remaining healthy ends of intestine are brought through openings in the abdomen. Stool will pass through the opening (called a stoma) and then into a collection bag. The colostomy may be temporary or permanent, depending on the amount of intestine that needed to be removed.

Treatment