Pancreas
The pancreas is a major digestive organ that produces and secretes enzymes including trypsin, amylase, and lipase, which digest proteins, starch, and fat respectively. Pancreatitis, inflammation of the pancreas, may be caused by alcohol, gallstones, or infection by the mumps virus. Chronic inflammation can result in malabsorption. Symptoms of pancreatic cancer, more common in the elderly, include jaundice, abdominal or back pain, weight loss, or poor appetite. This cancer is usually fatal, but surgical cure is possible.
Liver
The liver manufactures and secretes bile salts, which help emulsify fats to facilitate digestion and absorption. Malabsorption of bile salts due to disease or resection of the small intestine can lead to bile salt depletion and fat malabsorption, known as steatorrhea. Obstruction of the bile duct, caused by such problems as gallstones and pancreatic tumors, causes backup of bile, resulting in jaundice. Liver cancer is often fatal, because its symptoms are often found in conjunction with other diseases of the liver, such as cirrhosis.
Colon
After passing through the small intestine and traversing the ileo-cecal valve, the residual food matter enters the large intestine, or colon, in liquid form. The colon absorbs fluid and electrolytes from the food and forms a compacted stool mass. The anal sphincter controls passage of stool out of the rectum, the lowest point of the colon. Constipation is a common medical complaint often due to inadequate fiber and fluid intake, but chronic constipation can be a sign of colon cancer in older people, and requires medical evaluation.
Colon cancer arises from benign growths called polyps, and may be prevented by regular medical examinations with removal of polyps before they become cancerous. Treatment involves surgical resection of the cancerous segment, and reconnection of the remaining portion of the colon.
A colostomy, in which an external opening of the intestine is created for fecal matter, is rarely necessary unless the cancer occurs in the lower portion of the rectum. Rectal bleeding may be a sign of colon tumors, but it is most often due to hemorrhoids or fissures (tears in the anal lining) caused by straining related to constipation. Both are easily treated by sitz baths, stool softeners, and increased fiber in the diet.
Rectal bleeding with diarrhea may be due to acute or chronic colon inflammation, or colitis. Acute colitis is often a brief self-limited condition caused by an infectious agent such as Shigella or Campylobacter. Chronic ulcerative colitis may cause serious disability, requires special care, and carries an increased risk of colon cancer after many years of disease.
Irritable bowel syndrome is probably the most common cause of gastrointestinal complaints. Also known as spastic colon, this condition can cause alternating diarrhea and constipation, abdominal cramps, and bloating, without weight loss, bleeding, or other detectable signs of colon inflammation. It is believed to be a motility disorder, often exacerbated by stress and certain foods. Diverticulosis, in which there are multiple small protrusions through the wall of the colon, is a very common condition in the elderly and may produce symptoms similar to irritable bowel syndrome. These protrusions, or diverticuli, may cause more serious complications, such as infection (diverticulitis) and massive rectal bleeding.