Irritable Bowel Syndrome
Sutter Davis Hospital Gastroenterology

Definition
Irritable bowel syndrome (IBS) is one of the most common disorders that doctors see.  IBS is when food is forced through your intestines more quickly, causing gas, bloating and diarrhea.  Fortunately, unlike more serious intestinal diseases such as ulcerative colitis and Crohn's disease, irritable bowel syndrome doesn't cause inflammation or changes in bowel tissue or increase your risk of colorectal cancer. In many cases, you can control irritable bowel syndrome by managing your diet, lifestyle and stress.

Causes
No one knows exactly what causes irritable bowel syndrome. The walls of the intestines are lined with layers of muscle that contract and relax as they move food from your stomach through your intestinal tract to your rectum. Normally, these muscles contract and relax in a coordinated rhythm. But if you have irritable bowel syndrome, the contractions may be stronger and last longer than normal. In some cases, however, the opposite occurs. Food passage slows, and stools become hard and dry. 

Symptoms
The signs and symptoms of irritable bowel syndrome can vary widely from person to person and often resemble those of other diseases. Among the most common are:

• Abdominal pain or cramping
• A bloated feeling
• Gas (flatulence)
• Diarrhea or constipation — sometimes alternating bouts of constipation and diarrhea
• Mucus in the stool

Treatment

• Lifestyle Changes:  In most cases, you can successfully control mild signs and symptoms of irritable bowel syndrome by learning to manage stress and making changes in your diet and lifestyle. But if your problems are moderate or severe, you may need more than lifestyle changes alone can offer.
  
• Medications:  Two medications for IBS exist, Alosetron (Lotronex) and Lubiprostone (Amitiza).  Alosetron is a nerve receptor antagonist that's supposed to relax the colon and slow the movement of waste through the lower bowel.  treat women age 18 and older who have IBS with constipation. Its effectiveness in men is not proved. Amitiza is a chloride channel activator that you take twice a day. It works by increasing fluid secretion in your small intestine to help with the passage of stool. Common side effects include nausea, diarrhea and abdominal pain.