DIARRHEA

Diarrhea is an abnormal increase in the frequency, fluidity and volume of bowel movements. More than three soft, loose, or watery bowel movements in a day constitute diarrhea. In a healthy adult, most cases of diarrhea last from 24 to 48 hours and are not serious. Diarrhea can be more dangerous to infants and older people because of an increased risk of dehydration, upsetting body chemistry and depleting important body salts. Left untreated, it can lead to shock. Persistent or severe diarrhea requires medical attention. A sudden onset after years of regularity can suggest a serious digestive disorder, such as colon cancer. Diarrhea accompanied by symptoms such as weight loss, abdominal pain, or rectal bleeding requires a doctor's attention.

Causes

Under normal circumstances, the colon absorbs water from food residue, leading to semisolid feces. When the small intestine becomes inflamed, it fails to absorb food and instead secretes additional water and salts into the digestive tract. The colon cannot absorb the excess water, resulting in diarrhea. Most frequently, diarrhea is due to a viral infection or a change in diet. Sometimes, it can be traced to changes in the bacterial population of the digestive tract due to taking antibiotics or to foreign travel. Another cause can be increased frequency or intensity of contractions in the digestive tract, causing food to pass too quickly through the colon. Other common causes include food poisoning, gastroenteritis, celiac disease, lactose intolerance, malabsorption, diverticular disease, inflammatory bowel disease, irritable bowel syndrome, anxiety, overconsumption of alcohol, and reaction to medications.

Diagnosis and Treatment

If symptoms last longer than 48 hours, it is important to seek medical attention. For moderate cases, the doctor may try to treat the symptoms and observe the person. In more severe cases, the doctor will conduct a physical examination and may order such tests as blood tests, stool analysis, a lower gastrointestinal (GI) series (an X-ray procedure also called a barium enema), and sigmoidoscopy and colonoscopy (examinations of the rectum and colon using flexible viewing tubes passed through the anus). The symptoms of diarrhea provide clues to its cause. Diarrhea accompanied by nausea and vomiting is usually due to gastroenteritis. Bloody diarrhea that lasts for more than a few days is a sign of inflammatory bowel disease, while mucus is associated with irritable bowel syndrome, inflammatory bowel disease, and cancer. Loose, yellow, greasy, strong-smelling feces that are hard to flush are a symptom of malabsorption. Food poisoning, food allergy, drug toxicity, or anxiety can bring on watery diarrhea. Doctors advise resting and drinking clear fluids until diarrhea subsides. Because watery diarrhea can rapidly cause a loss of body fluids and crucial body salts, oral rehydration fluid may be needed; available over-the-counter at pharmacies, this specially prepared solution contains water, salts, and glucose. Other over-the-counter medications may relieve symptoms. In severe cases, the doctor may prescribe drugs that slow intestinal activity and ease cramping. To prevent diarrhea, it is important to wash hands thoroughly after using the toilet and before preparing food. When diarrhea is due to underlying problems, it is important to seek treatment.

Diarrhea caused by E. coli

Escherichia coli (E. coli) diarrhea is frequent, liquid bowel movements caused by E. coli bacteria, which normally inhabit the digestive tract of humans without harm. However, a strain of E. coli (enterohemorrhagic) that is most commonly associated with contaminated hamburger meat causes bloody diarrhea and sometimes death. Another type of E. coli bacteria is responsible for many cases of traveler's diarrhea.

Contaminated hamburger meat is the most common source of E. coli infection. There also have been instances of apple cider contamination. In day care centers, human transmission of E. coli has taken place through contact with fecal matter. Three to four days after exposure to the enterohemorrhagic E. coli bacillus, watery diarrhea develops. In most people, this rapidly progresses to bloody diarrhea. Other symptoms include nausea, vomiting and a low-grade fever. Symptoms generally last for a week, followed by spontaneous recovery. However, a life-threatening complication called hemolyticuremic syndrome (HUS) occurs in approximately one in ten cases. This syndrome, which affects primarily very young children and older people, can lead to kidney failure.

Diagnosis and Treatment
The presence of bloody diarrhea suggests a diagnosis of E. coli infection. Stool analysis can confirm the diagnosis. However, if stool samples are taken after 48 hours of infection, culture results may be negative or inconclusive.

Dehydration due to E. coli diarrhea is treated with oral rehydration fluid, a solution that contains water, salts, and glucose that is available over-the-counter at pharmacies. In severe cases, intravenous fluids are required. Medications to reduce the contraction of the intestines should not be used in cases of bloody diarrhea. Treatment of HUS is with clotting factors, plasma exchange, and kidney dialysis. Prevention of E. coli diarrhea is with careful hygiene and thorough cooking of all meat and poultry products.

Traveler's Diarrhea

Traveler's diarrhea is diarrhea caused by ingesting contaminated water or food while traveling in areas with poor sanitation. Abdominal cramps, fever, dehydration, nausea and vomiting may also occur. In many cases, over-the-counter medications control diarrhea. Dehydration can be treated by drinking adequate clear liquids. Because watery diarrhea can rapidly cause a loss of body fluids and crucial body salts, it is best to drink oral rehydration fluid (a solution of water, salts and glucose that is available over-the-counter at pharmacies). A doctor may prescribe an antibiotic for more severe cases. Persistent diarrhea may require testing to determine its cause. Tests may include analysis of a stool sample, blood tests, a lower gastrointestinal (GI) series (an X-ray procedure also called a barium enema), and sigmoidoscopy or colonoscopy, in which the colon and rectum are examined by using a slim, flexible, lighted tube inserted through the anus. If a bacterial infection or parasite is the cause, the doctor will prescribe medication. To prevent diarrhea, doctors recommend that travelers use bottled water, avoid fresh fruits, and eat only thoroughly cooked foods. Thorough cooking destroys most infectious organisms.