Diarrhea Health Article

Definition

Diarrhea is an increased frequency of stools or bowel movements (more than two or three per day) or liquidity of feces.

Description

In a normal adult, about 10 quarts (liters) of fluid waste leaves the stomach each day. All but a liter and a half is absorbed in the small intestine. The unabsorbed contents enter the large bowel or colon. Most of the fluid in the feces is reabsorbed by the large intestine. The fluid loss is about 100 milliliters each day. From a strictly medical perspective, diarrhea is defined as stool weight of more than 250 grams in 24 hours. In practice, the calculation of stool weights is restricted to persons with chronic diarrhea.

There are three broad classes that encompass most cases of diarrhea.

• Non-inflammatory diarrhea. This is described as a watery, non-bloody bowel movement that is associated with diffuse abdominal cramping, nausea, vomiting or bloating. The most common cause of non-inflammatory diarrhea is a bacterium that produces a toxin. Common examples of non-inflammatory bacteria include Escherichia coli, Staphylococcus aureus, Bacillus cereus and Clostridium perfringens. Some viruses and amoeba such as Giardia lamblia also cause non-inflammatory diarrhea. This diarrhea is typically mild but may be voluminous, involving large amounts of fluid (10 to 200 mL/kg/day). Such fluid loss results in dehydration and loss of electrolytes. There is usually no blood loss.
• Inflammatory diarrhea. This is usually characterized by the presence of fever and blood in the stool and is associated with left lower quadrant cramps, urgency and tenesmus (anal spasms). Common causes of inflammatory diarrhea include infection with Campylobacter or Yersinia species or infection with some species of Escherichia coli. Diarrhea due to these pathogens tends to be less voluminous, less than 1 liter per day.
• Enteric fever. This is characterized by abdominal tenderness, confusion, prolonged high fever, prostration and occasionally a rash. Common causes of enteric fever-related diarrhea include Salmonella typhi or Salmonella paratyphi. Multi-organ disease is frequently encountered.

Inflammatory diarrhea must be distinguished from ulcerative colitis.

Non-professionals may use the term diarrhea in reference to increased incidence of bowel movements, a sense of fecal urgency, increased stool liquidity or fecal incontinence.

Causes and symptoms

Many cases of non-inflammatory diarrhea are caused by the organisms listed in the description section. The symptoms of diarrhea include nausea, weakness and dehydration. After more that three of four episodes of diarrhea, lethargy develops. Occasionally, diffuse abdominal cramping is experienced.

Inflammatory diarrhea is characterized by fever, nausea, sweating (diaphoresis) and lower abdominal tenderness and cramping. Tenesmus is common but not always present. Weakness and dehydration are often present. Lethargy develops after three or four episodes of diarrhea.

Diarrhea that is associated with enteric illness will be accompanied by prolonged high fever, confusion, prostration, respiratory distress and abdominal tenderness. Organisms that cause diarrhea have been described.

In babies and young children, dehydration is a significant problem that must be rapidly corrected to avoid severe consequences. Lethargy may be the most prominent symptom in these children.

In cases of chronic diarrhea, anemia may be present due to blood loss. Fatigue and lethargy are the most common observable symptoms. Laboratory tests can be used to confirm anemia due to blood loss. The same persons should be tested for ova and parasites in the stool.

Diagnosis

The causative agent of diarrhea may be recovered from a stool sample. Once recovered, it is grown in a laboratory, using standard culture techniques and procedures. Among persons with dysentery, the rate of positive identification of agents using bacterial culture is 60 to 75%. Persons with a recent history of possible exposure to amoeba, whether through travel or from sexual preference, should have a wet mount examination of stool for amoeba.

Laboratories should be alerted to the possibility of exposure to E. coli if exposure to improperly prepared food is suspected.

Stool should be examined for ova and parasites in persons with diarrhea that persists for more than 10 days. Three such examinations for ova and parasites should be performed.

Rectal swabs should be considered for persons suspected of having Neisseria gonorrhoeae, Chlamydia or herpes simplex virus.

Sigmoidoscopy should be considered for persons with severe rectal pain, tenesmus or rectal discharge. Sigmoidoscopy is often useful for differentiating infective diarrhea from ischemic or ulcerative colitis.

Treatment

There are four main elements of treatment: rehydration, diet, antidiarrheal agents, and antibiotic therapy.