TOC | GI-Disorders | Medline Drugs Info
Infectious Diarrhea or Colitis
difficile diarrhea & colitis
C.difficile is a noninvasive Gram positive, sore-forming, ibligate anaerobid bacillus, which produce toxins A & B.
It can be cultured from the stool in 5 % of healthy adults, in 10-30% of asymptomatic hospital & nursing patients. Therefore, the mere presence of C.difficile does not necessarily indicate disease.
Antibiotics most frequently associated with this infection are clindamycin, ampicillin, amoxicillin, and cephalosporins, but all antibiotics may predispose patients to C difficile infection.
traveler's diarrhea has been a hotly contested issue for many
years. Although several antibiotics have been shown to be of benefit in
preventing this illness (e.g., doxycycline [Vibramycin],
trimethoprim-sulfamethoxazole [Bactrim], norfloxacin * [Noroxin], ciprofloxacin
[Cipro]), the routine use of these agents for prophylaxis is generally not
recommended. Arguments against prophylaxis include the side effects
of antimicrobial therapy (e.g., skin rashes including erythema multiforme,
vaginal candidiasis, photosensitivity reactions, bone marrow toxicity, and
anaphylaxis). In addition, altering gut flora may predispose to resistant
jejuni Colitis Rx:
- usually self-limited with no treatment needed except for symptomatic relief, e.g. bismuth subsalicylate (Pepto-Bismol)
- supportive treatment with attention to fluid and electrolyte balance may be needed in more severe cases
Salmonella Gastroenteritis Rx:
Yersinia -induced diarrhea Rx:
Enterotoxic Escherichia coli diarrhea Rx:
Vibrio cholerae Rx:
|For those patients with diarrhea of 2-3
days' duration, work-up is rarely necessary unless fever, bloody diarrhea,
or severe abdominal pain is present.
Viruses are the major cause of gastroenteritis in the United States and indeed worldwide, accounting for up to 30% to 40% of acute episodes. There is limited utility in doing special viral cultures because specific viruses are rarely isolated, and knowing the identity of the virus does not alter management.
Patients with small-volume, bloody diarrhea and lower abdominal cramping and tenesmus are likely to have colitis. When diarrhea is the result of an infection, invasive bacteria are the most likely cause.
Large-volume, watery diarrhea and diffuse abdominal cramps are typical of small intestinal infection.
A detailed history of recent travel (within 6 months), recent antibiotic use (within 6-8 weeks), contact with individuals who are ill, and specific dietary ingestions during foodborne outbreaks can suggest an infectious etiology.
Because symptoms generally resolve within 24-48 hours, most patients with acute infectious diarrhea will not require any specific treatment. The primary therapy for all patients in this setting is oral hydration. Patients with dysentery (bloody diarrhea) require evaluation because this population may benefit from antimicrobial therapy.
Fever and dysentery are often due to infection by an invasive organism, such as Salmonella, Shigella, Campylobacter, enteroinvasive and enterohemorrhagic E coli, Aeromonas spp, some noncholera vibrios, or amebiasis. Patients with acute onset of diarrhea with fever and either blood in their stools or evidence of fecal leukocytes should be given empiric antibiotic therapy. The drug of choice in this clinical setting is a quinolone antibiotic as Ciprofloxacin (because the most likely organisms to be isolated are generally susceptible to the quinolones). Once a specific pathogen is isolated and sensitivities to antibiotics are identified, therapy can be modified as needed.
Organism & The Recommended Antimicrobial Treatment for Infectious Diarrhea
The most critical therapy in diarrheal illness is hydration, preferably with oral rehydration solution (ORS). The composition of this fluid is 90 mm sodium, 80 mm chloride, 111 mm glucose, and 10 mm citrate (or bicarbonate) per liter. Whereas antibiotic therapy is indicated only in a small number of instances, hydration remains the mainstay of diarrheal therapy.
In general, antimicrobial therapy is indicated in the following situations: treatment of infectious colitis due to Shigella, diarrhea due to C. difficile, cholera, traveler's diarrhea, amebiasis, and giardiasis.
Gastroenteritis due to nontyphoidal Salmonella is usually self-limited (diarrhea lasting longer than 1 week should suggest an alternative diagnosis), and therefore antibiotic therapy is not indicated. It may, in fact, prolong carriage and lead to an increased rate of relapse in children. However, treatment should be strongly considered in newborns (to prevent meningitis); in patients older than 50 (especially those with atherosclerosis); in immunosuppressed patients (e.g., persons who have AIDS, organ transplant recipients); in patients with inflammatory bowel disease; and in patients with bone and joint prostheses, chronic arthritides, and hemoglobinopathies.
Antibiotic therapy may be withheld in most cases of diarrheal illness due to the other major bacterial enteric pathogens, as these are self-limited illnesses. Antibiotic therapy may be indicated in patients who present with high fever, bloody diarrhea, more than eight stools per day, dehydration, and symptoms for more than 1 week and in immunocompromised patients. Empirical antibiotics may be given to prevent the need for hospitalization in ill patients.