Course Diarrhea and Dehydration

Bacterial Dysentery

A child is classified as having dysentery if the mother or caregiver reports blood in the child’s stools. Bloody diarrhea in young children is usually a sign of invasive enteric infection that carries a substantial risk of serious morbidity and death. About 10% of all diarrhea episodes in children under 5 ears old are dysenteric, but these cause up to 15% of all diarrheal deaths. Dysentery is especially severe in infants and children who are undernourished or who develop clinically-evident dehydration during their illness. Diarrheal episodes that begin with dysentery are more likely to become persistent than those that start without blood in the stools.

Evaluate children with acute bloody diarrhea. Administer appropriate fluids to prevent or treat dehydration, and provide food. In addition, they should receive for 5 days an oral antimicrobial active against Shigella, since this is the responsible organism in most cases (up to 60%) of dysentery in children.

It is essential to know the sensitivity of Shigella local strains, because antimicrobial resistance is common. A number of antimicrobials often used for the management of dysentery, such as amoxicillin and trimethoprim-sulfamethoxazole (TMP/SMX), may be ineffective for treating shigellosis irrespective of the local strain sensitivity. If available, consider ceftriaxone, a fluoroquinolone (in patients older than 18 years), or azithromycin for resistant strains. Ideally a stool culture is performed to identify the organism and guide treatment according to antimicrobial sensitivity. Hospital referral is recommended if the child is malnourished or if there is a previous underlying illness that can complicate the diarrheal disease.

Some regions of Latin America, such as Argentina, have a high incidence of hemolytic-uremic syndrome, a very severe condition caused by Shiga toxin-producing strains of E. coli, and associated with acute renal failure. Antibiotic treatment may precipitate renal failure. In these regions, before starting empiric antibiotic therapy, take a sample of stools for culture that will provide results within 48 hours.

Evidence of improvement in bloody diarrhea include defervescence, less blood in stools, less frequent evacuations, improved appetite, and a return to normal activity. If there is little or no improvement after 2 days, refer the child to a hospital for further evaluation and treatment. If referral is not possible, perform a stool culture in order to identify the organism and adjust antibiotic therapy. If the child is improving, the antimicrobial should be continued for 5 days.

Amoebic Dysentery

Amoebic dysentery is caused by Entamoeba histolytica, a protozoan parasite, and also presents with bloody diarrhea. It is transmitted by fecal-oral route, particularly through contaminated water and food. The most severe forms occur in infants, pregnant women, and malnourished children. As in Shigella-associated dysentery, the stools often contain visible blood, and diarrhea may be associated with fever and abdominal pain. Hepatomegaly may be present.

Complications include fulminant colitis, toxic megacolon, bowel perforation, and liver abscess.

When a microscopic test reveals amoebic trophozoites or cysts, or when a patient with bloody diarrhea has failed two different antibiotic series, give metronidazole (30 mg/kg/day for 5-10 days).