E. Coli 0157:H7 (cont.)
Charles Patrick Davis, MD, PhD
Charles Patrick Davis, MD, PhD
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
In this Article
What is the treatment for E. coli 0157:H7?
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Patients, especially healthy adults, often require no treatment for E. coli O157:H7 since many infections are self–limited. Moreover, for the acute diarrheal illness, antibiotics have not proven useful. In fact, some studies have shown that antibiotics may increase the chances of developing HUS (up to 17-fold). This effect is thought to occur because the antibiotic damages the bacteria, causing them to release even more toxin. Most investigators suggest antibiotic use only if a patient is septic, that is, there is evidence that the bacterium has spread to parts of the body other than the intestine. In addition, use of atropine and diphenoxylate (Lomotil), drugs that are commonly used to control diarrhea, also may increase symptoms and trigger complications.
When necessary, treatment includes the replacement of fluids and electrolytes to treat or prevent dehydration. Infection with E. coli 0157:H7 should be treated by a physician especially in children and the elderly. HUS and TTP require complex supportive care (for example, plasma exchange) in the hospital. Patients with kidney failure may need dialysis. Consultation with a critical care specialist often is recommended for the care of patients that develop HUS or TTP.
What are the complications and outcomes of infection with E. coli 0157:H7?
Although these conditions have been presented in the symptoms section, they are presented here again because they are actual complications that can occur after the initial disease begins. Patients without these complications usually have excellent outcomes (a good prognosis). Individuals who develop the following complications have outcomes that range from good to poor, depending on their overall health and how quickly they are diagnosed, treated, and respond to treatment.
Hemorrhagic diarrhea (hemorrhagic enterocolitis)
The incubation period between exposure to EHEC bacteria, including E. coli O157:H7, and the onset of symptoms is usually three to four days but may be longer in some individuals. Symptoms of EHEC infection include severe abdominal pain and abdominal tenderness which often is associated with bloody diarrhea. Curiously, there often is little or no fever. The diarrhea typically lasts for six to eight days. Dehydration and blood loss can lead to death in some patients if not corrected early.
Hemolytic-uremic syndrome (HUS)
Hemolytic-uremic syndrome (HUS) is the most worrisome complication of EHEC infection, especially in children, because it is a serious and potentially fatal complication. "Hemolytic" refers to the breakup of red blood cells which leads to anemia. There also is destruction of platelets which leads to low blood levels of platelets (thrombocytopenia), which in turn promotes abnormal bleeding. "Uremic" refers to failure of the kidneys. In addition, problems in the brain with seizures and coma may occur.
Hemolytic-uremic syndrome most commonly affects children under the ages of 10 years and is the most common cause of acute kidney failure in infants and young children. It occurs in about 6% to 10% of hemorrhagic colitis caused by E coli 0157:H7 and usually occurs approximately 7 to 10 days after the onset of diarrhea. Early intervention usually results in better outcomes.
Thrombotic thrombocytopenic purpura (TTP)
Persons infected with E. coli 0157:H7, particularly the elderly, can develop a syndrome similar to HUS called thrombotic thrombocytopenic purpura or TTP with clotting of blood within small blood vessels; anemia due to fragmentation of red blood cells; and a shortage of platelets (thrombocytopenia) that results in easy bruising, neurologic abnormalities, impaired kidney function, and fever. TTP is a serious consequence of E. coli 0157:H7 infection that requires early and aggressive treatment since it results in death in about 10% of all patients who develop it.
Reviewed by Jay W. Marks, MD on 6/20/2012