Hemolytic uremic syndrome
Hemolytic uremic syndrome (HUS) is a serious condition primarily affecting children, characterized by acute kidney failure, hemolytic anemia, and a low platelet count. It is most commonly triggered by an infection with a specific strain of Escherichia coli (E. coli), particularly the O157:H7 variant. Initial symptoms often include gastrointestinal distress such as vomiting, fever, cramping, and diarrhea, which can develop into more severe issues like red blood cell destruction and impaired kidney function. As the condition progresses, individuals may experience reduced urine output, pallor, bruising, blood in urine and feces, extreme fatigue, and even seizures.
Treatment for HUS is predominantly supportive, focusing on maintaining fluid and electrolyte balance. In severe cases, interventions like dialysis or kidney transplantation may be necessary. Notably, certain treatments such as antibiotics and platelet transfusions can exacerbate the condition and are generally avoided. Although HUS is uncommon, it has been linked to larger outbreaks due to contaminated food and water, highlighting the importance of food safety. Research efforts are ongoing to improve prevention and treatment strategies, including potential immunization against the toxin-producing bacteria.
Hemolytic uremic syndrome
ALSO KNOWN AS: Gasser syndrome
ANATOMY OR SYSTEM AFFECTED: Blood, circulatory system, gastrointestinal system, kidneys, nervous system, urinary system
DEFINITION: A predominantly childhood disorder produced primarily by a strain of Escherichia coli bacteria and characterized by acute kidney failure, hemolytic anemia, and a low platelet count
CAUSES: Infection with E. coli or other bacteria that produce toxins which enter the bloodstream
SYMPTOMS: Initially, vomiting, fever, cramping, and diarrhea; progressing to red blood cell destruction, poor kidney function, reduced urine output, paleness, bruises, blood in urine and feces, extreme fatigue, irritability, seizures, increased blood pressure, swollen limbs
DURATION: Acute
TREATMENTS: Supportive measures; in severe cases, dialysis or kidney transplantation
Causes and Symptoms
In the majority of cases, hemolytic uremic syndrome develops after the digestive system has been infected by the O157:H7 strain of Escherichia coli (E. coli). Undercooked meats, contaminated fresh vegetables and fruits, unpasteurized dairy products and juices, and contaminated water are the primary sources of this bacterium. Hemolytic uremic syndrome can be passed from person to person. Less common sources include Shigella, Salmonella, Yersinia, and Campylobacter bacteria.
Following a siege of gastroenteritis that typically lasts for three to ten days and usually includes vomiting, fever, cramping, and diarrhea, hemolytic uremic syndrome develops when the E. coli produce toxins that enter the bloodstream and begin destroying red blood cells and platelets. The damaged red blood cells block tiny blood vessels in the kidneys, making it more and more difficult for the kidneys to function. Resulting symptoms can include reduced urine output, paleness, small body bruises, blood in the urine and stool, extreme fatigue, irritability, seizures, increased blood pressure, and swollen limbs.
Treatment and Therapy
Once an individual is diagnosed with hemolytic uremic syndrome, the typical treatment is mostly supportive. Maintaining normal electrolyte and water levels in the body eases the immediate symptoms and helps prevent further complications. Vital signs are monitored frequently, as is the weight of the patient. Blood transfusions are necessary only when there is severe anemia.
Depending on urine output and electrolyte abnormalities, dialysis may be used. On rare occasions, the victim may require a kidney transplant. Administration of antimotility agents, antibiotics, or platelet transfusions seems to worsen the outcome.
Perspective and Prospects
Hemolytic uremic syndrome was first described by Swiss hematologist Conrad von Gasser in 1955. Although it is an uncommon illness, striking examples exist in which many individuals have been infected during a particular time frame. In 2000, more than two thousand people developed hemolytic uremic syndrome symptoms after drinking contaminated water in Walkerton, Ontario, Canada; seven died. Three months later, forty individuals experienced hemolytic uremic syndrome symptoms after eating at a Sizzler restaurant in Milwaukee, Wisconsin; one died. In 2006, more than 180 individuals were identified with hemolytic uremic syndrome symptoms in the United States as a result of contaminated spinach grown in California; three died. In 2011, fenugreek seeds contaminated with E. coli O104:H4 caused an epidemic of hemolytic uremic syndrome, affecting 3,800 people, most of whom were adults; thirty-six died. Smaller outbreaks have occurred since then in the United States and throughout the world, such as an outbreak in France in 2019 from raw cow's milk cheese that affected twenty pediatric patients, all of whom they survived.
Research into treating hemolytic uremic syndrome has focused on preventing its onset by using chemical agents that bind the toxins produced by E. coli O157:H7 within the intestines. Strategies involving immunization are also being developed.
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