Hemolytic uremic syndrome (HUS) is a disease that usually affects infants and children. The most common form of HUS is caused by consuming food or water contaminated with strains of Escherichia coli bacteria called enterohemorrhagicE coli. The first symptoms of infection include diarrhea, which may be bloody. Toxins released by the bacteria are thought to damage the intestines and then spread through the blood to the kidneys. Hemolytic uremic syndrome may develop within 1 week of the appearance of diarrhea and is considered the most common cause of sudden kidney failure in children. Atypical HUS is a less common form and is associated with improper function of the complement system, blood proteins involved in the natural immune response. This form of HUS is sometimes hereditary and recurrent. The March 14, 2012, issue of JAMA includes an article on enterohemorrhagic E coli .
Hemolytic uremic syndrome is diagnosed when patients present with
thrombocytopenia (low numbers of platelets).
microangiopathic hemolytic anemia (anemia caused by damage to red blood cells). Patients may appear pale because of anemia.
decreased kidney function, sometimes with decreased urine output (oliguria) or no urine production at all (anuria). Patients may develop hypertension and edema (swelling).
Although patients with HUS may be dehydrated, fluids are given very carefully so that the kidneys, which may not be functioning at normal capacity, are not overwhelmed.
Urine output, a marker for kidney function, is monitored very closely.
Patients with HUS may require dialysis (blood filtering) to temporarily perform the functions of the kidney.
Patients may receive blood transfusions if their blood counts are very low.
Antibiotics are generally not used to treat HUS because of concerns that killing the bacteria would release more toxins and worsen symptoms.
Patients with atypical HUS may be treated with plasma (fluid portion of blood) to replace complement proteins or antibodies (blood proteins that are part of the immune system) that block complement activation.
The course of HUS varies from patient to patient. Some may require hospitalization for a short time while others may require monitoring and care in the intensive care unit and even dialysis or plasma exchange (removal, treatment, and replacement of the blood plasma). In severe cases, other organ systems can be affected. Most patients with HUS require close follow-up after they are discharged from the hospital to ensure that their kidney function improves or remains normal. Patients with atypical HUS tend to have a recurrent course of disease that may lead to renal failure.
Centers for Disease Control and Prevention www.cdc.gov/osels/ph_surveillance /nndss/casedef/hemolyticcurrent.htm
Mayo Clinic www.mayoclinic.com/health/hemolytic-uremic-syndrome/DS00876
National Kidney and Urologic Diseases Information Clearinghouse kidney.niddk.nih.gov/kudiseases/pubs/childkidneydiseases /hemolytic_uremic_syndrome/
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Sources: Centers for Disease Control and Prevention, Mayo Clinic, National Kidney and Urologic Diseases Information Clearinghouse
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Punnoose AR, Lynm C, Golub RM. Hemolytic Uremic Syndrome. JAMA. 2012;307(10):1098. doi:10.1001/jama.2012.225