Hemolytic-uremic syndrome

}} In medicine, hemolytic-uremic syndrome (or haemolytic-uraemic syndrome, abbreviated HUS) is a disease characterised by microangiopathic hemolytic anemia, acute renal failureand a low plateletcount (thrombocytopenia).

Signs and symptoms

The classic childhood case of HUS occurs after bloody diarrheacaused by E. coli O157:H7, a strain of E. coli that expresses verotoxin(also called Shiga toxin). The toxin enters the bloodstream, attaches to renalendotheliumand initiates an inflammatoryreaction leading to acute renal failure(ARF) and diffuse intravascular coagulation(DIC). The fibrinmesh destroys red blood cellsand captures thrombocytes, leading to a decrease of both on full blood count.

HUS occurs after 2-7% of all E. coli O157:H7 infections.

Adult HUS has similar symptoms and pathology but is an uncommon outcome of the following: HIV; antiphospholipid syndrome (associated with Lupus erythematosusand generalized hypercoagulability); post partum renal failure; malignant hypertension; scleroderma; and cancer chemotherapy(mitomycin, cyclosporine, cisplatin and bleomycin).

A third category is referred to as Familial HUS. It represents 5-10% of HUS cases and is due to an inheritied deficiency leading to uncontrolled complement systemactivation. Recurrent thromboses result in a high mortality rate.

Diagnosis

Clinically, HUS can be very hard to distinguish from thrombotic thrombocytopenic purpura(TTP). The laboratoryfeatures are almost identical, and not every case of HUS is preceded by diarrhea. The only distinguishing feature is that in TTP, neurologicalsymptoms occur more often, but this is not always the case.

Treatment

Treatment is generally supportive with dialysisas needed. Platelettransfusionmay actually worsen outcome. Mortality of HUS is 3-5%.

Often, plasmapheresisis also initiated, when there is diagnostic uncertainty between HUS and TTP.

Prognosis

About one-third of persons with hemolytic-uremic syndrome have abnormal kidney function many years later, and a few require long-term dialysis. Another 8% of persons with hemolytic uremic syndrome have other lifelong complications, such as high blood pressure, seizures, blindness, paralysis, and the effects of having part of their colonremoved.

Impact on society

HUS and the E. Coli infections which caused it have been the source of much negative publicity for the FDA, meat industries, and fast-food restaurantssince the 1990's, especially in the Jack in the Boxcontaminations. It was also featured in the Robin Cooknovel Toxin.

See also

• E. coli O157:H7
• Shigellosis
• Microangiopathic hemolytic anemia

External links

• OMIM235400

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Hemolytic-uremic+syndrome Wikipedia article Hemolytic-uremic syndrome.