Hemolytic–uremic syndrome
| Hemolytic–uremic syndrome | |
|---|---|
| Specialty | Hematology  |
In medicine, hemolytic-uremic syndrome (or haemolytic-uraemic syndrome, abbreviated HUS) is a disease characterised by microangiopathic hemolytic anemia, acute renal failure and a low platelet count (thrombocytopenia).
Signs and symptoms
The classic childhood case of HUS occurs after bloody diarrhea caused by E. coli O157:H7, a strain of E. coli that expresses verotoxin (also called Shiga toxin). The toxin enters the bloodstream, attaches to renal endothelium and initiates an inflammatory reaction leading to acute renal failure (ARF) and disseminated intravascular coagulation (DIC). The fibrin mesh destroys red blood cells and 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 erythematosus and 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 system activation. Recurrent thromboses result in a high mortality rate.
Epidemiology
HUS has a peak incidence between 6 months and 4 years of age (Corrigan and Boineau, 2001).
Diagnosis
Clinically, HUS can be very hard to distinguish from thrombotic thrombocytopenic purpura (TTP). The laboratory features are almost identical, and not every case of HUS is preceded by diarrhea. The only distinguishing feature is that in TTP, neurological symptoms occur more often, but this is not always the case.
Treatment
Treatment is generally supportive with dialysis as needed. Platelet transfusion may actually worsen outcome.
In severe cases or when there is diagnostic uncertainty between HUS and TTP, plasmapheresis is the treatment of choice.
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 colon removed. The overall mortality rate from HUS is 5-15%. Older children and adults have a worse prognosis (Chu and Hemphill, 2004).
Impact on society
HUS and the E. coli infections which caused it have been the source of much negative publicity for the Food and Drug Administration (FDA), meat industries, and fast-food restaurants since the 1990's, especially in the Jack in the Box contaminations. It was also featured in the Robin Cook novel Toxin. In 2006, an epidemic of harmful E. coli emerged in the United States due to contaminated spinach. 183 known cases have been reported, including 29 cases of HUS.
See also
External links
References
- Corrigan JJ Jr, Boineau FG (2001). "Hemolytic-uremic syndrome". Pediatr Rev. 22 (11): 365–9. PMID 11691946.
- Chu P, Hemphill RR (2004). "222: Acuired hemolytic anemia". In Tintinalli JE, Kelen GD, Stapczynski JS (ed.). Emergency Medicine: A Comprehensive Study Guide (6th Edition ed.). New York, NY: McGraw-Hill.
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