Hemolytic uremic syndrome (HUS) facts
What is a "syndrome?"
In medicine, a syndrome is defined as a collection of symptoms (patient complaints), signs (findings on physical examination), and laboratory or imaging findings that tend to group together and be associated with a specific disease or illness.
What is hemolytic uremic syndrome (HUS)?
Hemolytic uremic syndrome (HUS) is a disease of two body systems, the blood stream and the kidney. Hemolysis describes the destruction of red blood cells. In hemolytic uremic syndrome, blood within capillaries, the smallest blood vessels in the body, begins to clot abnormally. When red blood cells pass through the clogged capillaries, they are sheared apart and broken. (hemo=blood +lysis=destruction). The second failed system, kidney failure (uremia), occurs when urea and other waste products build up in the bloodstream because the kidneys cannot filter and dispose of them. (urea=a waste chemical + emia= in the blood).
HUS is also related to another disease caused by a similar normal clotting process within the capillaries called thrombotic thrombocytic purpura (TTP). Within the medical literature, these two conditions are often considered together. HUS is more widely known, however, because it has been discussed in the press because of its relationship to a special type of E. Coli (Escherichia coli) infection associated with food poisoning.
HUS can be classified as typical or atypical. The typical type is associated with gastrointestinal (GI) signs and symptoms including vomiting and diarrhea. Atypical HUS is not associated with GI symptoms.
What causes hemolytic uremic syndrome?
While the cause of HUS has not been established with certainty, researchers believe that an abnormal inflammatory reaction is stimulated in the blood stream causing platelets (the parts of the blood that form clots) to sludge in small blood vessels and form blood clots where they are not supposed to. This uses up the platelets and causes a shortage of them in the rest of the body. This abnormal reaction may be caused by a yet unidentified chemical that is produced in blood plasma (the fluid or non-cellular part of the bloodstream).
The triggering events for HUS are varied and include:
Learn more about: Ticlid
Only the diarrheal form of HUS is considered to be typical HUS and is usually a disease of infants and children younger than 3 years of age.
The others are classified as atypical HUS and also include the familial form of the disease in which a gene mutation affects the blood clotting mechanism.
What are the signs and symptoms of hemolytic uremic syndrome?
In typical HUS, gastroenteritis occurs with abdominal cramping, vomiting and profuse bloody, watery diarrhea, as a symptom up to a week before the onset of HUS. This may cause significant dehydration, weakness and lethargy, as well as electrolyte imbalances because of the loss of sodium, potassium, and chloride in the vomit and diarrhea. These symptoms may resolve before the onset of anemia and the kidney failure symptoms of HUS.
The anemia and uremia usually present with weakness, lethargy, and sleepiness. Seizures may occur. Purpura or small areas of bleeding in the skin may be seen because of low platelet counts (thrombocytopenia).
How is hemolytic uremic syndrome diagnosed?
The health care professional will have a suspicion of the disease based on the history and physical examination, especially in a small child who has had the typical bloody diarrhea. Abnormal laboratory tests help confirm the diagnosis. These abnormal findings may include:
In atypical HUS, history is very important to search for other potential causes of the disease. Unfortunately, the case may not be found in up to half of cases of atypical HUS.
One of the distinguishing findings between HUS and TTP is a normal neurologic examination. The brain function is normal in HUS.
What is the treatment for hemolytic uremic syndrome?
Typical HUS in children tends to be self-limiting, and supportive care is often all that is needed. This may include intravenous fluids for rehydration and rebalancing of electrolytes like sodium and potassium, which can be lost with the diarrhea.
Blood transfusions are only used for the most severe cases of anemia in which the hemoglobin falls below 6 or 7 g/dL (depending on age, the normal value is 11-16).
Kidney failure may be managed expectantly (by observation and supportive care), and dialysis is not often required.
Adults with atypical HUS tend to become more ill and need more aggressive therapy than children with the condition. In addition to the supportive care discussed above, plasmapheresis or plasma exchange may be required. Since it is thought there is an abnormal chemical in the plasma stimulating the abnormal clot formation, removing the plasma and replacing it with donor plasma is helpful in treating adult HUS.
Dialysis may be needed while awaiting recovery of the kidneys from the illness.
Eculizumab (Soliris) has been approved by the FDA for the treatment of atypical HUS. It is a monoclonal antibody that decreases the blood clotting in the capillary blood vessels, decreasing the potential destruction of cells. This type of therapy decreases the body's immune capabilities, and the risk of infection increases.
What is the prognosis of hemolytic uremic syndrome?
Typical HUS in children tends to be self-limiting, and full recovery is most likely.
Adults do less well. Without aggressive therapy like plasmapheresis and dialysis, up to 25% of those affected with atypical HUS may die in the acute phase of the disease, and 50% may have developed long-term kidney impairment.
Patients with HUS not related to a diarrheal illness have a worse prognosis than those whose illness is due to gastrointestinal infection.
In those patients with genetically caused HUS, relapsing illness is common as are kidney failure requiring dialysis and death.
What is hemolytic uremic syndrome (HUS)?
Hemolytic uremic syndrome (HUS) is a disease of two body systems, the blood stream and the kidney. Hemolysis describes the destruction of red blood cells. In hemolytic uremic syndrome, blood within capillaries, the smallest blood vessels in the body, begins to clot abnormally. When red blood cells pass through the clogged capillaries, they are sheared apart and broken. (hemo=blood +lysis=destruction). The second failed system, kidney failure (uremia), occurs when urea and other waste products build up in the bloodstream because the kidneys cannot filter and dispose of them. (urea=a waste chemical + emia= in the blood).
HUS is also related to another disease caused by a similar normal clotting process within the capillaries called thrombotic thrombocytic purpura (TTP). Within the medical literature, these two conditions are often considered together. HUS is more widely known, however, because it has been discussed in the press because of its relationship to a special type of E. Coli (Escherichia coli) infection associated with food poisoning.
HUS can be classified as typical or atypical. The typical type is associated with gastrointestinal (GI) signs and symptoms including vomiting and diarrhea. Atypical HUS is not associated with GI symptoms.
What causes hemolytic uremic syndrome?
While the cause of HUS has not been established with certainty, researchers believe that an abnormal inflammatory reaction is stimulated in the blood stream causing platelets (the parts of the blood that form clots) to sludge in small blood vessels and form blood clots where they are not supposed to. This uses up the platelets and causes a shortage of them in the rest of the body. This abnormal reaction may be caused by a yet unidentified chemical that is produced in blood plasma (the fluid or non-cellular part of the bloodstream).
The triggering events for HUS are varied and include:
Learn more about: Ticlid
Only the diarrheal form of HUS is considered to be typical HUS and is usually a disease of infants and children younger than 3 years of age.
The others are classified as atypical HUS and also include the familial form of the disease in which a gene mutation affects the blood clotting mechanism.
What are the signs and symptoms of hemolytic uremic syndrome?
In typical HUS, gastroenteritis occurs with abdominal cramping, vomiting and profuse bloody, watery diarrhea, as a symptom up to a week before the onset of HUS. This may cause significant dehydration, weakness and lethargy, as well as electrolyte imbalances because of the loss of sodium, potassium, and chloride in the vomit and diarrhea. These symptoms may resolve before the onset of anemia and the kidney failure symptoms of HUS.
The anemia and uremia usually present with weakness, lethargy, and sleepiness. Seizures may occur. Purpura or small areas of bleeding in the skin may be seen because of low platelet counts (thrombocytopenia).
How is hemolytic uremic syndrome diagnosed?
The health care professional will have a suspicion of the disease based on the history and physical examination, especially in a small child who has had the typical bloody diarrhea. Abnormal laboratory tests help confirm the diagnosis. These abnormal findings may include:
In atypical HUS, history is very important to search for other potential causes of the disease. Unfortunately, the case may not be found in up to half of cases of atypical HUS.
One of the distinguishing findings between HUS and TTP is a normal neurologic examination. The brain function is normal in HUS.
What is the treatment for hemolytic uremic syndrome?
Typical HUS in children tends to be self-limiting, and supportive care is often all that is needed. This may include intravenous fluids for rehydration and rebalancing of electrolytes like sodium and potassium, which can be lost with the diarrhea.
Blood transfusions are only used for the most severe cases of anemia in which the hemoglobin falls below 6 or 7 g/dL (depending on age, the normal value is 11-16).
Kidney failure may be managed expectantly (by observation and supportive care), and dialysis is not often required.
Adults with atypical HUS tend to become more ill and need more aggressive therapy than children with the condition. In addition to the supportive care discussed above, plasmapheresis or plasma exchange may be required. Since it is thought there is an abnormal chemical in the plasma stimulating the abnormal clot formation, removing the plasma and replacing it with donor plasma is helpful in treating adult HUS.
Dialysis may be needed while awaiting recovery of the kidneys from the illness.
Eculizumab (Soliris) has been approved by the FDA for the treatment of atypical HUS. It is a monoclonal antibody that decreases the blood clotting in the capillary blood vessels, decreasing the potential destruction of cells. This type of therapy decreases the body's immune capabilities, and the risk of infection increases.
What is the prognosis of hemolytic uremic syndrome?
Typical HUS in children tends to be self-limiting, and full recovery is most likely.
Adults do less well. Without aggressive therapy like plasmapheresis and dialysis, up to 25% of those affected with atypical HUS may die in the acute phase of the disease, and 50% may have developed long-term kidney impairment.
Patients with HUS not related to a diarrheal illness have a worse prognosis than those whose illness is due to gastrointestinal infection.
In those patients with genetically caused HUS, relapsing illness is common as are kidney failure requiring dialysis and death.
Source: http://www.rxlist.com
The anemia and uremia usually present with weakness, lethargy, and sleepiness. Seizures may occur. Purpura or small areas of bleeding in the skin may be seen because of low platelet counts (thrombocytopenia).
Source: http://www.rxlist.com
We respect your privacy and aim for the best website experience in compliance with local laws. Allowing cookies enables a tailored experience, while disabling them may reduce personalization. For more information, please read our Privacy Policy and Cookie Policy.