Hemolytic Uremic Syndrome

Disease database

Hemolytic Uremic Syndrome (HUS) is a rare but serious condition that primarily affects children and can lead to life-threatening complications. It is characterized by the triad of hemolysis, acute kidney injury, and thrombocytopenia. HUS is most commonly caused by an infection with certain strains of Escherichia coli (E. coli), particularly the strain known as E. coli O157:H7. In this article, we will explore the various aspects of Hemolytic Uremic Syndrome, including its symptoms, causes, diagnosis, and treatment options.

Hemolysis: Destruction of Red Blood Cells

Hemolysis refers to the destruction of red blood cells, which are responsible for carrying oxygen throughout the body. In HUS, the damaged red blood cells can clog the small blood vessels, leading to a decrease in the number of circulating red blood cells and causing anemia. Anemia can result in fatigue, weakness, and pale skin.

Thrombocytopenia: Low Platelet Count

Thrombocytopenia is a condition characterized by a low platelet count. Platelets are essential for blood clotting, and a decrease in their number can lead to abnormal bleeding and bruising. In HUS, the damaged red blood cells can activate the clotting system, leading to the formation of small blood clots throughout the body. These clots can consume platelets, resulting in thrombocytopenia.

Acute Kidney Injury: Impaired Kidney Function

Acute kidney injury is a sudden loss of kidney function, which can occur as a result of the small blood clots that form in HUS. The clots can block the tiny blood vessels in the kidneys, impairing their ability to filter waste products from the blood. This can lead to a buildup of toxins and fluid in the body, causing symptoms such as decreased urine output, swelling, and high blood pressure.

Abdominal Pain, Diarrhea, and Vomiting: Early Symptoms

One of the early symptoms of HUS is abdominal pain, which can range from mild discomfort to severe cramping. This is often accompanied by diarrhea, which may be bloody, and vomiting. These gastrointestinal symptoms usually appear a few days after exposure to the bacteria and can last for several days.

Fever and Neurological Symptoms: Advanced Stage

In some cases, HUS can progress to a more advanced stage, characterized by fever and neurological symptoms. The fever is usually low-grade and may be accompanied by irritability, confusion, seizures, or even coma. These neurological symptoms are a result of the damage caused by the small blood clots to the brain and nervous system.

Causes and Risk Factors

The primary cause of HUS is infection with certain strains of E. coli, particularly E. coli O157:H7. This strain produces toxins that can damage the lining of the blood vessels, leading to the formation of blood clots. HUS can also be caused by other infections, such as pneumonia or a urinary tract infection. Additionally, certain genetic factors and underlying medical conditions can increase the risk of developing HUS.

Diagnosis and Treatment

Diagnosing HUS involves a combination of clinical evaluation, laboratory tests, and imaging studies. Blood and urine tests can help assess kidney function, detect anemia and thrombocytopenia, and identify the presence of the E. coli bacteria or its toxins. Imaging studies, such as ultrasound or CT scan, may be performed to evaluate the kidneys and other organs.

There is currently no specific cure for HUS, and treatment primarily focuses on supportive care. This includes maintaining fluid and electrolyte balance, managing blood pressure, and providing dialysis if necessary. In severe cases, blood transfusions or plasma exchange may be required to replace damaged blood cells or remove toxins from the bloodstream.

Prevention and Prognosis

Preventing HUS involves practicing good hygiene, particularly when handling and preparing food. It is important to thoroughly cook meat, wash fruits and vegetables, and avoid cross-contamination between raw and cooked foods. Additionally, drinking pasteurized milk and avoiding unpasteurized juices can reduce the risk of infection.

The prognosis for HUS varies depending on the severity of the condition and the promptness of treatment. While most children recover fully, some may experience long-term complications, such as kidney damage or high blood pressure. Close monitoring and follow-up care are essential to ensure the best possible outcome.


Hemolytic Uremic Syndrome is a rare but serious condition that primarily affects children. It is characterized by the triad of hemolysis, acute kidney injury, and thrombocytopenia. Early symptoms include abdominal pain, diarrhea, and vomiting, while more advanced stages may present with fever and neurological symptoms. HUS is most commonly caused by infection with certain strains of E. coli, and there is currently no specific cure. However, with prompt diagnosis and supportive care, the prognosis for HUS can be favorable. Practicing good hygiene and food safety measures can help prevent the occurrence of HUS. If you suspect HUS or have any concerns, it is important to seek medical attention promptly to ensure appropriate evaluation and management.

Haroon Rashid, MD
Rate author
Urgent Care Center of Arlington, VA
Add a comment