Definition

Hemolytic uremic syndrome is a condition characterized by damage and inflammation of small blood vessels in the kidney. This damage can cause the formation of blood clots in the blood vessels. The clotting can block the filtering system in the kidney and cause kidney failure. Hemolytic uremic syndrome can threaten life and affects people of all ages, although it is more common in children. 

In some cases, hemolytic uremic syndrome may be caused by Escherichia coli (E. coli) bacterial infection and is characterized by diarrhea for several days. Other conditions can also cause hemolytic uremic syndrome, especially in adults. This condition is quite serious and requires prompt and appropriate treatment to achieve maximum recovery.

Causes

The most common cause of hemolytic uremic syndrome is E. coli bacterial infection. This cause is most frequent in cases of hemolytic uremic syndrome experienced by children under 5 years of age. E. coli bacteria are normally found in the human intestine. These bacteria are considered normal and beneficial for the body's digestive system; only a few strains cause diarrhea.

A strain of E. coli bacteria can produce a toxin called Shiga toxin. This strain is known as ECTS. ECTS can release the Shiga toxin into the bloodstream, damaging blood vessels. The damage occurs not only to the blood vessels but also to blood components, such as red blood cells and platelets, leading to premature death of these cells. The kidneys are also affected, as the immune system response directly affects kidney cells or the accumulation of dead red blood cells and platelets in the kidney filtration system, causing blockages. This is what leads to the condition known as hemolytic uremic syndrome.

Additionally, other conditions can also cause hemolytic uremic syndrome, such as:

• Other infections. Some other infections that can cause this condition include infections from bacteria like pneumococcus sp., Shigella dysenteriae, Salmonella typhi, HIV, or influenza.
• Use of certain medications. Medications that can impact include cancer treatments or those used to lower the immune system.
• Complications of pregnancy and complications of autoimmune diseases or cancer.
• In some cases, hemolytic uremic syndrome can also be inherited genetically from parents to children. However, it only manifests when there are triggering factors.

Risk factor

The risk factors for hemolytic uremic syndrome depend on the cause of the disease. Because the majority is caused by E. coli infection, the risk will increase under these conditions:

• Consumption of contaminated meat or products
• Swimming in pools or lakes contaminated with feces
• Having close contact with infected individuals, such as family members or someone in childcare
• Children aged 5 years and below (toddlers)
• Adults aged 65 years and above
• People with weakened immune systems
• Individuals with genetic alterations that make them more susceptible

Symptoms

The symptoms of hemolytic-uremic syndrome vary depending on the cause of the condition. In cases caused by E. coli bacterial infection, the symptoms will be closely related to gastrointestinal issues. Some of these symptoms include:

• Diarrhea, sometimes with blood
• Abdominal pain, cramps, or bloating
• Vomiting
• Fever

Hemolytic uremic syndrome can be caused by many factors, but a common denominator is the damage to blood vessels. This damage can lead to anemia, decreased red blood cells, blood clot formation due to decreased platelets, and kidney damage. Some symptoms associated with these conditions include:

• Paleness, especially in the face and under the eyelids
• Extreme fatigue
• Shortness of breath
• Easy bruising without an obvious cause
• Abnormal bleeding, such as sudden nosebleeds or bleeding gums
• Swelling (edema) in the legs, face, hands, or other parts of the body
• Dizziness or confusion, seizures, or stroke
• High blood pressure
• Inability to urinate

Diagnosis

Diagnosis of hemolytic uremic syndrome is established by the doctor through inquiry into the symptoms, physical examination, and diagnostic tests. Some common tests include:

• Blood tests: These are performed to assess red blood cell damage and the concentration of other blood components. The examination may reveal a decrease in platelets, and red blood cells and an increase in creatinine. Creatinine is a waste product usually excreted by the kidneys. Elevated levels indicate potential kidney damage.
• Urine tests or urinalysis: Urinalysis is useful for examining urine content such as protein, blood, and signs of infection.
• Stool analysis: This examination is performed on stool samples to detect the bacteria that cause hemolytic-uremic syndrome.
• Renal ultrasound: This examination is performed to ensure that the cause of the disease is not a blockage in the urinary tract.

Management

The treatment of hemolytic uremic syndrome typically involves hospitalization to prevent dehydration and electrolyte imbalances. The key aspect of treatment is fluid replacement. Doctors may administer the following treatments during hospitalization:

• Intravenous infusion to restore electrolytes essential for proper bodily function.
• Blood transfusion, which can involve administering red blood cells and platelets intravenously to alleviate symptoms of anemia and assist in blood clotting, respectively.
• Administration of medications tailored to lower blood pressure or prevent further damage to blood vessels based on the cause and symptoms of the syndrome.
• Surgery and other procedures, such as kidney dialysis or transplantation, plasma exchange, or kidney cleansing, may be performed depending on the symptoms experienced.

Additionally, doctors will focus on maintaining fluid and electrolyte balance, controlling blood pressure, managing seizures, and ensuring optimal nutrition. The management of hemolytic uremic syndrome often requires collaboration among specialists in nephrology, hematology, neurology, and intensive care.

Complications

Complications of hemolytic uremic syndrome vary and can pose life-threatening risks. Some of the complications include:

• Kidney failure, which can occur acutely or chronically
• High blood pressure
• Stroke or seizures.
• Coma
• Blood clotting issues, eventually leading to bleeding
• Heart problem
• Gastrointestinal problems, such as those affecting the intestines, gallbladder, or pancreas

Prevention

Preventive measures aim to avoid E. coli bacterial infections and other causes. Some of these measures involve dietary adjustments, such as:

• Avoid consuming unpasteurized milk or juice.
• Washing hands before eating and after using the bathroom or changing a baby's diaper.
• Regularly cleaning and washing eating utensils.
• Thoroughly cooking meat.
• Storing meat in the refrigerator if not to be consumed immediately.
• Avoid leaving meat at room temperature to prevent bacterial growth.
• Separating raw meat from ready-to-eat food and avoiding placing ready-to-eat food on plates that previously held raw meat.
• Placing meat at the bottom of the refrigerator to prevent blood drips.
• Wash fruits and vegetables before consuming.
• Avoiding swimming in unclean locations and refraining from swimming when experiencing diarrhea.

When to see a doctor?    

It's crucial to seek medical attention immediately if experiencing the above symptoms. Some warning signs to watch out for include decreased urine output, severe swelling, unexplained bruises, spontaneous bleeding of unknown origin, no urination for 12 hours or more, and extreme fatigue. If experiencing these signs, bring your child or yourself to the emergency department. Follow the recommended treatment by the doctor to ensure proper management of the disease.

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