Hemolytic Uremic Syndrome

Overview

Hemolytic uremic syndrome (HUS) is a condition that disrupts the small blood vessels in the kidneys, leading to the destruction of red blood cells and a decrease in platelet count, which is crucial for clotting. While it can affect individuals of any age, it predominantly impacts young children.

The primary cause of HUS is specific strains of Escherichia coli (E. coli) bacteria. Symptoms commonly include diarrhea, abdominal pain, elevated blood pressure, and reduced urine output. Although the kidneys are primarily affected, other organs may also be involved.

HUS can potentially lead to kidney failure, posing a serious threat. However, timely treatment often results in full recovery, especially in children. Treatment typically involves intravenous fluids, blood plasma, and medication administration.

Symptoms

Generally, hemolytic uremic syndrome damages blood vessels, leading to the breakdown of red blood cells and the formation of blood clots, ultimately resulting in kidney damage.

Acute kidney damage symptoms include:

• Oliguria, or reduced production of urine
• Blood in the urine
• Feeling ill as a result of elevated blood toxin levels
• Severe fatigue
• Bruised easily
• Elevated blood pressure, or hypertension
• Edema, or swelling, in the hands, face, or ankles or less frequently, in other parts of the body
• Dyspnea, or breathing difficulties
• Dizziness, convulsions, or stroke
• The skin or the mucous membranes in the nose and mouth appear pale

Hemolytic uremic syndrome symptoms triggered by E. coli bacteria may involve bloody diarrhea, stomach pain, bloating, fever, and vomiting.

Immediate emergency care is necessary if there is no urine output for 12 hours or longer. Generally, consult a healthcare provider if bloody diarrhea or prolonged diarrhea accompanied by reduced urination, swelling, bruising, unusual bleeding, or extreme fatigue are experienced.

Causes

The majority of the numerous E. coli variants are usual and pose no harm. However, certain strains of E. coli have the potential to cause hemolytic uremic syndrome.

Hemolytic uremic syndrome is primarily caused by specific strains of E. coli bacteria, with the most common being E. coli O157:H7 in North America. These strains, also known as Shiga toxin-producing E. coli (STEC), release a toxin called Shiga, which damages the lining of the small intestines, leading to diarrhea.

Atypical hemolytic uremic syndrome (aHUS) is a rare form of the condition that can be inherited within families. While not everyone who carries the gene for aHUS develops the syndrome, certain factors such as infections, specific medications, or underlying health issues can trigger its manifestation.

Hemolytic uremic syndrome can also be caused by:

• Other infections: Such as influenza virus, HIV infection, and pneumococcal infection.
• Complications of existing conditions: Such as pregnancy or illnesses like cancer or autoimmune diseases.
• Certain medications: Such as those used to prevent organ rejection in recipients of donated organs and certain cancer treatments.

Risk factors

E. coli-caused hemolytic uremic syndrome is often contracted by consuming undercooked or contaminated food and drinks, such as ground beef, unpasteurized milk or juice, and unwashed raw fruits and vegetables.

E. coli can also spread through person-to-person contact via an oral-fecal route, such as swimming in pools or lakes contaminated with fecal matter containing the bacteria.

Individuals at the highest risk of developing hemolytic uremic syndrome include children aged 5 or younger, individuals with weakened immune systems, and those with specific genetic alterations.