Hemolytic Uremic Syndrome (HUS)

Hemolytic uremic syndrome (hee-mah-lit-ick yer-ee-mik sin-drohm) is a condition that blocks the small blood vessels in your kidneys. The blockage destroys your red blood cells (hemolytic anemia) and reduces the number of platelets (thrombocytopenia) in your blood.

Hemolytic uremic syndrome (HUS) can affect anyone. But you’re more likely to get it from a bacterial infection that causes loose poop (diarrhea), especially Escherichia coli (E. coli). However, a syndrome is a group of symptoms that may have different causes. So,even though you’re more likely to get HUS from E. coli, you could get it from something else.

HUS can affect other organs in your body, including your heart and brain. But it most commonly affects your kidneys.

Contact a healthcare provider if you have bloody diarrhea or diarrhea that lasts longer than three days. Without treatment, a severe case of HUS can be deadly.

What are the different types of hemolytic uremic syndrome?

Types of hemolytic uremic syndrome include:

• “Typical” hemolytic uremic syndrome. This is the most common type. You’re more likely to get hemolytic uremic syndrome from a bacterial infection that affects your small intestine and large intestine (collectively your bowels).
• Atypical hemolytic uremic syndrome (aHUS). You inherit aHUS from a biological parent.
• Secondary hemolytic uremic syndrome. Secondary HUS coexists with other conditions.

What is atypical hemolytic uremic syndrome?

Atypical hemolytic uremic syndrome (aHUS) is a rare type of HUS. Common symptoms include:

• Low levels of red blood cells.
• Low platelet count.
• Sudden (acute) kidney failure.
• High blood pressure (hypertension) or worsening control of your blood pressure.

Atypical hemolytic uremic syndrome is usually a genetic disorder. That means biological parents pass it down to their children. Genetic mutations in some of your genes that encode proteins can cause aHUS. An illness, infection or an environmental factor triggers the mutation to activate.

How common is hemolytic uremic syndrome?

Hemolytic uremic syndrome affects between 5% and 15% of people who have E. coli diarrhea. aHUS is very rare, occurring in less than 1 person in 1 million people.