What is AHUS?

what is atypical hus?

Atypical – this is a less common form of the disease

Haemolytic – tells us that the blood system is involved

Uraemic – this tells us that the kidneys are involved

Syndrome – more than one thing is going on at the same time

  • aHUS is an ultra-rare disease caused by a fault in the complement system. The complement system is part of your body’s immune response that attacks bugs.
  • Your body has an in-built system of protector proteins that stop complement from attacking your own cells. In aHUS, complement starts to attack the body’s own cells, especially those that line the blood vessels. This leads to clots forming within the small vessels.
  • The most commonly affected organ is the kidney but all organs can be affected. Left untreated it can be a life-threatening illness and the majority of people would develop end stage kidney failure.

Why Does AHUS Happen?

  • A genetic fault in the complement system or the protector proteins causes complement to target the body’s own cells.
  • Some patients may also develop autoantibodies to the protector proteins. These autoantibodies then stop the protector protein from doing its job.

When Does AHUS Occur?

An episode of aHUS can occur at any age, even though you may have been born with the genetic fault. This is because there is usually a ‘trigger’ that starts off the process.

Common triggers include:

  • Gastro-intestinal illness
  • Respiratory illness
  • Medications
  • Pregnancy – especially the third trimester of pregnancy and the period immediately post-delivery.

What does AHUS feel like?

  • Most patients will begin by feeling generally unwell with increasing tiredness. Sometimes it may feel like you have picked up a bug or a virus that doesn’t seem to be getting better.
  • If you are at risk of developing aHUS and are concerned about any symptoms then you should seek medical advice.
doctor consulting

Find out more

Diagnosing aHUS


Treating aHUS

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