A rose by any other name … what’s the fuss?

aHUS, or atypical Hemolytic Uremic Syndrome, is what is known to be the illness that affects a very few patients around the world.

But it is also known as atypical Haemolytic Uraemic Syndrome by those who prefer the Latin, rather than Greek, word root of the terms (or even which spell checker used!).

Sometimes the name appears as Atypical hemolytic uremic syndrome, followed by aHUS for short, in contradiction to the way the lower and upper case first letters are used.

Others put a hyphen in too to give atypical Hemolytic-Uremic Syndrome, but never aH-US.

Others have called it STEC-HUS to differentiate it from STEC+HUS, which is associated with the E. coli trigger i.e.  negative evidence of E. coli found. STEC is sometimes replaced with STx to give STx-HUS.

The two versions of HUS have been differentiated in the past by the diarrhoea symptom D+HUS with and D-HUS without, but it could be present in both versions. Ecoli related HUS is usually taken to be HUS, and rarely typical HUS or tHUS.

The atypical form can also be called Sporadic HUS, Familial HUS, Inherited HUS to confuse matters more between a random and genetic form of the disease.

Indeed, in recent years aHUS has been increasingly taken to be only the disease mediated by inherited significant variants (mutations) in the Complement System sometimes called Complement HUS. Sometimes that is broken down into H-HUS or I-HUS or MCP-HUS depending on the component of Complement implicated.

A new Secondary HUS (SHUS or sHUS?) is being used to describe other precipitating conditions. DGKE associated HUS is taking on as a description of a type of aHUS cause by a mutation in something called diacylglycerol kinase epsilon.

Some of the precipitating conditions have their own description such as P-aHUS, which is the aHUS associated with the pregnancy trigger; and DEAP-HUS describes the aHUS which is caused by Anti-Factor H Antibodies. DEAP being the catchier form of “Deficiency of CFHR (complement factor H-related) plasma proteins and Autoantibody Positive” Also S pneumonia HUS for the HUS precipitated by Sepsis pneumonia.

Having the term Secondary HUS means that atypical HUS also becomes Primary HUS which is if course is  Complement HUS basically.

When Conrad von Gasser first described the illness he had observed, he wrote it on a patient’s medical record in his own words “Haemolytishe-Uraemishe Syndrom” preferring the Latin word roots and using the hyphen, although the last two words are not as clearly written  as the first. By the time his description was published it had become “Hamolytisch-uramishen Syndroms”. There was even an initial thought to call it Gasser Syndromes (note the plural)

But just as Von Gasser chose to split what was at that point commonly known as TTP (and that is a whole other story!), it is inevitable that more and more differentiation of the disease by research will produce more and more  differentiating terminology. aHUS has become inadequate.

So, Primary Haemolytic-Uremic Syndromes or PHUSS is as good a compromise as possible; but for simplicity the alliance remains the aHUS alliance.

Click here for an article discussing names and synonyms and more by Loirat and Fremaeux-Bacchi

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