Steatorrhoea and elastase

Question

Hello,

My little 3 year old daughter has a high steatorrhoea but a normal faecal elastase. How can we explain this?
I thought that one without the other is impossible. She is treated with Creon and I was told that she has a pancreatic insufficiency but I thought that in this case faecal elastase should be abnormal…

Answer

Hello,
Exocrine pancreatic insufficiency occurs in most of 85% of patients with
cystic fibrosis.
The determination of steatorrhoae and the determination of faecal elastase
are two different methods to evaluate the pancreatic function.

The faecal elastase is a proteolytic pancreatic enzyme which can be measured
in a stool sample. A faecal elastase over 200μg / g of stool reflects a normal
pancreatic function, under 100μg / g a severe exocrine pancreatic insufficiency,
and between 100 and 200 a moderate pancreatic insufficiency. The faecal
elastase is unaffected by the pancreatic enzyme replacement therapy. This
laboratory test has a good sensitivity. It is the most commonly used to
confirm the exocrine pancreatic insufficiency. For the newborns diagnosed by
neonatal screening who have an initial elastase in the normal ranges, the
faecal elastase must be regularly performed, because these patients can
become pancreatic insufficient later, especially in the first year of live.

The determination of steatorrhoae is the gold standard but it requires to
collect stools during 3 days; this test must be assessed taking into account
the fat consumption. The interpretation of an abnormal steatorrhea may be
difficult, depending on the diet, the stool collection, and some factors
that may interfere such as suppositories, fatty ointments, etc ...

A abnormal steatorrhoae (over 3.5g to 7 g/24h depending on the age) reflects a fat malabsorption, usually due to a pancreatic etiology but sometimes due to another etiology: intestinal (intestinal resection for example) , biliary...

Regarding your daughter, the question you ask is quite relevant. In fact,
the faecal elastase is normal and it does not allow the diagnosis of
exocrine pancreatic insufficiency. To analyze precisely this situation, some
elements are to clarify: what about clinical signs of malabsorption before
enzyme replacement treatment? Did the treatment improve these signs and the
steatorrhea? Has the normal rate of faecal elastase been checked several
times?

If the normality of faecal elastase was confirmed, another cause of
steatorrhea should be considered. Feel free to discuss again this issue with
your medical team.

Sincerely
Dr Michèle Gérardin

14.02.2012