Wednesday, 10 June 2015

I learned a new word today... (Easter eggs - 'Constipation' in babies and things you might not know about lactulose)

Why I have stopped using lactulose to treat babies

This month’s Archive of Disease in Childhood published an interesting paper on defecation patterns in infants. (1)  The most interesting thing for me was that I learned a new word: dyschezia.  The definition of dyschezia is difficulty with defaecation.  While it might seem like a superfluous word to those of us who use terms like constipation and painful, in the context of this article it has an important place in medical terminology because it makes a valuable distinction.

It has long bothered me that babies are referred to as being constipated.  Certainly they might go for days without passing stools and when they finally do they often do their best tomato impression.  While constipation is not the wrong word for what babies go through, it creates the impression that there is significant overlap with the constipation that is so common among older children and this is just not the case.

So what is happening to babies?  The truth is that we just don’t know.   Babies seem to be born with a tendency for their gastrointestinal tract to cause all sorts of alarming symptoms.  We use diagnoses such as colic and posseting in an attempt to give labels to things that seem to be normal phenomena in babies.  These problems are self-limiting however and are probably a feature of a GI tract that is 'learning' how to function effectively.  The trouble with each of these is that they have significant counterparts made up of a list of less common but very significant medical problems. 

Every baby who presents with symptoms that could be due to abdominal pathology should be carefully assessed to exclude such problems including urinary tract infection and surgical problems.  The full list of possibilities is much longer of course but the major clues that the baby does not have these is that they should be alert but settled, thriving and hydrated, afebrile and have no alarming signs or symptoms.
So if we are left with a baby which is not opening its bowels, straining at stool and intermittently getting upset, what do we do?  One thing that I am quite convinced of is that lactulose is not the best medicine for babies no matter what the problem. 

This brings me back my new word: dyschezia.  When babies fail to pass stools, or they strain and show signs of discomfort, they don’t have constipation in the way that a six year old has constipation.  The baby has a gut that is doing something but ineffectively while the six year olds guts are just not doing the thing at all.  “That’s fine,” you may say. “Lactulose is a stool softener so it will help the baby pass stool in this way.”  That’s what I used to believe too until a helpful pharmacist told me about how lactulose really works.  Lactulose does have an osmotic effect but it is also an irritant because when metabolised by the gut bacteria the result is chemicals such as acetic acid, lactic acid and formic acid.

So if a baby is failing to open its bowels because it’s a baby then I prefer not to use lactulose.  If I think that the problem is that the baby has guts that are trying, then driving them harder seems unfair.  I like to think about what we advise parents about how sensitive baby skin is.  How much more sensitive will their gut lining be?

What does work?    If anything is going to work, a glycerine suppository could be tried and in my experience is often successful.  More often the answer is time.  Essentially dyschezia is a common and transient phenomenon which will eventually resolve and is not a risk factor for constipation later in childhood. (1)  As is often the way in paediatrics, time spent looking for the correct diagnosis and explaining things properly to the parents is time well spent.

Finally, I think that dychezia is a terrible word, right up there with erythema toxicum on the list of things that I will never say to parents that their child has.  Can anyone out there suggest a better one?

Edward Snelson
Junior gunner, Crimson Permanent Assurance

(1) Defecation patterns in infants: a prospective cohort study (Kramer et Al, Arch Dis Child, doi:10.1136/archdischild-2014-307448)

Disclaimer:  I don’t know what babies are thinking either.

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