Non-specific abdominal pain and medically unexplained symptoms

In the early days of GPpaedsTips, I wrote about how I don't like to diagnose non-specific abdominal pain unless constipation has been ruled out.  I think that especially in the pre-teens, undiagnosed constipation is a big factor in mysterious abdominal pains.  In the child where such causes have been ruled out, it is curious that we have kept the term 'non-specific abdominal pain' (NSAP) or 'recurrent  abdominal pain' (RAP) when the label of 'medically unexplained symptoms' (MUS) fits just as well, if not better.

First of all, let's deal with the elephant in the room.  Medical terminology is always evolving and it is sometimes hard to keep up.  Many of us heard different terms used when we first studied medicine (such as functional or psychosomatic) for what seem to be the same clinical scenarios that are now labelled as MUS.  I don’t like perpetual re-labelling of problems. Medically unexplained symptoms, for me, is an exception to this dislike.  MUS removes the judgement of how much a problem is psychological and how much it is physical.  MUS acknowledges that there is always a combination of the physical and psychological.  How much of each component exists is neither measurable nor essential to know.  Is it 60:40 or 30:70?  I don’t know.

The other benefit of calling the situation MUS is that it recognises the possibility that an unknown physical cause may exist.  If a symptom has no medical explanation, the problem may be that medicine has failed to explain the symptom.  Although very few MUS scenarios end up with a eureka moment later on, a significant physical cause is sometimes found.

One definition of MUS is, "symptoms for which a treating physician or other healthcare providers have found no medical cause, or whose cause remains contested."(1)  When a young person presents with recurrent abdominal pains, once the physical medical causes have been ruled out, what we are left with is a medically unexplained symptom.  Labelling the scenario as NSAP is historical and has the potential to be revisited.

Is there anything wrong with the label of NSAP?  I can see two potential pitfalls, both of which arise from that way that it sounds a lot like a diagnosis.  The first problem is that both family and clinician may see the matter as closed.  This carries the risk that a diagnosis might be missed, especially if it is one that easily goes beneath the radar, such as coeliac disease.  This publication lists various pathologies that were found following a diagnosis of NSAP. (2)

Nor should we over-investigate.  As discussed in a recent review article on MUS in ADC (3), the problem here is the "impossibility of proving a negative."  Rather than give every child with abdominal pain an endoscopy, the middle way of leaving the diagnosis open while observing and looking for a recognisable pattern may be safer than labelling as NSAP.

The second problem is that any psychological component may not be addressed.  Is there a psychological component in NSAP?  I would say that there always is but for different reasons depending on the scenario.  The more physical the problem, the more distressing it is to have chronic symptoms that cannot be easily explained or be treated.  If the symptoms could be described as being secondary to a psychological cause, then the psychological component is self-evident.  There is no chronic abdominal pain scenario that I can think of that would not benefit from a dual physical-psychological approach.

I think that this dual approach is what tends to be done with NSAP already, whether it is managed by GP, paediatrician, gastroenterologist or surgeon.  An open minded and holistic approach is essential when managing medically unexplained abdominal pain in young people.


Managing medically unexplained abdominal pain in young people in Primary Care

In some cases, a cause of abdominal pain is obvious.  Common pathologies are constipation and reflux oesophagitis.  Both can be managed in Primary Care if there are no red flags and the problem responds to treatment.  Even when the cause is less obvious, the cause is often constipation, which is why it is worth really asking in detail about diet, bowel habit and the pain.  I also believe that a trial of macrogol laxatives is often a good strategy in the absence of an obvious cause.

In more extreme cases, there may be red flags such as weight loss, or bloody mucousy stools.  These children should be referred though an urgent route (inpatient or out-patient depending on the circumstances).  If the symptoms are severe enough to warrant immediate admission and investigation, laparoscopy finds a cause in about half of patients. (4)

There are also cases where there appears to be a psychological cause, often related to stresses such as school, bullying or even abuse.  It is still important to consider physical causes but there is nothing wrong with moving to address the psychosocial causes early on.

In some cases there is genuine ongoing uncertainty.  The usual pathway for these children is to refer to paediatric surgeons, paediatrics or paediatric gastroenterology for further investigation.  After this, clinical psychologists are often involved.  I don't know what they do.  Witchcraft or something.

Edward Snelson
@sailordoctor
Unexplained Medic

Disclaimer - If you can't explain it, it's not my fault.   You're clearly not trying hard enough.

References

1. Medically unexplained symptoms, Wikipedia
2. Sanders, D et al, A New Insight into Non-Specific Abdominal Pain, Ann R Coll Surg Engl 88(2); 2006 Mar
3. Cottrell, D, Fifteen-minute consultation: Medically unexplained symptoms, Arch Dis Child Educ Pract Ed 2016;101:114-118
4. Decadt, B. et al, Randomized clinical trial of early laparoscopy in the management of acute non-specific abdominal pain, British Journal of Surgery, Vol 86, Issue 11, pages 1383–1386, 1 November 1999