what is functional abdominal pain?Posted: 08/04/2013
i remember the weariness on the paediatric gastroenterologist’s face when he diagnosed my daughter. she was admitted to hospital with suspected appendicitis. she had routine blood and urine tests and an ultrasound scan which looked for her appendix and checked her right ovary. a stool sample was tested (faecal calprotectin) and was within normal limits. these are tests to exclude infectious or inflammatory diseases. the consultant acknowledged my daughter was in pain, and that her pain was real, then said, ‘We cannot find anything that is causing the pain. We think the pain is functional in nature.’
functional? what on earth did that mean? i remember distinctly the exasperation and disbelief – and looking from him to my daughter, who was curled up in tears – how could there not be a cause for the pain? it made no sense.
what i didn’t know then, but do now know, is that functional abdominal pain is relatively common, affecting up to 15% of school children. it affects girls more than boys, and peaks during late childhood, early adolescence. my daughter’s experience of FAP is not typical. she is disabled by pain, yet the frequency and severity of her symptoms, the fact that the pain remains localised in the lower right-hand side of her abdomen, all these things made no difference to the diagnosis. if there is a spectrum of FAP, it seems not to matter. my daughter was discharged after a brief meeting with the team clinical psychologist, and no follow-up appointment with gastroenterology offered.
i have the distinct impression that Paediatric Gastroenterolgy is tired of FAP, wearied by it and the drain it has on resources, and is to a very large extent intolerant of parents who ‘don’t get it’. parents who don’t get it are rapidly labeled as part of the problem – which is a neatly invidious position to be placed in.
so what is functional abdominal pain?
No evidence of an inflammatory, anatomical, metabolic, or neoplastic process that explains symptoms. Criteria fulfilled at least once a week for at least two months – must include all of the following:
- Episodic or continuous abdominal pain.
- Insufficient criteria for other functional gastrointestinal disorders.
Functional abdominal pain describes continuous, nearly continuous, or frequently recurrent pain localized in the abdomen but poorly related to gut function.
Functional abdominal pain is divided into two categories.
Functional abdominal pain syndrome (FAPS), also called “chronic idiopathic abdominal pain” or “chronic functional abdominal pain,” describes pain for at least six months that is poorly related to gut function and is associated with some loss of daily activities.
Unspecified functional abdominal pain is functional abdominal pain which fails to meet criteria for FAPS.
Chronic functional abdominal pain (CFAP) is the ongoing presence of abdominal pain for which there is no known medical explanation. CFAP is characterized by chronic pain, with no physical explanation or findings (no structural, infectious, or mechanical causes can be found). It is theorized that CFAP is a disorder of the nervous system where normal nociceptive nerve impulses are amplified “like a stereo system turned up too loud” resulting in pain. Alternately it is hypothesized that there exists in the intestine a protozoan (namely blastocystis) which is interacting with the sympathetic nervous system and causing the pain.