Studies have seen that 90% of those with IBS experience abdominal bloating and distension. We would agree with this statistic. Most of our patients with IBS report abdominal bloating and distension. In fact, they often say these symptoms are the most bothersome of their symptoms and that they have a huge effect on their quality of life.
There is often confusion between abdominal bloating and distension. Abdominal distension is the physical swelling of the abdominal beyond its regular size. Bloating is the feeling of fullness, pressure or gas within the abdomen. You may experience these symptoms individually or together.
Many of our patients have reported abdominal distension so severe that they look six months’ pregnant, and bloating so extreme that they can barely move. In fact, we know patients who have even avoided going to major life events because of these symptoms.
There are several factors that contribute to both bloating and distension. Today we will be focusing abdomino-phrenic dyssynergia (APD). Studies have shown that APD is a major contributor to abdominal distension in those with functional gut disorders, such as IBS and functional dyspepsia.
You, like many other people, are probably wondering what is APD? Under normal conditions, when we eat, the volume of food in our stomach increases, and the abdominal wall responds correctly.
There should be a coordinated response with relaxation of the diaphragm (the large dome-shaped muscle below your lungs), meaning it moves up and contraction of the abdominal wall. This allows the space in our stomach to expand without there being protrusion of the abdominal wall and abdominal distension.
However, in those with APD there is contraction of the diaphragm, meaning that it is pulled down and relaxation of the abdominal wall meaning that it goes outwards. This leads to abdominal distension.
We often have patients tell us that they get distended no matter what they eat! Many patients feel they are dismissed as being dramatic when they say this. However, a 2019 study* has proved they are right. In this study, participants ate lettuce, which is a food that produces a minimum amount of gas when digested. They saw that there was abdominal distention even after eating lettuce due to APD.
You may now be wondering why APD occurs and how you can stop it from happening. The truth is that we are still unsure exactly why APD occurs, although it has been suggested that it may be in part due to dysregulation of the gut-brain axis.
Treatment of APD is challenging. Diaphragmatic breathing might help but is not proven. To try diaphragmatic breathing, put one hand on your stomach and one hand on your chest. Inhale slowly, trying not to let your chest rise while doing this. drawing breath down into your abdomen and allowing your abdomen to rise. When exhaling, contract your abdominal muscles and allow your stomach to fall. It has been suggested that this might need to be done consistently for 30 minutes after meals, so this is not a quick fix
It has also been suggested that other psychological-based treatments that have been seen to benefit IBS e.g. cognitive behavioural therapy and gut-directed hypnotherapy may also help to improve APD.
Biofeedback using electromyography has also been seen to reduce APD. So far this has mainly been studied in a research context and is not widely available
Do you suffer from APD? Try practising diaphragmatic breathing and let us know how you get on.
*Barba E, Sánchez B, Burri E, Accarino A, Monclus E, Navazo I, Guarner F, Margolles A, Azpiroz F. Abdominal distension after eating lettuce: The role of intestinal gas evaluated in vitro and by abdominal CT imaging. Neurogastroenterol Motil. 2019 Dec;31(12):e13703. doi: 10.1111/nmo.13703. Epub 2019 Aug 11. PMID: 31402544; PMCID: PMC6899808.
Damianos JA, Tomar SK, Azpiroz F, Barba E. Abdominophrenic Dyssynergia: A Narrative Review. Am J Gastroenterol. 2023 Jan 1;118(1):41-45. doi: 10.14309/ajg.0000000000002044. Epub 2022 Sep 30. PMID: 36191283; PMCID: PMC9810002.
