What Causes Pain and Hypersensitivity In IBS

februari 17, 2023

One of the most common symptoms that people with IBS experience is abdominal pain – symptoms that we regularly see at Nordic Clinic. An interesting thing about the gastrointestinal tract is the experience of pain is different. If you lacerate your forearm you’ll experience more pain than if someone squeezed it with a moderate amount of pressure. In the gut, pressure elicits pain while laceration does not.

As such, excess pressure due to gas and bloating in the intestine causes life-altering pain in those with IBS. Though most of the blame is placed on excess gas, studies indicate that even when gas is the same between those with IBS and controls, those with IBS experience pain while healthy controls do not.¹ This increased pain sensitivity is known as visceral hypersensitivity.

Pain and hypersensitivity is caused by multiple factors. Given that IBS is considered a disorder of the gut-brain axis, the gut, brain, and microbiome all play a role.

Causes of Visceral Hypersensitivity and Pain In IBS

Food antigens

Bacterial infection can initiate an immune response that leads to the production of IgE antibodies that cross-react with food (gluten, soy, wheat and dairy). Consumption of the offending food(s) leads to histamine release from mast cells in the gut and increased visceral hypersensitivity.²

Increased intestinal permeability (also known as “leaky gut”)

The role of the intestinal barrier is to prevent inappropriate activation of the immune system as food and bacteria move through the gut. When the gut becomes more permeable, this leads to the release of inflammatory cytokines that promote visceral hypersensitivity.³

Microbial dysbiosis

The microbiome plays an important role in promoting homeostasis in the gut. When the microbiome becomes perturbed, dysbiosis promotes inflammation, increases mast cells and increases permeability that promotes visceral hypersensitivity.⁴ Furthermore, bloating due to the overproduction of gas of specific microbes impacts motility and elicits pain.

Chronic stress

Research indicates that chronic stress increases visceral hypersensitivity.⁵ This is due to a complex interaction between the HPA axis, the autonomic nervous system, and the immune system. Furthermore, chronic stress alters the microbiome, increases mast cells, and impairs permeability.

Abdominophrenic dyssynergia

In healthy individuals, the brain-gut axis initiates a reflexive response to abdominal pressure that leads to relaxation of the diaphragm and contraction of the muscles of the anterior abdominal wall. In those with IBS, this reflex is lost leading to abdominal distension and increased pressure in the abdominal cavity that leads to pain.⁶

Address The Underlying Factors

Addressing pain in IBS requires identifying and treating the causes of pain. Identifying dietary triggers, reducing intestinal permeability, treating dysbiosis, cognitive behavioural therapy, and biofeedback to correct abdominophrenic dyssynergia are all important tools to use once the underlying causes are identified.