Our team of experts offers a comprehensive evaluation of abdominal symptoms including pain, bloating, gas, and constipation/diarrhea. Our services include medical, dietary and behavioral treatments for functional abdominal pain.
What Is Functional Abdominal Pain?
Abdominal pain is a common symptom of many GI disorders. Pain can be a sign of tissue damage, inflammation or dysfunction in the muscles of the gut. However, pain can develop or linger even when there are no visible abnormalities in the digestive tract. This type of pain is known as functional pain.
Functional abdominal pain is usually recurring or chronic. The pain can be intense and debilitating. Often, functional abdominal pain occurs with other uncomfortable GI symptoms. For example, people with irritable bowel syndrome experience pain as well as frequent abnormal bowel movements (diarrhea, constipation or both), gas and bloating. Functional abdominal pain can also occur even if no other GI symptoms are present.
What Causes Functional Abdominal Pain?
The causes of functional pain are complex. Genetic, environmental and behavioral factors are all believed to play a role.
Sometimes, repeated injury or infection in the digestive tract can leave the nerve endings hypersensitized to pain. In effect, normal bowel sensations that were once mild or even unnoticeable are perceived as intense and painful. However, some people develop functional pain disorders with no obvious cause.
The brain receives pain signals from the rest of the body and is responsible for perception and modulation of pain. Several areas of the brain are involved in pain signal processing, including regions involved in cognition (thought) and emotion. Because of this, certain mental experiences can "turn up" or "turn down" pain signals. For example, many people experience functional pain more intensely when they are emotionally distressed or under other forms of mental stress, such as lack of sleep. These brain regions also interact with the brain's "top-down" circuits that inhibit pain signaling from other parts of the body.
Opioid medications are sometimes used to treat chronic abdominal pain. However, long-term use of opioids can cause hypersensitivity to pain. Although the reasons for this are not entirely known, some evidence suggests that opioids affect the brain's ability to inhibit or suppress pain signals. This effect is sometimes mistaken for tolerance, leading to larger doses of opioid medication and a resulting "vicious cycle."
Treatment of Functional Abdominal Pain
Several types of antidepressant medications are used in the treatment of functional pain. These include:
- Tricyclic antidepressants (e.g., amitriptyline, desipramine)
- Selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, sertraline)
- Serotonin-norepinephrine reuptake inhibitors (SNRIs; e.g., duloxetine, venlafaxine)
Because these medications were originally developed to treat psychiatric disorders, some people are unsure about why their doctors recommend them for pain, or they feel concerned that the doctor thinks the pain is “all in their head.” However, because some of the same neurotransmitters that affect mood can also influence pain modulation circuits, these drugs serve a useful secondary purpose. Furthermore, the dosages that are helpful for pain are often lower than those used to treat depression and anxiety.
Several behavioral treatments, including various forms of cognitive-behavioral therapy and gut-directed hypnotherapy, can also help patients reduce and manage functional abdominal pain. These treatments are designed with several goals in mind:
- Taking advantage of the brain’s abilities to influence pain perception and pain signaling
- Reducing the stress response
- Coping with pain in ways that help improve quality of life
Functional abdominal pain can improve significantly with treatment, though many patients continue to experience some residual symptoms. The focus is not on pinpointing a single cause or "cure" but rather on finding a set of tools or strategies that are most effective for each individual.