Functional abdominal pain syndrome (FAPS) is a functional gastrointestinal disorder, which involves chronic or frequent pain that does not result from a specific, identifiable cause.
The primary symptom of FAPS is abdominal pain. The pain can often be very severe and impact the quality of life of patients significantly. This can even disrupt their normal daily routine due to inability to take part in certain activities. It can also have a financial impact on their wellbeing and may increase levels of stress.
The condition is not usually associated with gastrointestinal symptoms such as diarrhea or constipation, and the findings from imaging and laboratory tests are often unable to explain the cause of the pain.
The pain is actually associated with changes in the sensitivity to nerve impulses between the gut and the brain. It is, therefore, a functional problem and not associated with abnormal intestinal motility.
It is important to note that the symptoms of FAPS often appear or worsen after certain events, such as an infection, traumatic life events, or significant stress.
For people with FAPS, there is an alteration in the brain-gut axis and ability of the nervous system to regulate the pain signals for the gastrointestinal tract. As a result, even small stimuli that disturb the intestines can become amplified and lead to severe pain, known as central hypersensitivity.
In some cases, repeated injury to the abdomen may be associated with causing FAPS, due to over-sensitization of the nerve receptors in the area. For example, people who have had multiple abdominal surgeries, recurrent infections or a history of physical or sexual abuse are more likely to be affected by the condition.
The diagnosis of FAPS typically involves a series of diagnostic tests to identify the cause of the pain. This may include X-rays, ultrasound imaging, computed tomography (CT) scans, endoscopy, and blood tests. For patients with FAPS, these tests are not able to reveal a specific cause of the pain.
It can be helpful for patients to keep a pain diary to record symptoms and possible triggers that may have caused a flare-up of symptoms. Over time, this information can help to identify problematic time and causes of worsened symptoms, which can be helpful when developing management strategies.
The treatment aim for people with FAPS is to improve the control the symptoms of pain, daily function, and overall quality of life. It is not usually possible to provide complete relief of symptoms, so management of the pain is important.
The role of the brain in the experience of pain is an important factor in the treatment of FAPS. Certain factors, such as anxiety, depression, focusing on the pain can lead to increased severity of the pain. In contrast, relaxation and diversion techniques can help reduce the severity.
Non-pharmacological management techniques for FAPS include:
- Meditation or other relaxation techniques to manage stress
- Hypnosis or diversion therapy to refocus attention away from the pain
- Cognitive behavioral therapy (CBT) to change thoughts, perceptions, and behaviors related to symptoms of pain.
When an individual takes steps to increase the control of their pain, it is more likely that the symptoms will improve.
Pharmacological management also has a role to play in the management of pain associated with FAPS. Tricyclic antidepressants (e.g. amitriptyline) can help to block the transmission of nerve signals of pain from the abdomen to the brain. This typically takes several weeks for an effect to become evident, so treatment should be continued for at least 1-2 months to experience the effect. Selective serotonin-norepinephrine reuptake inhibitors (SNRIs) can also help to reduce symptoms in some cases.
The support of family, friends, and the community can also help to improve the response to pain for patients with FAPS. Additionally, it is important for the health practitioners involved in the care of the patient to be understanding and display empathy to foster a positive doctor-patient relationship, which helps to improve treatment outcomes.
Reviewed by Susha Cheriyedath, MSc