Chronic functional abdominal pain (CFAP) or functional abdominal pain syndrome (FAPS) is the ongoing presence of

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Common causes of pain in the abdomen include gastroenteritis and irritable bowel syndrome. About 15% of people have a m ...

for which there is no known medical explanation, and has the potential to interfere with all aspects of daily functioning. It is quite similar to, but less common than,

irritable bowel syndrome Irritable bowel syndrome (IBS) is a "disorder of gut-brain interaction" characterized by a group of symptoms that commonly include abdominal pain and or abdominal bloating and changes in the consistency of bowel movements. These symptoms may ...

(IBS), and many of the same treatments for IBS can also be of benefit to those with CFAP. The fundamental difference between IBS and CFAP is that in CFAP, unlike in IBS, there is no change in bowel habits such as

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel moveme ...

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

. Bowel dysfunction is a necessary diagnostic criterion of IBS. CFAP is characterized by

chronic pain Chronic pain is classified as pain that lasts longer than three to six months. In medicine, the distinction between acute and chronic pain is sometimes determined by the amount of time since onset. Two commonly used markers are pain that continue ...

, with no physical explanation or findings (no structural, infectious, or mechanical causes can be found), although the pain may originate in the viscera, fascial layers, muscles, or peripheral nerves. It is theorized that CFAP is a disorder of the

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...

where normal

nociceptive Nociception (also nocioception, from Latin ''nocere'' 'to harm or hurt') is the sensory nervous system's process of encoding noxious stimuli. It deals with a series of events and processes required for an organism to receive a painful stimulus, c ...

nerve impulses are amplified "like a stereo system turned up too loud" resulting in

pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...

. This

visceral hypersensitivity Visceral pain is pain that results from the activation of nociceptors of the thoracic, pelvic, or abdominal viscera (organs). Visceral structures are highly sensitive to distension (stretch), ischemia and inflammation, but relatively insensitive to ...

may be a stand-alone cause of CFAP, or CFAP may result from the same type of brain-gut nervous system disorder that underlies IBS. As with IBS, low doses of

antidepressant Antidepressants are a class of medication used to treat major depressive disorder, anxiety disorders, chronic pain conditions, and to help manage addictions. Common Side effect, side-effects of antidepressants include Xerostomia, dry mouth, weig ...

s have been found useful in controlling the pain of CFAP.

References

Further reading