Abdominal wall pain – classification, diagnosis and treatment suggestions

Abstract

Abdominal pain is generally believed to be a symptom of intra-abdominal disease. When no pathological findings are evident, abdominal pain is considered functional. Abdominal pain, however, may also originate in the abdominal wall. Consecutive patients with unexplained abdominal pain were enrolled in a prospective observational study in a gastroenterologic clinic during a period of three years. The following criteria were tested: Can abdominal pain be elicited by physical movement? Is the source of pain localized to a circumscribed site in the abdominal wall? Can pain be provoked by digital palpation in this area and does pain increase when the abdominal muscles are tensed? Clinical examination of 55 patients revealed small painful pits in the abdominal wall with varying intensity of pain when the abdominal muscles were contracted: in 39 patients the painful area was located in the semilunar line, in seven patients the pain originated in the linea alba between xiphoid and umbilicus, in five cases the painful spots were situated within the rectus muscle, and in four patients the pain was localized along the costal arch. Of the 39 patients with pain in the semilunar line, 16 had a BMI > 30, 12 presented with anxiety and depression, and 10 reported bloating and straining during defecation. Pain in the rectus muscle was associated with exercise. The patients with pain in the linea alba and at the costal arch suffered from obesity, anxiety or depression. These findings suggest that repeated forceful contractions of the abdominal wall muscles during exercise and straining, as well as chronic inflation of the abdominal wall by fat pads and by bloating, may cause strain and pain in the abdominal wall at sites predestined by anatomy. Symptom-specific anxiety may be a consequence of chronic unexplained abdominal pain. A novel classification of abdominal wall pain is proposed. The correct diagnosis will avoid repeated and costly investigations and relieve the patient's anxiety.