See under STOMACH, DISEASES OF; INTESTINE, DISEASES OF; DIARRHOEA; LIVER, DISEASES OF; PANCREAS, DISEASES OF; GALL-BLADDER, DISEASES OF; KIDNEYS, DISEASES OF; URINARY BLADDER, DISEASES OF; HERNIA; PERITONITIS; APPENDICITIS; TUMOUR.
Various processes that can occur include inﬂammation, ulceration, infection or tumour. Abdominal disease may be of rapid onset, described as acute, or more long-term when it is termed chronic.
An ‘acute abdomen’ is most commonly caused by peritonitis – inﬂammation of the membrane that lines the abdomen. If any structure in the abdomen gets inﬂamed, peritonitis may result. Causes include injury, inﬂammation of the Fallopian tubes (SALPINGITIS), and intestinal disorders such as APPENDICITIS, CROHN’S DISEASE, DIVERTICULITIS or a perforated PEPTIC ULCER. Disorders of the GALLBLADDER or URINARY TRACT may also result in acute abdominal pain.
General symptoms of abdominal disease include:
Pain This is usually ill-deﬁned but can be very unpleasant, and is termed visceral pain. Pain is initially felt near the mid line of the abdomen. Generally, abdominal pain felt high up in the mid line originates from the stomach and duodenum. Pain that is felt around the umbilicus arises from the small intestine, appendix and ﬁrst part of the large bowel, and low mid-line pain comes from the rest of the large bowel. If the diseased organ secondarily inﬂames or infects the lining of the abdominal wall – the PERITONEUM – peritonitis occurs and the pain becomes more deﬁned and quite severe, with local tenderness over the site of the diseased organ itself. Hence the pain of appendicitis begins as a vague mid-line pain, and only later moves over to the right iliac fossa, when the inﬂamed appendix has caused localised peritonitis. PERFORATION of one of the hollow organs in the abdomen – for example, a ruptured appendix or a gastric or duodenal ulcer (see STOMACH, DISEASES OF) eroding the wall of the gut – usually causes peritonitis with resulting severe pain.
The character of the pain is also important. It may be constant, as occurs in inﬂammatory diseases and infections, or colicky (intermittent) as in intestinal obstruction.
Swelling The commonest cause of abdominal swelling in women is pregnancy. In disease, swelling may be due to the accumulation of trapped intestinal contents within the bowel, the presence of free ﬂuid (ascites) within the abdomen, or enlargement of one or more of the abdominal organs due to benign causes or tumour.
Constipation is the infrequent or incomplete passage of FAECES; sometimes only ﬂatus can be passed and, rarely, no bowel movements occur (see main entry for CONSTIPATION). It is often associated with abdominal swelling. In intestinal obstruction, the onset of symptoms is usually rapid with complete constipation and severe, colicky pain. In chronic constipation, the symptoms occur more gradually.
Nausea and vomiting may be due to irritation of the stomach, or to intestinal obstruction when it may be particularly foul and persistent. There are also important non-abdominal causes, such as in response to severe pain or motion sickness.
Diarrhoea is most commonly due to simple and self-limiting infection, such as food poisoning, but may also indicate serious disease, especially if it is persistent or contains blood (see main entry for DIARRHOEA).
Jaundice is a yellow discoloration of the skin and eyes, and may be due to disease in the liver or bile ducts (see main entry for JAUNDICE).
Diagnosis and treatment Abdominal diseases are often diﬃcult to diagnose because of the multiplicity of the organs contained within the abdomen, their inconstant position and the vagueness of some of the symptoms. Correct diagnosis usually requires experience, often supplemented by specialised investigations such as ULTRASOUND. For this reason suﬀerers should obtain medical advice at an early stage, particularly if the symptoms are severe, persistent, recurrent, or resistant to simple remedies.