Differential of abdominal distension

Abdominal distension may be due to any of the famous `F's;

Fluid

This fluid may be inside the bowel or outside the bowel. As noted in the section on pathophysiology above fluid accumulates in the bowel in intestinal obstruction. But the patient may also have ascitis or a huge fluid filled cyst.

Fat

If the patient appears well covered `in fat', it is no harm to ask them if the abdomen appears distended to them. This huge abdomen may be quite normal for them. Alternatively there may be a huge lipoma or liposarcoma.

Flatus

The two main things that accumulate in the intestine to cause its distension are fluid and flatus. The characteristic finding on examination of flatus is a tympanic percussion note. The flatus may be due to obstruction, or a pseudo-obstruction.

Fetus

It is not unknown for a woman to conceal that she is pregnant, or to deny that she is pregnant in the hope that if she does not recognise the pregnancy it will not be true. This human response of denial, is not peculiar to women with an unwanted pregnancy but is seen in most people. The `Ostrict Maneuver' is how I like to describe it. I would advocate that all ladies, in the child bearing years, with acute abdominal problems should have a pregnancy test. You may occasionally get a false positive though, which may cause embarrassment to the medical staff. Sometimes a dermoid cyst may release enough HCG to register on the pregnancy test.

Friggen great mass

Huge retroperitoneal tumors, mesenteric cysts, ovarian cysts, etc may cause abdominal distension.