Megarectum

What it means

An abnormal dilation of the rectum. There is a large filled rectum as a result of underlying innervation or muscular abnormalities, which remains after disimpaction of the rectum.

Patients with idiopathic megarectum have a dilated rectum but the proximal colon is usually of normal diameter. The condition usually starts in childhood or adolescence, and fecal impaction is common. By contrast, patients with idiopathic megacolon usually do not experience impaction, and the symptoms often begin in adult life [PMID:9301507].

Rare diseases that can present with this1

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category