Intussusception

In a nutshell

One segment of bowel telescopes into the next, dragging its mesentery with it, obstructing venous drainage before arterial supply. This produces episodic colicky pain, a palpable sausage-shaped mass, and eventually redcurrant-jelly stool as the ischaemic mucosa sloughs blood and mucus, a late sign that should not be waited for. First-line treatment is air enema reduction; surgery is reserved for failure, perforation, or shock.

Classic presentation

An infant around 6–18 months with sudden episodic severe colicky abdominal pain, drawing up the legs, episodic pallor/lethargy, and a palpable right-sided sausage-shaped mass, with redcurrant-jelly stool as a late feature.

Key points

• 1The trapped mesentery, not the bowel obstruction alone, drives the pathology: venous congestion first (mass, pain), ischaemia later (redcurrant-jelly stool).