Primary enteroliths may be divided into:
(1) true enteroliths: precipitation of material normally found in the GI tract
(2) false enteroliths (bezoars or foreign bodies)
Risk factors for enterolith formation:
(1) Crohn's disease or other cause of enteritis
(2) small bowel diverticulum (Meckel's, jejunal, other)
(3) partial bowel obstruction (stricture with luminal stasis, migrated stent)
(4) consumption of material that can precipitate in an alkaline environment (including various calcium salts)
(5) consumption of indigestible material
Obstruction may be partial, complete or intermittent. Obstruction usually occurs at a site of luminal narrowing such as stricture, fistula or at the ileocecal valve.
Differential diagnosis:
(1) bezoar (may overlap with enterolith)
(2) gallstone ileus
(3) foreign body
A fecalith is similar but found in the appendix or colon.
