Marked dilatation of the colon may be seen in a number of conditions.
Conditions that may be associated with megacolon:
(1) ulcerative colitis or Crohn's disease
(2) Clostridium difficile disease
(3) colon volvulus
(4) ischemic colitis
(5) associated with enteric colitis (typhoid fever, Shigella, E. coli O157, Yersinia, etc)
(6) viral colitis (recurrent CMV, rotavirus, etc)
(7) toxic (Amanita phalloides poisoning, chemotherapy, lead, etc)
(8) Behcet's disease
(9) associated with psychogenic disorders
(10) neurogenic (spinal cord injury, Chaga's disease, multiple system atrophy, neurofibromatosis, diabetic neuropathy, myotonic dystrophy, multiple sclerosis, other)
(11) Hirschsprung's disease
(12) obstructive (stricture, malrotation, scleroderma. irradiation)
(13) pheochromocytoma
(14) chronic laxative abuse (?)
(15) amyloidosis
(16) hypothyroidism
(17) porphyria
(18) amebic colitis
(19) idiopathic
The presentation may range from asymptomatic to fulminant (toxic).
