Causes of megaduodenum may be classified as:
(1) obstructive
(2) nonobstructive (localized chronic intestinal pseudo-obstruction with hypoperistalsis)
(2a) myopathic
(2b) neuropathic
(2c) other
Obstructive megaduodenum:
(1) annular pancreas
(2) tumor
(3) mesenteric fibromatosis
(4) duodenal malformation (atresia, stenosis, diaphragm, other)
Myopathic megaduodenum (either due to loss of muscle cells or loss of muscle function):
(1) scleroderma
(2) amyloidosis
(3) myopathy
(4) dermatomyositis
(5) SLE
(6) myxedema
(7) injection of botulinum toxin (reversible)
Neuropathic megaduodenum:
(1) damage to myenteric plexus
(2) diabetic neuropathy
(3) congenital hypoganglionosis
Other:
(1) Ehlers-Danlos syndrome
