The exact mechanism is not known. The probable explanation is imbalance in the regulation of colonic motor activity by the autonomic nervous system. It has been postulated that reactivation of varicella zoster virus (which causes chickenpox and shingles) in the enteric ganglia may be a cause of<unk> . Acute megacolon develops because of abnormal intestinal motility. Normal colonic motility requires integration of myogenic, neural, and hormonal influences. The enteric nervous system is independent but is connected to the central nervous system by sympathetic and parasympathetic nerves. The targets of the enteric neurons are muscle cells, secretory cells, endocrine cells, microvasculature, and inflammatory cells. The neurons in the enteric plexuses are stimulated by a food bolus, which both distends the gut and stimulates the mucosal surface, leading to the release of factors that stimulate interneurons. The stimulated interneurons transmit excitatory signals proximally, which cause contraction and inhibitory signals distally, and these in turn cause relaxation. These signals are transmitted by the neurotransmitters acetylcholine and serotonin, among others. Acute megacolon can also lead to ischemic necrosis in massively dilated intestinal segments. This is explained by Pascal's law and Laplaces's law. Pascal's principle states that a change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid; the pressure across all parts of the lumen is equal. Laplace's law states that: where T=wall tension, p=pressure, r=radius, t=wall thickness. Since the wall tension is proportionate to the radius, a dilated intestinal segment has a greater wall tension than a nondilated segment; if the dilatation and tension are sufficiently great, blood flow may be obstructed and ischemia of the bowel will occur.<unk>  may precipitate volvulus.
Ogilvie syndrome
Fitz-Hugh–Curtis syndrome
Havana syndrome
Löffler's syndrome
Secretan's syndrome
Lucey–Driscoll syndrome
Jackson–Weiss syndrome
Gómez–López-Hernández syndrome