Clinical Features and Colonic Motor Disturbances in Chronic Megacolon in Adults

Abstract

Background Chronic megacolon is a rare disease of the colonic motor function characterized by a permanent increase in colonic diameter. Methods We reviewed electronic medical records of all patients diagnosed with chronic megacolon from 1999 to 2014 at Mayo Clinic. Our aim was to summarize clinical and motility features, including colonic compliance and tone measured by colonic barostat-controlled 10cm long infinitely compliant balloon. Colonic compliance curves were compared to healthy (40) and disease (47) control groups. Results Among 24 identified patients, the mean maximal colonic diameter on abdominal radiograph was 12.7±0.8cm. The cause of megacolon was idiopathic in 16/24, and secondary in 8/24. A relatively high prevalence (10/24) of comorbid pelvic floor dyssynergia was identified. At the time of this report, 16 patients had undergone colectomy. In general, megacolon presented high fasting colonic volume at relatively low pressures (16-20mmHg), suggesting high colonic compliance; similarly, volumes at operating pressures that ensured apposition of the balloon to the colonic wall suggested low colonic tone. Median balloon volume at 44mmHg distension was 584mL (IQR 556.5-600) in patients with megacolon compared to 251mL (212-281) in healthy, 240mL (207-286) in functional constipation and 241mL (210.8-277.5) in diarrhea-predominant irritable bowel syndrome controls. Colon's tonic response to feeding was generally intact, and there was frequently maintained phasic contractile response to feeding. Conclusions Chronic megacolon is a severe colonic dysmotility, manifesting radiologically with increased colonic diameter; it can be proven by measuring colonic compliance, and typically requires colectomy because of failed medical therapy.

Familial chronic megacolon presenting in childhood or adulthood: Seeking the presumed gene association

“…The occurrence of chronic megacolon in six members in one family is unusual in the absence of MEN2B syndrome, which causes megacolon or achalasia . Similarly, the observation of so many affected members in one family contrasts with the scarcity of chronic megacolon presenting beyond infancy, which was diagnosed in 24 patients at Mayo Clinic over a 15‐year period . This is in contrast to Hirschsprung's disease, which results in megacolon in the neonatal period or infancy and affects about 1 in 5000 live births …”

“…Chronic megacolon is characterized by increase in colon diameter or increase in colonic compliance, and it presents most frequently in the neonatal period in association with well‐defined mutations or syndromes. The development of the enteric nervous system (ENS) is relevant to congenital Hirschsprung's disease and neonatal intestinal pseudo‐obstruction.…”

“…In children presenting with Hirschsprung's disease, several chromosomal and related Mendelian syndromes may be associated including Down's syndrome, Waardenburg syndrome and other dominant sensorineural deafness, the Congenital Central Hypoventilation and Mowat‐Wilson and other brain‐related syndromes, and a number of other autosomal recessive syndromes including Shah‐Waardenburg, Bardet‐Biedl, and Cartilage‐hair hypoplasia, Goldberg‐Shprintzen, and other syndromes related to cholesterol and fat metabolism . Such syndromes associated with megacolon in neonates or infants were not observed in a previous series of 24 patients with chronic megacolon reported from Mayo Clinic …”

Evaluating the safety and the effects on colonic compliance of neostigmine during motility testing in patients with chronic constipation

“…We studied 144 patients with medically refractory constipation who underwent a colonic motility study at Mayo Clinic between January 2010 and April 2015. Patients with chronic megacolon diagnosed by radiographic studies or a colonic motility study were excluded from this analysis.…”

Editorial: Identifying Colonic Motor Dysfunction in Chronic Constipation with High-Resolution Manometry: Pan-Colonic Pressurizations

“…A colonic barostat can also guide pharmacological therapy in constipation,(5) and by contrast to colonic transit and manometry, also diagnose megacolon. (6) For example, the acute effects of intravenous neostigmine on colonic tone predicted the long term effects of pyridostigmine on colonic transit. (5)…”