Adult-onset megacolon with focal hypoganglionosis: A detailed phenotyping and prospective cohort study

BACKGROUND

In this prospective cohort study, we evaluated features of "adult-onset megacolon with focal hypoganglionosis."

METHODS

We assessed the radiologic, endoscopic, and histopathologic phenotyping and treatment outcomes of 29 patients between 2017 and 2020. Data from community controls, consisting of 19,948 adults undergoing health screenings, were analyzed to identify risk factors. Experts reviewed clinical features and pathological specimens according to the London Classification for gastrointestinal neuromuscular pathology.

KEY RESULTS

The median age of the patients with adult-onset megacolon with focal hypoganglionosis at symptom onset was 59 years (range, 32.0-74.9 years), with mean symptom onset only 1 year before diagnosis. All patients had focal stenotic regions with proximal bowel dilatation (mean diameter, 78.8 mm; 95% confidence interval [CI], 72-86). The comparison with community controls showed no obvious risk factors. Ten patients underwent surgery, and all exhibited significant hypoganglionosis: 5.4 myenteric ganglion cells/cm (interquartile range [IQR], 3.7-16.4) in the stenotic regions compared to 278 cells/cm (IQR, 190-338) in the proximal and 95 cells/cm (IQR, 45-213) in the distal colon. Hypoganglionosis was associated with CD3+ T cells along the myenteric plexus. Colectomy was associated with significant symptom improvement compared to medical treatment [change in the Global Bowel Satisfaction score, -5.4 points (surgery) vs. -0.3 points (medical treatment); p < 0.001].

CONCLUSIONS AND INFERENCES

Adult-onset megacolon with focal hypoganglionosis has distinct features characterized by hypoganglionosis due to inflammation. Bowel resection appears to benefit these patients.

Colonic Pseudo-obstruction With Transition Zone: A Peculiar Eastern Severe Dysmotility

Background/Aims

Previous studies from Korea have described chronic intestinal pseudo-obstruction (CIPO) patients with transition zone (TZ) in the colon. In this study, we evaluated the pathological characteristics and their association with long-term outcomes in Korean colonic pseudo-obstruction (CPO) patients with TZ.

Methods

We enrolled 39 CPO patients who were refractory to medical treatment and underwent colectomy between November 1989 and April 2016 (median age at symptoms onset: 45 [interquartile range, 29–57] years, males 46.2%). The TZ was defined as a colonic segment connecting a proximally dilated and distally non-dilated segment. Detailed pathologic analysis was performed.

Results

Among the 39 patients, 37 (94.9%) presented with TZ and 2 (5.1%) showed no definitive TZ. Median ganglion cell density in the TZ adjusted for the colonic circumference was significantly decreased compared to that in proximal dilated and distal non-dilated segments in TZ (+) patients (9.2 vs 254.3 and 150.5, P < 0.001). Among the TZ (+) patients, 6 showed additional pathologic findings including eosinophilic ganglionitis (n = 2), ulcers with combined cytomegalovirus infection (n = 2), diffuse ischemic changes (n = 1), and heterotropic myenteric plexus (n = 1). During follow-up (median, 61 months), 32 (82.1%) TZ (+) patients recovered without symptom recurrence after surgery. The presence of pathological features other than hypoganglionosis was an independent predictor of symptom recurrence after surgery (P = 0.046).

Conclusions

Hypoganglionosis can be identified in the TZ of most Korean CPO patients. Detection of other pathological features in addition to TZ-associated hypoganglionosis was associated with poor post-operative outcomes.

Molecular and Cellular Characteristics of the Colonic Pseudo-obstruction in Patients With Intractable Constipation

BACKGROUND/AIMS

Chronic intestinal pseudo-obstruction (CIPO) is a disorder characterized by recurrent symptoms suggestive of obstruction such as abdominal pain, proximal distension with extremely suppressed motility in the absence of lumen-occluding lesion, whose etiology/ pathophysiology is poorly understood. In this study we investigated a functionally obstructive lesion that could underlie symptoms of CIPO.

METHODS

We studied colons surgically removed from 13 patients exhibiting clinical/pathological features of pseudo-obstruction but were unresponsive to standard medical treatments. The colons were characterized morphologically, functionally and molecularly, which were compared between regions and to 28 region-matched controls obtained from colon cancer patients.

RESULTS

The colons with pseudo-obstruction exhibited persistent luminal distension proximally, where the smooth muscle was hypertrophied with changes in the cell phenotypes. Distinct luminal narrowing was observed near the distal end of the dilated region, close to the splenic flexure, previously referred to as the "transition zone (TZ)" between the dilated and non-dilated loops. Circular muscles from the TZ responded less to depolarization and cholinergic stimulation, which was associated with downregulation of L-type calcium channel expression. Smooth muscle contractile protein was also downregulated. Myenteric ganglia and neuronal nitric oxide synthase (nNOS) positive cells were deficient, more severely in the TZ region. Interstitial cells of Cajal was relatively less affected.

CONCLUSIONS

The TZ may be the principal site of functional obstruction, leading to proximal distension and smooth muscle hypertrophy, in which partial nNOS depletion could play a key role. The neuromuscular abnormalities probably synergistically contributed to the extremely suppressed motility observed in the colonic pseudo-obstruction.

Repetitive Colonoscopic Decompression as a Bridge Therapy before Surgery in a Pregnant Patient with Chronic Intestinal Pseudo-Obstruction

Chronic intestinal pseudo-obstruction is a rare clinical syndrome which is characterized by intestinal obstruction without occluding lesions in the intestinal lumen and pregnancy is one of the important aggravating factors. Here, we report a case of a woman with intractable intestinal pseudo-obstruction that was precipitated by pregnancy. She could not make any stool passage for more than 4 weeks until a fetal gestational age of 17 weeks was reached. However, the patient could be maintained by repetitive colonoscopic decompressions and finally total colectomy could be performed successfully at a fetal gestational age of 21 weeks.