BACKGROUND: Chronic intestinal pseudo-obstruction (CIPO) is a rare intestinal disorder characterized by impaired propulsion of the digestive tract and associated with symptoms of intestinal obstruction, despite the absence of obstructive lesions. CIPO includes several diseases. However, definitive diagnosis of its etiology is difficult only with symptoms or imaging findings.
METHODS: A 56-year-old man was referred to our hospital due to a 3-year history of continuous abdominal distention. Imaging, including computed tomography of the abdomen, and endoscopy revealed marked dilatation of the entire small intestine without any obstruction point. Therefore, he was diagnosed with CIPO. Since medical therapy didn\'t improve his symptoms, enterostomy and percutaneous endoscopic gastro-jejunostomy were performed. These procedures improved abdominal symptoms. However, he required home central venous nutrition due to dehydration. The pathological findings of full-thickness biopsies of the small intestine taken during surgery revealed decreased number and degeneration of ganglion cells in the normal plexus. These findings led to a final diagnosis of CIPO due to acquired isolated hypoganglionosis (AIHG).
CONCLUSIONS: Here, we report the case of a patient with CIPO secondary to adult-onset AIHG of the small intestine. Since AIHG cannot be solely diagnosed using clinical findings, biopsy is important for its diagnosis.

Chronic intestinal pseudo-obstruction (CIPO) may be a primary or secondary phenomenon and is often multifactorial. Treatment is largely directed at improving colonic motility. The use of cholinesterase inhibitors such as pyridostigmine has been hypothesized to increase acetylcholine in the bowel, improving symptoms and transit times.
A systematic review of the use of pyridostigmine in CIPO was conducted using scientific and commercial search engines identifying scientific studies enrolling adult human subjects, published from 2000 to 2022 in the English language.
Four studies were identified including two randomized controlled trials (RCT) and two observational studies. The studies had heterogenous inclusion criteria, dosing regimens and reported outcomes. Two studies were identified as being at high risk of bias. All studies reported improved patient outcomes with use of pyridostigmine, and low rates (4.3%) of mild cholinergic side effects. No major side effects were reported.
The use of pyridostigmine in management of CIPO is biologically plausible due to its ability to increase colonic motility, and early studies on its role are uniformly suggestive of benefit with low side-effect profile. Four clinical studies have been conducted to date, with small sample sizes, heterogeneity and high risk of bias. Further high-quality studies are required to enable assessment of pyridostigmine\'s utility as an effective management strategy in CIPO.

Smooth muscle disorders affecting both the intestine and the bladder have been known for a decade. However, the recent discovery of genes associated with these dysfunctions has led to the description of several clinical phenotypes. We performed a systematic review of all published cases involving seven genes with pathogenic variants, ACTG2, MYH11, FLNA, MYLK, RAD21, MYL9 and LMOD1, and included 28 articles describing 112 patients and 5 pregnancies terminated before birth. The most commonly described mutations involved ACTG2 (75/112, 67% of patients), MYH11 (14%) and FLNA (13%). Twenty-seven patients (28%) died at a median age of 14.5 months. Among the 76 patients for whom this information was available, 10 (13%) had isolated chronic intestinal pseudo-obstruction (CIPO), 17 (22%) had isolated megacystis, and 48 (63%) had combined CIPO and megacystis. The respective proportions of these phenotypes were 9%, 20% and 71% among the 56 patients with ACTG2 mutations, 20%, 20% and 60% among the 10 patients with MYH11 mutations and 50%, 50% and 0% among the 7 patients with FLNA mutations.

Hollow visceral myopathy (HVM) is described as impaired intestinal function and motility in the absence of mechanical obstruction. In this case report, we describe a unique case of an 18-year-old female who presented to the hospital with complaints of persistent nausea, vomiting, inability to tolerate oral feeds, and substantial weight loss for 2 months. After appropriate investigations, a diagnosis of gastroparesis was established. The patient was started on metoclopramide, which led to significant symptomatic improvement, and she was eventually discharged home. One month after discharge, she presented to the hospital with symptoms similar to her initial presentation. After further laboratory and radiological investigation, she was diagnosed with severe gastroparesis and chronic intestinal pseudo-obstruction. Over the next month, the patient was given an extensive trial of multiple prokinetic agents such as mirtazapine, ondansetron, pyridostigmine, octreotide, and promethazine, but she failed to show clinical improvement. Due to failure of medical therapy, a nasojejunal feeding tube was placed for enteral nutrition. However, the patient reported worsening of her symptoms despite slow feeding rates; hence, a decision was made to start the patient on total parenteral nutrition and transfer her to a larger tertiary center for higher level of care. At the tertiary hospital, the patient was continued on total parenteral nutrition and underwent extensive evaluation. Ultimately, she was diagnosed with HVM after a laparoscopic full-thickness intestinal biopsy showed histopathological evidence of the disease. She underwent isolated small intestine transplant, which led to significant improvement of her symptoms and was eventually discharged home. The patient continues to be symptom-free and follows up with Gastroenterology and Transplant Surgery regularly. This case report highlights a rare clinical condition, HVM, as a potential diagnosis in patients with clinical features of intestinal obstruction without mechanical obstruction.

Patients with anti-CV2/collapsin response mediator protein (CRMP)5 antibodies present with more frequent chorea, cerebellar ataxia, uveo/retinal symptoms, and Lambert-Eaton myasthenic syndrome or myasthenia gravis. Chronic intestinal pseudo-obstruction (CIPO) is an intestinal motility dysfunction disease dysmotility that is caused by a neuromuscular disease with recurrent or persistent intestinal obstruction in the absence of mechanical obstruction. We report the case of a patient with CRMP5 antibody-positive paraneoplastic neurological syndrome (PNS) that is associated with autonomic dysfunction (presenting most remarkably as CIPO). CIPO is one of the rarest forms of PNS. Some PNS patients who are positive for anti-CV2/CRMP5 antibodies may have fatal complications such as CIPO. To detect if PNS patients are at risk for CIPO, a timely diagnosis and appropriate treatment are required.

Visceral myopathy is one of the causes of chronic intestinal pseudo-obstruction. Most cases pathologically reveal degenerative changes of myocytes or muscularis propia atrophy and fibrosis. Abnormal layering of muscularis propria is extremely rare. We report a case of a 9-mo-old Thai male baby who presented with chronic intestinal pseudo-obstruction. Histologic findings showed abnormal layering of small intestinal muscularis propria with an additional oblique layer and aberrant muscularization in serosa. The patient also had a short small bowel without malrotation, brachydactyly, and absence of the 2(nd) to 4(th) middle phalanges of both hands. The patient was treated with cisapride and combined parenteral and enteral nutritional support. He had gradual clinical improvement and gained body weight. Subsequently, the parenteral nutrition was discontinued. The previously reported cases are reviewed and discussed.