Chronic idiopathic intestinal pseudo-obstruction (CIIP)
What is CIIP?
CIIP is a clinical syndrome caused by ineffective intestinal motility and characterised by signs and symptoms of intestinal obstruction in the absence of an occluding lesion of the intestinal lumen. The criteria for diagnosis include definite signs and symptoms of obstruction with documentation of an ileus or air-fluid levels on plain x-ray or a dilated duodenum, small intestine, or colon on barium X rays.
A number of these pts will have had previous laparotomies at which obstruction was found.
What are the causes of pseudo-obstruction?
Pseudo-obstruction may be congenital or acquired, primary or secondary. CIIP is a term that has been used to denote the primary syndrome. Regardless of the underlying cause, 2 main groups can be identified based on histopathology and patterns of motility abnormalities: visceral myopathy and visceral neuropathy.
Secondary causes- systemic sclerosis, amyloidosis, myxedema, diabetes, opiates,
hypoparathyroidism, anticholinergics, tricyclic antidepressants etc.
What are the structural changes that occur in pseudo-obstruction?
- Pseudo-obstruction result in marked enlargement anywhere along the GIT, as in megaoesophagus, megaduodenum, megacolon etc.
- Small intestinal diverticulosis due to disordered muscle contractions.
What are the clinical features?
- Abdominal pain, distension and vomiting
- Bacterial overgrowth secondary to stagnant loop syndrome and diverticulosis may lead to diarrhoea and steatorrhea.
- Predominant colonic involvement usually causes constipation or megacolon or both
- Both small and large bowel involvement may cycle from diarrhoea to constipation depending on the relative involvement of each organ.
- Oesophageal involvement- dysphagia, chest pain, reflux symptoms
- Gastric involvement- symptoms of gastroparesis
What are the laboratory findings?
- Exclude secondary causes- TSH, Scl-70
- Plain AXR. In 20% of pts plain x-rays may be normal. Barium contrast study of the entire GIT should be done whenever pseudo-obstruction is suspected. The most important goal being to exclude mechanical obstruction.
- Antroduodenal manometry is used to determine the pathophysiology of symptoms in CIIP. Manometry is useful to distinguish myopathy from neuropathy. Antroduodenal manometry also may be used to suggest prognosis and likely response to treatment. If the migrating motor complex is present, patients are likely to tolerate enteral feeding. In patients showing symptoms of intestinal pseudo-obstruction, the presence of normal manometry studies should lead to the consideration of emotional or factitious disorders
- Transit Studies document prolonged whole-gut transit times in CIIP. Radio-opaque marker studies may be useful to identify the site of functional obstruction.
- Increasingly, full-thickness biopsy specimens are obtained to seek a specific pathologic diagnosis. Full thickness biopsies can be obtained via laparoscopy, with or without placement of a feeding jejunostomy. Biopsy samples should be analyzed in referral laboratories for a wide range of known abnormalities.
Discuss the treatment of CIIP?
No treatment is curative. The goal of treatment is to alleviate symptoms and restore and maintain nutrition
- Prokinetic therapy with cisapride, erythromycin, octreotide, and tegaserod should be attempted. Octreotide is the most potent enterokinetic medication currently available. Tegaserod, a prokinetic with a similar mode of action to cisapride but no cardiac toxicity, may be helpful particularly in patients with colonic involvement.
IV Erythromycin (3mg/kg tds) for 5-7 days- It is not very effective for chronic therapy
IV Metoclopramide 10 mg IV qds similarly can be used during the acute phase
Pts with scleroderma may benefit from SC octreotide (50mch at night). It should not be used where there is clinical evidence of bacterial overgrowth, as it can slow the small bowel transit time in healthy adults. - The acetylcholinesterase inhibitor neostigmine is effective therapy for acute colonic pseudo-obstruction in adults and in children.
- Broad-spectrum antibiotics are useful in treating pts with bacterial overgrowth.
- Diet- diet low in fat, lactose, residue with small frequent meals 6-8 times/day.
- Palliative surgery to decompress, remove, or bypass bowel may be valuable in pts incapacitated by their intestinal symptoms. Before deciding on a particular operation, it is extremely important to determine which symptoms are palliated and from which area of the intestine these symptoms emanate.
- Limited or extensive small bowel resections, abdominal colectomy and ileorectal anastomosis, decompress gastrostomy etc
- Small intestinal transplantation/Home parenteral nutrition