OVERVIEW
Pseudo-intestinal obstruction (IPO) is a dysfunction of the muscle movement of the intestinal wall due to neuroinhibition, toxin stimulation, or lesions of the smooth muscle of the intestinal wall itself. Clinical signs and symptoms of intestinal obstruction, but without the presence of mechanical intestinal obstruction factors inside and outside the intestines, so it is also known as dynamic intestinal obstruction, a syndrome without intestinal lumen obstruction. According to the course of the disease, there are acute and chronic, paralytic intestinal obstruction and spasmodic intestinal obstruction belongs to acute pseudo-intestinal obstruction, chronic pseudo-intestinal obstruction has two kinds of primary and secondary. The disease can occur at any age and is more common in females than males, with a family history.
Etiology
It is generally believed that chronic pseudointestinal obstruction is caused by lesions of intestinal muscles or nerves, which can be divided into the following two categories.
1. Primary chronic pseudo-obstruction of intestine
It is also known as chronic idiopathic pseudoenteric obstruction, the etiology of which is unclear and may be related to chromosomal dominant inheritance. Many patients have family history, and can involve some organs other than gastrointestinal tract (such as bladder), so some people call it familial visceral myelopathy or hereditary jejunal visceral myelopathy, which can be categorized into the following three types according to the lesions of the intestinal wall.
(1) Myopathic pseudomyelopathy (visceral myelopathy) The lesions are mainly in the smooth muscle of the intestinal wall, which can be classified as familial or sporadic, and the main pathological changes are degenerative changes in the circular or longitudinal muscle of the intestinal wall, which is more serious in the latter case, and the muscle is sometimes completely atrophied and replaced by collagen.
(2) Neuropathic pseudoenteric obstruction (visceral neuropathy) The lesions are mainly in the nerves of the intermuscular plexus of the intestinal wall, which are sporadic or familial, and the pathological changes mainly occur in the intermuscular plexus of the intestinal wall, which are manifested as the degenerative changes and swelling of the neurons and neuronal protrusions, and in some cases there are also the other parts of the nervous system being involved.
(3) Acetylcholine receptor defective pseudoenteric obstruction There is no organic abnormality of muscles or nerves, but there is an abnormality of intestinal motility as measured by physiological tests, which may be related to the defective function of muscarinic acetylcholine receptors in the intestinal smooth muscle in some of the cases.
2. Secondary chronic pseudo-intestinal obstruction
Most of them are secondary to other diseases or caused by drug abuse. The diseases and drugs related to chronic pseudointestinal obstruction are:
(1) small intestinal smooth muscle disease ① collagen vascular disease scleroderma, progressive systemic sclerosis, dermatomyositis, polymyositis, systemic lupus erythematosus; ② infiltrative muscle disease amyloidosis; ③ primary muscle disease ankylosing muscular dystrophy, progressive muscular dystrophy; ④ other Waxing pigmentation, non-tropical stomatitis diarrhea.
(2) Endocrine diseases (1) Thyroid gland function decrease; (2) Diabetes mellitus; (3) Pheochromocytoma.
(3) Neurological disorders Parkinson’s disease, familial dysautonomia, Hirshsprung’s disease, Chang’s disease, psychosis, small bowel ganglion disease.
(4) Pharmacologic causes ① Toxic drugs Lead poisoning, mushroom poisoning; ② Drug side effects Phenothiazines, tricyclic antidepressants, anti-Parkinson’s disease drugs, ganglionic blockers, chlorhexidine.
(5) Electrolyte disorders Hypokalemia, hypocalcemia, hypomagnesemia, uremia.
(6) Others Jejunal bypass, jejunal diverticulum, spinal cord injury, malignant tumors.
Among them, systemic sclerosis to chronic pseudo-intestinal obstruction is common, and its main pathological changes for the intestinal wall smooth muscle atrophy and fibrosis, but also to the lesions of the circular muscle for more; amyloidosis can be seen in the intestinal wall muscle layer with a large amount of starch deposition; mucous edema intestinal wall muscle layer with mucous edema material; diabetes mellitus in the intestinal wall muscle and intermuscular plexus is often no obvious changes.
Symptoms
The main manifestations are chronic or recurrent nausea and vomiting, abdominal pain, and abdominal distension. Abdominal pain is often located in the upper abdomen or around the umbilicus, persistent or paroxysmal, often accompanied by varying degrees of diarrhea or constipation, some diarrhea and constipation alternately. There may be dysphagia, urinary retention, incomplete bladder emptying and recurrent urinary tract infections, thermoregulatory dysfunction, and dilated pupils. Physical examination shows abdominal distension, tenderness, but no muscle tension; vibratory water sounds can be heard, and bowel sounds are weakened or absent. Weight loss and malnutrition are common. The disease is difficult to diagnose and is often considered when no mechanical cause of intestinal obstruction is found after repeated cesarean sections.
Examination
Abdominal X-ray images do not show the intestinal distention and gas-fluid surfaces seen with mechanical intestinal obstruction; GI manometry shows esophagus, abnormal gastrointestinal function; and histologic examination of the small bowel with positive Smith silver staining can clarify the diagnosis. If it is necessary to differentiate between pseudo intestinal obstruction and mechanical intestinal obstruction, barium enema of the small intestine can be carried out, the method is to inject barium after inserting a soft catheter with a copper ball into the proximal side of the jejunum through the oral cavity for fluoroscopy or radiography, and the diagnostic rate of this method for organic lesions of the small intestine reaches 98%, and if it is a pseudo intestinal obstruction, there is no organism obstruction lesions to be seen.
Diagnosis
The possibility of this disease should be considered in patients with intestinal obstruction with one or more of the following conditions.
1. Bowel obstruction begins in childhood or adolescence, and the abdominal distension does not completely disappear between episodes of bowel obstruction.
2. There are similar patients in the family.
3. People with dysphagia or weakness of urination.
4. Malignant disease.
5. Diseases that can cause pseudo-obstruction or drugs that can cause pseudo-obstruction.
6. Jejunal diverticulosis.
7. signs of Raynaud’s phenomenon or scleroderma.
Complications
Pseudo intestinal obstruction can have dysphagia when the esophagus is involved; urinary retention when the bladder is involved; paralysis of the eye muscles and ptosis when the eye muscles are involved. Chronic pseudo-intestinal obstruction may show malnutrition such as anemia and hypoproteinemia due to malabsorption.
Treatment
1. Non-surgical treatment
There is no specific treatment for this disease, and comprehensive treatment can be taken to reduce the dilatation of small intestine, use antibiotics, restore the normal peristaltic function of the stomach and intestines and total gastrointestinal nutrition.
(1) Dietary therapy Requires a low-fat, low-lactose and low-fiber diet. The fat is not more than 40g, and preferably long-chain fat, lactose is not more than 0.5g/100cal, and fiber is not more than 1.5g/100cal, because the patient’s symptoms and signs are closely related to the degree of small intestinal dilatation, and the degree of small intestinal dilatation is related to the volume and type of the food intake, and the malabsorbed fat can be broken down by the bacteria in the small intestine into fatty acid, which stimulates the secretion of large amounts of small intestinal fluid to make the small intestinal It stimulates the large secretion of small intestinal fluid, causing the small intestine to dilate. This disease is often accompanied by varying degrees of small intestinal mucosal injury, so that the catabolism of lactose is affected, thus making the intestinal lumen gas production and fluid secretion increase, aggravating the dilatation of the small intestine. In addition peristaltic dysfunction of the intestinal collaterals of long-term food accumulation, especially more fibrous food can form fecaliths, which can produce mechanical intestinal obstruction on the basis of pseudo intestinal obstruction, appropriate amount of vitamin B12, vitamin D, vitamin K and trace elements, etc., and fasting should be used in acute episodes, and continuous gastrointestinal decompression.
(2) Antibiotic treatment Bacterial overgrowth in the small intestine can cause fat malabsorption and steatorrhea. Treatment with antibiotics can reduce the symptoms, and the choice of antibiotics should preferably be based on the results of the culture of small intestinal fluid.
(3) Pharmacological treatment The aim is to stimulate the contraction of the small intestine and restore the normal peristaltic function of the small intestine. Cisapride is a new non-cholinergic stimulant, which selectively acts on the gastrointestinal tract, causing its intermuscular plexus to release acetylcholine, thus increasing muscle contraction activity, and avoiding systemic side effects, with good clinical results. Erythromycin has gastric actin-like effect, which can effectively promote gastrointestinal peristalsis, and has certain efficacy in the treatment of pseudo-small bowel obstruction.
(4) Total Gastrointestinal Parenteral Nutrition (TPN) As this disease has different degrees of absorption disorders and malnutrition, coupled with poor dietary and drug therapy, surgery is only effective for some patients. Therefore, most of the patients need TPN treatment, especially the severe patients, long-term TPN treatment is the only way to maintain life.
2. Surgical treatment
Once the disease is diagnosed, in principle, surgery is not performed, but when the symptoms persist and mechanical intestinal obstruction cannot be completely excluded, caesarean section is necessary. If the cause of mechanical intestinal obstruction is not found during the operation, a total resection of the diseased intestinal segment should be carried out, and histologic examination should be performed to clarify the nature of the lesion. Different surgical methods are used for different parts of the lesion. When esophageal symptoms are predominant, balloon dilatation is feasible; when gastric symptoms are predominant, vagotomy plus sinus resection and gastrojejunostomy with Roux-en-Y anastomosis are feasible; if duodenal dilatation is predominant, small intestinal suspension fistulas are feasible with decompression and combined with TPN for better results. It has been reported that small bowel fistula combined with the application of intestinal stimulants, for myopathic pseudointestinal obstruction patients, can be restored to its intestinal smooth muscle contraction ability, if the lesion is limited to a section of small intestine, feasible short-circuit surgery, radical resection of diseased intestinal segments is the more ideal treatment. If the small bowel lesion is more extensive, combined with long-term TPN treatment after near-total resection of the small bowel, it is practically difficult to do, for severe patients, small bowel transplantation may be a promising treatment, but only animal experiments have been conducted, and clinical application has not yet been reported.
Prognosis
The prognosis of acute pseudo-intestinal obstruction is good. With the cure of the primary disease and active treatment, acute pseudointestinal obstruction can be cured quickly. However, early detection and early treatment must be emphasized, and untimely treatment can lead to perforation.