Intestinal pseudoobstruction

Intestinal Pseudo-obstruction is a clinical syndrome caused by severe impairment in the ability of the intestines to push food through. It is characterised by the signs and symptoms of intestinal obstruction without any lesion in the intestinal lumen.^[1] Clinical features can include abdominal pain, nausea, severe distension, vomiting, dysphagia, diarrhea and constipation, depending upon the part of the gastrointestinal tract involved.^[2] The condition can begin at any age and it can be a primary condition (idiopathic or inherited) or caused by another disease (secondary).^[3]

It can be chronic^[4] or acute.^[5]

Causes

In primary chronic intestinal pseudo-obstruction (the majority of chronic cases), the condition may be caused by an injury to the smooth muscle (myopathic) or the nervous system (neuropathic) of the gastrointestinal tract.^[6]

In some cases there appears to be a genetic association.^[7] One form has been associated with DXYS154.^[8]

Secondary chronic intestinal pseudo-obstruction can occur as a consequence of a number of other conditions, including Kawasaki disease,^[9] Parkinson's disease, Chagas' disease, Hirschsprung's disease, intestinal hypoganglionosis, collagen vascular diseases, mitochondrial disease, endocrine disorders and use of certain medications.^[6] The term may be used synonymously with enteric neuropathy if a neurological cause is suspected.

Clinical manifestations

Clinical features of intestinal pseudo-obstruction can include abdominal pain, nausea, severe distension, vomiting, dysphagia, diarrhea and constipation, depending upon the part of the gastrointestinal tract involved.^[2] In addition, in the moments in which abdominal colic occurs, abdominal x-ray shows intestinal air fluid level. All of these features are also similar in true mechanical obstruction of the bowel.^[3]

Diagnosis

Attempts must be made to determine whether there is a secondary cause amenable to treatment.^[6]

Primary (idiopathic) intestinal pseudo-obstruction is diagnosed based on motility studies, x-rays and gastric emptying studies.

Treatment

Secondary chronic intestinal pseudo-obstruction is managed by treating the underlying condition.

There is no cure for primary chronic intestinal pseudo-obstruction. It is important that nutrition and hydration is maintained, and pain relief is given. Drugs that increase the propulsive force of the intestines have been tried, as have different types of surgery.

Medical treatment

Prucalopride,^[10][11] Pyridostigmine,^[3] Metoclopramide, cisapride, and erythromycin may be used, but they have not been shown to have great efficacy. In such cases, treatment is aimed at managing the complications. Linaclotide is a new drug that has not yet received approval by Food and Drug Administration but in the future looks promising in the treatment of Chronic intestinal pseudo-obstruction, Gastroparesis and Inertia coli.^[12][13]

Intestinal stasis, which may lead to bacterial overgrowth and subsequently, diarrhea or malabsorption is treated with antibiotics.

Nutritional deficiencies are treated by encouraging patients to avoid food high in fat and fibre, which are harder to digest and increase abdominal distention and discomfort, and have small, frequent meals (5-6 per day), focusing on liquids and soft food. Reducing intake of poorly absorbed sugar alcohols may be of benefit. Referral to an accredited dietitian is recommended. If dietary changes are unsuccessful in meeting nutritional requirements and stemming weight loss, enteral nutrition is used. Many patients eventually require parenteral nutrition.^[6]

Total Parenteral Nutrition (TPN) is a form of long-term nutritional treatment needed for patients that have severe pseudoobstruction. After a period of no improvement of intestinal function or motility the decision to start TPN will be made and the surgical procedure to add a long-term, more permanent IV to administer TPN will occur. Types of IV catheters to be placed will be a PICC line or central line which include mediports, Broviac, or Hickman lines depending on how long the physicians believe the patient will require TPN. Patients that are deemed TPN dependent will require constant check ups to monitor the catheter is working properly, check liver enzyme levels and look for signs of blood infections as catheter blockage, liver damage, and infections of catheters are the main complications associated with long term TPN use and can result in sepsis and/or additional surgeries if not properly monitored. TPN nutritional feeds are given over a period of several hours to all day infusions and is a mixture of all the vitaimins, minerals, and calories similar to what one would get eating orally daily as well as any other specific nutritional needs the patient needs at the moment. TPN formal is typically changed depending on loss/gain of weight, and bloodwork results and is specially formulated to meet each individual patient's needs.^[14]

Use of octreotide has been described.^[15][16]

Cannabis has long been known to limit or prevent nausea and vomiting from a variety of causes. This has led to extensive investigations that have revealed an important role for cannabinoids and their receptors in the regulation of nausea and emesis. With the discovery of the endocannabinoid system, novel ways to regulate both nausea and vomiting have been discovered that involve the production of endogenous cannabinoids acting centrally.^[17] The plant Cannabis has been used in clinic for centuries, and has been known to be beneficial in a variety of gastrointestinal diseases, such as emesis, diarrhea, inflammatory bowel disease and intestinal pain. Moreover, modulation of the endogenous cannabinoid system in gastrointestinal tract may provide a useful therapeutic target for gastrointestinal disorders.^[18] While some GI disorders may be controlled by diet and pharmaceutical medications, others are poorly moderated by conventional treatments. Symptoms of GI disorders often include cramping, abdominal pain, inflammation of the lining of the large and/or small intestine, chronic diarrhea, rectal bleeding and weight loss. Patients with these disorders frequently report using cannabis therapeutically.^[19]

In a 2012 animal study, cannabichromene was shown to normalize gastrointestinal hypermotility without reducing the transit time. The study notes that this of potential clinical interest, as the only drugs available for intestinal dysmotility are often associated with constipation.^[20]

Surgical and other procedures

Intestinal decompression by tube placement in a small stoma can also be used to reduce distension and pressure within the gut. The stoma may be a gastrostomy, jejunostomy, ileostomy or cecostomy, and may also be used to feed, in the case of gastrostomy and jejunostomy, or flush the intestines.

Colostomy or ileostomy can bypass affected parts if they are distal to (come after) the stoma. For instance, if only the large colon that is affected, an ileostomy may be helpful. Either of these ostomies are typically placed at or a few centimeters below the patients belly button per doctor recommendation based on the affected area of the intestines as well as concerns for patient comfort and future physical growth for children.^[21]

The total removal of the colon, called a colectomy or resection of affected parts of the colon may be needed if part of the gut dies (for instance toxic megacolon), or if there is a localised area of dysmotility.

Gastric and colonic pacemakers have been tried. These are strips placed along the colon or stomach which create an electric discharge intended to cause the muscle to contract in a controlled manner.

A potential solution, albeit radical, is a multi-organ transplant. The operation involved transplanting the pancreas, stomach, duodenum, small intestine, and liver, and was performed by Doctor Kareem Abu-Elmagd on Gretchen Miller, the subject of the Discovery Channel program Surgery Saved My Life.^[22]

Related disorders

• Ogilvie syndrome: acute pseudoobstruction of the colon in severely ill debilitated patients.
• Hirschsprung's disease: enlargement of the colon due to lack of development of autonomic ganglia.
• Intestinal neuronal dysplasia: a disease of motor neurons leading to the bowels.
• Bowel obstruction: mechanical or functional obstruction of the bowel most commonly due to adhesions, hernias or neoplasms.
• Enteric neuropathy: alternative name sometimes used for diagnosis in UK

References

External links

• 00530 at CHORUS