Short Bowel Syndrome

What is Short Bowel Syndrome?

Short Bowel Syndrome (SBS) is a condition characterized by malabsorption of nutrients which occurs as a result of surgical removal of the small intestine, or in some rare cases – due to complete dysfunction of major portions of the bowel. It is a rare condition caused by either acquired or congenital factors. It may affect both children and adults.

The condition is also referred to by other names, such as Short Gut Syndrome or simply Short Gut.

Short Bowel Syndrome Epidemiology

Studies on the incidence and/or prevalence of this condition are not easy to make due to its rarity. In the UK, the average number of patients was 2 in per million, based on the number of individuals requiring long term home parenteral nutrition. In Spain, the affected population was nearly 1.8 in per million (as recorded in 2002).

Short Bowel Syndrome Causes

SBS can be caused by various acquired or congenital factors, which include:

• Gastroschisis
• Tumors of small intestine
• Trauma or injury to small intestine
• Bypass surgery for treating obesity
• Necrotizing enterocolitis in premature newborns
• Crohn’s disease, which is an inflammatory disease of digestive tract
• Surgery to get rid of diseases or damaged portions of the small intestine
• Volvulus, a condition which involves spontaneous twisting of small intestine that shuts off blood supply, leading to death of tissue

Short Bowel Syndrome Symptoms

The symptoms of SBS include:

• Fatigue
• Diarrhea
• Weight loss
• Malnutrition
• Fluid depletion
• Abdominal pain
• Abdominal bloating
• Swelling or edema, primarily of the legs
• Steatorrhoea, accompanied by malodorous stools

SBS patients may also exhibit complications that are caused by insufficient absorption of minerals and vitamins, such as vitamins A, E, D, K and B12 as well as calcium, iron, magnesium, zinc and folic acid. These may give rise to symptoms of:

• Anemia
• Hyperkeratosis or scaling of skin
• Muscle spasms
• Easy bruising
• Bone pain
• Poor blood clotting

Short Bowel Syndrome Diagnosis

The following tests are normally conducted to detect whether or not a child or an adult is having this syndrome:

• CT scans
• Endoscopy
• Liver biopsy
• Electrolytes
• Fecal fat test
• Colonoscopy
• Creatinine tests
• CT enterography
• Abdominal x-rays
• Stool sample tests
• Coagulation profile
• Bone densitometry
• Indirect calorimetry
• Blood chemistry tests
• Vitamin levels in blood
• Abdominal ultrasounds
• Breath hydrogen analysis
• X-rays of the small intestine
• Complete blood count or CBC
• Serum levels of magnesium, calcium and phosphorus

Short Bowel Syndrome Differential Diagnosis

A number of conditions show signs and symptoms similar to that of SBS. Hence, while determining the presence of SBS, a doctor needs to differentiate it from these similar disorders. The differential diagnosis of SBS includes distinguishing its signs from those of other conditions such as:

• Coeliac disease
• Anorexia nervosa
• Bacterial overgrowth
• Active Crohn’s disease
• Small bowel malignancy
• Other factors leading to chronic diarrhea, malabsorption and growth failure

Short Bowel Syndrome Associated Conditions

A number of diseases are closely associated with SBS. These include the following:

• Trauma
• Gastroschisis
• Crohn’s disease
• Intestinal atresias
• Radiation enteritis
• Intestinal volvulus
• Meconium peritonitis
• Necrotising enterocolitis
• Ischaemic bowel infarction
• Congenital short small bowel
• Mesenteric vascular accidents
• Recurrent intestinal obstruction

Short Bowel Syndrome Treatment

At present, there are no definite curative options for SBS. Treatment for SBS is primarily aimed at relieving the symptoms. Prescription medications may be administered to manage the condition which includes:

• Anti-diarrheal medicines like Loperamide and Codeine
• Mineral supplements, vitamins and L-Glutamine powder intermixed with water
• Proton pump inhibitors and H2 blockers to reduce the amounts of stomach acids
• Lactase supplements, which can improve symptoms of bloating and diarrhea that are connected with lactose intolerance
• Folic acids, vitamin B12 and dietary irons to treat anemia
• Intravenous supplements of minerals and vitamins
• Imodium, to control the symptoms of diarrhea by giving the small intestines adequate time to absorb nutrients and water
• Ursodeoxycholic acid, that can prevent and/or dissolve cholesterol gallstones
• Oral antibiotics, that can prevent or cure overgrowth of small bowel bacteria
• Medications that can slow down normal movement of intestines
• The agent teduglutide, which is a glucagon-like peptide-2 analog that is developed by the NPS Pharmaceuticals

The medications should also be accompanied by a high-calorie diet that supplies all the necessary minerals and vitamins as well as various types of fats, proteins and carbohydrates.

Nutritional Management

As the intestines of SBS patients are not able to absorb adequate amounts of nutrients, doctors may recommend administering intravenous or tube feeding. These procedures are:

Parenteral Nutrition (PN)

Parenteral Nutrition involves administration of a specially-made nutritional formula directly into the patient’s bloodstream with the help of intravenous channels (IV). The formula is carefully prepared by the dietician to meet the specific energy needs of the patient. Delivering the nutrients straight to the bloodstream also allows to bypass the involvement of the digestive system altogether.

The special formula is generally administered daily over a course of 12-24 hours. If the patient requires a long-term PN support, the length of such a session will be reduced gradually.

Enteral Nutrition (EN)

In this procedure, the nutritional formula is administered through a tube. It is also referred to as tube feeding. This can be accomplished in two ways:

• Using a Gastrostomy tube or G-tube that is passed through the opening into the stomach of  patients
• Using a Jejunostomy tube or J-tube that is passed through the opening into a small portion of the small intestine

Surgery

The decision to settle for surgical operation on a SBS patient requires fine judgment. A surgery is undertaken only after careful consideration and after all the other therapeutic options has been exhausted. Some patients may require operation due to the complications presented by stasis of the enteric contents, bacterial overgrowth and prolonged parenteral nutrition.

It is sometimes possible to use surgery to reshape the small intestine of patients to increase surface area of intestines and prolong the duration of time required for the food to pass through, thereby giving intestines more opportunity to extract nutrients.

Common surgical procedures to manage SBS include:

STEP procedure

The STEP procedure was developed in early 2000s by MDs Tom Jaksic and Heung Bae Kim of the Children’s Hospital Boston. It involves lengthening of the bowel of patients which allows avoiding the necessity for intestinal transplantation. The process also creates a narrow space that allows the food to move through the digestive tract at an appropriate pace and carries bacteria and/or waste products out of the body.

Bianchi procedure

The Bianchi procedure also lengthens the dilated bowel by cutting one half of the bowel and sewing it to the other half.

Patients who do not respond well to the above-mentioned treatment procedures might be required to undergo an intestinal transplant. A number of transplant types exist, which include:

• Intestinal transplant
• Intestinal/liver transplant
• Multivisceral transplant; which involves removal of the intestines along with liver, spleen and the stomach on certain occasions

Short Bowel Syndrome Diet

SBS patients should avoid sodas, sugary desserts and fruit juices as these may increase the risk of diarrhea. Intake of salt may be increased depending on the status of the bowel. Diet for these patients depends on their condition. A diet with higher fat content is recommended for patients having 100 centimeters of jejunum intact, closing to nearly 50% or 60%. Carbohydrates should make up 20% to 30% of total daily calorie intake. Daily consumption of fibers should be limited to 15 grams or less. Lactose should be minimized or removed from diet if the patient is having lactose intolerance. The calcium levels should be kept at appropriate levels to lower the chances of Osteoporosis. An oral rehydration solution might be required due to difficulties in sodium absorption. The patient should also avoid bowel stimulants like alcohol and caffeine. The diet should also be supplemented by vitamin supplies. Chewing the food properly and adequately is necessary to facilitate nutrient absorption.

Short Bowel Syndrome Complications

A number of complications might emerge from SBS. These include:

• Gallstones
• Weight loss
• Malnutrition
• Renal failure
• Hemorrhage
• Wound sepsis
• Kidney stones
• Bowel necrosis
• Bowel obstruction
• Pulmonary embolism
• Anastomotic disruption
• Acute rejection of the transplant
• Osteomalacia or weakened bones
• Chronic rejection of the transplant
• Bowel dysfunctions and dysmotility
• Postoperative pulmonary dysfunction
• Metabolic acidosis caused by diarrhea
• Bacterial overgrowth in small intestine
• Hepatic, mesenteric or portal vein thrombosis
• Lymphoproliferative malignancies or disorders
• Thrombosis precluding sufficient access for feeding
• Infections associated with the venous feeding catheter
• Systemic sepsis with opportunistic organisms or ordinary pathogens
• Stasis of the intestinal contents without or with bacterial overgrowth
• Nervous system problems that are caused by low levels of vitamin B12
• Complications related to any of the underlying conditions, such as liver disease

Short Bowel Syndrome Prognosis

As there are no cures for this condition, survival of the patient and overall outcome may depend on a number of factors. The most common reason for death is liver failure which occurs after chronic hepatic parenchymal damage. The 4-year survival rate of newborn infants on TPN is approximately 70%. The 5-year survival rate is close to 20% in the same population with lower than 10% expected intestinal length. Many individuals die due to reduced venous access or severe septic complications. Pharmacological bowel compensation can help patients to avoid long term parenteral nutrition. Studies suggest that non-transplant surgical procedures can lead to clinical improvement of the condition in about 80% of patients. Early postoperative complications might lead to a higher mortality rate. However, 80% to 90% of patients who survive this critical stage are alive even after one year and almost 60% is alive after 4 years.

References:

http://www.patient.co.uk/doctor/Short-Bowel-Syndrome-%28SBS%29.htm

http://www.childrenshospital.org/az/Site1581/mainpageS1581P0.html

http://en.wikipedia.org/wiki/Short_bowel_syndrome

http://www.nlm.nih.gov/medlineplus/ency/article/000237.htm