SHORT BOWEL SYNDROME

PRESENTOR:DR PASHIMODERATORS: PROF MUNKONGE/

DR BVULANI

PRESENTATION LAY OUT• INTRODUCTION• EMBRYOLOGY• AETIOLOGY• PATHOPHYSIOLOGY• CLINICAL PRESENTATION• MANAGEMENT• COMPLICATIONS

INTRODUCTIONShort bowel syndrome or short gut• Defined as malabsorption resulting from

anatomical or functional loss of a significant length of the small intestines

• Intestinal failure due to a loss of intestine resulting in inadequate length of bowel for maintaining the nutrition and hydration of the individual without either intravenous or oral supplementation.

• It is intrinsic bowel disease resulting in an inability to sustain growth, hydration, or electrolyte homeostasis

• Many causes in infants and newborns are removal of half or more of the small intestine, injuries or defects present at birth, NEC, intussusception, congenital defects, Crohns disease

Normal bowel lengths at birth• The minimum length of small bowel required for

infant survival on enteral feeds is 25 cm in the presence of an intact ileocaecal valve (ICV) and colon

• 40 cm without an ICV and large bowel.• Normal intestinal length vary in the range of 250

cm to 300 cm of small bowel at term.• The estimated length in a preterm infant of 26 and

32 weeks gestation is 70 cm and 120 cm, respectively.

INTESTINAL FAILURE• SBS has been documented as been a subset of

intestinal failure• Mucosal enteropathies and motility disorders are

other subsets described under intestinal failure• But in practice intestinal failure and short gut are

often used interchangeably• The management of SBS is resource-intense,

requiring the availability of intensive care, TPN, and expert medical and surgical intervention.

• In most countries in Africa where TPN is not available, the outcomes are poor.

• the incidence of SBS in neonates is around 3 per 100,000 births per year.

• In Africa, the incidence is unknown because survival is close to zero.

EMBRYOLOGY• Midgut is known to form the primary

intestinal loop• Derivative of midgut include duodenum distal

to the entrance of the bile duct, and continues to the junction of the proximal two-thirds of the transverse colon with the distal third

• Vitelline duct provides a temporal connection between the midgut and the yolk sac

• During the sixth week, the loop grows so rapidly that it protrudes into the umbilical cord

• It will return into the abdominal cavity in the 10th week

• At the end of these processes the midgut have undergone a total rotation of 270ᴼ counterclockwise

• During this development the midgut can have a number of abnormalities such as– Remnants of the vitelline duct, – Failure of the midgut to return to the abdominal

cavity,– malrotation, stenosis, – duplication of parts of the gut

AETIOLOGY• Primary: (Abnormal anatomically)

Born with short bowelCongenital anomalies e.g. Multiple Artesia's, Gastroschisis

• Secondary:NECHirschsprung diseaseIschemiaTumors

Crohns’s

PATHOPHYSIOLOGY• Small intestines of a neonate 250cm in length.• By adulthood the small intestines grows to

approximately 750cm• The effects of loss of bowel length depend on

the type and length of bowel remaining.• Small bowel motility is three times slower in

the ileum than in the jejunum. • The ileo-caecal valve also slows transit. • The colon has the slowest transit time

Jejunum• Long villi →Large absorptive surface area• High concentration of enzymes and transport

carrier/hormones cholecystokinin, serotonin, gastric inhibitory peptide, and secretin

• Large tight junction →Porous to large molecule• The ileum will take over in case of loss

Ileum• Short villi →Less absorptive capacity• Small tight junction →Less porous and increased absorption for fluid & electrolyte• Specific function of absorption of B12 and bile salts (specific receptors)• Synthesis of hormones e.g.Enteroglucagon & negative gastrin feedback• Complications of ileal loss include choleretic

diarrhoea, cholelithiasis, steatorrhoea

Ileocecal valve/colon

• Stops reflux of bacteria• Regulate fluid and nutrient exit• Loss decreases transit time and bacterial over

growth in small bowel• Colon is important for driving adaptation of the

gut.

Gut adaptation• Process by which the intestine adjusts to its

loss of length through hyperplasia of the mucosal surface so as to increase its absorptive capacity

• The bowel dilates, lengthens, and thickens to increase the efficiency of absorption.

• There is an increase in the number of cells in the proliferating zones of the crypts, and villus height increases, resulting in an increased surface area for absorption.

• Adaptation is driven by the increased load of fatty acids, carbohydrates, and proteins on the enteroglucagon-producing cells of ileum.

• Enteroglucagon stimulates ornithine decarboxylase, which in turn stimulates crypt cell proliferation

Clinical Presentation• Babies with severe SBS tend to be intolerant

of full enteral feeding, and will present vomiting, diarrhoea, or both.

• weight loss, fatigue, malaise, and lethargy. • These symptoms are protean but consistent

with the diarrheic diathesis and resultant dehydration, electrolyte imbalance, protein-calorie malnutrition, and loss of critical vitamins and minerals

• Vitamin and mineral deficiencies can lead to some specific symptoms

Acute phase • Starts immediately after bowel resection and

lasts 1-3 months • Ostomy output of greater than 5 L/d • Life-threatening dehydration and electrolyte

imbalances • Extremely poor absorption of all nutrients• Development of hypergastrinemia and

hyperbilirubinemia

Adaptation phase • Begins within 48 hours of resection and lasts up

to 1-2 years • Approximately 90% of the bowel adaptation takes

place during this phase. • Enterocyte hyperplasia and villous hyperplasia

and increased crypt depth occur, resulting in increased surface area. Intestinal dilatation and lengthening also occur.

• Luminal nutrition is essential for adaptation and should be initiated as early as possible. Parenteral nutrition is also essential throughout this period.

Maintenance phase • The absorptive capacity of the intestine is at

its maximum. • Nutritional and metabolic homeostasis can be

achieved by oral feeding, or patients are committed to receiving supplemental or complete nutritional support for life.

Management

Principles • Electrolyte and fluid balance first priority. • H2 receptor antagonist or proton pump

inhibitor.• NGT• Catheter• IV fluids• Na and K cardinal ions (normal saline + KCl)• Urine monitoring• A urine sodium level >30 mmol/l should be

maintained.

• Nutritional therapy only when the patient is haemodynamically and fluid stable.

• Nearly all patients with SBS will require parenteral nutrition to survive the period while the bowel adapts

• Oral feeds can be started at the same time as parenteral feed and gradually increased as tolerated by the patient.

Nutritional support• In infants, breast milk with oral sodium and

vitamin supplements• Older children > ORS then carbohydrates• Diet high in calories• Supplements of potassium, sodium, magnesium,• calcium, fat-soluble vitamins (vitamins A, D, and

E), and zinc. Vitamin B12 • Sodium is vital because it stimulates the bowel to

absorb, promoting adaptation• Loperamide

Medical Management• Aimed at improving complications induced by

intestinal failure. • Promoting bowel adaptation.

Supportive medication• Loperamide slows bowel transit time.• cholestyramine reduces the irritant effect of

bile salts on the colon • ursodeoxycholic acid reduces cholestasis, • oral antibiotics to reduce bacterial overgrowth

Surgical managementAims• correct mechanical obstruction• maximise bowel length. • intestinal transplant has become a reality• Stomas should be closed as early as possible

Bowel conservationIn initial surgical operation preserve as much intestine as possible.• use of a “second-look” operation• use of a temporary transparent plastic silo to

cover the bowel.

Autologous IntestinalReconstruction Surgery

Tapering• This procedure involves excision of the

antimesenteric border of the dilated portion of bowel.

longitudinal intestinal lengthening and tailoring operation (LILT)• Principle on the bifurcation of the mesenteric

vessels at the mesenteric border of the small bowel.

• The bowel is divided longitudinally between the mesenteric and antimesenteric borders along its dual blood supply.

• Two limbs are then closed and anastomosed end to end, thus doubling that length of bowel.

Iowa I operation• Principle on the formation of collaterals

between the antimesenteric portion of the small intestine and the abdominal wall in the first operation

• Transverse division, as well as isoperistaltic anastomosis of the bowel at a second operation

• Modifications were made

Serial transverse entroplasty (STEP)• Steppling device is used transversely across

the dilated bowel from the antimesenteric border, leaving 2 cm of the bowel diameter uncut.

• The next cut is made distally from the antimesenteric border via a small gap created in the mesentery

• A zigzag lengthening and tapering of the intestine ensues

Introduced in 2003 based on the following indications• Refractory SBS • Neonatal atresia with limited distal bowel • Severe bacterial overgrowth. • A contraindication to surgery is end-stage IFALD

with portal hypertension

http://www.orlive.com/childrenshospitalboston/videos/serial-transverse-enteroplastybowel-lengthening-and-tapering.

Complications • Intestinal failure–associated Liver disease• Catheter-associated bloodstream Infections• Decreased intestinal motility • Bacterial overgrowth

References • Langman’s Medical Book of Embyology 12th

edition• Coran Pediatric Surgery 7th Edition• Paediatric Surgery - A Comprensive Text for Africa –

volume 02.• www.slideshare.com• http://www.orlive.com/childrenshospitalboston/

videos/serial-transverse-enteroplastybowel-lengthening-and-tapering