Short Bowel Syndrome(SBS)

Jibran MohsinSurgical Resident

SIMS/Services Hospital, Lahore

Outline• Anatomy

• Physiology

• Definition

• Pathophysiology

• Classification(including etiology)

• Clinical Presentation

• Workup

• Treatment

Anatomy

Length of small gut* Neonate 250 cm

Adult Average 600 cm (Range 260- 800 cm)

Short Gut Syndrome 200 cm viable (Adult)>50 %-80% lost

Lifelong TPN Dependence(Minimal gut length required for life)

Adult With intact colon 60 cmWithout colon 100 cm

Infant With ileocecal valve 11 cmWithout ileoceal valve 12-25 cm

__________________________________________________________________*As a consequence, the infant and the young child have a favorable long-term prognosis compared to an adult in regards to potential intestinal growth after

intestinal resection

PhysiologyJejunum Ileum

Villi Long ShorterAbsorptive surface area Large LessTight Junction Relatively large

• epithelium more porous to larger molecules

• free and rapid flux of water and electrolytes

Tighter• permitting less flux of

water and electrolytes from the vascular space into the intestinal lumen

Water absorption Less effective More efficientAbsorption Carbohydrates, proteins, fat,

vitamins (iron-duodenum)Bile acids, vitamin B-12

GI hormones that affect intestinal motility

enteroglucagon and peptide YY

Etymology:• Duodenum (Latin: duodēnum Twelve ) (duodenum is 12 fingerbreadth long)• Jejunum (Latin: jejunus fasting )(because it was usually found to be empty after death).• Ileum (Greek: eilein to twist up tightly)

PhysiologyProximal jejunal resection is better tolerated than distal ileum

resection

Definition

Clinically defined by malabsorption, diarrhea, steatorrhea, fluid and electrolyte disturbances, and malnutrition due to ≥ 50 % (viable gut <200 cm) of structural or functional loss of small gut.

Pathophysiology

Underlying Disease

extensive bowel

resection

affects normal intestinal

physiology

alteration of intestinal

digestion and absorption

nutritional, metabolic,

and infectious consequences

Pathophysiology

• Loss of ileocecal valve– transit time is faster, and loss of fluid and nutrients

is greater

– Colonic bacteria colonize the small bowel, worsening diarrhea and nutrient loss.

Pathophysiology

Preservation of the colonMERITS DEMERITS

colonic water absorption could be increased to as much as five times its normal capacity following small bowel resection

increase incidence of urinary calcium oxalate stone formation(Oxalate is normally bound by calcium in the small bowel and thus is insoluble when it reaches the colon. After massive enterectomy, much of this calcium is bound by free intraluminal fats)

Colonic bacteria metabolize undigested carbohydrates(starch & fibres) into short-chain fatty acids, such as butyrate, propionate, and acetate. (up to 500 kcal/day)

small intestinal bacterial overgrowth.( in absence of ileocecal valve)

Natural History( 3 Phases)

• Acute Phase

• Adaption Phase

• Maintenance Phase

Acute Phase

• Starts immediately after bowel resection and lasts 1-4 months

• Ostomy output of greater than 5 L/day (as high as 6-8 L/day)

• Life-threatening dehydration and electrolyte imbalances

• Extremely poor absorption of all nutrients

• Development of hypergastrinemia and hyperbilirubinemia

Adaption Phase• Enterocyte hyperplasia + villous hyperplasia + increased crypt depth

increased surface area;• intestinal dilatation and lengthening increased capacity/Low transit

time(reduction in volume and frequency of bowel movements)_______________________________________________________

• Begins within 48 hours of resection and lasts up to 1-2 years

• ~ 90% of the bowel adaptation takes place during this phase

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

Maintenance Phase

• Absorptive capacity of the intestine is at its maximum

Classification

Congenital versus AcquiredCONGENITAL ACQUIRED

Congenital Short Small Bowel * NEONATAL PERIOD ADULT

Necrotizing enterocolitis Crohn disease

Intestinal atresias radiation enteritis

Intestinal volvulus mesenteric vascular accidents

OLDER INFANTS and CHILDREN

Trauma

Intussusception with ischemic small-intestinal injury

recurrent intestinal obstruction

* Also associated with gastroschisis ,omphalocele and meconium peritonitis.

ClassificationStructural versus functionalSTRUCTURAL FUNCTIONAL

Any insult leading to

< 200 cm or loss of ≥ 50% of viable small bowel

Increased risk of developing SBS ( NOT ALWAYS)

PREDISPOSING FACTORS• premorbid length of small bowel

• segment of intestine that is lost,

• Age of the patient (infant tolerate better)

• Remaining length of small bowel and colon,

• Presence or absence of the ileocecal valve

Length maintained BUT function is lost

For example:

Radiation Enteritis

Cloacal Extrophy

Classification

SBS due to proximal jejunal resection versus SBS due to distal ileum resection

Clinical Presentation

• Diarrhea ± steatorrhea– dehydration and electrolytes disturbances

• Significant weight loss, fatigue, malaise, and lethargy

• Malnutrition– Mineral deficiencies (folate, iron, calcium, magnesium,

zinc)– Vitamins deficiencies (A,D, E, K , B complex esp B12)– Macro-nutrient deficiencies (CHO,Protein,fat)

Clinical Presentation• Recurrent bacterial enteritis

• Stones and related problems– Gall stones due to altered bile metabolism– Renal stones due to high oxalate

• Vomiting, bloating, GERD, gastric ulceration

• Failure to thrive

• Drug toxicities

• Bowel Obstruction (potential complication)

Clinical Presentation

• TPN related issues– Line sepsis and fulminant liver failure

• Enteral Feeding related issues– gastrostomy or nasogastric tube issues

Clinical Presentation• During the physical examination, pay close attention to these clinical signs

– Vitals

– State of hydration

– State of nutrition, as measured by a patient's weight for height and anthropometric measurements

– Signs of sepsis

– Form of nutritional therapy used in the patient (eg, central line access or enteral access)

– Specific clinical signs of nutritional deficiency

– Signs of liver disease

Workup

• Hematological and Biochemical investigations

• Radiological investigations

• Microbiological investigations

• Histopathological investigations

• Miscellaneous

WorkupHematological and Biochemical investigations

CBC • Anemia (MCH, MCHC, MCV)• Thrombocytosis/thrombocytopenia• Hyper segmented neutrophils

Albumin (half life 21 days) • good indicator of hepatic protein synthesis• indicator of overall nutritional status

Prealbumin ( 3-5 days) • indicator of acute nutritional status• monitor the efficacy of nutrition support regimens

AST/ALT • TPN induced liver failure

Electrolytes(Na, K, Cl, Zn, Ca, Mg,Cr, Se, PO4

-3)• TPN monitoring

BUN • Renal reserve• Dehydration(>20:1)• Overfed with protein

Vitamins Level

Coagulation Profile • Deranged Liver function

Workup

Hematological and Biochemical investigations Frequency*

Electrolytes, BUN, creatinine, calcium, magnesium, phosphorous Twice weekly

Comprehensive metabolic panel, CBC, triglycerides, cholesterol Weekly

Folate, vitamin B-12, vitamin E, copper, zinc, selenium Monthly

*both in initial phase and the late period or at the time of presentation for instability

Workup

Radiological investigations

Plain Chest X-ray Post CV line insertion

Plain Abdominal X-ray Suspected bowel obstruction

Barium imaging of the bowel

Abdominal USG fungal balls in the kidney (sepsis)

Renal Stones and related problems

Gall stones and related problemsLiver failure (spleen, ascites, liver texture, Portal vein flow-Duplex)

CT-Abdomen identify persistent sepsisPotential Liver/Bowel transplant

Angiography

Workup

Microbiological investigations

• Blood cultures (both central and peripheral sites)

• Urinalysis and blood culture (specifically to search for fungal infection)

• CV line tip

SOURCE of SEPSIS: • Line Sepsis,

• Gut mucosal atrophy bacterial translocation • Skin flora penetration

Workup

Histopathological investigations

• Liver biopsy(rare)– TPN related liver problems

Workup

Miscellaneous

• Upper GI endoscopy– to assess for peptic ulcer disease and possible signs

of liver disease e.g. esophageal varices, hypertensive gastropathy

• Dual radiographic absorptiometry– Bone density estimation in Metabolic Bone Disease

Treatment(aggressive MULTI DISCPLINARY APPROACH)

MEDICAL CARE• Nutrition

– Early aggressive enteral feeding– Parenteral nutrition

• Aggressive Hydration

• Electrolytes replacement

• Acid reducing agents(PPI, H2 blocker)

• Antibiotics for bacterial overgrowth

• Bile salt chelators (Cholestyramine)

• Psychosocial support

SURGICAL CARE

• Nontransplant surgery

• Small bowel ± liver transplantation

Nutrition

Early aggressive enteral nutrition* as soon as patient can tolerate

most important stimulus for intestinal adaptation

Early discontinuation of parenteral therapy.

Prolonged NPO

Gut MUCOSAL ATROPHY

BACTERIAL TRANSLOCATION

SEPSIS

Enteral Nutritioncrypt cells proliferate, leading to an increase in crypt depth and lengthening of the

intestinal villi.

nutrient receptors

production of trophic intestinal hormone and secretions

production of digestive enzymes

Facilities bile flow prevent cholestasis

Common Concerns with enteral nutrition

Fat Intolerance

(increase in stool output with the appearance of fecal-reducing substances)

• LCFA(high energy density) better tolerated• carbohydrates parenterally and providing fats enterally• Continuous enteral feeds is better tolerated than bolus feeds

High stool volume and frequency

• DON’T STOP or substantially lower the volume and frequency of feeds in response to changes in stool volume

(as long as it does not compromise the child's hydration, acid base balance, and serum electrolyte levels)RATIONALE:Most of fluid and electrolytes disturbances can be corrected by IV formula• Decreasing amount of carbohydrates within the enteral feeds • decreasing the volume and concentration of feeds• Avoid fibers

GERD, Vomiting Decreasing either the volume or rate of feeds

Early Aggressive Enteral Nutrition

Elemental/modular formulas RATIONALE

CHO mixture of monosaccharides and polysaccharides is preferred to disaccharides

in order to limit osmotic load

Fat Medium-chain triglycerides (MCT) readily absorbed in the stomach and proximal small bowel improving fat and total energy absorption

long-chain triglycerides (LCT) • prevent essential fatty acid deficiency• 10% of the patient's energy needs• trophic effect on the intestinal mucosa

Protein Oligopeptide formulas are better absorbed than elemental amino acid formulas

di-tripeptide absorption exceeds that of amino acids.

Concentration

either one-fourth or one-half strength increasing in volume before increasing energy density/conc.

Factors predictive of achieving independence from TPN

• Residual Bowel length

• Intact colon

• Intact ileocecal valve

• Healthy (versus diseased) residual small gut

• Jejunal resection (versus ileal resection)

• Bacterial overgrowth

• Dysmotility

• Teduglutide– enhancement or

restoration of the structural and functional integrity of the remaining intestine

Micronutrients

Supplementation Rationale/Route

Water soluble Vit A, Vit D, and Vit E In case of significant steatorrhea (IV)

Calcium Oral route for bone mineralization and growth(Dual energy x-ray absorptiometry (DEXA) scan)

Vitamin K Not required ( synthesize by enteric bacteria)(monitored by PT time)

deficiency of water-soluble vitamins is rare except Vitamin B12

Vitamin B12 IV on a monthly basis or as a nasal gel

Micronutrients

IV iron infusion bacterial overgrowth or malabsorption

Zinc secondary to increased fecal losses

manganese and selenium pharmacologic doses as required.

Copper associated with anemia and cardiomyopathy

Bacterial overgrowth• Predisposing factor

– Absence of ileocecal valve– Dysmotilty of residual gut

• Manifestations– deconjugation of bile salts and depletion of bile salt stores– Vitamin B12 deficiency Pernicious anemia– carbohydrate malabsorption worsening of osmotic diarrhea– metabolic lactic acidosis CNS disturbances– Dehydration

• Treatment– metronidazole alternating with either kanamycin or oral gentamicin

• Codeine and loperamide– to slow intestinal transit time– DEMERIT: leads to bacterial overgrowth

• Octreotide– Rarely used for concerns of the effect on growth and

worsening cholestatic liver disease

• Glutamine and CCK– No selective advantage

Surgical Care

• Diverting ileostomy– In case of malfunctional colon

• Central Venous line insertion

• PEG (percutaneous endoscopic gastrotomy)

• Reversal of stoma– To capitalize on absorptive capacity of all residual gut

Surgical Care

To slow transit time*• Segmental reversal of small

bowel

• Interposition of segment of colon between segments of small gut

• Construction of small gut valves

• Retrograde electrical pacing of small gut

To increase gut length/area

• LILT ( Longitudinal Intestinal Lengthening and tailoring) or Bianchi procedure

• STEP (Serial transerve enteroplasty procedure)

LILT (Bianchi1980) Procedure

Separation of dual blood supply Longitudinal division Iso-peristaltic end-to-end anastomosis

STEP

Serial applications of an intestinal stapling device, with firings oriented perpendicular to long axis of intestine

By 2013, amongst 111 patients operated 47 % cases had achieved enteral autonomy by 21 months.

1st performed in 2003 on 2-year-old baby who had been born with gastroschisis

Intestinal Transplantation

• Indications– Life threatening complications due to intestinal

failure or long term TPN• Impending or overt liver failure• Thrombosis of major central veins• Frequent episodes of catheter-related sepsis• Frequent episodes of severe dehydration.

Available at surgicalpresentations