Small Bowel Everything you ever wanted to know and more

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Small Bowel
Everything you ever wanted to know and more
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Basic Anatomy

• 270-290 cm from pylorus to cecum
• Duodenum 20 cm
• Jejunum 100 cm
• Ileum 150 cm

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Studying the SB

• UGI and SB follow-through
• Enteroclysis
• CT
• Enteroscopy
• Push enteroscopy (up to 100 cm past LOT)
• Double balloon enteroscopy (to TI ideally)
• Capsule endoscopy (beware obstruction)

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Small bowel obstruction

• Etiology
• Extrinsic
• Adhesions (1)
• Hernias (3)
• Abscess
• Mass
• Intrinsic
• Mass (2)
• Foreign body (bezoar, gallstone)

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SBO Pathophysiology

• Hyperperistalsis
• Bowel dilatation
• Third-spacing
• Decrease in mucosal blood flow
• Bacterial translocation

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SBO Presentation

• Crampy abdominal pain
• Nausea
• Vomiting
• Obstipation
• PE Vitals Abdominal exam scars, hernias,
  bowel sounds, tenderness, peritonitis Rectal exam

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Imaging/Labs

• AXR
• /- CT scan
• BMP, CBC, possible lactate

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Surgical vs. Medical Treatment

• Suspicion for strangulation or bowel compromise
• Resuscitate and operate
• Simple obstruction
• Conservative management (NGT decompression,
  resuscitate, serial exams)
• Failure or decompensation
• Operate
• Operation Adhesiolysis /- bowel resection

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Is the bowel viable?

• Warm saline-soaked lap pads
• Time and patience
• Doppler
• Fluorescein fluorescence
• Planned second look

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SB Diverticular Disease

• Duodenal diverticula
• Asymptomatic no treatment
• Symptomatic (biliary obstruction, hemorrhage,
  perforation, diverticulitis, blind loop)
  choledochoduodenostomy or choledochojejunostomy
  vs. resection or duodenal diverticulization
• Jejunoileal diverticuli
• Resect if symptomatic (bleeding, perf)

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Meckels Diverticulum

• True diverticulum
• Rule of 2s 2 population, symptomatic in 2, 2
  years of life, 2 feet from ICV
• Rx
• Bleeding Small bowel resection
• Diverticulitis ?SBR vs. diverticulectomy
• Incidental finding in child Diverticulectomy
• Incidental finding in adult Diverticulectomy if
  low risk

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Crohns Disease

• Can involve GI tract from mouth to anus
• 40 ileocolic, 30 SB only, 30 colon or
  anorectum only
• Transmural inflammation, non-caseating granuloma
  formation
• Skip lesions
• Usually spares rectum
• Medical and surgical treatment is palliative

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Crohn's Epidemiology

• 3-7/100,000
• Most common in Caucasian populations
• Highest incidence in N. America and Europe
• Bimodal distribution (20-30s and 60s)
• Etiology unclear
• Increased risk of developing SB adenocarcinoma
  (100x)

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Crohns Presentation

• Relapsing/remitting abdominal pain and diarrhea
  with weight loss
• Extra-intestinal manifestations (30)
• Skin lesions (erythema nodosum and pyoderma
  gangrenosum)
• Arthritis and arthralgias
• Uveitis and iritis
• Hepatitis and pericholangitis
• Aphthous stomatitis

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Crohns Diagnosis

• Barium study of small bowel (linear ulcers,
  transverse sinuses, and clefts)
• Endoscopy (discrete ulcers,cobblestoning, skip
  lesions
• Adjunctive labs ASCA positive/pANCA negative

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Crohns Medical Management

• Aminosalicylates (Pentasa, Asacol)
• Antibiotics (Flagyl, cipro)
• Corticosteroids
• Immunosuppresive drugs (6-MP, aza)
• Anti-TNFa (Infliximab)

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Crohns Surgery

• Reserved for complications and failures of
  medical management (75)
• Indications
• 1 Obstruction
• 2 Fistula
• 3 Perforation/Abscess
• 4 Perianal disease
• 5 Toxic megacolon

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Operative Motto

• Operative treatment of a complication should be
  limited to that segment of bowel involved with
  the complication and no attempt should be made to
  resect more bowel even though grossly evident
  disease may be apparent.
• -Schwartz

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Surgical Options

• Small bowel resection
• Ileocolic resection
• Strictureplasty
• Take mucosal bx first

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Small Bowel Tumors

• Represent 2 of all GI malignancies
• Presentation intermittent or partial SBO,
  bleeding, pain, perforation, weight loss
• Malignant lesions usually will cause sx based
  on tumor infiltration
• Benign lesions may/may not cause sx based on
  intussusception
• Dx SBFT, enteroclysis, CT, enteroscopy

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Benign Lesions

• Adenomas
• Lipomas
• Hemangiomas
• Hamartoma
• Usually asymptomatic
• Should be excised or resected if symptomatic.

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Malignant Tumors

• Metastatic Disease (cervix, ovaries, renal,
  stomach, colon pancreas, melanoma)
• Adenocarcinoma
• Carcinoids
• Malignant GIST
• Lymphoma

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Adenocarcinoma

• 50 SB tumors
• More frequently proximal SB
• Treatment Wide resection with 10-cm margins,
  ?adjuvant tx
• Prognosis poor usually late stage when diagnosed

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Carcinoids

• From Kulchitsky cells enterochromaffin cells
• Produce 5-HIAA, chromogranins, neuropeptide K,
  substance P
• 80 found within 2 of TI
• AIR Appendix (45), Ileum (28), Rectum (16)
• 10 have carcinoid syndrome (diarrhea, blushing,
  bronchospasm, hypotension, endocardial fibrosis
  R heart failure)
• Metastatic carcinoid or tumors that bypass the
  portal system
• Fibrotic, desmoplastic reaction in mesentery

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Carcinoid Diagnosis

• Dx High index of suspicion!!
• urine 5-HIAA
• CT (mesenteric shortening)
• SBFT
• octreotide scan

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Carcinoids

• Treatment Segmental resection
• Beware Carcinoid crisis with general anesthesia
  (Rx somatostatin, hydrocortisone, antihistamine)
• ?prep all patient with preoperative octreotide
• Adjuvant doxo, 5-FU, streptozocin,
  chemoembolization bulky liver disease
• Palliative for carcinoid syndrome octreotide
• Experimental radionuclide somatostatin agonists
  smart bomb

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Even more SB Tumors

• Lymphoma
• Ileum
• Risk factors immunodeficiency, celiac disease
• Rx Wide resection with nodes
• GIST
• Jejunum/ileum
• Segmental resection

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Acute Mesenteric Ischemia

• Acute-onset pain, out of proportion to exam,
  fever, Heme () stool
• MI, A-fib, mural thrombus, mitral valve disease
• Dx CT scan (good for bowel, large vessels),
  angiogram, MRA

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Embolus vs. Thrombus

• Embolus
• Acute onset without antecedent sx
• Lodge distal to middle colic and jejunal branches
  of SMA
• Sparing of proximal jejunum and R colon

• Thrombus
• Antecedent intestinal angina
• Origin of vessel
• Entire SB and R colon affected

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Nonocclusive Mesenteric Ischemia (NOMI)

• Optimize fluid resuscitation
• Improve CO
• Eliminate vasopressors
• Selective vasodilatory injection (papaverine)
• Bowel resection for frankly necrotic bowel

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Mesenteric Embolic Disease

• Surgical embolectomy
• Exposure of SMA
• Transverse or longitudinal arteriotomy (vein
  patch)
• 3 and 4-Fr Fogarty embolectomy

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Acute Mesenteric Thrombotic Disease

• Bypass
• Antegrade or retrograde
• Conduit autologous greater saphenous vein (acute
  situation)
• Inflow supraceliac aorta, infrarenal aorta,
  iliac artery

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Outcome

• Perioperative mortality 62
• Multiorgan failure, ischemia/reperfusion insult
• Long-term TPN 31

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Chronic Mesenteric Ischemia

• Chronic post-prandial abdominal pain in a
  vasculopath
• Dx Duplex, angiogram

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Management

• Visceral Bypass
• One or two-vessel bypass
• Inflow supraceliac, infrarenal
• Conduit Vein or PTFE/Dacron
• Endovascular
• PTA
• not many studies supporting management

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Enterocutaneous Fistula

• Prevention preoperative nutritional status, good
  technique, perioperative hemodynamics, bowel prep
• Disability
• Electrolyte imbalance
• Malnutrition
• Sepsis
• Low-output lt200cc/ 24 hr versus high gt200 cc/24 hr

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Fistula Initial Management

• Resuscitate
• Imaging
• Consider abx
• Nutritional support
• Control of fistula drainage
• Skin care
• Consider somatostatin

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Impediments to Fistula Closure

• High output (gt500 mL/24 hr)
• Severe disruption of intestinal continuity (gt50
  of bowel circumference)
• Active inflammatory bowel disease of bowel
  segment
• Cancer
• Radiation enteritis
• Distal obstruction
• Undrained abscess cavity
• Foreign body in the fistula tract
• Fistula tract lt2.5 cm in length
• Epithelialization of fistula tract

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Secondary Management

• Fistulogram (one week later)
• Define anatomy
• Rule out distal obstruction
• Failure of conservative management
• Operate small bowel resection

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Short Gut Syndrome

• Less than 200 cm healthy small intestine
• Downside of TPN
• Liver failure
• Cholelithiasis
• Line sepsis
• Venous thrombosis
• Adaptive response 1-2 years

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Short Gut Medical Therapy

• Diarrhea Immodium, lomotil, opiods
• Bile salt-induced diarrhea cholestyramine
• Electrolyte losses replete IV/PO
• Hypergastrinemia H2 blocker or PPI
• Vitamin/Mineral deficiencies Monitor and replete
• Bacterial overgrowth Flagyl, tetracycline
• Enteral nutrition with supplemental TPN

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Short Gut Surgical Therapy

• Reanastomose
• Gastrostomy over jej
• Intestinal valves (iatrogenic intussusception
• Reversed segment
• Tapering enteroplasty (Bianchi procedure)
• Intestinal tranplantation

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The End