Small Bowel Flashcards
What are the cancers of the small bowel to be aware of?
- Carcinoid
- SB Lymphoma
- Leiomyosarcoma
- Adenocarcinoma
Tell me about carcinoid tumour of the SB
- Location – most often in ileum, followed by jejunum then duodenum
▪ Hindgut Carcinoid → hematochezia, rarely symptomatic
▪ Midgut Carcinoid → flushing and diarrhoea due to high levels of serotonin secretion (with bulky / metastatic disease), small bowel obstruction secondary to intense desmoplastic reaction caused by the tumour
▪ Foregut Carcinoid → systemic symptoms, atypical presentation - Diagnostic Ix: 24hour urine level for serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA)
- Intraoperative findings: fibrosis of mesentery causing obstruction → en-bloc resection including mesentery
- Carcinoid crisis → administer octreotide
What is carcinoid syndrome?
- Release of vasoactive substances into systemic circulation; characterized by cutaneous flushing, sweating, bronchospasm,
colicky abdominal pain, diarrhoea, right-sided cardiac valvular fibrosis (carcinoids confined to the GIT typically do not cause carcinoid syndrome as vasoactive substances undergo ‘first-pass’ effect in liver, hence carcinoid syndrome is strongly associated with metastatic disease) - Diagnosis: elevated urinary 5-HIAA (5-hydroxyindoleacetic acid).
- Treatment: octreotide (causes gallbladder sludge) +/- interferon alpha (will usually require cholecystectomy if surgical
intervention is performed)
Tell me about the subgroups and presentations of SB lymphoma?
- 3 subgroups:
▪ Immunoproliferative small intestinal disease lymphoma (IPSID): variant of extranodal marginal zone lymphoma of MALT; secretes alpha heavy chains
▪ Enteropathy-associated T cell lymphoma (EATL): highly associated with gluten-sensitive enteropathy
▪ Others, eg diffuse large B cell, mantle cell, Burkitt, follicular - Presentation:
▪ IPSID: abdo pain, chronic diarrhea, malabsorption, severe LOW
▪ EATL: acute bleeding, obstruction, perforation - Ix & Tx: See gastric lymphoma section.
Clinical presentation of enteric fistula?
- Abdominal discomfort / distention and tenderness
- Nausea / vomiting
- Fever, chills (is patient septic?)
- Enteric contents appear in the surgical wound (is the fistula controlled or uncontrolled?)
Classifications of an enteric fistula?
- Low output: less than 200ml / day
- Moderate output: 200 – 500ml / day
- High output: more than 500ml / day
RIsk factors for nonclosure of fistula?
- Foreign Body, Radiation, Inflammation (i.e. inflammatory bowel disease) or infection (i.e. tuberculosis), Epithelialization of fistula
tract, Neoplasia, Distal Obstruction, Steroids [FRIENDS} - High Output Stoma (> 500ml/day), Uncontrolled or Proximal Fistulas
Investigations to be done for enteric fistulas?
- Biochemical – FBC, CRP, U/E/Cr, Ca/Mg/Phos (assessment for sepsis, hydration status, electrolytes abnormalities)
- Radiological – CTAP (assessment for intra-abdominal sepsis, underlying pathology), gastrografin meal/follow-through (delineate
anatomy of the fistula)
Management of enteric fistulas?
A common acronym in management of ECF is SNAPP. Initial assessment should evaluate if the patient is septic, if the fistula is controlled and what is the volume of the fistula. Surgical management is usually one of the last steps.
Sepsis
- CT imaging to identify intra-abdominal collections
- Antibiotics – any associated cellulitis / intra-abdominal sepsis (i.e. abscess or peritonitis)
- Percutaneous drainage of intra-abdominal abscess
Nutrition
- Fluid & electrolytes intravenous replacement – the aim is for patients to have no thirst or signs of dehydration
- Nutritional support – enteral or parenteral nutrition
- Reducing intestinal fluid losses (from stoma / fistula) – measure output of fistula
- Review meds – stop prokinetics, start anti-cathartics (i.e. loperamide, diphenoxylate (lomotil), somatostatin analogues (i.e.
octreotide), start high dose PPI to reduce gastric output
Anatomy (definition of fistula anatomy)
- Radiological contrast studies to assess bowel length, site of origin of fistula and anatomy of fistulous tract
- Delineate tract & assess for complications with CT scan (with oral and rectal contrast)
Protection of Skin
- Protect surrounding skin, small bowel output is caustic and can cause excoriation of skin around a stoma
Proposing a procedure to address the fistula / Planned Surgery
- Surgical intervention is usually delayed – definitive surgery should be deferred till nutrition optimization attained, sepsis
eradicated and maturation of adhesions has occurred
- Timing of surgery impacts on mortality rates and ECF recurrence rates. Minimum waiting time is ~ 6 week, though 6-12 months
waiting time is ideal
- Surgical Intervention – adhesiolysis, take down fistula, bowel resection ± anastomosis, ± stoma (if anastomosis is in area of
residual sepsis) ± feeding jejunostomy
What is the definition of Meckel’s Diverticulum
Blind out-pouching of the antimesenteric aspect of the small intestine (ileum) that has all four layers of the small bowel wall (i.e. true congenital diverticulum), covered with serosa; resulting from - It results from incomplete obliteration of the vitelline duct / persistent remnant of the omphalomesenteric duct (connects mid-gut* to yolk sac in the foetus) – usually obliterated by 7th week
What are the rules of 2 in meckel’s divert
- 2 inches in length, 2cm wide,
- 2 feet (60cm) from ileocaecal valve
- 2% of the population
▪ No familial predisposition
▪ Increased prevalence in children with malformation of umbilicus, alimentary tract, nervous system, CVS system - 2:1 (M:F)
- 2-6% becomes symptomatic
▪ Increased risk in (1) presence of ectopic tissue, (2) age <50yrs, (3) diverticulum length >2cm, (4) males, (5) broad based
diverticulum, (6) presence of fibrous bands
▪ < 50% of patients present with symptoms before 2 years of age - 2 types of ectopic tissue (choristoma*)
▪ Gastric (60%) – gastric acid secretion can produce inflammation, peptic ulceration / bleeding, strictures with subsequent IO
▪ Pancreatic (6%)
▪ May have both types of tissue or other types (i.e. jejunal, colonic, rectal, hepatobiliary)
Presentations of Meckel’s Divert
- Asymptomatic: incidental finding during abdominal surgery or imaging
- Symptomatic:
▪ Hematochezia / Melena (most common in children): usually massive & painless, due to peptic ulceration o GI bleeding due to Meckel is rare in adults > 30 years
▪ Intestinal Obstruction (most common presentation in adults):
o Recurrent Intussusception – Meckel’s diverticulum act as the lead point
o Volvulus
o Abdominal Wall Hernia – Littre’s Hernia (at inguinal (50%), femoral (20%)) o Meckel’s Diverticulitis – inflammation results in reduced luminal diameter
▪ Meckel’s Diverticulitis: may present exactly like acute appendicitis
▪ Chronic Peptic Ulceration: pain, although related to food, is felt around the umbilicus (diverticulum is midgut)
▪ Others: umbilical fistula, perforation etc.
▪ Tumour – most commonly carcinoid (76%), adenocarcinoma (11%), GIST (11%)
Investigations for Meckel Divert?
Biochemical Investigations: depends on clinical presentation (i.e. intestinal obstruction / lower BGIT / meckel diverticulitis)
Imaging:
- Meckel’s Scan: Technetium-99m pertechnetate scan (detects gastric mucosa)
- Barium studies: small bowel enteroclysis
- CT angiography (for bleeding meckel’s diverticulum) – help detect signs of bleed (0.3ml/min)
- Contrasted CTAP not helpful as hard to distinguish Meckel’s diverticulum from small bowel loops
Management of Meckel’s Divert?
- Asymptomatic16
▪ Detected on imaging: do not perform elective resection
▪ Detected during surgery: [controversial*]
o Resect in children up to young adulthood
o Resect in adult (<50yrs) – (higher risk for symptoms – age < 50, male gender, diverticulum length > 2cm and ectopic
features within a diverticulum (palpable abnormalities)17 – ?leave in-situ if have broad base and short length o Do not resect in patients (> 50yrs) - Symptomatic
▪ NBM, IV drip, correct electrolyte imbalance
▪ IO: treat as per small bowel intestinal obstruction algorithm
▪ Bleeding GIT: treat as per BGIT algorithm
▪ Diverticulitis: IV antibiotics + surgical intervention (open or laparoscopic)
o Broad base: wedge ileal resection with anastomosis o Narrow base: resection of the diverticulum
Compare Crohn’s vs UC
Systemic Manifestations of IBD
Investigations for Crohn’s Disease
- Diagnosis requires endoscopic biopsy and clinicopathological correlation)
- Ultrasound: for diagnosing ileal CD
- Contrast radiographic studies: assess location & extent of disease, look for strictures & fistulae
▪ Barium meal/follow through: small bowel series & enema (cobblestone)
▪ CT scan with oral & IV contrast
▪ MRI - Endoscopy: look for typical features (i.e. skip lesions of ulcerated erythematous oedematous mucosa, pseudopolyps – see picture)
▪ Colonoscopy with tissue biopsy (non-caseating granulomas)
▪ OGD: upper GIT involvement
▪ Endoanal U/S (EUS): identify fistula tracts
Management of Crohn’s
Classification of UC
Investigations for UC
Management of UC
