General Surgery GI Flashcards
Midgut structures, arterial supply, venous drainage and innervation
structures: jejunum, ileum, cecum, large intestine up to left colic flexure
supplied by superior mesenteric artery
drained by superior mesenteric vein to portal system
innervated by lesser (T10-T11) and least (T12) splanchnics from sympathetic system and vagus nerve from parasympathetic system
Hindgut structures, arterial supply, venous drainage and innervation
structures: descending colon, sigmoid colon, rectum, anal canal
supplied by inferior mesenteric artery
drained by inferior mesenteric vein to portal system
innervated by lumbar splanchnics (L1-L2) from sympathetic system and pelvic splanchnics (S2-S4) from parasympathetic
Division of the compartment of greater sac
greater sac divided by transverse, ascending and descending colon into supra colic compartment, infra colic compartment, right paracolic gutter and left paracolic gutter
the infra colic and supra colic compartment communicate via paracolic gutters
Jejenum vs ileum
wall, caliber: jejunum have thicker walls with larger diameter whereas ileum have thinned walls with smaller diameter
location: jejunum located in upper left quadrant whereas ileum is located in lower right quadrant
vascularity: jejunum have greater vascularity so it appears darker and more red whereas ileum have lesser vascularity so it appears lighter and more pink
vasa recta: vasa recta is long in jejunum and short in ileum
mesenteric fat: jejunum have less mesenteric fat and ileum have more mesenteric fat
circular folds: jejunum have tightly packed circular folds whereas ileum have sparse circular folds and absent circular folds distally
intestinal villi: jejunum have more numerous and prominent villi whereas ileum have less numerous and less prominent villi
lymphoïde mode follicules: jejunum have no aggregates (no Peyer’s patches) whereas ileum contain Peyer’s patches
Arterial supply of jejenum vs ileum
both jejunal and ileal arteries are branches from superior mesenteric artery (15-18 arteries in total)
jejunum / ileum artery -> arcade -> vasa recta
jejunum have fewer, larger arteries that loops and have longer vasa recta (straight arteries) than ileum
What is the ileoceacal junction
ileum terminates by partly invaginating into cecum, forming the ileocecal valve
How to locate the appendix
appendix location can vary, it is usually localized by tracing to origin of taenia coli
Blood supply of midgut
mid gut supplied by superior mesenteric artery (SMA) at L1 level
superior mesenteric artery have branches to feed small intestines and branches to feed large intestines
all of branches of SMA that course toward the left are jejunal arteries and ileal arteries supply small intestines
branches of SMA that course toward the right include ileocolic artery (with ileal and colic branches), appendicular artery, right colic artery and middle colic artery that supply the large
intestines
the ileocolic artery split into ileal and colic branches that supply ascending colon
appendicular arteries is a branch of ileocolic artery that supply the appendix
the right colic artery is a branch of SMA that supply the ascending colon
middle colic artery is a branch of SMA that supply the transverse colon
Venous drainage of midgut
midgut drained by superior mesenteric vein (SMV), which drain to the portal vein (portal system)
SMV branches are paired and travel with arteries with same name (jejunal veins, ileal veins, ileocolic vein, right colic vein, middle colic vein, appendicular vein)
the SMV and its branches are always anterior to its correspondent SMA and its branches
large intestine intraperitoneal and retroperitoneal components
large intestines include cecum, appendix, ascending colon, transverse colon, descending colon and sigmoid colon
cecum, appendix, transverse and sigmoid colon are intraperitoneal and covered by mesentery
ascending colon, descending colon and rectum are retroperitoneal
What are the taenia coli
taenia coli = 3 strips of longitudinal muscle extending length of large colon
the longitudinal muscle names are taenia libera, taenia omentalis and taenia mesocolica
pulling force of taenia coli result in haustra (sacculated appearance that look like pouches)
taenia coli unite at base of appendix and then splay out to form outer wall of rectum
Locations of longitudinal taenia muscles
taenia omentalis is underneath the greater omentum
taenia libera is anterior
taenia mesocolica is posterior
what are epiploic appendages
epiploic appendages are small pouches of peritoneum filled with fat along the colon
what are semilunar folds
semilunar folds are ridges inside the large intestine between taenia coli that separate the haustra
rectosigmoid junction landmarks
- located anterior to S3 vertebra
- termination of sigmoid mesocolon (mesentery)
- colon traits (taenia coli, haustra, appendages) end at rectosigmoid junction
- taenia coli stop being distinct bands, flare out and become continuous muscle layer covering the rectum
Rectum, its components and pouches
rectum is part of the large intestine that is retroperitoneal and fixed
ampulla of rectum is the inferior dilatation of rectum
lowest extent of peritoneal cavity forms a pouch
rectovesival pouch between rectum and bladder in male
rectouterine pouce between rectum and uterus in female
drainage of excess peritoneal fluid and peritoneal dialysis at these pouches
where is the anorectal junction roughly located
pelvic diaphragm
anal canal and its components
in anal canal, interior (mucosa) and exterior (skin) surfaces are divided by pectinate line
anal columns are longitudinal ridges that elevate, which is due to superior rectal artery and vein
anal sinuses are grooves between anal columns that secrete mucus
Embryological origin, innervation, arterial supply, venous drainage and lymphatic drainage of tissue above the pectinate line (visceral)
Endoderm
Autonomic: distension sensation
Superior Rectal A. (IMA)
Superior Rectal V. (IMV –> Portal drainage)
Visceral pattern (internal iliac lymph nodes –> chyle cistern)
Embryological origin, innervation, arterial supply, venous drainage and lymphatic drainage of tissue below the pectinate line (body wall/somatic)
Ectoderm
Somatic: pain sensation (inferior rectal N.)
Inferior Rectal A. (from internal iliac artery)
Middle/inferior rectal V. (int iliac V. –> IVC, caval drainage)
Body wall drainage pattern (superficial inguinal lymph nodes –> body wall)
Branches of inferior mesenteric artery
1 = IMA
2 = left colic artery, a branch of IMA, supplies left part of transverse colon and descending colon
3 = sigmoid arteries (usually 2 or 3 arteries), branches of IMA, supply sigmoid colon
4 = superior rectal artery, a continuation of IMA after sigmoidal arteries are given off
blue arrows = marginal artery of Drummond that anastomose between SMA and IMA along length of entire large colon
marginal artery encircles the entire colon
Venous drainage of hindgut
hindgut drained by inferior mesenteric vein (IMV), which drain to the portal vein (portal system)
IMV branches are paired and travel with arteries with same name (right colic vein, sigmoidal veins, superior rectal vein)
IMV and its branches are always posterior to the correspondent IMA and its branches
Lymphatic drainage of midgut and hindgut
lymph nodes generally associated with arteries (nodes along arteries) to bypass portal venous system
this is unique to GI, where lymph usually follows veins elsewhere in the body
small intestine lymph follows arterial lymph nodes to chyle cistern to thoracic duct
large intestine lymph follows arterial lymph nodes to chyle cistern to thoracic duct
anal canal lymph superior to pectinate line follow arterial lymph node to chyle cistern to thoracic duct (gut drainage pattern)
anal canal lymph inferior to pectinate line drain to superficial inguinal lymph nodes (body wall drainage pattern)
Overall Regulation of GI System
3 types of regulation of GI system
1) Nervous system control
autonomic innervation (sympathetic and parasympathetic)
as a rule, sympathetic always inhibit GI function and parasympathetic always stimulate GI function
enteric nervous system
2) Endocrine control
secretion of hormones into bloodstream
e.g. secretin, CCK, somatostatin, VIP, gastrin
3) Paracrine control
secretion of signalling molecule into interstitial for communication between nearby cells
Role of CCK and Secretin
CCK and secretin are hormones released by duodenum
fatty chyme stimulate release of CCK
acidic chyme stimulate release of secretin
CCK inhibit gastric emptying, stimulate pancreatic growth, stimulate release of pancreatic enzyme and stimulate release of bile from gallbladder
secretin stimulate release of basic pancreatic fluid and basic bile
CCK and secretion potentiate each other’s effect
Overview of digestion and absorption
1) Mouth
mastication
saliva
2) Stomach
pepsin
gastric acid secretion
intrinsic factor
3) Liver
bile acid
4) Pancreas bicarbonate amylase protease lipase / colipase
5) Duodenum, jejunum
water and electrolyte absorption
nutrient absorption
90% of digestion and absorption occur in duodenum
6) Terminal ileum
bile salt transport
vitamin B12 absorption
absorption of fat soluble vitamins
7) Colon
water absorption
bacterial fermentation of disaccharide into short chain fatty acids and acids (CO2, methane)
short chain fatty acids are used by colonic epithelium or metabolized by liver
Digestion and absorption of proteins
1) Digestion in stomach
proteins denatured in gastric acid
pepsinogen (secreted by chief cells in stomach) is activated in gastric acid to pepsin, which cleave protein into peptides
2) Digestion in duodenum
pancreatic proteases cleave peptides into oligopeptides (2-6 amino acids) and amino acids
trypsin, chymotypsin, elastase and carboxypeptidase
duodenum mucosal enzyme enterokinase cleave and activate trypsin, which then cleave and activate chymotrypsin
brush border enzymes cleave oligopeptides into tri-peptides, dipeptides and amino acids
aminopeptidase, carboxypeptidase, dipeptidase
3) Absorption in small intestine
amino acids are absorbed into enterocytes by co-transport with Na
dipeptides and tripeptides are absorbed into enterocytes by co-transport with H+ and hydrolyzed into amino acids inside the cell
4) Absorption into blood
amino acids leave epithelial cell by facilitated diffusion, which then enter capillary blood in villi to hepatic portal vein to liver
Digestion and absorption of carbohydrates
1) Digestion in mouth salivary amylase (secreted by salivary glands) break starch (amylose and amylopectin) into oligosaccharides disaccharide (lactose and sucrose) and monosaccharides (glucose and fructose) go through mouth, esophagus and stomach without any digestion
2) Digestion in duodenum
pancreatic amylase further break starch into oligosaccharides (maltose, maltotriose, dextrin)
3) Digestion in small intestine
brush border enzyme (lactase, maltase and sucrase) break disaccharide (lactose, maltose and sucrose) into monosaccharides (glucose, fructose, galactose)
4) Absorption in small intestine
monosaccharide absorbed into enterocytes
glucose and galatose are absorbed into enterocytes via co-transport with Na
fructose enter enterocytes by facilitated diffusion
all monosaccharides leave epithelial cells via facilitated diffusion, which then enter capillary blood in villi to hepatic portal vein to liver
Digestion and absorption of fat
1) Mixing in mouth and stomach
fat (triglyceride, phospholipid and cholesterol) are crushed and mixed in mastication within the mouth and stomach
small amount of fat broken by gastric lipase
2) Emulsification to fat droplets in duodenum bile salts (secreted by liver into gallbladder) that emulsify (surround) fat, to break it down into fat droplets and make it soluble in water
3) Digestion in duodenum
pancreatic lipase cleave triglyceride into fatty acids and a monoglyceride
pancreatic phosphlipase break phospholipids into fatty acids and lysophosphatidylcholine
pancreatic cholesterol esterase break cholesterol into sterol
4) Emulsification to micelle in duodenum
cleaved fatty acids, monoclygeride, choline and sterol are emulsified by bile salt into micelles
5) Absorption of micelle in small intestine (mainly duodenum and jejunum)
fatty acids leave micelle and diffuse into enterocytes
in enterocytes, fatty acids and monoglycerides are reformed into triglycerides, which are packaged with triglycerides, cholesterol, phospholipids and protein to form chylomicron (a
lipoprotein particle)
chylomicron exit enterocyte by exocytosis and enter lacteals in villi, where they enter the lymphatics
short chain fatty acids and glycerol are absorbed directly into blood stream and do not enter the lymph system
bile salts are absorbed in ileum
6) Transport from lymph into blood
lymphatics carry chylomicron to thoracic duct, where it enters the blood stream to the liver
Hernia epidemiology
affects more commonly males than females, males have 25% lifetime risk of hernia whereas females have 2% lifetime risk of hernia
50% hernias are indirect inguinal hernia; 25% hernias are direct inguinal hernia; 5% hernias are femoral hernias
most common hernias in male and female are indirect inguinal hernia, but male are more predisposed to indirect hernia due to opening of inguinal canal
females are more pre-disposed to femoral hernias
Hernia risk factors
increased intra-abdominal pressure
body habitus that increase intra-abdominal pressure: obesity, pregnancy, ascites
activities that increased intra-abdominal pressure: chronic cough, constipation, straining on urination / defecation, heavy lifting
congenital abnormality (patent processus vaginalis)
previous history of hernia and hernia repair
Hernia anatomical classification
A) Internal hernia
B) External hernia
1) groin hernia
a) indirect inguinal hernia: herniation originating from deep inguinal ring lateral to inferior epigastric artery descending into scrotal sac or labia majora
b) direct inguinal hernia: herniation through Hesselbach’s triangle, medial to inferior epigastric artery usually does not descent into scrotal sac
“MD don’t LIe” = Medial to inferior epigastric artery is the Direct hernia; Lateral to inferior epigastric artery is the Indirect hernia
c) pantaloon hernia: combined direct and indirect groin hernia with peritoneum draped over inferior epigastric vessels
d) femoral hernia: herniation into femoral canal below inguinal ligament medial to femoral vein within femoral canal
femoral hernia have highest risk of incarceration and strangulation
2) epigastric hernia
epigastric hernia: defect in linea alba above umbilicus causing hernia
3) incisional hernia
incisional hernia: ventral hernia at site of wound closure
4) other types of hernia
Littre’s: hernia involving Meckel’s
Amyand’s: hernia containing ruptured appendix
lumbar hernia
obturator hernia
parastomal hernia
umbilical hernia
Spigelian hernia: ventral hernia through linea semilunaris
Hernia complications
incarceration, where hernia cannot be reduced
strangulation, where an irreducible hernia have ischemia
strangulation of hernia can cause intestinal obstruction, necrotic bowel, sepsis
strangulated hernia is a surgical emergency
Hernia clinical presentation
History:
swelling or fullness at hernia site, mass of variable size, hernia enlarges with coughing / lifting / straining and disappears in supine position
aching sensation radiating into area of hernia, tender at end of day relieved with supine position or with reduction
abdominal fullness, burning / gurgling / aching sensation
no pain or tenderness on palpation of hernia
incarcerated hernia: painful enlargement of previous hernia, irreducible either spontaneously or manually through defect, may have symptoms of bowel obstruction (nausea &
vomiting, distended abdomen, constipation, obstipation)
strangulated hernia: irreducible hernia with increasing pain and tenderness, symptoms of bowel obstruction (nausea & vomiting, distended abdomen, constipation, obstipation), fever,
chills
Physical Exam (of Groin Hernia):
on inspection, bulges at femoral or inguinal areas with patient standing while straining down
in male, palpation by invaginating loose skin of scrotum with index finger up into inguinal canal to feel for any palpable herniation descending onto finger while patient strains down or
coughs
in female, palpation with open hand over groin area to detect impulse of hernia descending during straining or coughing
incarcerated hernia: irreducible hernia
strangulated hernia: fever, distended abdomen, peritonitis
Hernia diagnosis
usually physical exam sufficient for diagnosis of hernia
may use ultrasound or CT to aid in diagnosis of hernia
CT useful for diagnosis of obturator hernia, internal abdominal hernia, Spigelian femoral hernia in obese patients
Hernia management for non-incarcerated non-strangulated hernias
a) small, minimally symptomatic, first occurrence hernia
surgical repair is not necessary and patients can be followed expectantly
if no surgical repair, then patients counselled on symptoms of incarceration and strangulation, so that they can seek prompt healthcare evaluation
b) all other hernia
surgical repair (herniorrhaphy) for all other hernias
symptomatic, large or recurrent hernia should have surgical repair within 1 month of detection
surgical repair of hernia to prevent incarceration and strangulation; or to treat symptoms; or for cosmesis
surgical repair can be open or laparoscopic, depending on surgeon preference, usually uses mesh for tension-free closure
repair can be done with plug in hernia defect with patch over it or patch alone
Post-surgical complications of hernia surgery
recurrence (15-20% risk), which is less common with mesh / tension-free surgical repair
scrotal hematoma (3% risk) from compromised venous return of testes
nerve (ilioinguinal or genital branch of genitofemoral) entrapment
stenosis or occlusion of femoral vein, causing acute leg swelling
ischemic colitis
Hernia management for acutely incarcerated or strangulated hernia
acutely incarcerated hernia have risk of subsequent strangulation, so patients should undergo attempts at reduction followed by surgical repair
strangulated hernia should undergo emergent surgical repair
hernia definition
hernia = fascial defect resulting in protrusion of a viscus into an area in which it is not normally contained
complete hernia definition
complete hernia = hernia sac and contents protrude through defect
incomplete hernia definition
incomplete hernia = partial protrusion through defect
internal hernia definition
internal hernia = sac herniating into or involving intra-abdominal structure
external hernia definition
external hernia = sac protruding completely through abdominal wall
sliding hernia definition
sliding hernia = part of wall of hernia formed by protruding viscus
ex. sliding hernia where cecum forms part of hernia wall
Richter’s hernia definition
Richter’s hernia = only part of circumference of bowel (usually anti-mesenteric border) is incarcerated or strangulated, so may not cause bowel obstruction
What is Hesselbach’s triangle
Anatomical triangle formed by 3 borders:
medial border = lateral margin of rectus abdominis
lateral border =
inferior epigastric artery
inferior = inguinal ligament
Most common complication of hernia repair
most common complication of hernia repair include hematoma, penile ecchymosis, scrotal ecchymosis, wound infection, chronic pain
Types of IBD
many types of inflammatory bowel disease including
Crohn’s disease (CD): relapsing transmural inflammation and ulceration of GI tract anywhere from mouth to anus
Ulcerative colitis (UC): inflammation and ulceration of rectum extending proximally to large bowel
other IBD include microscopic colitis, diversion colitis, radiation colitis, drug induced colitis, indeterminate colitis
Epidemiology of IBD
highest incidence and prevalence of IBD in Europe and North America
bimodal age distribution, with 1st peak at age 20-30 and 2nd peak at age 60
highest prevalence in Caucasian and African American
lowest prevalence in Asians and Hispanics
Pathophysiology of IBD
aetiology of IBD unknown, but hypothesized to be a multifactorial disease
genetic predisposition, dysregulation in mucosal immune system and environmental trigger cause chronic inflammation in GI tract, resulting in IBD
UC vs CD overall severity
overall, CD is worse than UC, because CD has many complications (e.g. peri-anal disease, obstructions) and it can affect any part of the GI tract
Crohn’s location
rectal bleeding
diarrhea
abdominal pain
fever
palpable mass
recurrence after surgery
endoscopic features
Histologic features
Radiologic features
Complications
Colon cancer risk
Location- any part of GI tract
Small bowel + colon 50%
Small bowel only 30%
Colon only 20%
rectal bleeding uncommon
diarrhea less prevalent
abdominal pain post-prandial/colicky
fever common
palpable mass frequent (25%) RLQ
recurrence after surgery common
endoscopic features
Discrete aphthous ulcers
Patchy lesions
Pseudopolyps
Histologic features Transmural distribution with skip lesions Focal inflammation Sometimes non caseating granulomas Deep fissuring + aphthous ulcerations Strictures Glands intact
Radiologic features
cobblestone mucosa
frequent strictures and fistulae
AXR: bowel wall thickening “string sign”
Complications
Strictures
Fistulae
Perianal disease
Colon cancer risk increased if >30% of colon involved
UC location
rectal bleeding
diarrhea
abdominal pain
fever
palpable mass
recurrence after surgery
endoscopic features
Histologic features
Radiologic features
Complications
Colon canc
Locationisolated to large bowel
always involves rectum, may progress proximally
rectal bleeding very common (90%)
diarrhea frequent small stools
abdominal pain pre-defecatory urgency
fever uncommon
palpable mass rare (if present, likely cecum full of stool)
recurrence after surgery none-post colectomy
endoscopic features Continuous diffuse inflammation Erythema Friability Loss of normal vascular pattern Pseudopolyps
Histologic features Mucosal distribution Continuous disease (no skip lesions) Granulomas absent Gland destruction, crypt abscess
Radiologic features
Lack of haustra
Strictures rare and suggests complicating cancer
Complications
Toxic megacolon
Colon cancer risk increased except in proctitis
Common presentation of IBD
Symptoms abdominal pain, frequent bowel movement, diarrhea bloody stools urgency failure to thrive or weight loss
Extraintestinal manifestations of IBD
Derm- erythema nodosum, pyoderma grangenosum, perianal skin tags, oral mucosal lesions, psoriasis
Rheum
Peripheral arthritis, ank spondylitis, sacroiliitis
Ocular
Uveitis (vision threatening), episcleritis (benign)
Hepatobiliary
Cholelithiasis, PSC, fatty liver
Urologic
Calculi, ureteric obstruction, fistulae
Others VTE vasculitis osteoporosis vitamin deficiencies (B12, ADEK) Cardiopulmonary disorders Pancreatitis (rare)
Most of these are more common in CD except sacroiliitis (equal)
Complications of IBD, their pathophysiology, clinical presentation, diagnosis and treatment
- Toxic Megacolon:
most commonly in UC
pathophysiology: inflammation result in colonic paralysis and obstruction with high risk of perforation
clinical presentation: fever, tachycardia, leukocytosis, peritoneal signs on abdominal exam
treatment: fluid resuscitation, NG tube, IV Solumedrol, immediate surgical colectomy
2. Bowel Perforation
pathophysiology: perforation of intestinal content into abdominal cavity, resulting in bacterial infection and peritonitis
clinical presentation: fever, chills, nausea & vomiting, severe abdominal distention, peritoneal signs on abdominal exam
diagnosis: free gas / air under diaphragm on X-ray
treatment: fluid resuscitation, IV antibiotics, surgery
3. Dysplasia
pathophysiology: IBD leads to dysplasia, which increase risk of colorectal carcinoma
clinical presentation: dysplasia associated lesion or mass (DALM) on endoscopy
treatment: surveillance colonoscopy, prophylactic colectomy in high risk patients
Crohn’s disease epidemiology
incidence 1-6/100,000, prevalence 10-100/100,000
common in Caucasian and Ashkenazi Jews
M=F
Crohn’s disease clinical presentation
recurrent abdominal cramps, diarrhea and weight loss
most commonly affect terminal ileum and ascending colon
ileitis: vomiting, post-prandial pain, RLQ mass
fistula, fissure, abscess
Crohn’s disease investigations
colonoscopy with biopsy
CT enterography for involvement of small bowel
elevated ESR and CRP
Crohn’s disease management
non-pharmacological: smoking cessation
anti-diarrheal: Loperamide (Imodium), Diphenoxylate (Lomotil)
mild CD: 1) antibiotics (Metronidazole or Ciprofloxacin); and 2) 5-ASA (5-Aminosalicyclic acid)
moderate CD: 1) steroid Prednisone or Budesonide; and 2) immune-modulator Azathioprine (AZA; Imuran), 6-Mercaptopurine (6-MP) or Methotrexate (MTX)
severe CD: surgery and / or biologics Infliximab (Remicade) or Adalimumab
surgery indicated in complications of fistula, obstruction, abscess, perforation, bleeding and medically refractory disease
Ulcerative colitis epidemiology
incidence 2-10/100,000, prevalence 35-100/100,000 (more common than Crohn’s)
M=F
inflammation to rectum or left colon more common
Ulcerative colitis clinical presentation
chronic abdominal cramps / pain with defecation, diarrhea and rectal bleeding
may have tenses, urgency, incontinence
systemic symptoms include fever, anorexia, weight loss and fatigue in severe cases
Ulcerative colitis clinical classification
mild UC: <4 stools / day and nothing else
moderate UC: >4 stools / day with minimal signs of toxicity (fever, tachycardia, anemia, high ESR)
severe UC: >6 stools / day and signs of systemic toxicity (fever, tachycardia, anemia, high ESR)
fulminant UC: >10 stools / day; continuous bleeding requiring blood transfusion; systemic toxicity (fever, tachycardia, anemia, high ESR); abdominal tenderness and distension; and
colonic dilation on abdominal plain film
Ulcerative colitis investigation
sigmoidoscopy with mucosal biopsy for diagnosis, which can be substituted with CT colonography
Ulcerative colitis management
total colectomy for refractory & severe UC, colonic stricture, life-threatening UC complications (severe bleeding, toxic megacolon, impending perforation), dysplasia or carcinoma
mild UC: 1) 5-ASA
moderate UC: 1) 5-ASA; and 2) steroid Prednisone or Budesonide
severe UC: 1) surgery; and 2) Cyclosporine
consider adding immunomodulator AZA or 6-MP; or biologics Infliximab for moderate to severe UC
General indications for surgery in IBD
severe disease: intractable symptoms and failure to respond to medical therapy, extra-intestinal manifestations, chronic disability, failure to thrive in children, poor quality of life
GI emergencies: toxic megacolon, bowel perforation, uncontrolled hemorrhage, bowel obstruction
structural abnormalities: fistula, stricture
infectious: abscess
malignancy: pre-cancerous lesions, colorectal cancer
General principles of surgery in IBD
surgeries can alleviate symptoms, address complications and improve quality of life
principle of to conserve as much bowel as possible (i.e. resect as little as possible to avoid short gut syndrome)
perioperative management:
a) optimize medical status with bowel rest, which may require TPN if >7 days of NPO
b) hold immune suppressive therapy pre-op, provide pre-op stress dose of corticosteroid if patient had recent steroid therapy, taper steroids post-op
c) DVT prophylaxis
Surgery in Crohn’s Disease specific indications
structural lesions (stricture, fistula): bowel resection and anastomosis (or stoma if active inflammation, perforation, fistula)
small bowel obstruction due to stricture or inflammation: bowel resection and anastomosis
stricture: stricturoplasty (widening of lumen in bowel stricture)
abscess: surgical incision and drainage
peri-anal disease: appropriate surgical treatment for types of peri-anal disease
Surgery in Crohn’s Disease complications
small bowel resection -> short bowel syndrome
short bowel syndrome if functional small intestine <50% or <200cm
short bowel syndrome = malabsorption disorder due to surgical removal of small intestine resulting in diarrhea, steatorrhea, malnutrition
symptoms: abdominal pain, diarrhea, steatorrhea, weight loss, malnutrition, fatigue
vitamin A, D, E, K, folic acid, B12, Ca, Mg, iron, zinc deficiency
hypo calcium increases risk of kidney stones
ileal resection -> watery diarrhea, steatorrhea, gall stones
<100cm resection cause watery diarrhea due to impaired bile salt absorption treated with cholestyramine or anti-diarrheal (Loperamide)
>100cm resection cause steatorrhea due to reduced mucosal surface area for fat absorption and bile salt deficiency treated with fat restriction and medium chain triglycerides
decreased bile absorption -> increased risk of gallstone
any abdominal surgery -> fistula, adhesions
Surgery in Crohn’s Disease prognosis
post surgical removal, 10 year recurrence rate: 25-50% in ileocolic region, 50% in small bowels, 50% in large bowels
proportion requiring re-operation due to recurrence: primary resection have 20% re-operation, bypass have 50% re-operation, stricturoplasty have 10% re-operation
80-85% of patients who require surgery will lead normal lives
post surgery, 15% mortality risk at 30 years
Surgery for UC indications
severe to fulminant UC: total colectomy with ileal pouch - anal anastomosis
can resect only portion of colon that is pathologic (e.g. proctocolectomy, rectal mucosectomy)
decrease colorectal cancer: total proctocolectomy
in surgical emergencies: total colectomy and ileostomy with Hartmann closure of rectum, rectal preservation
Complications of surgery in UC
early: anastomotic leak, dehydration from high stoma output, bowel obstruction, transient urinary dysfunction
late: stricture, anal fistula / abscess, pouchitis, poor anorectal function, infertility
Surgery for UC prognosis
post surgery, 5% mortality risk at 10 years
IBS epidemiology
prevalence of 20% in North America
females > males
IBS pathophysiology
likely due to visceral hypersensitivity with possible psychological or environmental trigger
IBS clinical presentation
GI symptoms: chronic abdominal pain or discomfort; chaotic defecation (period of normal bowel movement punctuated by episodes of constipation and / or diarrhea)
abdomen exam: unremarkable
80% IBS cases improve over time and have normal life expectancy
IBS diagnosis
diagnosis based on symptoms alone (Rome criteria) see Tony’s page 118
IBS subtypes
subtype of IBS based on consistency of stool and percentage of time
IBS-C = IBS with mainly constipation
IBS-D = IBS with mainly diarrhea
IBS-M = mixed IBS with some constipation or diarrhea
IBS-U = untyped IBS
IBS investigations
if benign history and physical exam, diagnosis clinically on Rome 3 criteria and no investigations required
additional investigations to be considered:
blood work: CBC, TSH, albumin, CRP, tTG
stool C & S O & P, fat excretion
sigmoidoscopy
Management of IBS
1) make positive diagnosis of IBS
comfort / reassure patient, address patient concerns and establish patient-doctor relationship to enhance placebo effect (most effective treatment)
explain, support, aim for realistic goals
2) diet and lifestyle advice balanced and healthy diet exercise dietary fiber or fiber supplement for constipation if lactose intolerance, restrict diary if food intolerance, eliminate food from diet reduce sorbitol, reduce fructose avoid caffeine and alcohol
3) if suspected psychological trigger (anxiety, depression or phobia)
behavioural therapy
drugs
consider relaxation therapy, biofeedback, hypnosis, stress reduction
4) if severe symptoms, drugs to address the symptoms
pain: anti-spasmodic before meals (Hyoscine, Pinaverium, Trimebutine), tricyclic antidepressants (TCA), selective serotonin re-uptake inhibitor (SSRI)
diarrhea: Loperamide, Diphenoxylate, cholestyramine
constipation: osmotic or other laxatives
What is a peptic ulcer
defect (erosion, ulceration) of inner mucosal lining that penetrate muscularis mucosal layers of the stomach (gastric ulcer) or duodenum (duodenal ulcer)
Etiology of peptic ulcer
gastric acid is necessary for ulcer to form, but it does not cause peptic ulcer
1) H. pylori infection
H. pylori infection cause 60% gastric ulcer and 90% duodenal ulcer
2) NSAID
NSAID cause 35% gastric ulcer and 7% duodenal ulcer
3) gastric cancer
other: physiologic stress induced in severely ill patients, Zollinger-Ellison syndrome, chemotherapy or radiation ulcer, alcohol, CMV infection, ischemia, idiopathic
Peptic ulcer clinical presentation
GI symptoms: asymptomatic (70% cases), nausea, dyspepsia (classically worse with food in gastric ulcer and better with food in duodenal ulcer)
abdominal exam: usually benign exam, may have epigastric tenderness
Complications of peptic ulcers pathophysiology, symptoms, presentation, treatment
1) Upper GI Bleed (10-15% cases)
pathophysiology: erosion of ulcer into blood vessel (classically gastroduodenal artery by duodenal ulcer), causing upper GI bleeding
symptoms: hemetemesis, melena
treatment: ABC, fluid resuscitation, IV PPI, endoscope injection of epinephrine / cauterization / hemoclip, interventional radiology angiography with embolization / coiling, surgery if
severe or recurrent bleeding
2) Perforation (2% cases)
pathophysiology: erosion through entire lining, resulting in perforation through stomach or duodenum
symptoms: acute onset severe abdominal pain
abdominal exam: peritoneal signs
imaging: free air on X-ray (70% cases) or abdominal CT
treatment: surgery
3) Obstruction (2% cases)
pathophysiology: ulcer can cause inflammation & swelling or can heal & scar, which obstruct the GI tract, classically at gastric outlet by duodenal ulcer
symptoms: nausea & vomiting, abdominal pain, obstipation, constipation
abdominal exam: distended abdomen, succussion splash on auscultation, may have peritoneal signs if ischemia or perforation
treatment: NG decompression, correct fluid & electrolyte imbalance, high dose PPI therapy, surgery
4) Fistula / Penetration (<1% cases)
pathophysiology: ulcer can penetrate to adjacent organs, forming a fistula connecting the 2 organs
ulcer in duodenum can penetrate into pancreas, causing pancreatitis
gastric ulcer can penetrate into liver or colon, causing perforation
General indications for gastric and duodenal ulcer surgery
unresponsive to medical treatment (including endoscopy)
hemorrhage
perforation
obstruction
Peptic ulcer surgery procedures
gastrectomy = removal of portion of stomach usually with reconstruction (Billroth 1, Billroth 2, Roux-en-Y)
Billroth 1 = removal of pylorus and anastomosis of proximal stomach to duodenum
Billroth 2 = (removal of antrum and pylorus of stomach with) anastomosis of greater curvature of stomach to jejunum
Roux-en-Y = proximal segment of stomach anastomosis with jejunum, distal stomach to duodenum anastomosis with jejunum
vagotomy = transection or removal of portion of vagus nerve to decrease gastric secretion
pyloroplasty = widening of pylorus to facilitate gastric emptying
gastrojejunostomy = anastomosis between dependent portion of stomach to jejunum to facilitate gastric emptying
suture ligation = oversew of an vessel to stop bleeding
Pauchet procedure = distal gastrectomy extending along lesser curvature to include ulcer
