Atresia, Volvulus,
Meckel's diverticulum
--- Content provided by FirstRanker.com ---
Anatomy
? Smal intestine: 6 meters
? Large intestine: 1.5 meters.
--- Content provided by FirstRanker.com ---
? The first 25 cm of the smal intestine (duodenum) is retroperitoneal? Jejunum marks the entry of the smal intestine into the peritoneal
cavity, terminates where the ileum enters the colon at the ileocecal
--- Content provided by FirstRanker.com ---
valve? Large intestine is subdivided into cecum, ascending, transverse, &
descending colon.
--- Content provided by FirstRanker.com ---
? Sigmoid colon begins at the pelvic brim and loops within the peritoneal
cavity
--- Content provided by FirstRanker.com ---
? Rectum begins at about the level of the third sacral vertebra.? Reflection of the peritoneum from the rectum over the pelvic floor
creates a cul de sac known as the pouch of douglas
--- Content provided by FirstRanker.com ---
Vasculature
--- Content provided by FirstRanker.com ---
? Superior mesenteric artery: proximal jejunum to hepatic flexure of colon? Inferior mesenteric artery: remainder of colon to the level of rectum
? Superior hemorrhoidal branch of the inferior mesenteric artery: upper
--- Content provided by FirstRanker.com ---
rectum
? Hemorrhoidal branches of the internal iliac or internal pudendal artery:
--- Content provided by FirstRanker.com ---
lower rectum--- Content provided by FirstRanker.com ---
? venous drainage follows essential y the same distribution? connected by an anastomotic capil ary bed between the superior and
inferior hemorrhoidal veins, providing a connection between the
--- Content provided by FirstRanker.com ---
portal and systemic venous systems.
? Since the colon is a retroperitoneal organ in the ascending and
--- Content provided by FirstRanker.com ---
descending portions, it derives considerable accessory arterial bloodsupply and lymphatic drainage from a wide area of the posterior
abdominal wal .
--- Content provided by FirstRanker.com ---
Smal Intestinal Mucosa
--- Content provided by FirstRanker.com ---
? The most distinctive feature of the smal intestine is its mucosal lining,
which is studded with innumerable vil i
--- Content provided by FirstRanker.com ---
? Vil i: site for terminal digestion and absorption of foodstuffs? Between the bases of the vil i are the pit like crypts of Lieberk?hn
? Crypts of Lieberk?hn: contain stem cel s that replenish and
regenerate the epithelium
--- Content provided by FirstRanker.com ---
? In normal individuals, the vil us-to-crypt height ratio is about 4 to 5:1.
? Within the duodenum are abundant submucosal mucous glands,
termed Brunner glands.
--- Content provided by FirstRanker.com ---
? Brunner glands: secrete bicarbonate ions, glycoproteins, and
pepsinogen I and are virtual y indistinguishable from the pyloric
--- Content provided by FirstRanker.com ---
mucous glands.--- Content provided by FirstRanker.com ---
Colonic Mucosa? The function of the colon is to reclaim luminal water and electrolytes.
? Colonic mucosa has no vil i and is flat.
? Mucosa is punctuated by numerous straight tubular crypts
--- Content provided by FirstRanker.com ---
? Crypts contain abundant goblet cel s, endocrine cel s, and stem cel s.? Paneth cel s are occasional y present at base of crypts in the cecum&
ascending colon
--- Content provided by FirstRanker.com ---
? The regenerative capacity of the intestinal epithelium is remarkable.? Cel ular proliferation is confined to the crypts
? Turnover of the colonic surface epithelium takes 3 to 8 days
Atresia
--- Content provided by FirstRanker.com ---
Incidence of Atresia
--- Content provided by FirstRanker.com ---
? Duodenum : 35%
? Jejunum : 15%
--- Content provided by FirstRanker.com ---
? Ileum : 25%? Colon : 10%
? Multiple sites : 15%
--- Content provided by FirstRanker.com ---
Duodenal Atresia
? Failure of vacuolization of duodenum from it's solid cord stage
--- Content provided by FirstRanker.com ---
at 8-10th week gestation? Types :
? Duodenal stenosis
--- Content provided by FirstRanker.com ---
? Mucosal web? Gap separated by fibrous cord
? Complete gap
--- Content provided by FirstRanker.com ---
Associated anomalies
? Down Syndrome (30%)
--- Content provided by FirstRanker.com ---
? Malrotation
? Annular pancreas
--- Content provided by FirstRanker.com ---
? Biliary atresia? Congenital heart disease
? Anorectal malformations
--- Content provided by FirstRanker.com ---
Clinical features
? Presents in first 24hrs of life.
--- Content provided by FirstRanker.com ---
? 85% distal to ampulla of vater? Characterized by bilious emesis
? Abdominal distension is absent
--- Content provided by FirstRanker.com ---
? Visible gastric peristalsis
--- Content provided by FirstRanker.com ---
Imaging
? Check for patent anus/anorectal anomalies
--- Content provided by FirstRanker.com ---
? Abdominal x-ray: Double Bubble sign:? Air in the stomach, and 1st and 2nd portions of duodenum.
? If there is no distal air, the diagnosis is secure.
? If there is distal air, and urgent UGI contrast study is
--- Content provided by FirstRanker.com ---
needed to rule out midgut volvulus.
"Double Bubble" Sign
--- Content provided by FirstRanker.com ---
Management
--- Content provided by FirstRanker.com ---
? Nasogastric decompression? Duodenoduodenostomy
? Duodenojejunostomy
--- Content provided by FirstRanker.com ---
Types of jejunoileal atresia
--- Content provided by FirstRanker.com ---
Jejuno-ileal atresia
? Type I:
--- Content provided by FirstRanker.com ---
? Mesenteric development andintestinal length are normal
? Mucosa and submucosa forms a web or membrane
within the intestinal lumen
? Windsock Effect
--- Content provided by FirstRanker.com ---
Increased pressure proximal to the obstruction causes
the web to prolapse, pushing the web through the bowel
distally
--- Content provided by FirstRanker.com ---
Jejuno-ileal atresia
? Type II:
--- Content provided by FirstRanker.com ---
? Mesenteric development andoverall intestinal length is normal
? Small bowel lumen is not continuous
? Proximal small bowel ends in bulbous blind pouch
? Distal small bowel is flattened
--- Content provided by FirstRanker.com ---
? Proximal and distal small bowel connected by fibrous cord.--- Content provided by FirstRanker.com ---
Jejuno-ileal atresia? Type II a:
? Similar to Type II
--- Content provided by FirstRanker.com ---
? Small V-shaped mesenteric defectis present, bowel length is shortened
? Proximal blind end is markedly dilated & aperistaltic
? No fibrous cord connects the proximal & distal small bowel
--- Content provided by FirstRanker.com ---
Jejuno-ileal atresia? Type II b:
? Similar to Type II a
--- Content provided by FirstRanker.com ---
? Significant mesenteric defect is presentSuperior mesenteric artery is largely absent
Small bowel supplied by a single ileocolic or right colic
--- Content provided by FirstRanker.com ---
artery? Known as Christmas tree or apple peel deformity
Bowel wraps around a single perfusing artery
--- Content provided by FirstRanker.com ---
Jejuno-ileal atresia
--- Content provided by FirstRanker.com ---
? Type IV:
? Multiple JIAs of any
combination Types I ? II
--- Content provided by FirstRanker.com ---
Appears as a string of sausages due to multiple lesions
? Likely result of multiple ischemic insults or
inflammatory process
--- Content provided by FirstRanker.com ---
Pathophysiology
JIA is usually a vascular insult versus failure to recanalization of
--- Content provided by FirstRanker.com ---
Duodenal AtresiaIntrauterine vascular accident Necrosis of bowel segment in a
sterile environment Resorption and disappearnce of tissue
--- Content provided by FirstRanker.com ---
Malrotation, Volvulus (abnormal twisting of SMA),
Gastroschisis, Omphalocele
--- Content provided by FirstRanker.com ---
All result in blood supply / gut segment separation--- Content provided by FirstRanker.com ---
symptoms, physical exam findings.? Within the first day of life
? Depends on level of obstruction
--- Content provided by FirstRanker.com ---
Proximal
Distal
? Vomiting green bile
--- Content provided by FirstRanker.com ---
? Bowel sounds absent in distal small intestine? No meconium
? Abdominal distention
Proximal gut dilatation
--- Content provided by FirstRanker.com ---
Imaging
--- Content provided by FirstRanker.com ---
? Prenatal y
? Ultrasonography wil likely show excess amniotic fluid
--- Content provided by FirstRanker.com ---
(polyhydramnios)? First day of life
? Abdominal X-ray: Air Fluid level, Dilated proximal gut
--- Content provided by FirstRanker.com ---
? Water soluble contrast enema: exclude multiplestrictures, Flattened distal gut, Micro colon
--- Content provided by FirstRanker.com ---
Triple Bubble Presentation
Initial treatment
--- Content provided by FirstRanker.com ---
? Immediately a tube is placed orally into the stomach to evacuate
excess fluid and gasses
--- Content provided by FirstRanker.com ---
? Prevents vomiting and aspiration? Relieves GI discomfort
? IV Fluids and Nutrients are provided until surgery is available
--- Content provided by FirstRanker.com ---
? Surgical intervention is necessary to repair the bowel obstructionand blood supply
--- Content provided by FirstRanker.com ---
Surgical management
? Aim: Preserve as much bowel length as possible
--- Content provided by FirstRanker.com ---
? Dilated proximal part
? Resection and anastomosis
? Tapering enteroplasty if remaining bowel is short
--- Content provided by FirstRanker.com ---
? Multiple strictures:
? Multiple anastomosis over an endoluminal tube
--- Content provided by FirstRanker.com ---
Prognosis? Types I, II, and II a have good prognosis
? Fairly normal small bowel length results in almost normal
--- Content provided by FirstRanker.com ---
bowel function
? Types II b, IV is associated with complications
--- Content provided by FirstRanker.com ---
? Shortened small bowel is associated with short gutsyndrome and malabsorption
--- Content provided by FirstRanker.com ---
Volvulus
? Volvulus occurs when an air-filled segment of the colon twists about its
--- Content provided by FirstRanker.com ---
mesentery.
? Sigmoid colon is involved in up to 90% of cases, but volvulus can involve the
--- Content provided by FirstRanker.com ---
cecum (<20%) or transverse colon.? Volvulus may reduce spontaneously, but more commonly produces bowel
obstruction
--- Content provided by FirstRanker.com ---
? Chronic constipation may produce a large, redundant colon (chronic megacolon)
that predisposes to volvulus
--- Content provided by FirstRanker.com ---
? Symptoms: abdominal distention, nausea, and vomiting.? Symptoms rapidly progress to generalized abdominal pain and tenderness.
? Fever and leucocytosis are heralds of gangrene and/or perforation.
--- Content provided by FirstRanker.com ---
Sigmoid volvulus
--- Content provided by FirstRanker.com ---
? Can often be differentiated from cecal or transverse colon volvulus
by the appearance of plain x-rays of the abdomen.
--- Content provided by FirstRanker.com ---
? Sigmoid volvulus produces a characteristic bent inner tube orcoffee bean appearance
? Gastrografin enema shows a narrowing at the site of the volvulus
--- Content provided by FirstRanker.com ---
and a pathognomonic bird's beak
Plain X ray showing coffee bean appearance
--- Content provided by FirstRanker.com ---
Gastrografin enema showing "bird-beak" sign (arrow)
--- Content provided by FirstRanker.com ---
Management? Initial management: resuscitation followed by endoscopic detorsion
? Detorsion: by rigid proctoscope, but a flexible sigmoidoscope or
--- Content provided by FirstRanker.com ---
colonoscope might also be effective.
? Elective sigmoid colectomy should be performed after the patient has
--- Content provided by FirstRanker.com ---
been stabilized? Surgical exploration: evidence of gangrene or perforation, presence of
necrotic mucosa, ulceration, or dark blood noted on endoscopy
--- Content provided by FirstRanker.com ---
examination? If dead bowel is present at laparotomy, a sigmoid colectomy with end colostomy
(Hartmann procedure) may be the safest operation to perform.
--- Content provided by FirstRanker.com ---
Cecal Volvulus
--- Content provided by FirstRanker.com ---
? Nonfixation of the right colon.
? Rotation occurs around the ileocolic blood vessels and vascular impairment
--- Content provided by FirstRanker.com ---
occurs early.? Plain x-rays of the abdomen show a characteristic kidney-shaped, air-filled
structure in the left upper quadrant (opposite the site of obstruction), and a
--- Content provided by FirstRanker.com ---
gastrografin enema confirms obstruction at the level of the volvulus.? Cecal volvulus can almost never be detorsed endoscopically.
? Surgical exploration is necessary when the diagnosis is made.
--- Content provided by FirstRanker.com ---
? Right hemicolectomy with a primary ileocolic anastomosis can usually be
performed safely and prevents recurrence
--- Content provided by FirstRanker.com ---
Cecal Volvulus--- Content provided by FirstRanker.com ---
Meckel's Diverticulum? Failure of involution of the vitelline duct, which connects the lumen
of the developing gut to the yolk sac, produces a Meckel
--- Content provided by FirstRanker.com ---
diverticulum.
? True diverticulum: contains al three layers of the normal bowel
--- Content provided by FirstRanker.com ---
wall: mucosa, submucosa, and muscularis propria.? It may be a small pouch or a blind segment having a lumen greater
in diameter than that of the ileum and a length of up to 6 cm.
--- Content provided by FirstRanker.com ---
Rule of 2's
--- Content provided by FirstRanker.com ---
? 2% of the population have one
? 1/2 of symptomatic lesions usually present before the age of 2
years old, others most commonly in the first 2 decades of life
--- Content provided by FirstRanker.com ---
? Diveriticuli in adult patients only become symptomatic in about 2%
? 2 times more common in males than females
? Usually found within 2 feet of the ileocecal valve
? Usually are about 2 inches in length
--- Content provided by FirstRanker.com ---
? 1/2 contain heterotrophic mucosa (usually gastric, occasionallypancreatic)
Clinical Features:
--- Content provided by FirstRanker.com ---
? Lower GI bleeding
? Intestinal obstruction
? Local inflammation with or without perforation
? Rare presentations: Neoplasms
--- Content provided by FirstRanker.com ---
Diagnosis:
? Most accurate test, especially in children, is "Meckel's scan"- sodium
99-tc-pertechinetate, taken up by gastric mucosa
--- Content provided by FirstRanker.com ---
? Abdominal CT scan? If CT is negative barium studies should be done
? If bleeding with a negative scan, angiography may be helpful
--- Content provided by FirstRanker.com ---
Treatment? If symptomatic: prompt surgical intervention to resect the
diverticulum or segment of ileum containing the diverticulum.
--- Content provided by FirstRanker.com ---
? If not symptomatic: and found incidentally at surgery in children
under 2 y/o, resection is recommended.
--- Content provided by FirstRanker.com ---
? In asymptomatic adults, resection is controversial since onlyabout 2% of these patient's will become symptomatic and there
is about a 2% incidence of short or long term complications
--- Content provided by FirstRanker.com ---