LECTURE 6

Bowel motility disorders: Ileus, bowel obstruction,

strangulation

National O. Bogomolets Medical University

Faculty Surgery Department N1Kyiv 2008

Prof. Kucher M.

Bowel motility disorders:

• Ileus is a disruption of the normal propulsive gastrointestinal motor activity from non-mechanical mechanisms

• Motility disorders that result from structural abnormalities are termed mechanical bowel obstruction.

patients with a bowel obstruction still represent some of the most difficult and vexing problems that surgeons face with regard to the correct diagnosis, the optimal timing of therapy, and the appropriate treatment.

D. Chukhrienko classification Dnipropetrovsk, Ukraine,1958

• Morphology & Function1. Functional: spastic and paralytic (ileus) 2. Мechanical :

1. bowel obstruction. 1. Obstruction arising from extraluminal causes

such as adhesions, hernias, carcinomas, and abscesses 2. Obstruction intrinsic to the bowel wall

(e.g., primary tumors) 3. Intraluminal obturator obstruction

(e.g., gallstones, enteroliths, foreign bodies, and bezoars)

2. Strangulation obstruction (volvulus, nodulation, strangulated hernia) “closed loop obstruction”

3. Mixed (intussusceptions)

• Sigmoid is commonest site of colonic volvulus

• Accounts for 5% of large bowel obstruction in UK

• Usually seen in elderly or those with psychiatric disorders

• Commonest cause of obstruction in Africa / Asia

• >Incidence is 10 times higher than in Europe or USA

М. М. КучерКучер

if the neck of the if the neck of the hernia sack actually hernia sack actually

pinches off the supply pinches off the supply of blood to those of blood to those

organs which have organs which have become trapped inside, become trapped inside, the hernia is said to be the hernia is said to be

strangulatedstrangulated

Severe pain Fever Vomiting Gangrene

D. Chukhrienko classification Dnipropetrovsk, Ukraine,1958 (cont.)

• Clinical course– Acute – Chronic

• Level of the obstruction– Small bowel (high & low)– Colon & rectum

• Bowel passage– Total obstruction– Partial obstruction

• Cause– Congenital– Acquired

Causes of Mechanical Small Intestinal Obstruction in Adults

Lesions Extrinsic to the Intestinal Wall

• Adhesions (usually postoperative)• Hernia

– External (e.g., inguinal, femoral, umbilical, or ventral hernias)

• Internal (e.g., congenital defects such as paraduodenal, foramen of Winslow, and diaphragmatic hernias or

postoperative secondary to mesenteric defects)

• Neoplastic • Carcinomatosis• Extraintestinal neoplasms

• Intra-abdominal abscess

Causes of Mechanical Small Intestinal Obstruction in AdultsLesions Intrinsic to the Intestinal Wall• Congenital Malrotation• Duplications/cysts• Inflammatory• Crohn's disease• Infections• Tuberculosis• Actinomycosis• Diverticulitis• Neoplastic• Primary neoplasms• Metastatic neoplasms

• Traumatic• Hematoma• Ischemic stricture

• Miscellaneous• Intussusception• Endometriosis• Radiation enteropathy/stricture

•

Causes of Mechanical Small Intestinal Obstruction in Adults

• Intraluminal/Obturator Obstruction

• Gallstone

• Enterolith

• Bezoar

• Foreign body

Intraoperative findings of phytobezoar in the jejunum (arrow).

Causes of Mechanical Small Intestinal Obstruction in Adults

Causes of Mechanical Large Bowel Obstruction in Adults

Intramural causes • Carcinoma• inflammation

– Diverticulitis – Crohn's disease – lymphogranuloma venereum – Tuberculosis– schistosomiasis)

• Hirschsprung's disease (aganglionosis)• ischemia• Radiation• Intussusception• anastomotic stricture

Causes of Mechanical Large Bowel Obstruction in Adults

Intraluminal causes of colorectal obstruction

• fecal impaction

• inspissated barium

• foreign bodies.

Causes of Mechanical Large Bowel Obstruction in Adults

• Extraluminal causes

• adhesions (the most common cause of small bowel obstruction, but rarely a cause of colonic obstruction)

• Hernias

• tumors in adjacent organs

• Abscesses

• volvulus

• A closed-loop obstruction occurs when both the proximal and distal parts of the bowel are occluded.

• strangulated hernia or volvulus almost always leads to this condition.

• The more common form of closed-loop obstruction, however, is seen when a cancer occludes the lumen of the colon in the presence of a competent ileocecal valve. In this situation, increasing colonic distention causes the pressure in the cecum to become so high that the vessels in the bowel wall are occluded, and necrosis and perforation can occur

Early in the course of an obstruction, intestinal motility and contractile activity increase in an effort to propel luminal contents past the obstructing point.

The increase in peristalsis that occurs early in the course of bowel obstruction is present both above and below the point of obstruction, thus accounting for the finding of diarrhea that may accompany partial or even complete small bowel obstruction in the early period.

Later in the course of obstruction, the intestine becomes fatigued and dilates, with contractions becoming less frequent and less intense.

As the bowel dilates, water and electrolytes accumulate both intraluminally and in the bowel wall itself.

This massive third-space fluid loss accounts for the dehydration and hypovolemia. The metabolic effects of fluid loss depend on the site and duration of the obstruction. With a proximal obstruction, dehydration may be accompanied by hypochloremia, hypokalemia, and metabolic alkalosis associated with increased vomiting.

Distal obstruction of the small bowel may result in large quantities of intestinal fluid into the bowel;

however, abnormalities in serum electrolytes are usually less dramatic. Oliguria, azotemia, and hemoconcentration can accompany the dehydration. Hypotension and shock can ensue.

Other consequences of bowel obstruction include increased intra-abdominal pressure, decreased venous return, and elevation of the diaphragm, compromising ventilation.

• As the intraluminal pressure increases in the bowel, a decrease in mucosal blood flow can occur. These alterations are particularly noted in patients with a closed-loop obstruction in which greater intraluminal pressures are attained.

• Increasing of intestinal wall permeability

• putrefaction, bacterial decay and fermentation

In the absence of intestinal obstruction, the jejunum and proximal ileum of the human are virtually sterile.

With obstruction, however, the flora of the small intestine changes dramatically, in both the type of organism (most commonly Escherichia coli, Streptococcus faecalis, and Klebsiella species) and the quantity, with organisms reaching concentrations of 109 to 1010/mL.

Studies have shown an increase in the number of indigenous bacteria translocating to mesenteric lymph nodes and even systemic organs.

Clinical Manifestations

• The cardinal symptoms of intestinal obstruction include

• colicky abdominal pain

• nausea, vomiting

• abdominal distention

• failure to pass flatus and feces (i.e., obstipation).

Clinical course periods

• Initiating (ileus screem) - ~ 12 h

• Toxemia ~ 12- 36 h

• Peritonitis ~ >36 h

Clinical Manifestations• Physical Examination

– distended abdomen, with the amount of distention somewhat dependent on the level of obstruction.

– Previous surgical scars should be noted. – Early in the course of bowel obstruction, peristaltic waves

can be observed, particularly in thin patients, and auscultation of the abdomen may demonstrate hyperactive bowel sounds with audible rushes associated with vigorous peristalsis (i.e., borborygmi).

– Late in the obstructive course, minimal or no bowel sounds are noted. Mild abdominal tenderness may be present with or without a palpable mass; however, localized tenderness, rebound, and guarding suggest peritonitis and the likelihood of strangulation

Radiologic Examinations

Barium study showing the filling defect in the jejunum with claw-like appearance suspicious of intussusception. The bowel loop distal to the filling defect is collapsed (arrow).

CT scan of the abdomen showing the intraluminal hypodense filling defect with mottled appearance (arrow).

CT of Small Bowel Obstruction. Axial CT scan through the lower abdomen shows

multiple fluid-filled and dilated loops of small bowel (white arrows) and collapsed

right colon (red arrow) consistent with a mechanical small bowel obstruction

The CT-presentation of a closed loop obstruction in the small bowel

• 'U' or 'C' shaped loops of bowel. Point of obstruction has a beak-like appearance

• In some of these patients with SBO the proximal small bowel proximal to the point of obstruction may not be dilated.

• On the left we see images of a patient in whom obstruction was not suspected.

• This patient also received positive oral contrast. • Look for the major findings and then continue.

• First you will notice that the small bowel is not dilated.• When you go down to the pelvis you see a dilated loop of

bowel with inhomogeneous content and finally deep down in the pelvis there is a C-shaped dilated bowel indicating a closed loop obstruction.

• The other important finding in this patient is the 'Small Bowel Feces Sign' (SBFS: arrow).

• The SBFS is a very useful sign as it is seen at the zone of transition from normal to obstructed bowel and thus facilitating identification of the point and the cause of the bowel obstruction.

• The SBFS has been defined as gas and solid material within a dilated small-bowel loop that simulates the appearance of feces.

• Another important appearance of a closed loop obstruction is that of a radial array of dilated small bowel loops with the mesenteric vessels converging to a central point.

• This is almost always due to a small bowel volvulus.

• The findings of ischemia in closed loop obstruction are the same as in patients with other causes of mesenteric ischemia:

• bowel wall thickening• mesenteric edema• ascites• enhancement of the bowel in

ischemia can be normal, increased or there can be lack of enhancement.

Strangulating Obstructionclassic signs of strangulation have been

described and include

• Tachycardia• Fever• Leukocytosis• constant, noncramping abdominal pain• peritonism

• Bowel Obstruction: Longitudinal scan of the lower abdomen reveals multiple distended loops of bowel. Fecal material and air pockets are seen throughout the dilated bowel loops. Mural thickening and edema of hausstra are seen to invaginate the distended bowel.

Intussusception

Intussusception is a condition in which one segment of the bowel enfolds within another segment, causing obstruction

• It is the commonest abdominal emergency between 3 months and 2 years• Peak incidence is between 6 and 9 months• Most cases are idiopathic with the lead point due to enlarged Peyer's patches • Usually due to a viral infection• 5% are due to polyp, Meckel's diverticulum, duplication cyst or tumour• Commonest site involved is the ileocaecal junction

• Occurs when one part of bowel invaginates (intussusceptum) into an adjacent section (intussuscipiens)

• Results in intestinal obstruction and venous compression• If uncorrected it can result in arterial insufficiency and

necrosis

Intussusception

the radiographic signs of intussusception are: 1) target

sign, 2) crescent sign, 3) absent liver edge sign (also

called absence of the subhepatic angle), and 4) a

bowel obstruction

Intussusception

the radiographic signs of intussusception are: 1) target

sign, 2) crescent sign, 3) absent liver edge sign (also

called absence of the subhepatic angle), and 4) a

bowel obstruction

• This 6 month old boy presented with a short history of colicky abdominal pain and vomiting. The initial clinical impression was that he had gastroenteritis. Soon after admission he passed altered blood per rectum. He had a palpable abdominal mass on the right side of his abdomen suggesting that he hand an Intussusception. As he was well with no features of sepsis or peritonitis he underwent a water soluble contrast enema to both confirm the diagnosis and attempt reduction. This was unsuccessful and the Intussusception required surgical reduction.

This shows a typical apple-core

stricture of a colonic carcinoma.

This image is from a barium enema series showing a typical 'apple core' stricture. The appearances are typical of a colonic carcinoma

• This 40 year old man presented with short history of bloody diarrhoea. He was initially systemically well. Stool cultures were negative. A flexible sigmoidoscopy showed an acute colitis with biopsies confirming acute inflammation consist with ulcerative colitis. Despite being given parenteral steroids and mesalazine his symptoms failed to improve. Over 3 days he developed increasing abdominal distension. He became systemically unwell with features of peritonism. This plain abdominal x-ray was taken. It shows a dilated colon with evidence of mucosal oedema. The appearances are those of toxic dilatation. The patient proceeded to a subtotal colectomy and made an uncomplicated recovery

Treatment

• Fluid Resuscitation and Antibiotics

• Tube Decompression

• Resolution of symptoms and discharge without the need for surgery have been reported in 60% to 85% of patients with a partial obstruction

Operative Management

In general, the patient with a complete small bowel obstruction requires operative intervention.

A nonoperative approach to selected patients with complete small intestinal obstruction has been proposed by some, who argue that prolonged intubation is safe in these patients provided that no fever, tachycardia, tenderness, or leukocytosis is noted.

Nevertheless, one must realize that nonoperative management of these patients is undertaken at a calculated risk of overlooking an underlying strangulation obstruction and delaying the treatment of intestinal strangulation until after the injury becomes irreversible

laparoscopic management include those with the following symptoms:

1. Mild abdominal distention allowing adequate visualization

2. Proximal obstruction

3. Partial obstruction

4. Anticipated single-band obstruction

Ileus

• An ileus is defined as intestinal distention and the slowing or absence of passage of luminal contents without a demonstrable mechanical obstruction.

• An ileus can result from a number of causes, including drug induced, metabolic, neurogenic, and infectious

Causes of Ileus

• After laparotomy• Metabolic and electrolyte

derangements (e.g., hypokalemia, hyponatremia, hypomagnesemia, uremia, diabetic coma)

• Drugs (e.g., opiates, psychotropic agents, anticholinergic agents)

• Intra-abdominal inflammation• Retroperitoneal hemorrhage or

inflammation• Intestinal ischemia• Systemic sepsis

The treatment of an ileus is entirely supportive with nasogastric decompression and IV fluids.

• The most effective treatment to correct the underlying condition may be aggressive treatment of the sepsis, correction of any metabolic or electrolyte abnormalities, and discontinuation of medications that may produce an ileus

• Pharmacologic agents – Drugs that block sympathetic input (e.g., guanethidine) – stimulate parasympathetic activity (e.g., bethanechol – neostigmine) have been tried. – hormonal manipulation, using cholecystokinin or motilin,

has been evaluated, but the results have been inconsistent– IV erythromycin has been ineffective– cisapride, apparently beneficial in stimulating gastric

motility, does not appear to alter intestinal ileus.