Small Bowel

Obstruction Done by : Mohammad Almomani

1.Definition

2.Types

3.Presentation

4.Deferential Diagnosis

5.Management

Outline

Definition

• Blockage of the flow of GI contents through the small intestine

either by

• 1-mechanical(dynamic ) which may be partial or

complete, occurring at one or more locations ,Proximal or

distal .

• 2- functional (adynamic) cause in which there is no

mechanical obstruction; peristalsis is absent or inadequate

Classification

• Motility :functional VS mechanical

• Extent of obstruction : partial VS complete

• Pathological nature : simple VS complicated (strangulated)

• Level of obstruction : proximal VS distal

• Functional ( ileus ): ✴Post operative

✴Medications ( Narcotics )

✴Peritonitis

• Mechanical ✴Intraluminal (Fecal impaction,Foreign body ,Bezoars, Gallstone)

✴Intramural ( diverticulosis, strictures , Crohns disease,

malignancy )

✴External compression ( Adhesions, Hernia)

Causes of SBO: SHAVING

• Stricture

• Hernia

• Adhesions

• Volvulus

• Intussusception/IBD

• Neoplasm

• Gallstones

Top 3 Causes of SBO

(in order)

ABC

Adhesions

Bulge (hernias)

Cancer (neoplasms)

Top 3 Causes of LBO (in

order)

• Cancer

• Diverticulitis

• Volvulus

• Partial VS complete

• Simple VS complicated

( strangulation and ischemia , perforation ).

✴Pathophysiology :

blockage of passage increased intraluminal fluid and gas

increased intraluminal pressure decreased venous return venous congestion and decrease blood supply ischemia and death of involved intestine(STRANGULATION)

• Proximal VS distal .

In dynamic (mechanical) obstruction the bowel proximal to the

obstruction dilates and the bowel below the obstruction exhibits

normal peristalsis and absorption until it becomes empty and

collapses.

The distension proximal to an obstruction is caused by two factors:

● Gas overgrowth of bacteria

● Fluid digestive juices

PATHOPHYSIOLOGY

Clinical presentation

• The clinical features vary

according to:

• ● the location of the obstruction.

• ●complete or partial .

• ● the duration of the obstruction

.

• ● the underlying pathology.

• ● the presence or absence of

intestinal ischaemia.

Cardinal clinical features of acute obstruction :

● Abdominal pain

● Distension

● Vomiting

● constipation /obstipation

A complete small bowel obstruction has all the cardinal features

Other manifestations • Dehydration: is seen most commonly in small bowel obstruction .

Dehydration and electrolyte loss are therefore due to: ● reduced oral intake. ● defective intestinal absorption. ● losses as a result of vomiting. ● sequestration in the bowel lumen ● transudation of fluid into the peritoneal cavity.

• Bowel sounds: High-pitched bowel sounds are present in the vast majority of patients. Bowel sounds may be scanty or absent if the obstruction is longstanding and the small bowel has become inactive

Clinical features of strangulation :

● Constant, severe pain

● Tenderness with rigidity

● peritonism

● Shock

●Tachycardia

• Pyrexia : ischaemia; intestinal perforation

;inflammation or abscess

• Abdominal tenderness: Localised tenderness indicates impending or established

ischaemia.

The development of peritonism or peritonitis indicates overt

infarction and/or perforation.

P/E ✴V/S ( signs of dehydration or sepsis ) .

✴Abdominal examination ( scars , HERNIA , distention

peritonitis, , hyperactive bowel sounds or silent abdomen)

Laboratory Workup CBC.

KFT and electrolytes.

Lactate.

Blood gas analysis.

Imaging

• Plain films ( Abdominal X-rays supine and erect )

• Which one is more important ?

Dilated small bowel loops ( > 3 cm ) 3/6/9 rule

Paucity of air in the colon and rectum.

Gas in the small intestine.

Multiple air fluid levels on upright films

CT scan

• More sensitive and specific. ( 70-90%)

• Helps identify transition point.

• Can detect areas of compromised blood supply or

strangulation ( thickened wall, pneumatosis intestinalis or

perforation).

• Helps identify closed loop obstruction.

Enterolysis ( Small bowel

contrast study )

Treatment

• NPO.

• Fluid and electrolyte replacement (IVF maintenance and deficit ).

• Gastrointestinal drainage via a NGT .

• Serial abdominal examination

• Serial laboratory work up

• Relief of obstruction

• Surgical treatment is necessary for most cases of intestinal

obstruction but should be delayed until resuscitation is

complete, provided there is no sign of strangulation

If there is complete obstruction,without intestinal ischaemia delay the surgery until the patient resuscitated.

•Where obstruction is likely to be secondary to adhesions, continue conservative management for up to 72 hours in the hope of spontaneous resolution

Following relief of obstruction, the viability of the involved bowel should be carefully assessed :

-If viable :reduce the abdomen .

-If in doubt :the bowel should be wrapped in hot packs for 10 minutes with increased oxygenation and then reassessed.

-If non viable: resection .

Surgery Indications : • Non adhesive mechanical small bowel obstruction.

• Bowel ischemia or perforation.

• Closed loop obstruction ( emergency )

• Failure of adhesive SBO to resolve ( 48-72 hrs ?).

Indications for early surgical intervention: ● Obstructed external hernia

● Clinical features suspicious of intestinal strangulation