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TRANSCRIBED BY: Berry Beria

OUTLINE

I. Etiology and Classification II. Pathophysiology III. Symptoms IV. Physical Findings V. Laboratory and X-ray Findings VI. Management

ETIOLOGY AND CLASSIFICATION

75% of cases results from previous abdominal surgery secondary to adhesive bands or internal or external hernias

5-25% of patients will develop acute intestinal; obstruction that require hospitalization within the first few post-operative weeks

Incidence of post-operative intestinal obstruction may be lower following laparoscopic surgery than open procedures

However, laparoscopic gastric bypass procedure may be associated with an unexpected high rate of intestinal obstruction for unknown causes

Other causes of intestinal obstruction: 1. Intrinsic to the wall of intestines

Diverticulitis Carcinoma Regional enteritis

2. Luminal obstruction Gallstone obstruction Intussusception

Two other conditions must be differentiated from acute intestinal obstruction: 1. Adynamic ileus

Mediated via the hormonal component of the sympathoadrenal system and may occur after any peritoneal insult

May be caused by: i. Hydrochloric acid, colonic contents

and pancreatic enzymes ii. Retroperitoneal hematoma,

particularly associated with vertebral fracture

iii. Thoracic diseases like lower-lobe pneumonia, fractured ribs, and myocardial infarction

iv. Electrolyte imbalance particularly potassium depletion

v. Intestinal ischemia due to vascular occlusion or intestinal distention

vi. May also be caused by ureteral calculus and pyelonephritis

2. Primary intestinal pseudo-obstruction Chronic motility disorder that frequently

mimics mechanical obstruction Exacerbated by narcotic use

PATHOPHYSIOLOGY

Accumulation of gas and fluid proximal to and

within the segment Intestinal gas is usually consist of swallowed

air, mainly nitrogen, which is poorly absorbed from the intestinal lumen

Removal of air by continous gastric suction is a useful adjunct in the treatment of intestinal obstruction

Accumulation of fluid is due to: 1. Swallowed saliva 2. Gastric juice, biliary and pancreatic

secretions 3. Interference with normal sodium and

water transport

Closed-loop: the most feared complication of acute intestinal obstruction results from obstruction of the lumen at two

points by a single mechanism such as fascial hernia or adhesive band

closed loops have blood supply occluded by the hernia or band and once impairment of blood supply to the GI tract occurs, bacterial invasion supervenes and peritonitis develops

during peristalsis, when a closed-loop is present, pressures can reach 30-60mm H2O (perforation)

Systemic effects of extreme distention include elevation of the diaphragm with restricted ventilation and subsequent atelectasis

SYMPTOMS

Mechanical intestinal obstruction

1. Cramping, mid-abdominal pain which tends to be more severe the higher the obstruction

LEGEND Normal text : lecture and recording (basically from the book) Italics : Harrisons Principles of Internal Medicine 17th ed.

ACUTE INTESTINAL OBSTRUCTION DR. JONATHAN SANDEJAS September 16, 2010

During the first 12-24 hours of obstruction, there is a marked depression on the flux of sodium from the lumen to the blood, and consequently water, in the distended proximal intestine. After 24 hours, sodium and water move into the lumen contributing further to the distention and fluid losses with luminal pressures reaching 8-10cm H2O.

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TRANSCRIBED BY: Berry Beria

2. Pain occurs in paroxysms and the patient is relatively comfortable in the intervals between the pains

3. Audible borborygmi 4. Pain may become less severe as distention

progresses probably because motility is impaired in the edematous intestines

5. Pain is more localized, steady and severe and less colicky when there is strangulation

6. Vomiting is invariable it is earlier and more profuse the higher

the obstruction If obstructions are high in the intestines,

the vomitus consists of bile and mucus. With low ileal obstuctions, vomitus

become feculent i.e. orange-brown in color with a foul odor resulting from the overgrowth of bacteria proximal to the obstruction

7. Hiccups (singultus) are common 8. Obstipation and failure to pass gas by

rectum are invariably present when the obstruction is complete

Fig. 1. Air appears black on roentgenogram.

Adynamic ileus and colonic pseudo-obstruction 1. Only the discomfort from distention is

evident; no colicky pain 2. Vomiting may be present but rarely profuse 3. Complete obstipation may or may not occur 4. Singultus is common

PHYSICAL FINDINGS

Abdominal distention is the hallmark of all

forms of intestinal obstruction; most marked in colonic obstruction but least marked in small intestine obstruction

Less abdominal distension in cases of obstruction in the small intestines

More abdominal distension when the obstruction is in the colon

Tenderness and rigidity are usually minimal during the initial stages of obstruction and temperature is rarely >37.5C

Appearance of shock, tenderness, rigidity and fever indicates that there is contamination of the peritoneum with intestinal contents

Auscultation may reveal loud, high-pitched borborygmi coincident with colicky pain

A quiet abdomen does not eliminate the possibility of obstruction

A palpable abdominal mass usually signifies a closed-loop strangulating small bowel obstruction

LABORATORY AND XRAY FINDINGS

Both used to differentiate strangulation from

non-sttrangulation AND partial from complete obstruction

Leukocytosis with a shift to the left occurs when there is strangulation but a normal white cell count does not exclude strangulation

Elevated serum amylase Step-ladder pattern with air-fluid levels and

an absence of colonic gas are pathognomonic for small bowel obstruction

Fig. 2. Step-ladder sign in small bowel obstruction.

Complete obstruction is suggested when passage of gas or stool per rectum has ceased and when gas is absent in the distal intestine by x-ray

General haze (due to peritoneal fluid) and coffee bean-shaped mass are seen in strangulating closed loop obstruction

Thin barium upper GI series help differentiate between partial from complete (thick barium is avoided since retained barium sulfate may become inspissated)

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TRANSCRIBED BY: Berry Beria

CT scan is the most commonly used modality to evaluate postoperative patients for intestinal obstruction because of its ability in differentiating adynamic ileus, partial obstruction, and complete obstruction.

However, the sensitivity and specificity of CT scan for strangulating obstruction are low (50 and 80%, respectively).

MANAGEMENT Small intestinal obstruction.

Strangulating obstruction have higher mortality rates than non-strangulating obstruction

Strangulating obstructions are always managed by surgery after suitable preparation (fluid and electrolyte balance restored, decompression by NGT and replacement of potassium)

Operation may be done through laparascopic surgery with decreased incidence of wound complications

However, laparoscopic lysis of adhesions is associated with a longer operative time and higher conversion to open operation when compared to other laparoscopic procedures

Non-operative therapy is only safe in the presence of incomplete obstruction

Overall recurrence is 16% Colonic Obstruction

Mortality rate is 20% Surgery indicated for complete obstruction Incomplete obstruction

1. Colonoscopic decompression 2. Placement of a metallic stent if a malignant

lesion is present; however, this is a temporary solution (ultimate solution is surgery)

Fig. 3. Metallic stent used for decompression

indicated by the arrows.

Operative management of colonic obstruction are based on the cause of the obstruction and the patients over-all well-being

Success rate is almost 90% with left-sided lesion being more successfully stented than right-sided lesions

When obstruction is complete, early operation is mandatory especially when the iliocecal valve is incompetent (possibility of cecal perforation)

Obstruction on the left side of the colon: 1. Decompression by cecostomy 2. Transverse colostomy 3. Resection with end-colostomy formation

(Hartmanns procedure)

Lesions on the right or transverse colon: 1. Primary resection and anastomosis

Fig. 4. An example of metallic stent used for decompression. Adynamic Ileus

Usually responds to nonoperative decompression and treatment of the primary disease

Good prognosis Correction of electrolyte imbalance should be

performed Repetitive colonoscopy has been done to

decompress colonic ileus Neostigmine can be used is cases of colonic ileus

that have not responded to other conservative treatment

The lecture was basically lifted from Harrisons. Thanks Abi, Ralph, Faye, Paul, Joy, Alex, Ram. You know what was happening when I was making this trans and I couldnt have been more touched and uplifted by what you guys did. Thanks.

Barium should never be given by mouth to a patient with a possible colonic obstruction until possibility has been excluded.