Intestinal Obstruction

By Dr. AsfandPGR S.U IV

Is a partial or complete blockage of forward progression of intestinal contents (chyle) due to mechanical or functional causes

can occur at any level distal to the duodenum

Is a medical emergency (20% of acute surgical admissions & 5-10 % of acute abdomen patients)

Complications include bowel ischemia & Perforation

Introduction

Mechanical/Functional congenital/acquired; partial(incomplete or subacute)/complete; acute/acute on chronic/or chronic; simple/closed loop/strangulated; proximal/distal

Classification

EtiologyDynamic (Mechanical) Adynamic (Functional)

Intraluminal:Gallstones, Foreign Body, Round worms, impacted faeces, Bezoars, Meconium ileus

Intramural:TB stricture, IBD, Malignancy

Extraluminal:Bands/Adhesions, Hernia, Intussusception, Volvulus

Paralytic Ileus◦ Post Surgery/trauma◦ Electrolyte imbalance◦ Diabetes mellitus (DKA)◦ Uremia

Drugs – Narcotics, Anticholinergics

Mesenteric ischaemia Pseudo-obstruction

80% in small bowel – usually ileum20% in colon – usually sigmoid colon (70% CA, 30% due to diverticulosis, volvulus & inflammatory causes)

Incidence

Direct External compression◦ Adhesions◦ Hernia

Interruption of mesenteric blood flow

◦ Intussussception◦ Volvulus

Primary occlusion of mesentric blood vessles :

acute mesentric ischemia

Closed Loop Obstruction◦ Hernia◦ Adhesions

Strangulated intestinal obstruction(interference of mesenteric blood supply)

Continuous severe pain

Shock indicates underlying ischemia

Symptoms commence suddenly and recur regularly

Local tenderness associated with rigidity and rebound tenderness ( Blumbergs sign )

Features of Strangulation

Acute colonic pseudo-obstruction

It is massive colonic dilatation affecting caecum and Rt. colon with presentation of colonic obstruction without any mechanical blockage

It likely results from imbalance of autonomic regulation of colonic motility with excessive parasympathetic suppression causing atony to distal colon causing functional obstruction

The vast majority of patients are Elderly hospitalized patients with major TRAUMA; ILLENESS; MAJOR NON-INTESTINAL SURGERY

(Stress)

Afferent & Efferent limbs of bowel are obstructed

The rich bacterial flora w/in the loop adds to the production of gases causing rapid distension

Closed Loop Obstruction

Rapid distension inc luminal pressure Impaired circulation bowel necrosis & perforation fulminant peritonitis

Typically seen in colon with competent ileocaecal valve

Hernia, Adhesions, Volvulus

Closed Loop Obstruction

Pathophysiology/Features

Fluid & Gas accumulates

Further Distention of Intestine

Vigorous Contractions

Severe Colicky Abdominal

pain

BorborygmiVomiting/ Metabolic Alkalosis

High pitched Bowel Sounds

Inc contractions &Distention

Inc Intra-luminal Pressure

Defective absorption/Inc intestinal secretion

Inc venous pressureHence venous return impairs

Congestion, Edema --- jeopardizes Arterial supply – ischemia & Gangrene

Perforation Bacterial / toxintranslocation

Peritonitis/Bacteremia, Septicemia

Multiple air fluid levels

Severe Dehydration

Fluid & Electrolyte Imbalance

Dec Bowel Sounds

Shock Death

History Physical Examination Lab Tests Imaging• X-Ray (Abdomen & Chest)• Contrast enhanced CT Scan◦ Barium Studies◦ U/S◦ MRI

Diagnosis

These clinical features and also the clinical course vary according to the LEVEL & CAUSE of obstruction

History

Cardinal features

Abdominal pain

Distension Vomiting

Absolute constipation

Proximal small bowel

Distal small bowel

Large bowel

Severe vomiting Moderate vomiting Late vomiting

Less distension Central distension Early distension , pronounced

Colicky pain Central abdominal pain Less pain

Constipation late Varies in appearance Constipation is early feature

Severe dehydration Moderate Less dehydration

Comparison of clinical aspects

Distension - minimal /absent in mesenteric vascular occlusion

Fever signifies inflammation in bowel wall / ischemia / perforation

Hypothermia -- when septicemia due to poor pyrogenic response

Specific Points

Physical ExaminationOthers

Systemic examination If deemed necessary.•CNS•Vascular•Gynaecological•Muscuoloskeltal

Abdominal

•Abdominal distension and it’s pattern•Hernial orifices•Visible peristalsis•Tympanitic Abdomen•Cecal distension•Tenderness, guarding and rebound•Organomegaly•Bowel sounds

–High pitched–Absent

•Rectal examination

General

•Vital signs: P, BP, RR, T, Sat•dehydration•Anaemia, jaundice, LN•Assessment of vomitus if possible•Full lung and heart examination

visible peristalsis seen in obstruction

CBC Anemia, Leukocytosis Urea/ Creatinine Dehydration Serum Electrolytes

Random Blood Sugar - DM Coagulation Screen - DIC LFTs - Bilirubin & Alk Phosphatase Serum Amylase - non-specific

Lab Tests

Radiological EvaluationPlain X-Ray

Always request: Supine, Upright, lateral and CXR(Obstructive Series)

Diagnostic in 60% of cases but further evaluation (CT or barium studies) may be necessary in rest of the cases

Findings

Supine Film: Gas Distended Bowel Loops

Supine Film:◦ Gas distended Bowel

Loops

SBO LBO

Contd…… Upright Film

◦ Multiple Air Fluid levels “Stepladder pattern”

Flat surfaces at the Air Fluid interface

Difference Between Large & Small Bowel Obstruction

Small Bowel Large bowel

•Central (diameter 2.5cm to 5cm)•Vulvulae conniventes

•Peripheral ( diameter 5cm+) •Presence of haustration•Presence of solid faeces

vulvulae conniventes

CXR Upright Film:

◦ Gas under the diaphragm(perforated viscus)

Other Causes

IBDGall stone IleusIntussusception

Claw hand sign

Other causes

Paralytic Ileus

Massive Gastric Dilatation

Carcinoma (desc left colon)

Useful in patients with Hx of Abd CA & postsurgical pts

Role/Advantages:◦ Level of obstruction◦ Degree of obstruction & ischemia◦ Cause : volvulus, hernia, luminal & mural causes◦ Free fluid & Gas (perforated viscus)◦ Can detect closed loop obstruction & early

strangulation

CT Scan

SBO - Air Fluid level seen Adhesive Small Bowel Obstruction

Sigmoidoscopy (Rigid or flexible)◦ Performed when on Abd X-Ray large amounts of

colonic air extends down to the rectum◦ To rule out rectal or distal sigmoid obstruction

Barium Studies (follow through, Enema)◦ Performed if there is history of recurring obstruction or distal partial colonic obstruction (via sigmoidoscopy)◦ Gastrografin or Barium Sulphate◦ Limited use in acute setting

Adjunctive Tests

U/S, fast MRI ◦ They are performed if the clinical profile &

Physical Ex is consistent with Intestinal Obstruction despite Normal Abdominal Radiographs

◦ Also capable off detecting the cause of the obstruction

◦ Not routinely performed

Keep patient NPO

1. Nasogastric Intubation/Aspiration Reduce bowel distension Improve pulmonary ventilation Reduce risk of subsequent aspiration during

induction of anesthesia and post extubation• Non-vented Ryle’s tube• Vented Salem tube • Bakers Intestinal tube

2. Fluid and electrolyte replacement

General Management

3. Parenteral antibiotics Broad spectrum antibiotics- Ampicillin, Gentamycin,

Metronidazole, Cephalosporins To correct bacterial infection Mandatory for all patients undergoing small or large bowel

resection

4. Analgesia

5. Blood Transfusion FFP or platelet transfusions Often needed in critical patients

6. Indwelling Catheter Hourly Urine output monitoring

7. CVP For Fluid And Monitoring

PCWP (pulmonary capillary wedge pressure) monitoring

Needed in haemodynamically unstable patients

Follow Up

IMPROVEMENTConservative treatment is carried on.

DETERIORATIONSurgery indicated if no improvement occurs with in 24-48 hours

Specific Surgery:Therapy directed at underlying disease

Exploratory Laparotomy (emergent in critically ill patients)

Wide Midline Incision Revision of intestine & detection of level and

cause of obstruction Decompression of proximal obstruction Assess viability of bowel (peristalsis, colour,

vessel pulsations) Removal of obstruction

Operative procedures vary according to cause of obstruction

Surgical Treatment

Specific Management

Post operative adhesion obstruction usually resolves on conservative measures.

In adhesive obstructed cases, laparoscopic adhesiolysis (adhesive band lysis) maybe performed in selected patients or using open procedure

Adhesions

Investigations- Plain X-ray Duodenal obstruction- stomach & proximal

duodenum are distended- “double bubble” Jejunal & ileal obstruction- air fluid levels

present

Congenital atresia/stenosis

Treatment: Correct electrolyte & fluid deficits Duodenal atresia requires

duodenojejuostomy & spliting of the anastomosis with a feeding tube.

Congenital atresia/stenosis

Investigation: Plain x-ray of the small bowel - gas shows

malrotation & level of obstruction + A/F levels.

Barium meal (inv of choice)

Malrotation & neonatal volvulus

Treatment: The volvulus is reduced, the

transduodenal band (Ladd’s band) divided, the duodenum mobilised & the mesentry freed.

Appendicectomy is routinely performed to avoid diagnostic difficulty with appendicitis in the future (ladds operation)

Infarcted bowel necessitates resection.

Malrotation & neonatal volvulus

Investigation white cell count is raised A Merkel’s radioisotope scan will reveal acid

producing gastric mucosa.

Merkel’s diverticulum

Treatment: Excision of the inflammed diverticulum Presence of gastric mucosa requires the

resection of the ileal loop containing the diverticulum to ensure complete excision of all acid producing mucosa.

Merkel’s diverticulum

Plain x-ray Shows small dilated bowel loops Gastrograffin enema (in the absence of

acute obstruction) shows up the meconium

Meconium Ileus

Treatment: Colonic gastrograffin (enema) washouts

may restore patency Proximal ileum is anastomosed end to side

to the colon with a distal ileostomy to clear the obstruction.

Meconium Ileus

Investigations: Gastrograffin enema (‘claw sign’ of ileocolic

intussusception) In adults, a contrast CT scan of the

abdomen or barium enema is confirmatory.

Intussusception

Rx: Reduction of the intussusception by

hydrostatic pressure (in children) – done w/in 24 hrs

Surgical reduction by milking out the ISS; bowel resection if there is gross edema preventing reduction or vascular compromise.

Reduction via laparosopic approach

Intussusception

Investigations: Plain x-ray may be diagnostic ‘kidney bean-shaped’ shadow in the right

upper zone: Sigmoid volvulus ‘kidney bean-shaped’ shadow in the left lower zone: Caecal volvulus.

Volvulus of the bowel

Rx: Sigmoid volvulus may be relieved at right

sigmoidoscopy – if not then laparotomy & sigmoidopexy performed

Emergency laparotomy & resection of the volvulus for strangulated or recurrent cases.

Gangrenous bowel is exteriorised & resected, with the formation of a ‘double barrel’ colostomy (Paul-Mikulicz procedure).

Volvulus of the bowel

Investigations: White cell count: >20×109 /L Serum amylase: slightly raised (>200IU)Mesentric angiography

Rx: Laparotomy: superior mesentric

embolectomy; Resection of areas of non-viable bowel.‘second look’ laparotomy at 24 hours for

further resection of non-viable bowel.

Intestinal ischaemia (Acute)

In cases of strangulated Inguinal/femoral hernias the standard groin incision is given & the weakness repaired using hernioplasty or herniorrhaphy, with bowel resection if required.

Hernia

Thank You