mechanical small bowel obstruction

Mechanical SmallMechanical Small Bowel Bowel ObstructionObstruction

Rose Kakoza, Harvard Medical School Year IIIRose Kakoza, Harvard Medical School Year IIIGillian Lieberman, MDGillian Lieberman, MD

Rose Kakoza, HMS III Gillian Lieberman, MD

May 2006

AnatomyAnatomy


www.yoursurgery.com/ProcedureDetails.cfm?BR=1.

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http://www.accessmedicine.com.ezp1.harvard.edu/c

ontent.aspx?aID=2273113

http://www.yoursurgery.com/ProcedureDetails.cfm?BR=1&Proc=81

http://www.yoursurgery.com/ProcedureDetails.cfm?BR=1&Proc=81

DefinitionDefinition

A mechanical blockage arising from a structural A mechanical blockage arising from a structural abnormality that presents a physical barrier to abnormality that presents a physical barrier to the progression of gut contents the progression of gut contents

Rose Kakoza, HMS IIIGillian Lieberman, MD

EpidemiologyEpidemiology

~ 20% of patients admitted for acute abdomen ~ 20% of patients admitted for acute abdomen have an intestinal obstruction. have an intestinal obstruction.

SBO is responsible for 80% of these cases. SBO is responsible for 80% of these cases.

Adhesions and hernia are the most common Adhesions and hernia are the most common causes of SBOcauses of SBO


EtiologyEtiology

1.1.

IntraluminalIntraluminal

2.2.

IntramuralIntramural

BenignBenignMalignantMalignant

3.3.

Extrinsic Extrinsic


EtiologyEtiology

1. Intraluminal:1. Intraluminal:

Foreign bodyForeign body BezoarBezoar

GallstoneGallstone Wormball (Wormball (Ascaris lumbricoides)Ascaris lumbricoides)

Fecal impactionFecal impaction


EtiologyEtiology2. Intramural:2. Intramural:Benign:Benign:

AdenomaAdenoma LeiomyomaLeiomyoma

LipomaLipoma IntussusceptionIntussusception

Neonatal atresias and stricturesNeonatal atresias and stricturesThickening of the bowel wall with luminal Thickening of the bowel wall with luminal compromise may be seen, as in patients with Crohn compromise may be seen, as in patients with Crohn disease disease Intramural hematoma Intramural hematoma


EtiologyEtiology

2. Intramural, continued:2. Intramural, continued:MalignantMalignant

Primary adenocarcinomaPrimary adenocarcinomaMetastases (notably gastric and colonic carcinomas, Metastases (notably gastric and colonic carcinomas, ovarian cancers, and malignant melanomas) ovarian cancers, and malignant melanomas) LymphomaLymphoma


EtiologyEtiology

3. Extrinsic:3. Extrinsic:

Adhesions (~70%)Adhesions (~70%) HerniaHernia

Congenital intraperitoneal bands Congenital intraperitoneal bands Adjacent massAdjacent mass

VolvulusVolvulus


ClassificationClassification

Grading the Severity of Obstruction:Grading the Severity of Obstruction:

LowLow--grade or incomplete obstructiongrade or incomplete obstruction

HighHigh--grade obstructiongrade obstruction

Complete SBOComplete SBO


TerminologyTerminology

Simple Obstruction (Low grade)Simple Obstruction (Low grade)bowel obstruction with an intact blood supplybowel obstruction with an intact blood supply

Strangulating obstruction (High grade, Complete)Strangulating obstruction (High grade, Complete)bowel obstruction with resultant ischemiabowel obstruction with resultant ischemia


TerminologyTerminology

ClosedClosed--loop loop obstructionobstruction

HighHigh--gradegrade

Radiology Balthazar et al. 185 (3): 769


Morbidity and MortalityMorbidity and Mortality

Simple SBO is associated with a mortality rate of Simple SBO is associated with a mortality rate of 33--5%5%

Strangulated/Ischemic SBO is associated with a Strangulated/Ischemic SBO is associated with a mortality rate of up to 30%mortality rate of up to 30%


TreatmentTreatment

Simple SBO: Conservative medical managementSimple SBO: Conservative medical management

Ischemic SBO: SurgeryIschemic SBO: Surgery


Role of ImagingRole of Imaging

Distinguish simple from ischemic SBO.Distinguish simple from ischemic SBO.



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4ECB-8703-FEED8B464757}

Key QuestionsKey Questions

1.1.

Is the small bowel obstructed? Is the small bowel obstructed?

2.2.

Are there signs of ischemia? Are there signs of ischemia?

3.3.

What is the cause of the obstruction?What is the cause of the obstruction?


Abdominal Plain FilmsAbdominal Plain FilmsFirst line radiological test in suspected SBOFirst line radiological test in suspected SBO

Diagnostic of SBO in 50Diagnostic of SBO in 50--60% of cases60% of casesFalse negative rate of up to 20%False negative rate of up to 20%

Better for diagnosis of highBetter for diagnosis of high--grade obstructiongrade obstruction

Difficult to define the level of obstructionDifficult to define the level of obstruction


Is the small bowel obstructed?Is the small bowel obstructed?


Abdominal Plain Film: Signs of ObstructionAbdominal Plain Film: Signs of ObstructionMechanical Mechanical ObstructionObstruction

Lumen >3 cmLumen >3 cmTransition PointTransition Point

www.mypacs.net/cases/ SMALL-BOWEL-OBSTRUCTION-...


Companion Patient 1

http://www.mypacs.net/cases/SMALL-BOWEL-OBSTRUCTION-SECONDARY-TO-COLON-ADENOCARCINOMA-155915.html

Abdominal Plain Film: Signs of ObstructionAbdominal Plain Film: Signs of Obstruction

““The Rule of 3The Rule of 3’’ss””Lumen > 3 cmLumen > 3 cmFolds > 3 mm Folds > 3 mm > 3 air> 3 air--fluid levelsfluid levels


www.mypacs.net/cases/ SMALL-BOWEL-OBSTRUCTION-...

Companion Patient 2

http://www.mypacs.net/cases/SMALL-BOWEL-OBSTRUCTION-SECONDARY-TO-COLON-ADENOCARCINOMA-155915.html

Abdominal Plain Film: Signs of ObstructionAbdominal Plain Film: Signs of Obstruction

String of beads signString of beads sign


http://orion-group.net/journals/Journals/Vol9_May2001/26.htm

Companion Patient 3

Are there signs of ischemia?Are there signs of ischemia?


Abdominal Plain Film: Signs of IschemiaAbdominal Plain Film: Signs of Ischemia

Pseudotumor Pseudotumor signsign


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Companion Patient 4

Abdominal Film: Identifying CauseAbdominal Film: Identifying Cause


www.medicine.cmu.ac.th/.../ intussfig2-3.htmlCompanion Patient 5

http://www.medicine.cmu.ac.th/dept/radiology/pedrad/intussfig2-3.html

Abdominal CTAbdominal CT

Sensitivity for highSensitivity for high--grade obstruction is 81grade obstruction is 81--94%94%

Sensitivity for lowSensitivity for low--grade obstruction is 48grade obstruction is 48--50%50%

Superior to abdominal XSuperior to abdominal X--ray, US and MRI for ray, US and MRI for locating the site of obstructionlocating the site of obstruction


Abdominal CT: Signs of SBOAbdominal CT: Signs of SBO

Lumen >3 cmLumen >3 cm

Transition pointTransition point

Normal caliber Normal caliber postpost--stenotic stenotic bowelbowel


Balthazar et al. 205 (2): 519. (1997)

Companion Patient 6


String of String of beads signbeads sign


Eur. Radiol. (2001) 11: 1405-1422

Companion Patient 7


Small Small bowel bowel feces signfeces sign


Radiology.

1997 Nov;205(2):519-22

Companion Patient 8

Abdominal CT: Signs of IschemiaAbdominal CT: Signs of Ischemia

Target signTarget sign

Intestinal Intestinal pneumatosispneumatosis


Eur. Radiol. (2001) 11: 1405-1422

Companion Patient 9


Local Local mesenteric mesenteric congestion congestion and and hemorrhagehemorrhage


Eur. Radiol. (2001) 11: 1405-1422

Companion Patient 10


The The ““beak beak signsign””

Transition pointTransition point


Radiology.

1997 Nov;205(2):519-22



Whirl signWhirl signMesenteric Mesenteric rotationrotation


http://bhj.org/journal/2002_4402_apr/images/fig2_294.jpg


Abdominal CT: Identifying CauseAbdominal CT: Identifying Cause

Most sensitive test for the cause of SBOMost sensitive test for the cause of SBOCan identify cause of obstruction in 73Can identify cause of obstruction in 73--95% of cases95% of cases

Adhesions are suspected if no lesion is seen at Adhesions are suspected if no lesion is seen at the transition pointthe transition point


Abdominal CT: Identifying CauseAbdominal CT: Identifying Cause

Signs of neoplasiaSigns of neoplasiaPeritoneal nodulesPeritoneal nodulesAscitesAscitesIntrinsic massIntrinsic mass


Eur. Radiol. (2001) 11: 1405-1422 Companion Patients 13, 14, and 15

Small Bowel FollowSmall Bowel Follow--ThroughThrough

Useful for suspected Useful for suspected lowlow--grade obstructiongrade obstruction

Determining severity Determining severity of obstructionof obstruction


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Applying the Algorithm: Patient E.C.Applying the Algorithm: Patient E.C.History:History:

70 year old woman70 year old woman

with multiple medical comorbidities and a with multiple medical comorbidities and a history of history of multiple abdominal operationsmultiple abdominal operations

which include a partial gastrectomy with which include a partial gastrectomy with Billroth II reconstruction, a hysterectomy, and a cholecystectomBillroth II reconstruction, a hysterectomy, and a cholecystectomy. She y. She presented to the ED with a one day history of crampy abdominal ppresented to the ED with a one day history of crampy abdominal pain, and ain, and vomiting.vomiting.

Physical Exam:Physical Exam:Moderate distress. AAOx3. Anicteric, facial sym. No JVD or LAD sModerate distress. AAOx3. Anicteric, facial sym. No JVD or LAD supple upple Coarse B/L RRR Coarse B/L RRR mild dist, tend to palp diffusely, guarding. mild dist, tend to palp diffusely, guarding. No edema No edema

Social History:Social History:Retired nurses aide. Retired nurses aide. 80 pack year smoking history80 pack year smoking history, quit 12 years ago. No , quit 12 years ago. No EtOH, IVDU. EtOH, IVDU.

Family History:Family History:Mother Mother --> Hodgkin's disease. Brother > Hodgkin's disease. Brother --> CAD MI.> CAD MI.


Differential DiagnosisDifferential Diagnosis

GastrointestinalGastrointestinalAppendicitisAppendicitisBiliaryBiliary Tract DiseaseTract DiseaseSBOSBOAcute pancreatitisAcute pancreatitisDiverticulitisDiverticulitis



GenitourinaryGenitourinaryRenal ColicRenal ColicAcute urinary retentionAcute urinary retention

Gynecologic Gynecologic Acute pelvic inflammatory diseaseAcute pelvic inflammatory diseaseEctopic pregnancyEctopic pregnancy



VascularVascularAbdominal aortic aneurysmAbdominal aortic aneurysmMesenteric ischemiaMesenteric ischemia

ExtraabdominalExtraabdominal DiagnosesDiagnosesCardiopulmonary (pneumonia, PE, MI)Cardiopulmonary (pneumonia, PE, MI)Abdominal wall (rectus sheath hematoma, hernia)Abdominal wall (rectus sheath hematoma, hernia)



Toxic Metabolic Toxic Metabolic Diabetic Diabetic ketoacidosisketoacidosisAdrenal crisisAdrenal crisis

NeurogenicNeurogenicRectus nerve entrapmentRectus nerve entrapment

Nonspecific abdominal painNonspecific abdominal pain


Differential DiagnosisDifferential DiagnosisCauses of Acute Abdominal Pain Stratified by AgeFinal Diagnosis ≥50 Years (N = 2406) <50 Years (N = 6317)Biliary

tract disease 21% 6%

Nonspecific abdominal pain (NSAP) 16% 40%

Appendicitis 15% 32%Bowel obstruction 12% 2%

Pancreatitis 7% 2%

Diverticular disease 6% <.1%

Cancer 4% <.1%

Hernia 3% <.1%

Vascular 2% <.1%

Gynecologic <.1% 4%

Other 13% 13%


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Age Group Intraluminal Causes Intramural Causes

Extramural Causes

(Extrinsic Compression)

Neonates and infants <24 mo

Meconium

ileus, milk curd obstruction, foreign bodies

Congenital atresias, stenoses, and diaphragms; duplication cysts; intussusception; Henoch-Schönlein

purpura

Inguinal hernia, congenial bands, midgut

volvulus, postoperative adhesions

Children and young adults

Foreign bodies, A lumbricoides Crohn disease, tuberculosis, benign neoplasms, primary and secondary malignant neoplasms

Inguinal hernia, congenital and postoperative adhesions, midgut

volvulus, complications of appendicitis

Elderly persons Foreign bodies, gallstones, food bolus

Crohn disease, tuberculosis, primary and secondary neoplasia, potassium strictures, radiation strictures, complications of surgical anastomosis

Postoperative adhesions; femoral, inguinal, umbilical, or incisional

hernia; colonic and ovarian neoplasia; adhesion to an inflammatory process (eg, appendicitis or diverticulitis


http://www.emedicine.com/radio/topic781.htm

Patient E.C.: Abdominal Plain FilmsPatient E.C.: Abdominal Plain FilmsDilated loops of small bowel located centrally (blue arrows)

Prominent valvulae conniventes


PACS, BIDMC

Our Patient

Narrowed DifferentialNarrowed Differential

Small bowel obstructionSmall bowel obstructionAdhesionsAdhesionsNeoplasiaNeoplasiaHerniaHerniaInflammatory process (diverticulitis)Inflammatory process (diverticulitis)



http://mycourses.med.harvard.edu/vp_view.asp?frame=Y&case_id={5C97C091-D5E1-

4ECB-8703-FEED8B464757}

Patient E.C.: Signs of SBOPatient E.C.: Signs of SBO


PACS, BIDMC

Increased luminal diameterTransition Point

String of beads sign

Our Patient

Patient E.C.: Signs of IschemiaPatient E.C.: Signs of Ischemia

Small bowel feces sign


PACS, BIDMC Our Patient



Whirl Sign

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Whirl Sign




Whirl Sign

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slides)




Whirl Sign


Patient E.C.: Identifying CausePatient E.C.: Identifying Cause

No identifiable No identifiable cause seen at the cause seen at the transition pointtransition point


PACS, BIDMC

Our Patient

Patient E.C.: FollowPatient E.C.: Follow--upup

Underwent emergent exploratory laparoscopy Underwent emergent exploratory laparoscopy and LOA and LOA


RememberRemember……

““The Rule of 3The Rule of 3’’ss””Lumen > 3 cmLumen > 3 cmFolds > 3 mm Folds > 3 mm > 3 air> 3 air--fluid levelsfluid levels

Key QuestionsKey Questions1.1.

Is the small bowel Is the small bowel obstructed? obstructed?

2.2.

Are there signs of Are there signs of ischemia? ischemia?

3.3.

What is the cause of What is the cause of the obstruction?the obstruction?


ReferencesReferences1.

Eur. Radiol. (2001) 11: 1405-1422

2.

Radiology (1997) 204:507-512

3.

Eur. Radiol. (2006) 16:967-971

4.

Can Assoc Radiol J (2003) 54(2):93-99

5.

Radiology 2001 218:39-46

6.

AJR (2005) 185:1036-1044

7.

http://www.emedicine.com/radio/topic781.htm


AcknowledgementsAcknowledgements

Anne Catherine Kim, MDAnne Catherine Kim, MD

Larry Barbaras, WebmasterLarry Barbaras, Webmaster

Gillian Lieberman, MDGillian Lieberman, MD

Pamela LepkowskiPamela Lepkowski


mechanical small bowel obstruction

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