Bowel Obstruction

Donald E Thrall, DVM, PhD

Ross University

School of Veterinary Medicine

Basseterre, St. Kitts

Bowel Obstruction

Considered commonly

Important for patient that we be

correct

Seasoned radiologists sometimes

wrong

Many times patient not

obstructed…in my practice anyway

Radiographic technique

No preparation advised

Views

LL, RL, VD

Take advantage of gas as contrast medium

Technique

Analog: Hi mAs, low kVp

• Maximizes contrast

Digital: Technique less critical

Checklist Learn normal anatomy

Are there enlarged bowel

segments?

Roughly height of L2

in dogs

2x height of central

part of L4 in cats, or

12mm

These are guidelines!

Is it colon?

Distribution of enlarged

segments

Are there normal

segments too?

Contents?

Gas and solids

Gravel sign

Bowel gas pattern?

Crescents

Commas

Paisley

Wall thickness

Free peritoneal gas?

Canine

Feline

Bowel Obstruction

Hallmark sign is enlarged bowel

Is the enlarged bowel small intestine?

Is the problem due to mechanical vs.

paralytic bowel obstruction?

Mechanical vs. Paralytic Ileus

Mechanical

Usually two populations of bowel

• Normal and Enlarged

Enlargement usually greater in mechanical

• Leads to stacking

Usually fluid and gas in lumen

• Sometimes foreign material in mechanical

– Cloth

– Gravel sign

• Often just gas in paralytic ileus

These are only guidelines and there is overlap

PARALYTIC ILEUS (peritonitis)

A167198

A121444

PARALYTIC ILEUS (endotoxemia)

Two Populations The presence of some small bowel segments that are normal in diameter and

others that are significantly larger…2-3X

A173605

Gravel Sign Opaque ingested

particulate matter

collecting proximal

to obstruction

More common

in chronic

partial

obstruction

Overall, not

common

Just something

to look for

I1031690

MECHANICAL: foreign material in S.I.

I1031690

MECHANICAL: foreign material

A85613

MECHANICAL: stacking Stacking

Cat, 1y

Vomiting for one week

Treated symptomatically

2 sets of radiographs declared normal

except for fecal accumulation

Emergency radiographs declared “no

evidence of obstruction”

91495

•Enlarged bowel segment

1.5

0.5

Colon

•Not colon

Contents

•Gas and solids

What is this?

Normal bowel •Two Populations

Obstructed Cat

Learning Points

Problem started when small bowel

misidentified as colon

Small bowel can have fecal-like contents

Anatomy was misinterpreted

German shepherd, 8y

3 day history of anorexia

One day history of vomiting

Taken to rDVM

Referring radiograph report: Foreign material (bone) and intestines seemed displaced

Given fluids and sent home

Vomiting continued; went back to rDVM

Referred

Dog is indiscriminant eater (paper, cans)

Mostly an indoor dog

112554

R

• Two

Populations

• Foreign

Material in

S.I.

Staffordshire, 2y Began vomiting 4d ago after shredding

and eating a sock

Became anorexic the following day

Currently vomiting approximately 4 to 5 times daily

Evaluated by local veterinarian 1d ago and no diagnostics were performed

Now has intractable vomiting

112801

• Plication

• Crescents

• Plication and crescents

Courtesy Dr. W.R.Widmer

Some patients

where obstruction

was considered

Labrador retriever, 7y

Acute anorexia and vomiting for one day

Vomited brown fluid on way to ER

Hypovolemic shock

Soft/pliable abdomen

Mildly resents palpation

No overt organomegaly or masses

113468

No obstruction seen with US WOW!!!

Septic effusion on peritoneal tap

Surgery Jejunal perforation

Foreign material but no obstruction

Died

Learning points None

Would call obstruction again

Cat, 15y

Progressive weight loss over

3 years

Seems to vomit when fed

treats

Lethargy

Abdomen not painful

113669

No obstruction apparent with

sonography

Biopsy dx: Lymphoplasmocytic and

eosinophilic enteritis

Learning points

Chronic history

Intermittent vomiting

No abdominal pain

No bowel fluid

What to do if

you’re confused

Get Both L and R lateral

Jamie’s case

R

L

L

Pneumocolon

Re-Radiograph

After 4-24 hrs.

M152609

R

L

Initial Radiographs

Obstruction…can’t be sure.

L

R

24h Later

Signs have not abated

O refused US; took dog

to rDVM for xlap;

nylabone fragment

Obstruction???

24 hrs

No M158414

Upper GI Examination

Rarely done or done well in practice

Not enough barium

Wrong type of barium

Stopping too soon

Anti-motility drugs on board

Ultrasound

Teleradiology