Chest and Abdomen- Exam 3- Bowl Gas Patterns

What type of gas pattern is normal but sometimes can be abnormal

Intraluminal

Where is it normal to see intraluminal gas pattern

Stomach and bowel.

Where is intraluminal gas pattern abnormal to be seen

Gallbladder, portal vein, urinary bladder

You should recognize what with intraluminal gas pattern

Displacement of normal bowel gas distribution due pathology

-ascites or masses

What gas pattern is always abnormal and most commonly found within the peritoneal cavity (intraperitoneal air)

Extraluminal

What gas patter is normal but when in excess it's abnormal

Intramural air (wall, always abnormal)

What is the last type of gas pattern that is always abdnormal

Abscess

Intestinal obstruction accounts for what percentage of emergency department visits for acute abdominal pain

15%

What is the most common obstruction for intraluminal

Small bowel obstruction

What is the AKA for ileus intraluminal obstruction

Paralytic ileus or adynamic ileus

Types of intraluminal large bowel obstructions

Volvulus: sigmoid and fecal

Colitis

Gastric outlet obstruction

Biliary tree intraluminal obstruction is called

Gallstone ileus

Extraluminal obstructive types

Perforation

Intramural gas

Types of perforation for Extraluminal

Intarperiotneal

Extraperitoneal

Explain intraperitoneal perforation

Within peritoneum covering of the bowels

Explain extraperitoneal perforation

Within the walls themselves

Type of intramural gas locations for Extraluminal

Pneumatosis coli

Ischemic bowel

Gas forming infections

Normal gas pattern

What is special with small bowel obstruction and radiographic findings

May be apparent 6-12 hours before clincal symptoms

Symptoms of small bowel obstruction

Abdominal pain, vomiting and abdominal distention

Important values for the dilates loops of small bowel to be considered small bowel obstruction

> 30 mm (3 cm) proximal (jejunum)

>25 mm (2.5 cm) distal (ileum)

Air fluid levels for small bowel obstruction

>25 mm (2.5 cm) in length

Must be at different positions in the same loop (step ladder appearance)

What is it called in small bowel obstruction when small bubbles are trapped between bowel loops

String of pearls

What is a sign that is less commonly found in small bowel obstruction

Fluid-filled loops= gas less abdomen

-fluid displaces the air and you can't see it anymore

-VERY ADVANCED OBSTRUCTION

What is the most common cause of all intestinal obstructions

Mechanical small bowel obstruction

About 80% of all bowel obstructions are

Small bowel obstruction

Who is most commonly having small bowel obstruction

Western countries: post surgical adhesion

Incarcerated hernias

Gallstone ileus

Foreign bodies

Intussusception

Intraluminal masses

Malignancy

What must you do on x ray in order to see incarcerated hernias that can cause small bowel obstruction

Include inguinal regions of abdominal and limbo pelvic x rays

Gallstones that worked out of bile duct in to GI tract and probably perforated out of it

Gallstone ileus

It is often difficult to distinguish between an ileus and ______ on plain film so

Mechanical bowel obstruction

-so CT is often sued

Lack of forward movement cause a….

Paralytic ileus (aka adynamic ileus)

What can cause paralytic ileus (aka adynamic ileus)

Stasis of bowel contents WITHOUT mechanical obstruction

Postoperative, drugs, metabolic states, intra-abdominal inflammation

Small bowel should be

Less than 3 cm

Large bowel should be

Less than 6 cm

Appendix should be

Less than 6 mm

Cecum should be

Less than 9 cm

Example g the 3 6 9 diameter rule for gas pattern findings

Small bowel should be less than 3 cm

Large bowel should be less than 6 cm

Appendix should be less than 6 mm

Cecum should be less than 9 cm

Small bowel obstruction has what type of location

Central location

What does a small bowel obstruction look like

Stacked coins

Why does a small bowel obstruction look like stacked coins

Valvulae conniventes extending from wall to wall (folds extend from wall to wall)

Accumulations in small bowel obstruction suggest

Adhesions secondary to intra-abdominal surgery, hernias, tumors and Crohn's disease

With large bowel obstruction, the air is normally in

Rectum and sigmoid

Describe location of large bowel obstruction

Peripheral location

What does large bowel obstruction look like

Haustral markings don't extend form wall to wall (folds don`t go all the way across)

Small bowel obstruction vs large bowel obstruction

Example of a patient in a standing position and how can you tell

Because of the positioning of the air fluid levels

Example of another small bowel obstruction with air fluid levels, what position are the patients in

Standing

Example of the air fluid levels on side lying

When changing positions for x ray, do the air fluid levels in bowel obstruction move within or outside of the bowels

Move within the bowels

What happens as more fluid fills up in bowel obstruction

It pushes the air up and out until its passed out

Distended small bowel, showing stacked coins and having a large bowel obstruction

Showing the difference between air fluid levels in standing and supine positioning

Example of string of pearls/beads sign with small bowel obstruction

String of beads sign is seen with

Small bowels obstruction

Example of a large bowel obstruction that is too wide of a diameter

Do you get air fluid levels in both small and large bowel obstruction

Yes

What is more common large or small bowel obstruction

Small bowel obstruction

Example of someone having bowel obstruction and ulcerative colitis, how can you tell?

The smooth appearance of the descending colon

One more example comparing small bowel obstruction and large bowel obstruction

Example of both large and small bowel obstruction showing air fluid levels

Air in the peritoneum is called

Pneumoperitoneum

How can you see if someone has pneumoperitoneum

You can see the top of the liver, normally this should not be seen

What is something that you see with pneumoperitoneum

Riggers sign (aka double wall sign)

Explain out riglers sign (aka double wall sign) works

Normally you cant see the walls cause of the water density of the walls being in contact with the water density of the peritoneum but with air in between the two structures it allows the different layers to be seen

Good example of a normal wall vs a riglers sign (double wall sign)

Riglers sign seen with pneumoperitoneum, showing both the luminal surface and the peritoneal surface

Falciform ligament sign can be made visible by

Large amount of free air in the peritoneal cavity

Example of a massive pneumoperitoneum (you can tell its massive because the whole liver and spleen are visible)

Pneumoretroperitoneum is most commonly

Trauma related

How can we tell something is pneumoretroperitoneum

When you can see the whole kidney, normally you should not be able to see the top of it as clear as we do in the x ray

Pneumoretroperitoneum seen on CT

Example of air through the fibers of the psoas muscle

I think this is seen with pneumoretroperitoneum

Another example of pneumoretroperitoneum plus a colostomy bag

Good example of pneumoperitoneum

Football sign example

Normal gastric air bubble showing an air fluid levels

It's okay to have some air where and not where

Okay to see some air under the diaphragm on the left (gastric air bubble)

But when air is on the right side of the patient then its a problem

Patients who have small livers (cirrhosis) or flattened diaphragm due to lung hyperinflation (emphysema) a void is created within the upper abdomen above the liver. This space may be filled by bowel and this bowel is air filled then it may mimic free gas What is this called

Chilaiditi`s phenomenon

How do you get a false rigler/double wall sign

One big loop of bowel that doubled back on itself

Sigmoid volvulus showing coffee bean sign