extraluminal gas in the abdomen ch16 Flashcards
the four most common locations of extraluminal air are
- intraperitoneal (pneumoperitoneum)
- retroperitoneal
- air in the bowel wall (pneumatosis intestinalis)
- air in the biliary system (pneumobilia)
The three major radiographic signs of free intraperitoneal air are:
- air beneath the diaphragm
- visualization of both sides of the bowel
- visualization of the falciform ligament
On what side of the abdomen is it easier to see free air
right side- liver
left side more difficult because of gaster and splenic flexure
What is Chiladiti sign
occasionally, normal colon may be interpoed between the dome of the liver and the right hemidiaphragm and, unless a careful search is made for the presence of haustral folds characteristic of the colon, it may be mistaken for free air.
this normal interposition of the colon between the liver and right hemidiaphragm is called the chiladiditi sign.
What is Rigler sign
The ability to see both sides of the bowel wall is a sign of free intraperitoneal air called the Rigler sign
what is falciform ligament sign
when a large amount of free air is present and the patient is in the supine position, free air may rise over the anterior surface of the liver, surrounding the falciform ligament and rendering it visible
what is football sign
the lienar appereance of the falciform ligament combined with the oval-shaped collection of free air that distends the abdomen jas been linked to the appereance of a footnall with its laces
The most common cause of free intraperitoneal air is …
rupture of an air-containing loop of bowel, either stomach, small or large bowel
How can extraperitoneal air be recognized
- streaky, linear appereance outlining extraperitoneal structures
- mottled, blotchy appereance
- relatively fixed position, moving little if at all with changes in patient positioning
extraperitoenal air may outline extraperitoneal structures such as:
- psoas muscle
- kidneys, ureters, urinary bladder
- aorta, IVC
- inf border of the diaphragm
causes of extraperitoneal air
from bowel perforation secondary to either
- inflammatory disease (ruptured appendix)
ulcerative disease (e.g. chron disease)
- other causes of extraperitoneal air: blunt or penetrating trauma, iatrogenic manipulation, foreign body
- gas producing infection
what is pneumatosis intestinalis
pneumatosis intestinalis is air in the bowel wall
the easiest way to recognize air in the bowel is
on abdominal radiographs when it is seen in profile producing a linear radiolucency (black line) whose contous exactly parallels the bowel lumen
clues to help differentiate pneumatosis from fecal material include:
- presence of mottled gas in an area of the abdomen unlikely to contain colon
- lack of change in the appereance of the mottled gas pattern over several images in different position
Pneumatosis intestinalis can be divided into two major categories:
- primary form called pneumatosis cystoides intestinalis (affects left colon producing cyst like collection of air in the submucosa or serosa)
- secondary form that can occur in:
- chronic obstructive pulmonary diseases
- necrotizing enterocolitis in infants
- ichemic bowel disease
- obstructing lesions of the bowel like Hirschsprung disease or pyloric stenosis in children and obsructing carcinoma in adults
