Recognizing extraluminal air in the abdomen. Flashcards
3 major signs of free intraperitoneal air?
Air beneath diaphragm
Visualization of both sides of bowel wall
Visualization of falciform ligament
Best form of imaging for identifying free air
CT scans of abdomen
Does this pt have free air?
No! This is chilaidati syndrome. The colon may be interposed between dome of liver and right hemidiaphragm and may be mistaken for free air unless careful search is made for presence of haustral folds characteristic of colon.
What are the arrows pointing to?
Rigler sign! In the normal abdomen, we visualize only the air insdie the lumen of the bowel, not the wall of the bowel itself because the wall is soft tissue density surroudned by tissue of the same density. Intro of air into peritoneal caivty enables us to visualize wall of bowel itself since wall is now surrounded on bot hinside and outside by air. Ability to see both sides of bowel wall is sign of free intraperitoneal air is called rigler sign and requires LARGE amt of free air in order to be present.
What is indicated by the arrow? What does this represent?
The falciform ligament –courses over the free edge of the liver anteriorly (contains obliterated umbilical artery!!!) It is normally invisible but when a relatively large amt of free air is present and the pt is in the supine position, free air may rsie over the anterior surface of the liver, surround the falciform ligament, rendering it visible. The curvilinear appearance of the ligament combined wti hteh oval shaped collection of air that collects beneath and distends the abdominal wall has been likened to the appearance of a football with laces – called “football sign.”
Most common cause of free air
Perforated peptic ulcer
Does this patient have free air?
No. The stomach and splenic flexure normally have air in them.
What are the arrows pointing to?
Free air!!!
Extraperitoneal air is most frequently the result of?
Bowel perf 2/2 inflammatory disease (e.g., ruptured appendix) or ulcerative disease such as crohns
What are the arrows pointing to?
Retroperitoneal air 2/2 duodenal perforation.
What are the arrows pointing to?
Pneumatosis intestinalis! Thin curvilinear lucency that parallels lumen of adjacent bowel. Usually 2/2 necrotizing enterocolitis in a premature infant.
What is indicated by white circle
Pneumatosis cystoides intestinalis. This is a rare, primary form of pneumatosis intestinalis that usually affects left colon, producing cystlike collections of air in the submucosa or serosa.
What are the 2 major secondary forms of pneumatosis intestinalis?
Secondary forms of pneumatosis intestinalis are much more common. Can occur in either COPD (presumably 2/2 air from ruptured blebs dissecting through mediastinum to abdomen) OR diseases in which there is necrosis of the bowel wall such as necrotizing enterocolitis in infants or ischemic bowel dz in adults. Can also occur in obstructing lesiosn, such as hirschprungs or pyloric stenosis (children) or with obstructing CA in adults.
What are 2 complications of pneumatosis intestinalis?
Dissection of air into portal venous system (photo)
Rupture into peritoneal cavity – > pneumoperitoneum
What do you see here?
Necrosis of bowel 2/2 mesenteric ischemia. Multiple loops of bowel with punctate collections fo air throughout walls consistent with pneumatosis. Pneumatosis that results from bowel necrosis is a VERY ominous sign!!!
What do you see here?
Air in biliary tree. This is most often associated with necrotizing enterocolitis in infants but can also be seen in adults, usually with bowel necrosis
What do you see here?
Gallstone ileus! Note the dilated small bowel consistent with mechanical SBO. There is a large calcified gallstone in the small bowel lumen which means that the gallstone eroded throuhg the wall of the GB into the duodenum, producing a fistula between the bowel and the biliary system, impacting into the small bowel. IDK why its called ileus bc its an SBO?? but whatever.
