Pneumoperitoneum
Pneumoperitoneum describes gas within the peritoneal cavity, often due to critical illness. There are numerous causes and several mimics.
Pathology
The most common cause of pneumoperitoneum is the disruption of the wall of a hollow viscus. In children, the causes are different from the adult population and are considered in the neonatal pneumoperitoneum article.
The causes and, hence, the corresponding severity of accompanying illness, are variable:
- perforated hollow viscus
- peptic ulcer disease
- ischemic bowel
- bowel obstruction
- necrotizing enterocolitis
- appendicitis
- diverticulitis
- malignancy
- inflammatory bowel disease
- mechanical perforation
- trauma
- colonoscopy
- foreign bodies
- iatrogenic
- postoperative free intraperitoneal gas
- peritoneal dialysis
- vaginal "aspiration"
- cunnilingus
- douching
- sudden squatting
- postpartum exercises
- water-skiing
- mechanical ventilation
- pneumomediastinum
- pneumothorax
Radiographic features
Plain radiograph
Chest radiograph
An erect chest x-ray is probably the most sensitive plain radiograph for the detection of free intraperitoneal gas. If a large volume pneumoperitoneum is present, it may be superimposed over a normally aerated lung with normal lung markings.
- subdiaphragmatic free gas
- leaping dolphin sign
- cupola sign (on supine film)
- continuous diaphragm sign
Abdominal radiograph
Free gas within the peritoneal cavity can be detected on an abdominal radiograph. The signs created by the free intraperitoneal air can be further divided by anatomical compartments in relation to the pneumoperitoneum:
- bowel-related signs
- double wall sign (also known as Rigler sign or bas-relief sign)
- telltale triangle sign (also known as the triangle sign or telltale triangle)
- peritoneal ligament-related signs
- right upper quadrant signs
Ultrasound
Maybe useful in the appropriate clinical setting. A linear-array transducer (10-12 MHz) is considered more sensitive than a standard curvilinear abdominal transducer (2-5 MHz).
Recognized direct features include:
- enhancement of the peritoneal stripe (peritoneal stripe sign)
- either alone or associated with repeating, horizontal long-path reverberation artifacts which extend into the far field
- discrete, hyperechoic foci representing gas bubbles
- may adopt a linear arrangement, often associated with short path reverberation artifacts which appear as comet tails, or if tapering, ring down artifacts
- may also cluster in a manner that results in the attenuation and diffuse reflection of reflected ultrasound waves, which results in an underlying inhomogenous (or dirty) acoustic shadow
Ultrasonography may also be combined with dynamic maneuvers
- free intraperitoneal air is expected to demonstrate movement with patient position
- it may also be displaced with caudal pressure on the probe above the collection, reappearing with cessation of the pressure
- unlike air within the lung, does not demonstrate respirophasic changes
Differential diagnosis
- consider pseudopneumoperitoneum
See also
Siehe auch:
- Pneumothorax
- Linksseitenlage
- Rigler-Zeichen
- Divertikulitis
- Mesenterialinfarkt
- Mediastinalemphysem
- Nekrotisierende Enterokolitis
- Fremdkörper
- mechanischer Ileus
- Pseudopneumoperitoneum
- Chronisch-entzündliche Darmerkrankungen
- Magenulkus
- peritoneal cavity
- abnormales Gas im Abdomen
- Appendizitis
- Pneumoperitoneum beim Neugeborenen
- football sign
- tension pneumoperitoneum
- cupola sign
- freie retroperitoneale Luft
- properitonealer Fettstreifen
und weiter:
- Chilaiditisyndrom
- Magenperforation
- emphysematöse Cholezystitis
- continuous diaphragm sign
- falciform ligament sign
- Überblähung nach Endoskopie
- necrotising enterocolitis staging
- post-operative pneumoperitoneum
- Pneumatosis intestinalis bei immunsupprimierten Patienten
- Barotrauma der Lunge
- Dünndarmverletzung
- traumatische Jejunumperforation
- freies intraperitoneales Fett
- benignes posttraumatisches Pseudopneumoperitoneum