Thoracic causes of pneumoperitoneum - it is not all about perforation Poster No.: C-2590 Congress: ECR 2013 Type: Educational Exhibit Authors: E. Ilieva; Sofia/BG Keywords: Education, Plain radiographic studies, Thorax, Abdomen, Perception image, Education and training DOI: 10.1594/ecr2013/C-2590 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 12
Learning objectives To provide an overview of the most frequent thoracic causes of pneumoperitonem with the relevant radiologic signs; to underline the importance of looking carefully under the diaphragm on the chest X-rays; to suggest the proper radiographic technique if pneumoperitoneum is suspected but not obvious. Background Pneumoperitoneum, or air within the peritoneal cavity, frequently indicates a perforated abdominal viscus that requires emergent surgical management. Non-surgical spontaneous pneumoperitoneum (not associated with a perforated viscus) is an uncommon entity related to intrathoracic, intra-abdominal, gynecologic, iatrogenic and other miscellaneous causes, and is usually managed conservatively. The most common thoracic causes include mechanical ventilation, pneumomediastinum, pneumothorax, pre-existing pulmonary disease, cardiopulmonary resuscitation. For example, mechanical ventilation with positive end-expiratory pressure (PEEP) may cause free air in the abdomen by alveolar rupture and subsequent air dissection into the mediastinum and peritoneal cavity. Pneumoperitoneum could be easily missed when focused on the most obvious pathology on the chest X-ray, or on supine radiographs even if the entire abdomen is filled with air. Radiographic techniques: Upright chest which includes diaphragm Upright abdomen which includes diaphragm Left lateral decubitus view of the abdomen - Air is seen over the liver - Patient lies with left side down, right side up Supine abdominal view Supine decubitus abdominal view (optional) Right lateral decubitus view of the abdomen (optional) - Patient lies with right side down, left side up - For patients unable/unwilling to adopt the left lateral decubitus position Page 2 of 12
Images for this section: Fig. 3: Supine chest X-Ray in a pediatric patient with severe respiratory failure few hours after mechanical ventilation (PEEP) - pneumomediastinum, subcutaneous emphysema in the cervical area and outlined by air right liver contour Page 3 of 12
Fig. 4: Same patient as in Fig.3: Right lateral decubitus abdominal X-Ray (patient was not able to lie on the left) - intraabdominal free gas confirmed - "Rigler's sign", free air between the spleen and the left abdominal wall Page 4 of 12
Fig. 5: Supine chest X-Ray in a pediatric patient with pre-existing pulmonary disease (mucovisdiosis) after acute chest pain - bilateral pneumothorax, pneumomediastinum, Page 5 of 12
massive subcutaneous emphysema, outlined by air right liver contour, "continuous diaphragm sign" Fig. 6: Same patient as in fig.5: Supine decubitus abdominal X-Ray (patient was not able to lie neither on the left or on the right) - free air outlining bowels and intra-abdominal viscera, massive subcutaneous emphysema Page 6 of 12
Imaging findings OR Procedure details Three major findings: Free air beneath diaphragm (crescent sign) Visualization of both sides of the bowel wall (Rigler's sign) Normally, only the inside of the bowel (the lumen) is visible unless free air outlines the outer surface of the wall Visualization of the falciform ligament Long vertical line to the right of midline extending from ligamentum teres notch to umbilicus; a common structure outlined on the supine abdominal X-Ray Right upper quadrant (RUQ) gas (for small collections in supine position): Anterior subhepatic space free air Oblique linear area of hyperlucency outlining the posteroinferior margin of liver Air Anterior to Ventral Surface of Liver Single large area of hyperlucency over the liver Doges Capsign Triangular area of free air trapped below central tendon of diaphragm In cases of large pneumoperitonem the "continuous diaphragm sign" could be seen - the left and right hemidiaphragms contrasted by the free gas appear as a continuous structure in massive pneumoperitoneum. Images for this section: Page 7 of 12
Fig. 1: Upright chest X-Ray in a patient after thoracic trauma - massive subcutaneous emphysema, bilateral partial pneumothorax, pneumomediastinum might distract the attention from the subtle crescent lucency below the right hemidiaphragm (pneumoperitoneum - "crescent sign") Page 8 of 12
Fig. 2: Upright plain abdominal X-Ray in a patient after thoracic trauma, signs of pneumoperitonem - subtle crescent lucency below the right hemidiaphragm - "crescent sign", visualization of both sides of the wall of large bowel loops in right lower quadrant - "Rigler's sign", the medial liver contour is outlined by air Page 9 of 12
Page 10 of 12
Fig. 7: Schematic drawing showing air collections in black: a.oblong collection of air in right subhepatic space b.triangular-shaped collection of air in most posterior recess of right subhepatic space (hepatorenal fossa/morison's pouch), also known as Doge's cap sign c.circular collection of air projected over liver interposed between ventral liver surface and anterior abdominal wall Page 11 of 12
Conclusion Recognizing the presence of pneumoperitoneum due to causes other than perforated viscus on plain chest and abdominal radiographs frequently may avoid unnecessary surgical exploration of the abdomen and its associated morbidity. References 1. 2. 3. 4. nd Chen MY, Pope TL, Ott DJ: Basic Radiology, 2 ed. LANGE Clinical Medicine, 2004 Menuck L, Siemers PT, Pneumoperitoneum: Importance of Right Upper Quadrant Features, Am J Roentgenology 127:753-756, 1976 LearningRadiology.Com: Free Intraperitoneal Air Mularski RA Sippel JM, Osborne ML: Pneumoperitoneum: a review of nonsurgical causes, Crit Care Med 28(7):2638-44, 2000 Personal Information Elena Ilieva, UMHATEM Pirogov, Sofia, Bulgaria Page 12 of 12