Medical Image of the Month: Pneumoperitoneum with Rigler’s Sign

Figure 1. CT of the abdomen with contrast showing a large quantity of free air within the peritoneal cavity. The etiology of her free intraperitoneal air was not evident on this imaging study.

Figure 2. An upright chest radiograph performed six months later again demonstrates a large amount of free air under the hemidiaphragms, outlining both the spleen and the superior surface of the liver. Rigler’s sign (air on both the peritoneal and luminal side of bowel wall (arrows) - which clearly delineates the bowel wall) is in noted and supports the diagnosis of free intraperitoneal air.

Clinical Presentation: A 70-year-old Asian-American woman presented to the hospital with a distended and tympanic abdomen. She was otherwise asymptomatic. Her past medical history was significant only for an uncomplicated colonoscopy the previous summer. A CT scan showed free air within the peritoneal cavity (Figure 1). She was managed conservatively without a surgical intervention. After six months without a chest x-ray continued to show free air (Figure 2). She underwent an elective exploratory laparotomy without identification of a cause for her free intraperitoneal air. Her pneumoperitoneum completely resolved on follow up imaging.

Discussion: Pneumoperitoneum is a condition which commonly presents as an acute abdomen (1). Causes are numerous and include penetrating and blunt abdominal trauma, perforation of viscus, diaphragmatic rupture, fistula formation – among other etiologies. Work-up of pneumoperitoneum varies depending on the suspected etiology. In the presence of hemodynamic instability or peritoneal signs, the patient should proceed to an exploratory laparotomy immediately following airway maintenance and resuscitation. In the setting of a perforation or sepsis, broad-spectrum intravenous antibiotics are indicated. Stable patients are managed expectantly with NPO status, intravenous fluids resuscitation, serial vitals/abdominal imaging/labs, and nasogastric tube decompression if indicated for obstructive etiologies.

Rigler’s sign is well-demonstrated in the abdominal radiograph (figure 2). Rigler’s sign is the presence of air on both the luminal and peritoneal side of the bowel wall – which clearly delineates the bowel wall (1). This sign is highly suggestive of free intraperitoneal air. Rigler’s sign can be seen on a supine abdominal radiograph and can be helpful in the identification of free intraperitoneal air in a patient who may be too ill for upright radiographs or CT imaging.

Mohammad A. Mahmoud MD DO, Jonathon P. Mahn DO, and Alexander E. Brahmsteadt, MSIV.

Midwestern University | Arizona College of Osteopathic Medicine

Canyon Vista Medical Center

Sierra Vista, AZ USA

Reference

1. Levine MS, Scheiner JD, Rubesin SE, Laufer I, Herlinger H. Diagnosis of pneumoperitoneum on supine abdominal radiographs. AJR Am J Roentgenol. 1991 Apr;156(4):731-5.

Cite as: Mahmoud MA, Mahn JP, Brahmsteadt AE. Medical image of the month: pneumoperitoneum with Rigler's sign. Southwest J Pulm Crit Care. 2019;19(6):156-7. doi: https://doi.org/10.13175/swjpcc047-19 PDF 

Medical Image of the Week: Elemental Mercury Poisoning

Figure 1. Panel A: Abdominal x-ray showing radiopaque matter. Panel B: Repeat x-ray after colonoscopy.

A 34-year-old woman presented to the Emergency department with abdominal pain after ingestion of an unknown liquid that family felt might be poisonous. The patient had a past history of prior suicide attempts, as well as a history of polysubstance and alcohol abuse. The patient was confused, tangential and a difficult historian. The patient had a heart rate of 72, was normotensive, and had an oxygen saturation of 100% on room air.  She was confused and answered questions intermittently. The remainder of her physical examination including her neurological exam was normal. The initial serum chemistry, anion gap, lactate, liver function tests were normal. Urine drug screen was positive for benzodiazepines, for which the patient was prescribed. An abdominal x-ray was performed showing a radiopaque substance in the abdomen (Figure 1A). It was eventually determined she ingested elemental mercury. Blood levels were elevated, and she did eventually have hematochezia. Colonoscopy was performed which removed some of the metallic liquid mercury (Figure 1B).

Mercury in any form is poisonous, with mercury toxicity most commonly affecting the neurologic, gastrointestinal (GI) and renal organ systems (1). Poisoning can result from mercury vapor inhalation, mercury ingestion, mercury injection, and absorption of mercury through the skin.

Elemental mercury is poorly absorbed after ingestion but easily vaporizes at room temperature and is well absorbed (80%) through inhalation. Once absorbed elemental mercury is mostly converted to an inorganic divalent or mercuric form by catalase in the erythrocytes. This inorganic form has similar properties to inorganic mercury (e.g., poor lipid solubility, limited permeability to the blood-brain barrier, and excretion in feces).

Treatment of mercury toxicity consists of removal of the patient from the source of exposure, supportive care, and chelation therapy. Our patient had limited symptoms, and for this reason, chelation therapy was not performed. She made an uneventful recovery after discharge to psychiatry. Her blood levels eventually returned to normal in a few months.

Michel A. Boivin, MD

Pulmonary/Critical Care/Sleep Medicine

Department of Internal Medicine

University of New Mexico

Albuquerque, NM USA

Reference

1. Olson DA. Mercury poisoning. Medscape. August 14, 2017. Available at: https://emedicine.medscape.com/article/1175560-overview (accessed 5/22/18).

Cite as: Boivin M. Medical image of the week: Elemental mercury poisoning. Southwest J Pulm Crit Care. 2018;16(5):287-8. doi: https://doi.org/10.13175/swjpcc067-18 PDF 

Medical Image of the Week: Boerhaave's Syndrome During Colonoscopy

Figure 1. Chest X ray showing bilateral subcutaneous emphysema extending from the supraclavicular area and above to the neck.

Figure 2. Video of representative coronal views of the thoracic CT scan showing subcutaneous emphysema in the supraclavicular area and neck.

Figure 3. Fluoroscopic esophagram revealing a focus of oral contrast actively extravasating (white arrow) approximately at 2.5 cm above the gastro-esophageal junction consistent with a small perforation.

A 76-year-old woman with no significant past medical history underwent outpatient screening colonoscopy. The procedure was difficult due to a tortuous colon and only multiple diverticula were visualized. She vomited once during the procedure. In the immediate postoperative period, she complained of neck swelling. Her vital signs were stable. On examination, right sided neck and facial swelling with palpable crepitations were noticed as well as coarse breath sounds heard on auscultation of both lung fields. Immediate chest X-ray (Figure 1) was obtained which showed bilateral subcutaneous emphysema extending from the supraclavicular area and above to the neck. Subsequent thoracic CT scan showed extensive subcutaneous air within the soft tissues of the neck bilaterally, extending into the mediastinum and along the anterior chest wall (Figure 2). An esophagram (Figure 3) revealed a focus of oral contrast actively extravasating approximately at 2.5 cm above the gastro-esophageal junction consistent with a small perforation. She underwent left thoracotomy with esophageal repair. Further hospital course was uncomplicated and she was discharged to a sub-acute rehabilitation facility. 

Boerhaave's syndrome is a spontaneous perforation of the esophagus due to sudden increase in intra-esophageal pressure combined with negative intrathoracic pressure caused by straining or vomiting (1). The tear usually occurs at the left posterolateral wall of the lower third of the esophagus. Usually patients have severe retching and vomiting which is followed by excruciating retrosternal chest and upper abdominal pain after perforation. Other manifestations are odynophagia, tachypnea, dyspnea, fever, and shock. On physical examination subcutaneous emphysema (crepitation) is an important diagnostic feature. Chest radiograph usually reveals mediastinal or free peritoneal air as the initial manifestation, and hours to days later pleural effusion with or without pneumothorax, widened mediastinum, and subcutaneous emphysema are typically seen. The diagnosis of esophageal perforation can also be confirmed by water-soluble contrast esophagram using Gastrograffin, which reveals the location and extent of extravasation of contrast. Treatment depends upon the size and location of the perforation. Surgery is generally required for thoracic perforations while cervical perforations can often be managed conservatively with continuous nasogastric suction, intravenous broad-spectrum antibiotics, and parenteral nutrition.

Chandramohan Meenakshisundaram MD, Nanditha Malakkla MD and Venu Ganipisetti MD

Department of Internal Medicine

Presence Saint Francis Hospital

Evanston, IL USA

Reference

1. Nirula R. Esophageal perforation. Surg Clin North Am. 2014;94(1):35-41. [CrossRef] [PubMed]

Reference as: Meenakshisundaram C, Malakkla N, Ganipisetti V. Medical image of the week: Boerhaave's syndrome during colonoscopy. Southwest J Pulm Crit Care. 2015;11(1):42-44. doi: http://dx.doi.org/10.13175/swjpcc058-15 PDF