Medical Image of the Week: Spontaneous Pneumomediastinum

Figure 1. Upright chest radiograph showing pneumomediastinum tracking into neck and small right apical pneumothorax (arrows).

Figure 2. Coronal slice of CT chest showing extensive pneumomediastinum and subcutaneous emphysema (arrows).

Figure 3. CT scan of chest showing the Macklin effect with air tracking along the bronchovascular sheath in the left lower lobe.

A 24-year-old man with a past medical history significant for type I diabetes mellitus presented to the emergency department with complaints of nausea and vomiting for several days. He reported he had been on drinking alcohol heavily 4 days prior to presentation and subsequently had multiple episodes of vomiting. Initial laboratory evaluation was consistent with diabetic ketoacidosis (DKA). A routine chest x-ray was obtained to evaluate for an infectious etiology of his DKA and revealed pneumomediastinum and a small right apical pneumothorax (Figure 1). A CT scan of the chest was done and showed extensive pneumomediastinum as well as air tracking along the bronchovascular sheaths in the left lower lobe (Figure 2 and 3). It did not reveal evidence of esophageal injury.

Spontaneous pneumomediastinum (SPM) refers to pneumomediastinum that is not associated with noticeable cause such as esophageal rupture or trauma. It is typically a benign condition thought to be due to alveolar rupture and subsequent air tracking along the bronchial tree (1). It has been associated with a number of conditions including asthma, DKA, anorexia nervosa, and other conditions that lead to excessive coughing or vomiting. The radiographic appearance of air dissecting through the pulmonary intersitium along the bronchovascular sheath is known as the Macklin effect and can be seen in Figure 3.

Spontaneous pneumomediastinum typically resolves without complications but must be differentiated from the much more serious diagnosis of esophageal rupture, or Boerrhaave’s syndrome. Boerrhaave’s syndrome is more likely to present with fever, hemodynamic instability, and hydropneumothorax. All patients presenting with suspected SPM should be evaluated for esophageal perforation with a radiographic contrast swallow (2). In our case it was negative for evidence of esophageal disruption and the patient recovered completely.

Lucie Griffin DO and Erik Kraai MD

Division of Pulmonary, Critical Car, and Sleep Medicine

University of New Mexico Health Sciences Center

Albuquerque, NM USA

References

1. Murayama S, Gibo S. Spontaneous pneumomediastinum and Macklin effect: Overview and appearance on computed tomography. World J Radiol. 2014 Nov 28;6(11):850-4. [CrossRef] [PubMed]
2. Kelly S, Hughes S, Nixon S, Paterson-Brown S. Spontaneous pneumomediastinum (Hamman's syndrome). Surgeon. 2010 Apr;8(2):63-6. [CrossRef] [PubMed] 

Cite as: Griffin L, Kraai E. Medical image of the week: spontaneous pneumomediastinum. Southwest J Pulm Crit Care. 2016 Mar;12(3):115-6. doi: http://dx.doi.org/10.13175/swjpcc015-16 PDF

Medical Image of the Week: Coffee Bean and Whirlpool Signs

Figure 1. Supine abdominal x-ray demonstrating a large dilated loop of bowel and coffee bean sign (red circle).

Figure 2. Contrast CT abdomen (coronal section) showing markedly dilated sigmoid loop with the swirling mesentery (whirlpool sign) (red circle).

A 79-year-old woman with a history of Parkinson’s disease presented with altered mental status, poor oral intake, and multiple episodes of nausea and vomiting. An abdominal x-ray demonstrated dilated loops of bowel and the coffee bean sign concerning for sigmoid volvulus (Figure 1). The coffee bean sign occurs when a thick “inner wall” represents the double wall thickness of opposed loops of bowel while the thinner outer walls due single thickness. A contrast CT abdomen showed dilated sigmoid loop and whirlpool sign confirming sigmoid volvulus (Figure 2). She underwent a total colectomy with ileorectal anastomosis and full recovery.

Brittany Bartolome MS3¹, Choua Thao MD², Yaser Dawod MD², and Carmen Luraschi MD³

¹University of Nevada School of Medicine, Reno, NV USA

²Department of Internal Medicine, University of Nevada School of Medicine, Las Vegas, NV USA

³Division of Pulmonary and Critical Care, University of Nevada School of Medicine, Las Vegas, NV USA

Cite as: Bartolome B, Thao C, Dawod Y, Luraschi C. Medical image of the week: coffee bean and whirlpool signs. Southwest J Pulm Crit Care. 2016;12(1):30-1. doi: http://dx.doi.org/10.13175/swjpcc002-16 PDF

Medical Image of the Week: Duodenal Obstruction Secondary to Superior Mesenteric Artery Syndrome

Figure 1. Massive dilation of the gastric body with extension into the pelvis.

Figure 2. CTA demonstrating an acute aortomesenteric angle with the duodenum compressed.

Figure 3. Contrast MRI with impingement of the third part of the duodenum by the superior mesenteric artery and abdominal aorta.

The patient was a 46 year-old female admitted for accelerated hypertension.  Several days into her hospital stay she reported new complaints of progressive abdominal pain, vomiting, and constipation.  An abdominal radiograph confirmed severely dilated bowel and a subsequent CT scan of the abdomen was unable to identify a cause for bowel obstruction.  Endoscopy was performed with successful entrance of the first part of the duodenum.  MRI of the abdomen with contrast was ultimately able to delineate an obstruction of the third part of the duodenum between the superior mesenteric artery and the aorta.

Superior mesenteric artery syndrome is a rare but recognized cause for duodenal obstruction.  Patients may present with intermittent or progressive epigastric pain, nausea with bilious vomiting, and early satiety.  Medical management is largely conservative with gastric suctioning and pain management, with definitive treatment being surgical correction of the aortomesenteric angle.

Seth Assar, MD; Natasha Sharda, MD; Varun Takyar, MD; Bujji Ainapurapu, MD

Department of Medicine at South Campus

University of Arizona

Tucson, Arizona

References

1. Hines J, Gore R, Ballantyne G. Superior mesenteric artery syndrome. Diagnostic criteria and therapeutic approaches. Am J Surg. 1984;148:630–2. [CrossRef]
2. Felton BM, White JM, Racine MA. An uncommon case of abdominal pain: superior mesenteric artery syndrome. West J Emerg Med. 2012;13(6):501-2. [PubMed] 
3. Baltazar U, Dunn J, Floresguerra C, Schmidt L, Browder W. Superior mesenteric artery syndrome: an uncommon cause of intestinal obstruction. South Med J. 2000;93(6):606-8. [PubMed] 

Reference as: Assar S, Sharda N, Takyar V, Ainapurapu B. Medical image of the week: duodenal obstruction secondary to superior mesenteric artery syndrome. Southwest J Pulm Crit Care. 2013:7(2):84-6. doi: http://dx.doi.org/10.13175/swjpcc100-13 PDF