Imaging
Those who care for patients with pulmonary, critical care or sleep disorders rely heavily on chest radiology and pathology to determine diagnoses. The Southwest Journal of Pulmonary, Critical Care & Sleep publishes case-based articles with characteristic chest imaging and related pathology.
The editor of this section will oversee and coordinate the publication of a core of the most important chest imaging topics. In doing so, they encourage the submission of unsolicited manuscripts. It cannot be overemphasized that both radiologic and pathologic images must be of excellent quality. As a rule, 600 DPI is sufficient for radiographic and pathologic images. Taking pictures of plain chest radiographs and CT scans with a digital camera is strongly discouraged. The figures should be cited in the text and numbered consecutively. The stain used for pathology specimens and magnification should be mentioned in the figure legend. Those who care for patients with pulmonary, critical care or sleep disorders rely heavily on chest radiology and pathology to determine diagnoses. The Southwest Journal of Pulmonary, Critical Care & Sleep publishes case-based articles with characteristic chest imaging and related pathology. The editor of this section will oversee and coordinate the publication of a core of the most important chest imaging topics. In doing so, they encourage the submission of unsolicited manuscripts. It cannot be overemphasized that both radiologic and pathologic images must be of excellent quality. As a rule, 600 DPI is sufficient for radiographic and pathologic images. Taking pictures of plain chest radiographs and CT scans with a digital camera is strongly discouraged. The figures should be cited in the text and numbered consecutively. The stain used for pathology specimens and magnification should be mentioned in the figure legend.
Medical Image of the Week: Fat Embolism
Figure 1. A CT with IV contrast at the pelvic level showing a filling defect (red arrow) in left external iliac vein extending from left common iliac vein in axial (A), sagittal (B), and coronal (C) sections. Its attenuation coefficient (Hounsfield Unit) suggests fat embolus mixed with thrombus.
A 74-year-old woman presented to the hospital with a left femoral neck fracture after a fall. The next day she underwent an uneventful left hip hemiarthroplasty. About 3 hours postoperatively, she became lethargic, tachycardic, tachypneic, febrile, and hypotensive. An arterial blood gas analysis revealed mild hypoxemia with PaO2 / FiO2 ratio of 270. Hemoglobin decreased from 9.4g/dL to 7.7g/dL postoperatively. A chest x-ray showed only bibasilar opacities. Sepsis, acute postoperative blood loss anemia, and pulmonary embolism (PE) were entertained as a differential diagnosis. The patient was resuscitated with intravenous fluids and packed red blood cells, and was started on broad-spectrum antibiotics. Her hemodynamic status stabilized shortly thereafter. A CT chest with PE protocol and abdomen/pelvis down to thigh level was performed; no PE was identified. It did not show any intraabdominal pathology or signs of hemorrhage. However, it incidentally revealed fat embolus mixed with thrombus in the left common and external iliac veins (Figure 1). All microbiologic studies were negative. Therefore, she was thought to have fat embolism syndrome (FES) with transient systemic inflammatory syndrome (SIRS). An IVC filter was placed and anticoagulation was also started.
FES is a collection of symptoms and signs including respiratory insufficiency, petechial rash, and neurologic impairment associated with fat in the circulation (1). Fat emboli cause an intense inflammation (2), and FES shares many features characteristic of systemic inflammatory response syndrome (SIRS) (1). It is a diagnostic challenge as many of the manifestations are common to other critical illnesses (1). It is most commonly associated with long bone fractures and orthopedic procedures. Literature on radiographic finding of fat emboli in the venous system is rare (3); although neither necessary nor sufficient, its radiographic demonstration in the venous system can substantially aid in diagnosis of FES, as demonstrated in our case.
Hyeong J. Kim MD1, Michael Jesinger MD2, and Medhi Khosravi MD2
1 Division of Pulmonary, Critical Care, and Sleep Medicine, East Carolina University, Greenville, NC, USA
2 Internal Medicine, University of Kentucky, Lexington, KY, USA
3 Division of Pulmonary, Critical Care, and Sleep Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Lexington, KY, USA
References
- Mellor A, Soni N. Fat embolism. Anaesthesia. 2001 Feb;56(2):145-54. [CrossRef] [PubMed]
- Kwiatt ME, Seamon MJ. Fat embolism syndrome. Int J Crit Illn Inj Sci. 2013 Jan;3(1):64-8. [CrossRef] [PubMed]
- Harris AC, Torreggiani WC, Lyburn ID, Zwirewich CV, Ho SG, Munk PL. CT and sonography of traumatic fat embolism in the common femoral vein. AJR Am J Roentgenol. 2000 Dec;175(6):1741-2. [CrossRef] [PubMed]
Cite as: Kim HJ, Jesinger M, Khosravi M. Medical image of the week: fat embolism. Southwest J Pulm Crit Care. 2017;15(6):297-8. doi: https://doi.org/10.13175/swjpcc138-17 PDF
Medical Image of the Week: Fat Embolism Syndrome
A 33-year-old man presented to the emergency department with shortness of breath and hemoptysis. He was discharged two days prior after hospitalization for a motor vehicle accident, in which he suffered a fracture of the shaft of the right femur. He had undergone open reduction and internal fixation of the fracture four days prior to this admission. He had diffuse parenchymal disease on his admission chest x-ray. A CT scan of the chest demonstrated multilobar ground glass opacities (Figure 1).
Figure 1. Thoracic CT scan showing ground glass opacities.
Bronchoscopy demonstrated progressively bloody BAL aliquots in two different lobes, consistent with diffuse alveolar hemorrhage (DAH). His workup for other etiologies was negative, and he was given a diagnosis of DAH secondary to fat embolism syndrome.
Joshua Malo, MD and Kenneth S. Knox, MD
Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine
University of Arizona, Tucson, AZ
Reference as: Malo J, Knox KS. Medical image of the week: fat embolism syndrome. Southwest J Pulm Crit Care. 2014;8(4):246. doi: http://dx.doi.org/10.13175/swjpcc041-14 PDF