대한흉부영상의학회 Weekly Chest Cases

Case No : 449 Date 2006-06-05

Courtesy of Kyung-Hyun Do, MD, Joon Beom Seo, MD. / Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
Age/Sex 15 / M
Chief ComplaintSudden drowsy mentality one day after operation for chronic osteomyelitis

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Diagnosis With Brief Discussion

Diagnosis: Pulmonary Fat Embolism
Radiologic Findings: Preoperative initial chest radiograph is normal. One day after operation for chronic osteomyelitis in the shaft of left femur, chest radiograph shows multifocal patchy ground-glass opacity and consolidation in both lungs with predominantly peripheral rather than central.

Chest CT shows multifocal ground-glass opacity and consolidation confined to some lobules with a sharp margin between areas of involved and noninvolved lung, resulting in a geographic appearance, with predominantly non-dependent distribution. Smooth interlobular septal line thickenings are noted.
Brief Review: Fat embolism is an infrequent complication of long bone fracture, occurring in 1% - 3% of patients with simple tibial or femoral fractures but in up to 20% of individuals with more severe trauma. Less common causes include hemoglobinopathy, major burns, pancreatitis, overwhelming infection, tumors, blood transfusion, and liposuction. The mechanisms are not completely understood but presumably are twofold. The first mechanism is the production of free fatty acids, which initiates a toxic reaction in the endothelium. The process is further complicated by the accumulation of neutrophils and other inflammatory cells, which causes damage to the vasculature. The second mechanism is the mechanical obstruction of the pulmonary vasculature by fat globules and aggregates of red blood cells and platelets.

A combination of pulmonary, cerebral, and cutaneous symptoms typically occur within 12-24 hours of the traumatic event. The time lapse between the traumatic event and radiographic abnormalities is usually 1-2 days, which allows differentiation from traumatic contusion.

Chest radiographs may be entirely normal in mild cases, and even in severe cases, chest radiographs may be normal for the first 1 to 3 days. Radiographic changes appear 1-3 days after the embolic event and consist of subtle, increased attenuation or a pattern of alveolar pulmonary edema. The distribution of these opacities varies from a predominantly perihilar pattern to that of a more peripheral process. The lung apices are usually less severely involved. The opacities are caused by focal atelectasis, hemorrhage, alveolar edema, and infarction. On sequential examinations, radiographic findings return to normal after 2 days to 2 weeks, with an average resolution time of 1 week.

The CT findings of pulmonary fat embolism include focal areas of consolidation or ground-glass opacity and nodules, predominantly in the nondependent and peripheral portions, and in both upper lobes of the lungs.
References: 1. Han D, Lee KS, Franquet T, et al. Thrombotic and nonthrombotic pulmonary arterial embolism: spectrum of imaging findings. Radiographics. 2003;23:1521-1539.

2. Choi JA, Oh YW, Kim HK, et al. Nontraumatic pulmonary fat embolism syndrome: radiologic and pathologic correlations. J Thorac Imaging. 2002;17:167-169.

3. Georgopoulos D, Bouros D. Fat embolism syndrome: clinical examination is still the preferable diagnostic method. Chest. 2003;123:982-983.
Keywords: Lung, Vascular, Embolic, Thromboembolic,

No. of Applicants : 56

▶ Correct Answer : 39/56, 69.6%

- Hospital Marina Baixa de Villajoyosa, Spain Carlos F Munoz-Nunez
- Shinsegye Rad Clinic, Korea Gi Beom Kim
- Yonsei University Shinchon Severance Hospital, Korea Eun Hye Yoo
- Inje University Ilsan Paik Hospital, Korea Bae Geun Oh
- Dong-Eui Medical Center, Busan, Korea Hoon Sik Jung
- Hopital Calmette, CHRU, Lille Toledano Manuel
- Pgimer, Chandigarh, India Ashish Gupta
- Samsung Medical Center, Seoul, Korea Ha Young Kim
- Macky Memorial Hospital, Taipei, Taiwan Chia-Fu Tsai
- Seoul National University Children's Hospital, Korea Su-mi Shin
- Maimonides Medical Center; Brooklyn, New York, USA Naomi Twersky
- Kang-dong Sacred Heart Hospital, Korea Kyoung Ja Lim
- Inje University Ilsan Paik Hospital, Korea Seung Tae Lee
- KMC manipal, India Nabil Sherif Mahmood
- Pgimer, Chandigarh, India Ram Prakash Galwa
- Mackay Memorial Hospital, Taiwan Kuang-Hua Cheng
- Mackay Memorial Hospital, Taipei, Taiwan Sheng-Yeh Shen
- Hangang Sacred Heart Hospital, Korea Eil Seong Lee
- Ondokuz Mayis University, Samsun, Turkey Cetin Celenk
- Chung Gang University Hospital, Taiwan Fu-Tsai Chung
- Kashan Universityof Medical Sciences, Kashan, Iran Ebrahim Razi
- CHU Grenoble Bing Fabrice
- Radiologie Guiton, La Rochelle, France Denis Chabassiere
- Nottingham City Hospital, United Kingdom Rohit Kochhar
- Homs National Hospital, Homs, Syria Rami Abou Zalaf
- KangNam St.Mary Hospital, Korea LimChaeHun
- Annemasse, Polyclinique de Savoie, France Gay-Depassier Philippe
- Yonsei University, Shinchon Severance Hospital, Korea Hye-Jeong Lee
- Faculte de Medecine, France Abraham Bohadana
- Yonsei University, Shinchon Severance Hospital, Korea Yong Eun Chung
- Annecy Hospital, France Gilles Genin
- Annecy Hospital, France Antoine Lemarie
- Sam Anyang Hospital, Korea Jae Seung Seo
- Doctors Hospital, Nassau, Bahamas N.B.S.Mani
- Ultra Care, Coimbatore, India Debabrata Das
- China Medical University Hospital,Taiwan Jun-Jun Yeh
- MGM, Medical College, Indore, India Sonali Jain
- Samsung Medical Center, Seoul, Korea Yulri Park
- Seoul National University Hospital, Korea Chang Min Park

▶ Correct Answer as Differential Diagnosis : 3/56, 5.4%

- National Taiwan University Hospital, Taiwan Yu-Feng Wei
- Regional Imaging, Riverina, Australia Rashid Hashmi
- Incheon Sarang Hospital, Korea Jung Hee Kim

▶ Semi-Correct Answer : 3/56, 5.4%

- Mubarak Al Kabeer Hospital, Kuwait Varghese Sajeev P. J.
- Monaldi Hospital, Naples, Italy Gaetano Rea
- Diskapi Yildirim Beyazit Hospital, Ankara, Turkey Meric Tuzun

대한흉부영상의학회 Korean Society of Thoracic Radiology

Archive of Old Cases

Case No : 449 Date 2006-06-05

Discussion

No. of Applicants : 56